阅读说明：本技术 钝化方法 (Passivation method ) 是由 J·S·W·戈丁 B·温格 H·J·斯奈思 于 2020-03-06 设计创作，主要内容包括：本发明提供了一种用于生产钝化的半导体的工艺,所述工艺包括用钝化剂处理半导体,其中：半导体包括结晶化合物,所述结晶化合物包括：(i)一种或多种第一阳离子(A)；(ii)一种或多种金属阳离子(M)；以及(iii)一种或多种阴离子(X)；并且钝化剂包括包含氧-氧单键的化合物。还提供了钝化剂的组合物以及用途。(The invention provides a process for producing a passivated semiconductor, the process comprising treating a semiconductor with a passivating agent, wherein: the semiconductor includes a crystalline compound comprising: (i) one or more first cations (a); (ii) one or more metal cations (M); and (iii) one or more anions (X); and the passivating agent comprises a compound comprising an oxygen-oxygen single bond. Compositions and uses of the deactivant are also provided.)

1. A process for producing a passivated semiconductor, the process comprising treating a semiconductor with a passivating agent, wherein:

the semiconductor includes a crystalline compound including: (i) one or more first cations (a); (ii) one or more metal cations (M); and (iii) one or more anions (X); and is

The passivating agent includes a compound including an oxygen-oxygen single bond.

2. The process of claim 1, wherein the passivating agent comprises: a peroxy-containing compound; a compound comprising a peroxyhydroxy group; a compound comprising a perester group; a compound comprising a peracid anhydride group; a compound containing a peracid group; or ozone.

3. A process as claimed in claim 1 or 2, wherein the passivating agent comprises: a compound of the formula R-O-O-R; a compound of the formula R-C (O) -O-O-R; or a compound of the formula R-C (O) -O-O-C (O) -R,

wherein:

each R is independently selected from H, unsubstituted or substituted C_1-8Alkyl, unsubstituted or substituted C_1-8Alkenyl and unsubstituted or substituted aryl, optionally wherein each R is bonded together to form a ring.

4. A process as claimed in any one of the preceding claims, wherein the passivating agent comprises a compound selected from: hydrogen peroxide, urea peroxide, ozone, t-butyl hydroperoxide, t-butyl peroxybenzoate, di-t-butyl peroxide, 2-butanone peroxide, cumene hydroperoxide, dicumyl peroxide, bis (trimethylsilyl) peroxide, benzoyl peroxide, diacetyl peroxide, diethyl ether peroxide, dipropyl peroxydicarbonate, methyl ethyl ketone peroxide, peracetic acid, performic acid, perbenzoic acid, and m-chloroperoxybenzoic acid.

5. A process according to any one of the preceding claims, wherein the passivating agent comprises hydrogen peroxide or ozone,

preferably, wherein the passivating agent comprises hydrogen peroxide.

6. A process according to any one of the preceding claims, wherein the semiconductor comprises a perovskite.

7. A process according to any one of the preceding claims, wherein the semiconductor comprises a metal halide perovskite.

8. The process of any one of the preceding claims, wherein the semiconductor comprises the formula [ a [ ]][M][X]₃The crystalline compound of (1), wherein: [ A ]]Comprising one or more first cations; [ M ] A]Comprising one or more metal cations; and [ X ]]Comprises one or more anions selected from I^–、Br^–And Cl^–One or more halogenated anions of (a).

9. The process according to any one of the preceding claims, wherein the one or more first cations (A) are chosen from K⁺、Rb⁺、Cs⁺、(NR¹R²R³R⁴)⁺、(R¹R²N＝CR³R⁴)⁺、(R¹R²N–C(R⁵)＝NR³R⁴)⁺And (R)¹R²N–C(NR⁵R⁶)＝NR³R⁴)⁺Wherein R is¹、R²、R³、R⁴、R⁵And R⁶Each of which is independently H, unsubstituted or substituted C_1-20An alkyl group, or an unsubstituted or substituted aryl group,

preferably, wherein the one or more first cations are selected from Cs⁺、(CH₃NH₃)⁺And (H)₂N–C(H)＝NH₂)⁺。

10. Process according to any one of the preceding claims, in which the metal cation(s) (M) are chosen from Pb²⁺、Ca²⁺、Sr²⁺、Cd²⁺、Cu²⁺、Ni²⁺、Mn²⁺、Fe²⁺、Co²⁺、Pd²⁺、Ge²⁺、Sn²⁺、Yb²⁺、Eu²⁺、Bi³⁺、Sb³⁺、Pd⁴⁺、W⁴⁺、Re⁴⁺、Os⁴⁺、Ir⁴⁺、Pt⁴⁺、Sn⁴⁺、Pb⁴⁺、Ge⁴⁺Or Te⁴⁺，

Preferably, wherein the one or more metal cations comprise Pb²⁺And/or Sn²⁺。

11. The process of any one of the preceding claims, wherein the semiconductor comprises the formula [ a [ ]]Pb_zSn_(1-z)[X]₃Wherein z is 0.0 to 1.0.

12. The process of any one of the preceding claims, wherein the semiconductor comprises the formula Cs_x(H₂N–C(H)＝NH₂)_(1-x)PbBr_3yI_3(1–y)Wherein x is 0.0 to 1.0 and y is 0.0 to 1.0.

13. A process according to any preceding claim, wherein treating the semiconductor with the passivating agent comprises exposing the semiconductor to a composition comprising a solvent and the passivating agent,

preferably wherein the composition comprising the solvent and the deactivant comprises a solution of the deactivant in the solvent.

14. The process of claim 13, wherein the solvent comprises one or more polar solvents,

preferably, wherein the solvent comprises water and isopropanol.

15. A process according to any one of the preceding claims, wherein treating the semiconductor with the passivating agent comprises exposing the semiconductor to an aqueous solution of hydrogen peroxide,

preferably, wherein the aqueous solution of hydrogen peroxide comprises hydrogen peroxide at a concentration of 0.001M to 0.1M.

16. The process of any one of claims 1 to 12, wherein treating the semiconductor with the passivating agent comprises exposing the semiconductor to a vapor comprising the passivating agent.

17. The process of claim 16, wherein treating the semiconductor with the passivating agent includes exposing the semiconductor to a vapor comprising hydrogen peroxide,

preferably, wherein the process further comprises generating the hydrogen peroxide-containing vapor by heating a urea peroxide-containing composition.

18. A process as claimed in any one of the preceding claims, wherein the treatment with the passivating agent is carried out at not more than 0.5kW/m²Optionally wherein the semiconductor is irradiated at an intensity of no more than 0.1kW/m during treatment with the passivating agent²Is irradiated to the semiconductor.

19. A process according to any preceding claim, wherein the semiconductor is treated with the passivating agent for less than 1 hour, optionally wherein the semiconductor is treated with the passivating agent for less than 1 minute.

20. A process according to any one of the preceding claims, wherein the passivated semiconductor has an increased photoluminescence lifetime and/or an increased photoluminescence intensity compared to the semiconductor prior to passivation.

21. A process for producing a semiconductor device, wherein the process comprises producing a passivated semiconductor by a method according to any of the preceding claims.

22. The process of claim 21, wherein the semiconductor device is a photovoltaic device,

preferably, wherein the optoelectronic device is a photovoltaic device or a light emitting device.

23. A composition, comprising:

(i) a semiconductor as defined in any one of claims 1 and 6 to 12; and

(ii) a passivating agent as defined in any of claims 1 to 5,

wherein the concentration of the passivating agent is greater than or equal to 0.001 mol% relative to the amount of the semiconductor.

24. The composition of claim 23, wherein the semiconductor comprises a perovskite and the passivating agent comprises hydrogen peroxide.

25. Use of a composition comprising a passivating agent for passivating a semiconductor, with a power of not more than 0.5kW/m during passivation²Is irradiated to the semiconductor, wherein:

the semiconductor includes a crystalline compound including: (i) one or more first cations (a); (ii) one or more metal cations (M); and (iii) one or more anions (X); and is

The passivating agent includes a compound including an oxygen-oxygen single bond or an oxygen-oxygen double bond.

26. Use according to claim 25, wherein the passivating agent comprises an oxygen plasma or a compound as defined in any of claims 1 to 5.

Technical Field

The invention relates to a process for producing passivated semiconductors. Compositions comprising the deactivant and uses of the deactivant are also described.

The project leading up to this application has been according to MarieThe grant agreement No. 706552 subsidized the european union Horizon 2020 research and innovation program.

Background

The use of metal halide perovskites in photovoltaics, LEDs, and other optoelectronic devices has advanced significantly. In less than a decade, perovskites have become the precursor of the next generation of photovoltaic materials due to their simple processing routes and Power Conversion Efficiencies (PCEs) that currently have exceeded 23%. However, despite the great advances in photovoltaic performance, the understanding of the basic chemical reactivity of these organic-inorganic materials is still incomplete, which has an impact on their long-term stability.

The environment (especially exposure to light and oxygen) can affect perovskites (such as the prototype Methyl Ammonium (MA) lead perovskite iodide, MAPbI₃) The nature of (c). There is currently no discussion of whether the reaction of perovskites with oxygen and light in a humid environment is beneficial or detrimental to their utility as photoactive materials.

Brenes et al (Adv Mater 2018,30,1706208) describe the enhancement of photoluminescence of perovskites after light soaking in the presence of oxygen. This phenomenon is called photo-brightening. Aristodou et al (Nature Communications 8,15218(2017)) describe oxygen and light induced decomposition of perovskite solar cells. Anaya et al (J Phys Chem Lett 2018,9,3891-3896) describe a study of the effect of oxygen and light on the photoluminescent activation of organometallic halide perovskites. Palazon et al (ACS Appl Nano Mater 2018,1, 5396-. Ouyang et al (J Mater Chem A2019, 7,2275-2282) describe a computational study of the effect of oxygen on lead ammonium methyliodide.

Since photobrightening favors the optical properties of photoactive materials such as perovskites and the optical properties of other a/M/X materials, the process of light soaking in air requires conditions that are too difficult to control for easy use in the manufacturing process. Furthermore, photo-brightening does not appear to apply to all a/M/X materials in a predictable manner, and appears to be most effective on perovskites containing methylammonium cations. Photo-brightening is also a time-consuming process, typically taking several hours to become effective.

There is a need to develop a scalable, fast and efficient method of improving the optical properties (such as photoluminescence) of a/M/X materials (such as perovskites). There is also a need to develop a process that can use non-toxic materials. It would be further beneficial to develop a process that can be applied to a variety of different a/M/X materials, including those that do not contain organic cations. Furthermore, there is a need for a controllable and reproducible method.

Disclosure of Invention

The inventors investigated the mechanism of photo-brightening and determined the role of certain oxygen-containing compounds in this mechanism. On the basis of this study, it was found that the problems associated with photo-brightening can be circumvented, and that the benefits can only be retained by direct treatment of the a/M/X material with an oxygen-containing compound. It has been observed that oxygen-containing compounds passivate defects in a/M/X materials in a controlled manner, thereby improving the optical properties of the materials. The inventors have therefore developed a process for producing passivated semiconductors which is reproducible, reliable and efficient. This process has been found to result in significant and unexpected improvements in device performance.

The invention accordingly provides a process for producing a passivated semiconductor, the process comprising treating a semiconductor with a passivating agent, wherein: the semiconductor includes a crystalline compound comprising: (i) one or more first cations (a); (ii) one or more metal cations (M); and (iii) one or more anions (X); and the passivating agent comprises a compound comprising an oxygen-oxygen single bond.

The invention also provides a composition comprising: (a) a semiconductor comprising a crystalline compound, the crystalline compound comprising: (i) one or more first cations (a); (ii) one or more metal cations (M); and (iii) one or more anions (X); and (b) a passivating agent comprising a compound comprising an oxygen-oxygen single bond, wherein the concentration of the passivating agent is greater than or equal to 0.001 mol% relative to the amount of semiconductor.

The invention further provides the use of a composition comprising a passivating agent for passivating a semiconductor, with a power of not more than 0.5kW/m during passivation²The intensity of (a) irradiating the semiconductor, wherein: the semiconductor includes a crystalline compound comprising: (i) one or more first cations (a); (ii) one or more metal cations (M); and (iii) one or more anions (X); and the passivating agent includes a compound including an oxygen-oxygen single bond or an oxygen-oxygen double bond.

Drawings

Fig. 1 shows a schematic view of an apparatus for exposing a semiconductor to gaseous hydrogen peroxide, using a closed chamber (1), a reactant holder (2), a heat source (3), urea peroxide (4) and a semiconductor (5).

FIG. 2 shows the deposition of H at low concentration via solution deposition₂O₂FA treated in Isopropanol (IPA) solution of_0.83Cs_0.17Pb(Br_0.1I_0.9)₃Steady state photoluminescence measurements of the control film and the treatment film.

FIG. 3 shows exposure to H via gas deposition using carbamide peroxide₂O₂FA processed at different times_0.83Cs_0.17Pb(Br_0.1I_0.9)₃Intensity dependence of external photoluminescence quantum efficiency (PLQE) values of the film.

FIG. 4 shows the deposition of H via gas₂O₂FA before and after treatment_0.83Cs_0.17Pb(Br_0.1I_0.9)₃Powder x-ray diffraction (XRD) pattern of the thin film.

Fig. 5 shows PLQE for films treated with different passivating agents at 1 solar irradiance. Different phlegmatising agents are phenethyl ammonium iodide (PEAI) and Butyl Ammonium Iodide (BAI).

FIG. 6 showsInorganic CsPb (Br) treated with hydrogen peroxide for 5 minutes via urea peroxide (UHP) gas deposition as compared to untreated control film_0.1I_0.9)₃Steady state Photoluminescence (PL) spectra of the thin film.

FIG. 7 shows FA after treatment by exposure to oxygen plasma compared to the control film_0.83Cs_0.17Pb(Br_0.1I_0.9)₃Steady state photoluminescence measurement of the film.

FIG. 8 shows MAPbI after treatment by exposure to 30% ozone in oxygen compared to control₃Steady state photoluminescence measurement of the film.

FIG. 9 shows the passage of H via a gas deposition process, as compared to a control device₂O₂Processed FA_0.83Cs_0.17Pb(Br_0.1I_0.9)₃Current density-Voltage (J-V) characteristics of the device at AM1.5100mW/cm²And (5) simulating measurement under sunlight. p-i-n devices were treated with UHP for 40s and n-i-p devices were treated for 70 s. (a) Is the current-voltage characteristic of the champion p-i-n device under the light and shade conditions. (b) And (c) is the steady state photocurrent and efficiency of the device. (d) Is the current-voltage characteristic of the champion inverted n-i-p device under the light and shade conditions. (e) And (f) is the steady state photocurrent and efficiency of the device. The steady state measurement was made by holding the device at its maximum power point determined by JV for 1 minute.

FIG. 10 shows the passage of H through a gas deposition process using UHP as compared to a control device₂O₂Processed n-i-p constructed FA_0.83Cs_0.17Pb(Br_0.1I_0.9)₃Device parameters for forward and reverse current density-voltage (J-V) scanning of the device.

FIG. 11 shows the passage of H through a gas deposition process using UHP compared to a control device₂O₂Treated p-i-n constructed FA_0.83Cs_0.17Pb(Br_0.1I_0.9)₃Device parameters for forward and reverse current density-voltage (J-V) scanning of the device.

Fig. 12 shows the effect of annealing on PLQE of hydrogen peroxide treated perovskite films.

Fig. 13 shows the UV-Vis spectrum of the hydrogen peroxide treated perovskite film.

Detailed Description

Definition of

The term "crystalline material" as used herein refers to a material having a crystalline structure. The term "crystalline A/M/X material" as used herein refers to a material having a crystal structure comprising one or more A ions, one or more M ions, and one or more X ions. The a and M ions are typically cations. The X ion is typically an anion. The A/M/X material typically does not include any other type of ions.

The term "perovskite" as used herein refers to a perovskite having a chemical structure with CaTiO₃A material having a crystal structure related to the structure of (a) or a material comprising a layer of a material having a structure related to a CaTiO₃The structure of (1). CaTiO₃Can be represented by the formula ABX₃Wherein A and B are different size cations and X is an anion. In the unit cell, the a cation is located at (0, 0, 0), the B cation is located at (1/2, 1/2, 1/2), and the X anion is located at (1/2, 1/2, 0). The a cations are generally larger than the B cations. The skilled person will appreciate that when A, B and X are varied, the different ion sizes may result in the perovskite material structurally modified from CaTiO₃The adopted structure is twisted into a twisted structure with lower symmetry. If the material comprises a material having a chemical bond with CaTiO₃The symmetry will also be lower for the layers of the structure related to (a). Materials comprising layers of perovskite materials are well known. For example, with K₂NiF₄The structure of the type-structured material includes a layer of perovskite material. The skilled person will appreciate that the perovskite material may be of the formula [ a][B][X]₃Is represented by the formula (A)]Is at least one cation, [ B ]]Is at least one cation, [ X ]]Is at least one anion. When the perovskite comprises more than one a cation, the different a cations may be distributed over the a sites in an ordered or disordered manner. When the perovskite comprises more than one B cation, the different B cations may be distributed over the B sites in an ordered or disordered manner. When the perovskite comprises more than one X anion, different X anions may be presentDistributed over the X sites in an ordered or disordered manner. The symmetry of a perovskite comprising more than one A cation, more than one B cation, or more than one X anion will be greater than that of a CaTiO₃The symmetry of (2) is low. For layered perovskites, the stoichiometry may vary between the a ions, B ions and X ions. As an example, [ A ] may be employed if the ionic radius of the A cation is too large to be disposed within the 3D perovskite structure]₂[B][X]₄And (5) structure. The term "perovskite" also includes A/M/X materials that employ Ruddlesden-Popper phases. The Ruddlesden-Popper phase refers to a mixed perovskite having a layered component and a 3D component. Such perovskites may adopt the crystal structure a_n-1A’₂M_nX_3n+1Wherein A and A' are different cations and n is an integer from 1 to 8 or from 2 to 6. The term "mixed 2D and 3D" perovskite is used to refer to the presence of AMX₃Perovskite phase and A_n-1A’₂M_nX_3n+1Perovskite films of two regions or domains of perovskite phase.

The term "metal halide perovskite" as used herein refers to a perovskite having a formula comprising at least one metal cation and at least one halide anion.

The term "metal hexahalide" as used herein is meant to include compounds of the formula [ MX₆]^n-Wherein M is a metal atom, each X is independently a halide anion, and n is an integer of 1 to 4. The metal hexahalide may have structure A₂MX₆。

The term "monocationic" as used herein refers to any cation having a single positive charge, i.e., formula A⁺Wherein a is any moiety, e.g., a metal atom or an organic moiety. The term "dication" as used herein refers to any cation having a double positive charge, i.e., formula A²⁺Wherein a is any moiety, e.g., a metal atom or an organic moiety. The term "trication" as used herein refers to any cation having a double positive charge, i.e., formula A³⁺Wherein A is any moiety, e.g. a metalogenA daughter or an organic moiety. The term "tetracationic" as used herein refers to any cation having a four positive charge, i.e., formula A⁴⁺Wherein a is any moiety, e.g., a metal atom.

The term "alkyl" as used herein refers to a straight or branched chain saturated hydrocarbon group. The alkyl group may be C_1-20Alkyl radical, C_1-14Alkyl radical, C_1-10Alkyl radical, C_1-6Alkyl or C_1-4An alkyl group. C_1-10Examples of alkyl groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl or decyl. C_1-6Examples of alkyl groups are methyl, ethyl, propyl, butyl, pentyl or hexyl. C_1-4Examples of alkyl are methyl, ethyl, isopropyl, n-propyl, tert-butyl, sec-butyl or n-butyl. If the term "alkyl" is used without a prefix designating the number of carbons anywhere herein, it has from 1 to 6 carbons (and this applies to any other organic group mentioned herein as well).

The term "cycloalkyl" as used herein refers to a saturated or partially unsaturated cyclic hydrocarbon group. Cycloalkyl may be C_3-10Cycloalkyl radical, C_3-8Cycloalkyl or C_3-6A cycloalkyl group. C_3-8Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohexenyl, cyclohex-1, 3-dienyl, cycloheptyl, and cyclooctyl. C_3-6Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

The term "alkenyl" as used herein refers to a straight or branched chain hydrocarbon group comprising one or more double bonds. The alkenyl group may be C_2-20Alkenyl radical, C_2-14Alkenyl radical, C_2-10Alkenyl radical, C_2-6Alkenyl or C_2-4An alkenyl group. C_2-20Examples of alkenyl groups are vinyl (ethenyl), propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl and decenyl. C_2-6Examples of alkenyl are ethenyl, propenyl, butenyl, pentenyl and hexenyl. C_2-4Examples of alkenyl groups are ethenyl, isopropenyl, n-propenyl, sec-butenyl and n-butenyl. Alkenyl radicalTypically comprising one or two double bonds.

The term "alkynyl" as used herein refers to a straight or branched chain hydrocarbon radical comprising one or more triple bonds. Alkynyl may be C_2-20Alkynyl, C_2-14Alkynyl, C_2-10Alkynyl, C_2-6Alkynyl or C_2-4Alkynyl. C_2-10Examples of alkynyl are ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl and decynyl. C_1-6Examples of alkynyl groups are ethynyl, propynyl, butynyl, pentynyl and hexynyl. Alkynyl groups typically include one or two triple bonds.

The term "aryl" as used herein refers to a monocyclic, bicyclic or polycyclic aromatic ring containing from 6 to 14 carbon atoms, typically from 6 to 10 carbon atoms, in the ring portion. Examples include phenyl, naphthyl, indenyl, indanyl, anthracenyl, and pyrenyl. The term "aryl" as used herein includes heteroaryl. The term "heteroaryl" as used herein refers to a monocyclic or bicyclic heteroaryl ring typically containing six to ten atoms in the ring portion including one or more heteroatoms. Heteroaryl is typically a 5 or 6 membered ring containing at least one heteroatom selected from O, S, N, P, Se and Si. It may contain, for example, one, two or three heteroatoms. Examples of heteroaryl groups include pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, furanyl, thienyl, pyrazolidinyl, pyrrolyl, oxazolyl, oxadiazolyl, isoxazolyl, thiadiazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, quinolinyl, and isoquinolinyl.

The term "substituted" as used herein in the context of a substituted organic group refers to an organic group bearing one or more substituents selected from the group consisting of: c_1-10Alkyl, aryl (as defined herein), cyano, amino, nitro, C_1-10Alkylamino radical, di (C)_1-10) Alkylamino, arylamino, diarylamino, aryl (C)_1-10) Alkylamino, amino, amido, hydroxy, oxo, halo, carboxy, ester, acyl, acyloxy, C_1-10Alkoxy, aryloxy, halo (C)_1-10) Alkyl, sulfonic acid, thiol, C_1-10Alkylthio, alkylthio,Arylthio, sulfonyl, phosphoric, phosphonic, and phosphonic esters. Examples of substituted alkyls include haloalkyl, perhaloalkyl, hydroxyalkyl, aminoalkyl, alkoxyalkyl, and alkylaryl. When a group is substituted, it may carry 1, 2 or 3 substituents. For example, a substituted group may have 1 or 2 substituents.

The term "porous" as used herein refers to a material in which pores are disposed. Thus, for example, in a porous scaffold material, a pore is the volume within the scaffold where there is no scaffold material. The individual holes may be the same size or different sizes. The size of the pores is defined as "pore diameter". For most phenomena involving porous solids, the ultimate size of a pore is the ultimate size of its smallest dimension, referred to without any further precision as the width of the pore (i.e., the width of a slit-shaped pore, the diameter of a cylindrical or spherical pore, etc.). To avoid misleading dimensional changes when comparing cylindrical and slit-shaped holes, the diameter of the cylindrical hole (rather than its length) should be used as its "hole width" (J.Rouquerol et al, "Recommendations for the spectroscopy of holes Solids", Pure & appl.chem., Vol.66, No.8, pp.1739-1758,1994). The following differences and definitions were adopted in the previous IUPAC documents (K.S.W.Sing et al, Pure and appl.chem., vo1.57, n04, pp 603-919, 1985; and IUPAC "Manual on Catalyst Characterization", J.Haber, Pure and appl.chem., vo1.63, pp.1227-1246,1991): the micropores have a width (i.e., pore size) of less than 2 nm; mesopores have a width (i.e., pore diameter) of 2nm to 50 nm; and the macropores have a width (i.e., pore diameter) greater than 50 nm. Further, nanopores can be considered to have widths (i.e., pore diameters) less than 1 nm.

The pores in the material may include "closed" pores as well as open pores. A closed cell is a cell in a material that is not a connected cavity, i.e., a cell that is isolated within the material and is not connected to any other cell, and therefore, a fluid (e.g., a liquid, such as a solution) to which the material is exposed cannot enter the cell. On the other hand, "apertures" would allow such fluids to enter. The concepts of open and closed cell porosity are discussed in detail in J.Rouquerol et al, "Recommendations for the Characterization of Porous Solids", Pure & appl.chem., Vol.66, No.8, pp.1739-1758,1994.

Thus, open cell content refers to the fraction of the total volume of the porous material in which fluid flow is effectively occurring. Thus, it does not include closed cells. The term "open porosity" is interchangeable with the terms "interconnected porosity" and "effective porosity" and is often referred to in the art simply as "porosity".

Thus, as used herein, the term "no open porosity" refers to a material that has no effective porosity. Thus, materials without open porosity typically have neither macropores nor mesopores. However, materials without open porosity may include micropores and nanopores. Such micropores and nanopores are generally very small without adversely affecting materials requiring low porosity.

The term "dense layer" as used herein refers to a layer up to no mesopores or macropores. The dense layer may sometimes have micropores or nanopores.

The term "semiconductor device" as used herein refers to a device that includes a functional component, the device including a semiconductor material. The term may be understood as synonymous with the term "semiconductor device". Examples of semiconductor devices include photovoltaic devices, solar cells, photodetectors, photodiodes, photosensors, color-rendering devices, transistors, phototransistors, solid state transistors, batteries, battery electrodes, capacitors, supercapacitors, light emitting devices, lasers, or light emitting diodes. The term "optoelectronic device" as used herein refers to a device that generates, controls or detects light. Light is understood to include any electromagnetic radiation. Examples of optoelectronic devices include photovoltaic devices, photodiodes (including solar cells), phototransistors, photomultipliers, photoresistors, lasers, and light emitting diodes.

The term "consisting essentially of means that the composition includes components that consist essentially of it as well as other components, provided that the other components do not materially affect the essential characteristics of the composition. Generally, a composition consisting essentially of certain components will include greater than or equal to 95 wt% of those components or greater than or equal to 99 wt% of those components.

Process for producing passivated semiconductors

The invention provides a process for producing a passivated semiconductor, the process comprising treating a semiconductor with a passivating agent, wherein: the semiconductor includes a crystalline compound comprising: (i) one or more first cations (a); (ii) one or more metal cations (M); and (iii) one or more anions (X); and the passivating agent comprises a compound comprising an oxygen-oxygen single bond.

Passivation of semiconductors is a process that results in the elimination or reduction of the number of surface defects and/or body defects (bulk defects) that result in unwanted recombination processes. A passivated semiconductor is a semiconductor in which defects on the surface of the semiconductor or defects in the bulk have been passivated. Typically, a passivated semiconductor is a semiconductor in which surface defects have been passivated. Passivation may include passivation of vacancies or charge traps in the semiconductor. Passivation may include passivation by oxidizing neutral metal atoms in the semiconductor to metal cations. The passivation may thus be an oxidative passivation. For example, if the semiconductor prior to passivation includes a metal atom (e.g., having a zero oxidation state), the passivated semiconductor may include oxidized metal ions in the form of a metal oxide or metal hydroxide. For example, passivation of semiconductors including lead in the formula typically results in the production of passivated semiconductors including lead oxide (i.e., Pb ═ O bonds) and/or lead hydroxide (i.e., Pb — OH bonds).

Whether a semiconductor has been passivated can be determined by comparing the properties of the semiconductor before and after passivation. For example, the degree of passivation can be determined by performing photoluminescence spectroscopy and x-ray photoelectron spectroscopy.

The process includes treating the semiconductor with a passivating agent. The treatment comprises contacting the semiconductor with a passivating agent, for example, wherein the passivating agent is contained in a liquid or gaseous composition that is allowed to contact the surface of the semiconductor. Processing involves contacting the semiconductor with a passivating agent such that the semiconductor and passivating agent can interact. If there is already a trace amount of passivating agent in contact with the semiconductor, this does not in itself constitute the treatment of the semiconductor with the passivating agent. The treatment typically comprises applying a passivating agent to the semiconductor from the outside.

Passivating agent

The passivating agent includes a compound comprising an oxygen-oxygen single bond. A compound comprising an oxygen-oxygen single bond is a compound whose structure includes an oxygen-oxygen single bond in one or more of its resonance structures. For example, ozone (both of whose resonance structures include an oxygen-oxygen single bond and an oxygen-oxygen double bond) is a compound containing an oxygen-oxygen single bond. As used herein, oxygen (dioxygen, O)₂) And oxygen plasmas are not examples of compounds that include oxygen-oxygen single bonds.

The passivating agent typically comprises: a peroxy-containing compound; a compound comprising a peroxyhydroxy group; a compound comprising a perester group; a compound comprising a peracid anhydride group; a compound containing a peracid group; or ozone (O)₃). Peroxy is a group of the formula-O-. The hydroperoxy group is a group of the formula-O-H. Examples of perester groups are those of formula-C (═ O) -O-. A peracid group is a group of the formula-C (═ O) -O-H. The peracid anhydride group is a group of the formula-C (═ O) -O-C (═ O) -. Typically, the compound comprises a peroxy group or a hydroperoxy group.

The passivating agent may include: a compound of the formula R-O-O-R; a compound of the formula R-C (O) -O-O-R; or a compound of the formula R-C (O) -O-O-C (O) -R, wherein: each R is independently selected from H, unsubstituted or substituted C_1-8Alkyl, unsubstituted or substituted C_1-8Alkenyl and unsubstituted or substituted aryl, optionally wherein each R is bonded together to form a ring. Each radical being generally unsubstituted or selected from halogen, hydroxy, nitro, C_1-3Alkyl or phenyl groups. R is usually H, C_1-6An alkyl group, a phenyl group optionally substituted with one or more methyl, halo or nitro groups, or a benzyl group optionally substituted with one or more methyl, halo or nitro groups. R may be, for example, H, methyl, ethyl, isopropyl, tert-butyl, cumyl, phenyl or benzyl. In some cases, R may be-SiR₃Wherein R is C_1-3Alkyl, phenyl or benzyl.

The passivating agent may be present as a single compound or may be complexed with a second compound. For example, the passivating agent may be a compound comprising an oxygen-oxygen single bond complexed with urea.

The passivating agent typically comprises a compound selected from the group consisting of: hydrogen peroxide, urea peroxide, ozone, t-butyl hydroperoxide, t-butyl peroxybenzoate, di-t-butyl peroxide, 2-butanone peroxide, cumene hydroperoxide, dicumyl peroxide, bis (trimethylsilyl) peroxide, benzoyl peroxide, diacetyl peroxide, diethyl ether peroxide, dipropyl peroxydicarbonate, methyl ethyl ketone peroxide, peracetic acid, performic acid, perbenzoic acid, and m-chloroperoxybenzoic acid.

The passivating agent preferably comprises hydrogen peroxide or ozone. More preferably, the passivating agent comprises hydrogen peroxide. Accordingly, the invention provides a process for producing a passivated semiconductor, the process comprising treating the semiconductor with hydrogen peroxide.

The passivating agent may alternatively comprise an inorganic peroxide (e.g., alkali or alkaline earth metals such as barium peroxide, sodium peroxide, lithium peroxide, magnesium peroxide, and calcium peroxide) or an inorganic ozonide (e.g., potassium ozonide, rubidium ozonide, or cesium ozonide).

The deactivant may be present in a composition which may be a solid composition, a liquid composition or a gaseous composition. For example, the process may include treating the semiconductor with a composition including a passivating agent.

Semiconductor device and method for manufacturing the same

The semiconductor includes a crystalline compound comprising: (i) one or more first cations (a); (ii) one or more metal cations (M); and (iii) one or more anions (X). Thus, the semiconductor is typically an A/M/X compound.

Semiconductors are compounds of moderate conductivity between a conductor and a dielectric. The semiconductor may be a negative (n) -type semiconductor, a positive (p) -type semiconductor, or an intrinsic (i) -semiconductor. The semiconductor can have a bandgap (when measured at 300K) of 0.5eV to 3.5eV (e.g., 0.5eV to 2.5eV or 1.0eV to 2.0 eV).

The semiconductor typically includes a photoactive material. The semiconductor may be a photoactive material.

Semiconductors include crystalline compounds, but may also include amorphous materials, such as polymers. The semiconductor typically includes at least 50% by weight of the crystalline compound. The semiconductor may, for example, comprise at least 80 wt% or at least 95 wt% of the crystalline compound. The semiconductor may consist essentially of a crystalline compound.

The semiconductor is typically in the form of a layer. The semiconductor may include a crystalline compound layer. The semiconductor may consist essentially of a layer comprising a crystalline compound.

The process may be a process for producing a passivated semiconductor layer, the process comprising treating the semiconductor layer with a passivating agent. Treating the semiconductor layer with the passivating agent may include disposing the passivating agent on the semiconductor layer.

The layer typically has a thickness of at least 50nm or at least 100 nm. For example, the semiconductor may include a layer containing a crystalline compound, the layer having a thickness of 100nm to 700 nm. The thickness of the layer can be measured by electron microscopy.

The crystalline compound may comprise a compound having the formula [ A]_a[M]_b[X]_cThe compound of (1), wherein: [ A ]]Is one or more first cations; [ M ] A]Is one or more metal cations; [ X ]]Is one or more anions; a is an integer of 1 to 3; b is an integer from 1 to 3; and c is an integer from 1 to 8. If [ A ] is present]Is a cation (A), [ M ]]Is two kinds of cations (M)¹And M²) And [ X ]]Is an anion (X), the crystalline material may comprise formula A_a(M¹,M²)_bX_cThe compound of (1). [ A ]]One, two or more a ions may be represented. If [ A ] is present]、[M]Or [ X ]]Are more than one ion, those ions may be present in any proportion. For example, A_a(M¹,M²)_bX_cComprises a formula A_aM¹ _byM² _b(1-y)X_cWherein y is between 0.0 and 1.0, e.g., 0.05 to 0.95. Such materials may be referred to as mixed ion materials.

One or more metal anodesThe ion M may be one or more metal dications, one or more metal trications or one or more metal tetracations. The one or more first cations a are typically one or more monocations, for example, organic monocations and/or inorganic monocations. The anion or anions X are typically halide anion or anions (I)^–、Br^–、Cl^–Or F^–) Or one or more chalcogenide anions (e.g., O)^2–Or S^2–)。

The semiconductor preferably comprises a perovskite. Thus, semiconductors typically include the formula [ A][M][X]₃The crystalline compound of (1), wherein: [ A ]]Comprising one or more first cations; [ M ] A]Comprising one or more metal cations; and [ X ]]Including one or more anions. The one or more anions generally comprise a group selected from I^–、Br^–And Cl^–One or more halide anions of (a). [ A ]]May include a single first cation, and [ M]A single metal cation may be included. Thus, the crystalline compound may be of the formula AM [ X ]]₃The compound of (3), which may be, for example, a mixed halide perovskite. The perovskite is preferably a metal halide perovskite.

The perovskite may be an organic-inorganic perovskite, wherein the one or more first cations (a) comprise an organic cation. The perovskite may alternatively be one in which one or more first cations are metal cations (e.g., selected from K)⁺、Rb⁺And Cs⁺) All-inorganic perovskites of (a). As discussed above, the process of the present invention is capable of passivating both organic and inorganic perovskites.

The first cation or cations (A) are generally chosen from K⁺、Rb⁺、Cs⁺、(NR¹R²R³R⁴)⁺、(R¹R²N＝CR³R⁴)⁺、(R¹R²N–C(R⁵)＝NR³R⁴)⁺And (R)¹R²N–C(NR⁵R⁶)＝NR³R⁴)⁺Wherein R is¹、R²、R³、R⁴、R⁵And R⁶Each of which is independently H, unsubstituted or substituted C_1-20Alkyl or unsubstituted or substituted aryl. Each R¹、R²、R³、R⁴、R⁵And R⁶Preferably selected from H and C optionally substituted by phenyl_1-10An alkyl group. Each R¹、R²、R³、R⁴、R⁵And R⁶May be H or methyl.

Preferably, the one or more first cations are selected from Cs⁺、(CH₃NH₃)⁺And (H)₂N–C(H)＝NH₂)⁺. The one or more first cations preferably comprise Cs⁺And (H)₂N–C(H)＝NH₂)⁺. The one or more first cations may alternatively be Cs as the only first cation⁺Or as the only first Cation (CH)₃NH₃)⁺。

The metal cation(s) (M) are generally chosen from Pb²⁺、Ca²⁺、Sr²⁺、Cd²⁺、Cu²⁺、Ni²⁺、Mn²⁺、Fe²⁺、Co²⁺、Pd²⁺、Ge²⁺、Sn²⁺、Yb²⁺、Eu²⁺、Bi³⁺、Sb³⁺、Pd⁴⁺、W⁴⁺、Re⁴⁺、Os⁴⁺、Ir⁴⁺、Pt⁴⁺、Sn⁴⁺、Pb⁴⁺、Ge⁴⁺And Te^{4 +}。

Preferably, the crystalline compound comprises lead (Pb). For example, the one or more metal cations may include Pb²⁺. The one or more metal cations may include Sn²⁺. For example, the one or more metal cations may include Pb²⁺And/or Sn²⁺。

The semiconductor may comprise the formula [ A]Pb_zSn_(1-z)[X]₃Wherein z is 0.0 to 1.0. When z is 0.0, the formula includes Sn only²⁺As the one or more metal cations. When z is 1.0, the formula includes only Pb²⁺As the one or more metal cations. z may for example be 0.1 to 0.9, in which case the crystalline compound is a mixed metal perovskite. In this formula, [ A ]]Usually comprising Cs⁺、(CH₃NH₃)⁺And (H)₂N–C(H)＝NH₂)⁺And [ X ] is]Generally comprises I^–、Br^–And Cl^–One or more of (a).

Crystalline compounds may include, for example: formula CH₃NH₃PbI₃、CH₃NH₃PbBr₃、CH₃NH₃PbCl₃、CH₃NH₃PbF₃、CH₃NH₃PbBr_3yI_3(1-y)、CH₃NH₃PbBr_3yCl_3(1-y)、CH₃NH₃PbI_3yCl_3(1-y)、CH₃NH₃PbI_3(1-y)Cl_3y、CH₃NH₃SnI₃、CH₃NH₃SnBr₃、CH₃NH₃SnCl₃、CH₃NH₃SnF₃、CH₃NH₃SnBrI₂、CH₃NH₃SnBr_3yI_3(1-y)、CH₃NH₃SnBr_3yCl_3(1-y)、CH₃NH₃SnF_3(1-y)Br_3y、CH₃NH₃SnI_3yBr_3(1-y)、CH₃NH₃SnI_3yCl_3(1-y)、CH₃NH₃SnF_3(1-y)I_3y、CH₃NH₃SnCl_3yBr_3(1-y)、CH₃NH₃SnI_3(1-y)Cl_3yAnd CH₃NH₃SnF_3(1-y)Cl_3y、CH₃NH₃CuI₃、CH₃NH₃CuBr₃、CH₃NH₃CuCl₃、CH₃NH₃CuF₃、CH₃NH₃CuBrI₂、CH₃NH₃CuBr_3yI_3(1-y)、CH₃NH₃CuBr_3yCl_3(1-y)、CH₃NH₃CuF_3(1-y)Br_3y、CH₃NH₃CuI_3yBr_3(1-y)、CH₃NH₃CuI_3yCl_3(1-y)、CH₃NH₃CuF_3(1-y)I_3y、CH₃NH₃CuCl_3yBr_3(1-y)、CH₃NH₃CuI_3(1-y)Cl_3yOr CH₃NH₃CuF_3(1-y)Cl_3yThe perovskite compound of (a), wherein y is 0 to 1; formula (H)₂N–C(H)＝NH₂)PbI₃、(H₂N–C(H)＝NH₂)PbBr₃、(H₂N–C(H)＝NH₂)PbCl₃、(H₂N–C(H)＝NH₂)PbF₃、(H₂N–C(H)＝NH₂)PbBr_3yI_3(1-y)、(H₂N–C(H)＝NH₂)PbBr_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)PbI_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)PbI_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)PbCl_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)PbI_3(1-y)Cl_3y、(H₂N–C(H)＝NH₂)SnI₃、(H₂N–C(H)＝NH₂)SnBr₃、(H₂N–C(H)＝NH₂)SnCl₃、(H₂N–C(H)＝NH₂)SnF₃、(H₂N–C(H)＝NH₂)SnBrI₂、(H₂N–C(H)＝NH₂)SnBr_3yI_3(1-y)、(H₂N–C(H)＝NH₂)SnBr_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)SnF_3(1-y)Br_3y、(H₂N–C(H)＝NH₂)SnI_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)SnI_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)SnF_3(1-y)I_3y、(H₂N–C(H)＝NH₂)SnCl_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)SnI_3(1-y)Cl_3y、(H₂N–C(H)＝NH₂)SnF_3(1-y)Cl_3y、(H₂N–C(H)＝NH₂)CuI₃、(H₂N–C(H)＝NH₂)CuBr₃、(H₂N–C(H)＝NH₂)CuCl₃、(H₂N–C(H)＝NH₂)CuF₃、(H₂N–C(H)＝NH₂)CuBrI₂、(H₂N–C(H)＝NH₂)CuBr_3yI_3(1-y)、(H₂N–C(H)＝NH₂)CuBr_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)CuF_3(1-y)Br_3y、(H₂N–C(H)＝NH₂)CuI_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)CuI_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)CuF_3(1-y)I_3y、(H₂N–C(H)＝NH₂)CuCl_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)CuI_3(1-y)Cl_3yOr (H)₂N–C(H)＝NH₂)CuF_3(1-y)Cl_3yThe perovskite compound of (a), wherein y is 0 to 1; or formula (H)₂N–C(H)＝NH₂)_xCs_1-xPbI₃、(H₂N–C(H)＝NH₂)_xCs_1-xPbBr₃、(H₂N–C(H)＝NH₂)_xCs_1-xPbCl₃、(H₂N–C(H)＝NH₂)_xCs_1-xPbF₃、(H₂N–C(H)＝NH₂)_xCs_1-xPbBr_3yI_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xPbBr_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xPbI_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xPbI_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_{1- x}PbCl_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xPbI_3(1-y)Cl_3y、(H₂N–C(H)＝NH₂)_xCs_1-xSnI₃、(H₂N–C(H)＝NH₂)_xCs_1-xSnBr₃、(H₂N–C(H)＝NH₂)_xCs_1-xSnCl₃、(H₂N–C(H)＝NH₂)_xCs_1-xSnF₃、(H₂N–C(H)＝NH₂)_xCs_1-xSnBrI₂、(H₂N–C(H)＝NH₂)_xCs_1-xSnBr_3yI_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xSnBr_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xSnF_3(1-y)Br_3y、(H₂N–C(H)＝NH₂)_xCs_1-xSnI_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xSnI_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xSnF_3(1-y)I_3y、(H₂N–C(H)＝NH₂)_xCs_1-xSnCl_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xSnI_3(1-y)Cl_3y、(H₂N–C(H)＝NH₂)_xCs_1-xSnF_3(1-y)Cl_3y、(H₂N–C(H)＝NH₂)_xCs_1-xCuI₃、(H₂N–C(H)＝NH₂)_xCs_1-xCuBr₃、(H₂N–C(H)＝NH₂)_xCs_1-xCuCl₃、(H₂N–C(H)＝NH₂)_xCs_1-xCuF₃、(H₂N–C(H)＝NH₂)_xCs_1-xCuBrI₂、(H₂N–C(H)＝NH₂)_xCs_1-xCuBr_3yI_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xCuBr_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xCuF_3(1-y)Br_3y、(H₂N–C(H)＝NH₂)_xCs_{1- x}CuI_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xCuI_3yCl_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xCuF_3(1-y)I_3y、(H₂N–C(H)＝NH₂)_xCs_1-xCuCl_3yBr_3(1-y)、(H₂N–C(H)＝NH₂)_xCs_1-xCuI_3(1-y)Cl_3yOr (H)₂N–C(H)＝NH₂)_xCs_{1- x}CuF_3(1-y)Cl_3yWherein x is 0 to 1, and y is 0 to 1. x may be, for example, 0.05 to 0.95. y may be, for example, 0.05 to 0.95.

Preferably, the semiconductor comprises CH₃NH₃PbBr_3yI_3(1-y)、CsPbBr_3yI_3(1-y)Or Cs_x(H₂N–C(H)＝NH₂)_(1-x)PbBr_3yI_3(1–y)Wherein x is 0.0 to 1.0 and y is 0.0 to 1.0. For example, the semiconductor may include CH₃NH₃PbI₃、CsPbBr_3yI_3(1-y)Or Cs_x(H₂N–C(H)＝NH₂)_(1-x)PbBr_3yI_3(1–y)Wherein x is 0.05 to 0.95 and y is 0.05 to 0.95.

Preferably, the semiconductor comprises the formula Cs_x(H₂N–C(H)＝NH₂)_(1-x)PbBr_3yI_3(1–y)Wherein x is 0.0 to 1.0 and y is 0.0 to 1.0. Typically, x is from 0.05 to0.50 or 0.10 to 0.30. x may be, for example, 0.15 to 0.20. Typically, y is from 0.01 to 0.70 or from 0.20 to 0.60. y may be, for example, 0.30 to 0.50. The crystalline compound is preferably Cs_0.2(H₂N–C(H)＝NH₂)_0.8Pb(Br_0.4I_0.6)₃Or Cs_0.17(H₂N–C(H)＝NH₂)_0.83Pb(Br_0.4I_0.6)₃。

The semiconductor may alternatively comprise the formula [ A]₂[M][X]₆Wherein: [ A ]]Is one or more first cations; [ M ] A]Is one or more metal cations; and [ X ]]Is one or more anions. For example, the metal hexahalide may be Cs₂MI₆、Cs₂MBr₆、Cs₂MBr_6-yI_y、Cs₂MCl_6-yI_y、Cs₂MCl_6-yBr_y、(CH₃NH₃)₂MI₆、(CH₃NH₃)₂MBr₆、(CH₃NH₃)₂MBr_6-yI_y、(CH₃NH₃)₂MCl_6-yI_y、(CH₃NH₃)₂MCl_6-yBr_y、(H₂N–C(H)＝NH₂)₂MI₆、(H₂N–C(H)＝NH₂)₂MBr₆、(H₂N–C(H)＝NH₂)₂MBr_6-yI_y、(H₂N–C(H)＝NH₂)₂MCl_6-yI_yOr (H)₂N–C(H)＝NH₂)₂MCl_6-yBr_yWherein y is 0.01 to 5.99 and M is Sn²⁺Or Pb²⁺。

The semiconductor may alternatively comprise the formula [ A]₂[B^I][B^III][X]₆The double perovskite compound of (a), wherein: [ A ]]Is one or more first cations; [ B ]^I]Is one or more metal monocations; [ B ]^III]Is one or more metal trication; and [ X ]]Is one or more anionsAnd (4) adding the active ingredients. [ B ]^I]Can be selected from Li⁺、Na⁺、K⁺、Rb⁺、Cs⁺、Cu⁺、Ag⁺、Au⁺And Hg⁺Preferably selected from Cu⁺、Ag⁺And Au⁺。[B^III]May be selected from Bi³⁺、Sb³⁺、Cr³⁺、Fe³⁺、Co³⁺、Ga³⁺、As³⁺、Ru³⁺、Rh^{3 +}、In³⁺、Ir³⁺And Au³⁺Preferably selected from Bi³⁺And Sb³⁺. The double perovskite may be of the formula Cs₂AgBiX₆、(H₂N–C(H)＝NH₂)₂AgBiX₆、(H₂N–C(H)＝NH₂)₂AuBiX₆、(CH₃NH₃)₂AgBiX₆Or (CH)₃NH₃)₂AuBiX₆Wherein X is I^-、Br^-Or Cl^-. The double perovskite may be of the formula Cs₂AgBiBr₆The compound of (1).

Process conditions

The process is typically carried out at a temperature below 100 ℃. For example, the semiconductor may be treated with a passivating agent at a temperature of 10 ℃ to 90 ℃. The process may be carried out at room temperature. For example, the semiconductor may be treated with a passivating agent at a temperature of 15 ℃ to 35 ℃.

Semiconductors are typically treated by contacting the semiconductor with a composition that includes a passivating agent, which is either a liquid composition or a gaseous composition. The composition typically comprises at least 0.001 mol% of the passivating agent relative to the amount of crystalline compound present in the semiconductor. For example, the composition may include a total amount of passivating agent of at least 0.00001 mole for every 1 mole of semiconductor contacted with the composition. The composition may, for example, include a total amount of passivating agent of at least 0.0001 mole for every 1 mole of semiconductor contacted with the composition.

If the composition is a liquid composition, the concentration of the deactivant in the liquid composition is typically at least 0.001M, for example, from 0.001M to 1.0M. The concentration of passivating agent is typically 0.001M to 0.1M. Liquid compositions typically include a solvent and a passivating agent. The passivating agent is typically dissolved in a solvent.

Treating a semiconductor with a passivating agent typically includes exposing the semiconductor to a composition that includes a solvent and the passivating agent. The composition comprising a solvent and a deactivant preferably comprises a solution of the deactivant in the solvent. The solution may be an aqueous solution. An aqueous solution is a solution in which water is present.

The solvent may be any suitable solvent in which the passivating agent is soluble. Each solvent may be a polar solvent or a non-polar solvent. The solvent in the liquid composition typically comprises one or more polar solvents. The solvent typically comprises one or more of water, an alcohol (e.g., methanol, ethanol, isopropanol, or 2-ethoxyethanol), a ketone (e.g., acetone or methyl ethyl ketone), a nitrile (e.g., acetonitrile), a chlorinated hydrocarbon (e.g., dichloromethane, chlorobenzene, or chloroform), an ether (e.g., dimethyl ether or tetrahydrofuran), a sulfoxide (e.g., dimethyl sulfoxide), or an amide (e.g., dimethylformamide). The solvent typically comprises water and/or an alcohol. The solvent may include water and methanol, ethanol or isopropanol. Preferably, the solvent comprises water and isopropanol.

The semiconductor may be treated with a liquid composition including a passivating agent by disposing the liquid composition on the semiconductor. For example, the semiconductor may be immersed in the liquid composition, or the liquid composition may be spin-coated or spray-coated onto the semiconductor. The process may include immersing a semiconductor layer disposed on a substrate in a liquid composition including a passivating agent. The process may include spin coating or spray coating a liquid composition including a passivating agent onto a semiconductor layer disposed on a substrate.

Preferably, treating the semiconductor with the passivating agent comprises exposing the semiconductor to an aqueous solution of hydrogen peroxide. The aqueous solution may be a solution of hydrogen peroxide in water and isopropanol. Preferably, the aqueous hydrogen peroxide solution comprises hydrogen peroxide at a concentration of 0.0001M to 0.5M or 0.001M to 0.1M (e.g., 0.005M to 0.05M).

The composition may be an aqueous solution of ozone. The composition may thus comprise water and ozone.

The semiconductor is typically contacted with the liquid composition for 0.1 seconds to 100 seconds. For example, the semiconductor may be contacted with the liquid composition for 0.5 seconds to 10 seconds.

After treating the semiconductor with a composition comprising a solvent and a passivating agent, the passivated semiconductor may be dried to remove any residual solvent. Drying may comprise exposing the passivated semiconductor to compressed air or heating the passivated semiconductor, for example at a temperature of 30 ℃ to 150 ℃, optionally for 30 seconds to 30 minutes.

The process may include treating the semiconductor with a passivating agent by exposing the semiconductor to a vapor including the passivating agent. The composition comprising the passivating agent may thus be a gaseous composition.

The semiconductor may be treated with a (gaseous) composition comprising at least 5 vol.% of the passivating agent in gaseous or vapour form. For example, the partial pressure of the passivating agent in the gaseous composition may be at least 5% of the total pressure of the gaseous composition. The composition may comprise at least 10% by volume of the deactivant, at least 20% by volume of the deactivant or at least 30% by volume of the deactivant. The partial pressure of the passivating agent in the gaseous composition may be at least 10% of the total pressure of the gaseous composition, at least 20% of the total pressure of the gaseous composition, or at least 30% of the total pressure of the gaseous composition.

The semiconductor may be treated with the gaseous composition comprising the passivating agent at low pressure (e.g., under vacuum) or at higher pressure (e.g., at about atmospheric pressure). Thus, the semiconductor may be exposed to a vapour comprising a passivating agent in a chamber, wherein the pressure in the chamber is less than 1.0Pa, e.g. less than 10 Pa^-3Pa (vacuum deposition) or wherein the pressure in the chamber is from 100Pa to 10 Pa⁶Pa (i.e., about 0.01 atmosphere to 10 atmospheres).

Typically, the semiconductor may be exposed to a vapor including a passivating agent in a chamber at a pressure of 50000Pa to 150000Pa (approximately 0.5 atmosphere to 1.5 atmosphere). For example, the process may include placing a semiconductor in an enclosed chamber having a passivating agent source and heating the passivating agent source to generate a vapor including passivating agent.

Treating the semiconductor with the passivating agent may include exposing the semiconductor to a vapor including hydrogen peroxide. Preferably, the process further comprises generating a vapor comprising hydrogen peroxide by heating the composition comprising urea peroxide. Carbamide peroxide releases hydrogen peroxide upon heating.

Treating the semiconductor with the passivating agent can include exposing the semiconductor to ozone gas. For example, the substrate may be placed in a chamber comprising an ozone atmosphere. The amount of ozone present may be 10% to 50%, or 20% to 40% of the atmospheric volume (e.g., a partial pressure of 10% to 50% of the total pressure in the chamber). The gaseous composition comprising ozone may also comprise oxygen.

The process may also include an annealing step after the semiconductor is treated by the passivating agent. For example, the passivated semiconductor may be heated at a temperature of 30 ℃ to 150 ℃, optionally 30 seconds to 30 minutes.

Alternatively, the process optionally does not further include an annealing step after the semiconductor is treated by the passivating agent.

An advantage of the present invention is that no illumination (e.g., light soaking) is required to achieve passivation. Although the process can be carried out in bright or dark conditions, it can also be carried out without intense illumination. For example, passivation may occur under ambient light conditions inside a building. Passivation may be at an intensity of less than typical solar illumination (e.g., less than 100 mW/cm)²(e.g., less than 50mW/cm²) ) occurs. Thus, it may be no more than 0.5kW/m during treatment with the passivating agent²Is irradiated to the semiconductor. Optionally, it may be at no more than 0.1kW/m during treatment with the passivating agent²Is irradiated with an intensity of not more than 0.01kW/m or during the treatment with the passivating agent²Is irradiated to the semiconductor. The process may be carried out in the substantial absence of light or light.

The inventive process allows the semiconductor to be passivated quickly. However, a process such as photo-brightening may take several hours, while a process according to the invention allows to produce passivated semiconductors within a few seconds or minutes. Therefore, the semiconductor is typically treated with the passivating agent for less than 1 hour. Alternatively, the semiconductor is treated with the passivating agent for less than 1 minute.

Passivation of semiconductors can lead to many improvements in the optical properties of semiconductors. Passivated semiconductors typically have an increased photoluminescent lifetime and/or an increased photoluminescent intensity compared to the semiconductor before passivation.

Substrate

The semiconductor may be in the form of a layer comprising a crystalline compound disposed on a substrate. The substrate typically includes a layer of a first electrode material. The first electrode material may include a metal (e.g., silver, gold, aluminum, or tungsten) or a transparent conductive oxide (e.g., fluorine-doped tin oxide (FTO) or Indium Tin Oxide (ITO)). Typically, the first electrode comprises a transparent conductive oxide.

For example, the substrate may include a first electrode material layer and an n-type semiconductor layer. Typically, the substrate includes a transparent conductive oxide (e.g., FTO) layer and an n-type semiconductor (e.g., TiO)₂Or SnO₂) The dense layer of (1).

In some embodiments, the substrate comprises a layer of porous scaffold material. The porous support layer is typically in contact with a layer of n-type or p-type semiconductor material (e.g., an n-type semiconductor dense layer or a p-type semiconductor dense layer). The scaffold material is typically mesoporous or macroporous. The scaffold material may assist in charge transport from the crystalline material to adjacent regions. The scaffold material may also aid in the formation of a layer of crystalline material during deposition. The porous scaffold material is typically infiltrated with a crystalline material after deposition.

Typically, the porous scaffold material comprises a dielectric material or a charge transport material. The scaffold material may be a dielectric scaffold material. The scaffold material may be a charge transport scaffold material. The porous scaffold material may be an electron transporting material or a hole transporting scaffold material. An n-type semiconductor is an example of an electron transport material. A p-type semiconductor is an example of a hole transporting scaffold material. Preferably, the porous scaffold material is a dielectric scaffold material or an electron transporting scaffold material (e.g., an n-type scaffold material).

The porous scaffold material may be a charge transport scaffold material (e.g., an electron transport material such as titanium dioxide or alternatively a hole transport material) or a dielectric material such as alumina. The term "dielectric material" as used herein refers to a material that is an electrical insulator or extremely poor conductor of electrical current. Thus, the term dielectric does not include semiconductor materials such as titanium dioxide. The term dielectric as used herein generally refers to a material having a bandgap equal to or greater than 4.0 eV. (the band gap of titanium dioxide is about 3.2 eV.) of course, the skilled person can readily measure the band gap of the material by using well-known procedures that do not require undue experimentation. For example, the band gap of a material can be estimated by constructing a photovoltaic diode or solar cell from the material and determining the photovoltaic spectrum of action. The monochromatic photon energy at which the diode begins to produce photocurrent can be taken as the bandgap of the material; such as by Barkhouse et al, prog.photo novt: res.appl.2012; 20: 6-11. Reference herein to the band gap of a material is to the band gap measured by this method, i.e. as determined by recording the spectrum of photovoltaic action of a photovoltaic diode or solar cell constructed from the material and observing the monochromatic photon energy which begins to produce a significant photocurrent.

The thickness of the porous support layer is typically 5nm to 400 nm. For example, the thickness of the porous scaffold layer may be 10nm to 50 nm.

The substrate may for example comprise a layer of the first electrode material, a layer of the n-type semiconductor and a layer of the dielectric support material. Thus, the substrate may comprise a transparent conductive oxide layer, TiO₂Dense layer and Al₂O₃A porous layer.

Typically, the substrate includes a layer of a first electrode material and an n-type semiconductor layer or a p-type semiconductor layer.

Typically, the substrate comprises a layer of the first electrode material and optionally one or more further layers each selected from: an n-type semiconductor layer, a p-type semiconductor layer, and an insulating material layer. Typically, the surface of the substrate on which the precursor composition is disposed comprises one or more of a first electrode material, an n-type semiconductor layer, a p-type semiconductor layer, and a layer of insulating material.

Process for producing a device

The invention provides a process for manufacturing a semiconductor device, wherein the process comprises manufacturing a passivated semiconductor by a method according to any of the preceding claims.

The process also typically includes disposing a p-type semiconductor layer or an n-type semiconductor layer on the passivated semiconductor (which may be in the form of a layer). Typically, the process typically includes disposing a p-type semiconductor layer on the passivated semiconductor. The n-type or p-type semiconductor may be an organic p-type semiconductor. Suitable p-type semiconductors may be selected from polymeric or molecular hole transporters. Preferably, the p-type semiconductor is spiro-OMeTAD. The p-type semiconductor layer or the n-type semiconductor layer is typically disposed on the passivated semiconductor by solution processing, for example, by disposing a composition comprising a solvent and an n-type or p-type semiconductor. The solvent may be selected from polar solvents, for example chlorobenzene or acetonitrile. The thickness of the p-type semiconductor layer or the n-type semiconductor layer is generally 50nm to 500 nm.

The process also typically includes disposing a second electrode material layer on the p-type semiconductor or the n-type semiconductor layer. The second electrode material may be as defined above for the first electrode material. Typically, the second electrode material comprises, or consists essentially of, a metal. Examples of metals that the second electrode material may comprise or consist essentially of include silver, gold, copper, aluminum, platinum, palladium, or tungsten. The second electrode may be provided by vacuum evaporation. The thickness of the second electrode material layer is typically 5nm to 100 nm.

Typically, the semiconductor device is an optoelectronic device, a photovoltaic device, a solar cell, a photodetector, a photodiode, a photosensor (photodetector), a radiation detector, a color-rendering device, a transistor, a diode, a phototransistor, a solid state triode, a battery electrode, a capacitor, a supercapacitor, a light emitting device, a light emitting diode, or a laser.

Semiconductor devices are typically optoelectronic devices. Examples of optoelectronic devices include photovoltaic devices, photodiodes (including solar cells), phototransistors, photomultipliers, photoresistors, and light emitting devices. Preferably, the semiconductor device is a photovoltaic device or a light emitting device.

Composition comprising a metal oxide and a metal oxide

The present invention also provides a composition comprising: (i) a semiconductor; and (ii) a passivating agent, wherein the concentration of the passivating agent is greater than or equal to 0.001 mol% relative to the amount of semiconductor. The concentration of passivating agent is generally greater than or equal to 0.01 mol% relative to the amount of semiconductor or greater than or equal to 1.0 mol% relative to the amount of semiconductor. For example, from 0.0001 to 0.5 moles of passivating agent may be present per mole of semiconductor, for example from 0.001 to 0.1 moles of passivating agent.

The composition may comprise the semiconductor in an amount of 50 to 99.9 wt% relative to the total composition and the passivating agent in an amount of 0.001 to 20 wt% relative to the total composition weight.

For example, the composition may be a composition comprising the semiconductor in solid form (or dissolved in a solvent), and at least 0.001 mole of the passivating agent in solid, liquid or gaseous form is present per mole of semiconductor. If both the semiconductor and the passivating agent are present in solid form, the composition includes a combined solid form of the semiconductor and the passivating agent. If the semiconductor is present in solid form and the passivating agent is present in liquid form (e.g. dissolved in a solvent), the composition comprises the combined solid semiconductor and passivating agent in liquid form, e.g. the composition is a solution of the semiconductor layer and passivating agent disposed thereon. If the semiconductor is present in solid form and the passivating agent is present in gaseous form (e.g. as a vapour), the composition comprises the solid semiconductor and the gaseous passivating agent in combination, for example, wherein the composition is defined by a container comprising the solid semiconductor and the gaseous passivating agent.

The semiconductor is typically a perovskite. The phlegmatiser is typically a peroxy compound. The passivating agent is preferably hydrogen peroxide or ozone. More preferably, the passivating agent is hydrogen peroxide. Thus, the composition may comprise a passivating agent which is a perovskite semiconductor and which comprises hydrogen peroxide.

The composition may also include a solvent as defined herein. For example, the composition may comprise a solution of the semiconductor and the passivating agent in solid form. The composition may include a perovskite and an aqueous hydrogen peroxide solution. The composition may include a perovskite, hydrogen peroxide, water, and an alcohol (e.g., isopropanol).

Use of

The invention provides the use of a composition comprising a passivating agent for passivating a semiconductor, wherein: the semiconductor includes a crystalline compound comprising: (i) one or more first cations (a); (ii) one or more metal cations (M); (iii) one or more anions (X); the passivating agent includes a compound comprising an oxygen-oxygen single bond.

The inventors have found that certain oxygen-containing passivating agents can passivate semiconductors comprising crystalline compounds without the need for additional complex illumination. The invention therefore also provides the use of a composition comprising a passivating agent for passivating a semiconductor, during passivation at not more than 0.5kW/m²The intensity of (a) irradiating the semiconductor, wherein: the semiconductor includes a crystalline compound comprising: (i) one or more first cations (a); (ii) one or more metal cations (M); (iii) one or more anions (X); the passivating agent includes a compound including an oxygen-oxygen single bond or an oxygen-oxygen double bond. May be at no more than 0.1kW/m during passivation²May be irradiated with an intensity of not more than 0.01kW/m during the treatment with the passivating agent, or may be irradiated with an intensity of not more than 0.01kW/m during the treatment with the passivating agent²Is irradiated to the semiconductor. This use can be made substantially without illumination or light.

The passivating agent may comprise an oxygen plasma or a compound comprising an oxygen-oxygen single bond as defined herein. For example, the passivating agent may comprise oxygen plasma, hydrogen peroxide or ozone. The use according to the invention may be as further defined herein for the inventive process.

Embodiments of the present invention are described in more detail with reference to the following examples.

Examples

Materials and methods

FA_0.83Cs_0.17Pb(I_0.83Br_0.17)₃Perovskite thin film

FA_0.83Cs_0.17Pb(I_0.83Br_0.17)₃The solution was made from DMF: DMSO (dimethylformamide: dimethyl sulfoxide) in a 4:1 volume ratio and the following precursor salts were added to obtainTo obtain a stoichiometric solution of the desired composition: formamidine iodide (FAI) (great cell Solar), cesium iodide (CsI) (99.9%, Alfa Aesar), lead iodide (PbI)₂(99%, Sigma-Aldrich), lead bromide (PbBr)₂) (98%, Alfa Aesar). The solution was prepared on the same day of deposition. Obtaining a perovskite film by spin coating in a two-step method; first at 1000rpm for 10s and then at 6000rpm for 35s, with an acceleration of 2000 rpm/s. Solvent quenching was performed with anisole 10s before the end of the spin process. After a cleaning step consisting of a series of sonication steps, a spectroscopic sample was made on glass; first in hellmenex (5% in deionized water), then through pure deionized water, then acetone, and finally isopropanol. The substrate was then treated in a Model 42 series UVO washer from Jelight for 10 minutes. Alternatively, the substrate is exposed to O₂Plasma (Pico, plasma electronic) for 10 minutes.

All-inorganic perovskite CsPb (Br)_0.9I_0.1)₃Film(s)

CsPb (I) was prepared in DMSO with a concentration of 0.5M using the following precursor salts_0.1Br_0.9)₃Solution: cesium iodide (CsI) (99.9%, Alfa Aesar), lead iodide PbI₂(99%, Sigma-Aldrich), lead bromide (PbBr)₂) (98%, Alfa Aesar) and cesium bromide (99.9%, Alfa Aesar). The solution was prepared and stirred at room temperature for 24h before spin-coating. Obtaining a perovskite film by spin coating on clean glass in dry air in a two-step process; first at 4000rpm for 40s with an acceleration of 1000rpm/s and then at 6000rpm for 5s with an acceleration of 2000 rpm/s. Solvent quenching was performed with anisole 8s before the end of the spin process. The resulting film was then annealed at 150 ℃ for 15 minutes.

Hydrogen peroxide treatment

For the wet deposition method, a hydrogen peroxide solution (30 wt% in water, Sigma-Aldrich) was diluted in Isopropanol (IPA). Two beakers were prepared, one containing hydrogen peroxide diluted to different concentrations in 10mL of IPA and the second containing 80mL of IPA. The substrate was immersed in the first beaker for 1s and then washed in the second beaker for 2 s. They were then dried with a compressed air gun to remove any residual solution.

For the gas deposition method of hydrogen peroxide, 100mg of urea peroxide adduct (> 97%, Sigma Aldrich) was placed with the perovskite substrate in a large, covered petri dish to create a closed gas chamber heated to 60 ℃, and placed for different time intervals. Between 0 ℃ and 90 ℃, the hydrogen peroxide leaves the adduct as a pure gas, leaving the urea behind. The higher the temperature, the faster the hydrogen peroxide is released and the greater the concentration present in the chamber. Above 90 ℃, urea begins to decompose from the adduct, producing undesirable side reactants. The decomposition products of hydrogen peroxide are oxygen and water. Oxygen, water and urea are determined to be harmless according to safety and handling regulations, and therefore the end product of the treatment is completely non-toxic at an operating temperature of 60 ℃. The gas deposition process is outlined in fig. 1.

Oxygen plasma treatment

The perovskites were oxygen plasma post-treated using a low pressure plasma system (Pico, diene Electronic). The substrate was evacuated for 5 minutes, then re-oxygenated for 5 minutes, and finally plasma was generated and held for various times to post-treat the perovskite light absorbing layer.

Ozone treatment

An ozone generator (Ulsonix) supplies a stream of oxygen gas at 30% ozone, and the substrate is exposed to this stream for various time intervals.

X-ray and ultraviolet emission Spectroscopy (XPS/UPS)

Thermo Scientific K α X-ray photoelectron spectrometer was used for XPS measurements at an exit angle of 90 ° using a single chromated a 1K α X-ray source. Core level XPS spectra were recorded from an analysis area of 300 μm by 300 μm using an energy pass of 20eV (resolution approximately 0.4 eV). The spectrometer work function and binding energy scales were calibrated prior to the start of the experiment using fermi edges and 3d peaks recorded from polycrystalline silver (Ag) samples. The fitting process of extracting peak positions and relative stoichiometry from XPS data was performed using the Avantage XPS software package.

Steady state and time resolved Photoluminescence (PL)

Time-of-use single photon meterA number (TCSPC) device (FluoTime 300, PicoQuant GmbH) acquires time resolved PL measurements. Pulse frequency between 100kHz and 40MHz, pulse duration 117ps and fluence 30nJ/cm are used^-2The membrane samples were photoexcited with 507nm laser head (LDH-P-C-510, Pico Quant GmbH). The sample was exposed to a pulsed light source until stable photoemission was obtained. PL was collected using a high resolution monochromator and a Hybrid photomultiplier detector assembly (PMA Hybrid 40, PicoQuant GmbH).

The relative intensity steady state photoluminescence spectra were measured with a Horiba flurolol spectrofluorometer. The exposed area and position of the crystals are carefully controlled to achieve similar illumination and collection conditions. The excitation wavelength was 535 nm.

UV-Vis absorption

The absorption spectra were recorded on a Varian Cary 300 UV-Vis spectrophotometer.

Photoluminescence quantum efficiency (PLQE)

PLQE values were determined by irradiating a sample in an integrating sphere (Newport, 70682NS) with a 532nm continuous wave laser excitation source (Roithner, RLTMLL-5322W) according to the method of De Mello et al (adv. Mater.,1997,9, 230-. The beam intensity is modified using a neutral density filter.

Scanning electron microscope

SEM images were acquired using a field emission scanning electron microscope (Hitachi S-4300). The instrument uses an electron beam accelerated at 2.0kV, enabling operation at various currents.

Device fabrication

Devices were fabricated using fluorine doped tin oxide (FTO) coated glass (Pilkington) as the transparent electrode. The FTO was etched with 2M HCl and zinc powder to obtain the desired electrode pattern. The substrate was then cleaned following the same cleaning procedure as the spectroscopic slide.

For n-i-p devices by reacting SnCl₄.5H₂The O precursor was dissolved in IPA (17.5mg/ml) and stirred for 30 minutes, then the electron transport layer SnO was prepared by deposition via spin coating onto FTO at 3000r.p.m. for 30s₂. The film was then annealed at 100 ℃ for 20 minutesAnd then annealed at 180 c for 60 minutes. The substrate was then immersed in a chemical bath consisting of SnCl in deionized water₂·2H₂O (Sigma-Aldrich) (0.012M), 20.7mM urea (Sigma-Aldrich), 0.15M HCl (Fisher Scientific), and 2.87. mu.M 3-mercaptopropionic acid (Sigma-Aldrich). The substrate was held in an oven at 70 ℃ for 180 minutes and then sonicated in deionized water for 2 minutes. They were then washed with ethanol and annealed at 180 ℃ for 60 minutes. The electron blocking layer was deposited as 85mg/ml 2,2',7,7' -tetrakis- (N, N-di-p-methoxyaniline) -9,9' -spirobifluorene (spiro-OMeTAD) (Lumtec) in chlorobenzene. Then 20. mu.l of lithium bis (trifluoromethanesulfonyl) imide (Li-TFSI) (520mg/ml acetonitrile solution) and 7.5. mu.l of 4-tert-butylpyridine (TBP) were added per 1ml of spiro-OMeTAD solution. Spin coating was carried out at 2000rpm for 30 s. The samples were oxidized in a desiccator for at least 12 hours before being tested in a solar simulator. Then in high vacuum (10)^-6mbar) a 100nm thick silver electrode was deposited through a shadow mask.

For p-i-N inverted devices, poly [ N, N '-bis (4-butylphenyl) -N, N' -biphenylbenzidine as hole transport material](Poly TPD, 1-Material) was dissolved in toluene at a concentration of 1mg/mL together with 20 wt% of 2,3,5, 6-tetrafluoro-7, 7,8, 8-tetracyanoquinodimethane (F4-TCNQ, Lumtec), while for the electron transport Material [6, 6-tetracyanoquinodimethane (Lumtec) ]]methyl-phenyl-C61 butyrate (PC61BM, 99% Solene BV) and bathocuproine (BCP, 98% Alfa Aesar) were dissolved in chlorobenzene and isopropanol at concentrations of 20mg/mL and 0.5mg/mL, respectively. The perovskite absorption layer was deposited using a solvent quenching method (i.e., anti-solvent anisole (400 μ L) was added dropwise 10 seconds before the end of the spin casting process). In this embodiment, only the perovskite absorption layer and the electron transport layer are filled with nitrogen (O)₂、H₂O<1ppm) was processed in a glove box; the remaining manufactured and non-finished devices are processed and treated in ambient air. Finally, by applying vacuum (10)^-6mbar) was thermally evaporated to 70nm silver contacts to complete the inverted cell.

External quantum efficiency measurement

External Quantum Efficiency (EQE) was measured by a custom fourier transform photocurrent spectrometer based on a Bruker Vertex 80v fourier transform interferometer.The device was illuminated with an ami.5 filtered solar simulator. The device is calibrated to a Newport calibrated reference silicon solar cell with known external quantum efficiency. With a height of 0.0919cm²To shield the device from metal apertures of defined active area.

Current-voltage characteristic

Solar cell performance was measured using an AAB ABET sun 2000 solar simulator calibrated to measure solar cell performance at 100mW/cm²Provides simulated AM1.5 sunlight at irradiance of (a). The irradiance was calibrated using NREL calibrated KG5 filtered silicon reference cells. The current-voltage curve was recorded using a digital source meter (Keithley 2400). All solar cells are masked with metal holes that define the active area of the device, which in this case is 0.0925cm²。

X-ray diffraction measurements

By using Cu K_αThe irradiated Panalytical X-Pert Pro MPD acquired the diffraction pattern. The samples were either thin films deposited on glass or powders fixed with a small amount of grease.

Results and discussion

Mechanism of photo-brightening

The following uses Croger-Weck: (-Vink) defect representation method proposes that lead methyl ammonium triiodide (MAPbI)₃) The mechanism of photo-brightening in (1).

The reaction is initiated by the generation of electron-hole pairs upon absorption of a photon. The photogenerated holes may combine with iodide ions to form halogen atoms. It is reasonable that this reaction occurs with rapid site exchange of iodide anions from regular lattice sites to interstitial lattice sites.

I^x _I+h^·→I^· _I

Two halide atoms can combine to give one iodine molecule, which is a volatile gas, and can then be desorbed from the surface to give two anion vacancies.

2I^· _I→I_2(g)+2V^· _I

These vacancies can trap electrons, which can then react with lead ions to form Pb⁺Ions.

V^· _I+e′→(V^· _Ie′)^x

Pb^x _Pb+(V^· _Ie′)^x→(V^· _IPb_Pb′)^x

Disproportionation then occurs to produce atomic lead, with the PbPb "charge being compensated by two anion vacancies.

2Pb_Pb′→Pb^x _Pb+Pb_Pb″

Superoxide species are formed under light in the presence of oxygen. Due to the reactivity of superoxide as a strong proton scavenger and free radical reaction initiator, O₂ ^–If very close to the ammonium group, it will readily abstract the acid proton from the MA cation to form a hydroperoxy radical. Notably, to allow this reaction to occur, oxygen need not be trapped in the iodide vacancies, but may simply be physically adsorbed onto the surface.

O₂+e^-→O₂ ^–

This process produces methylamine, which easily escapes in the gas phase, leading to degradation. In the presence of an acid, the reaction will be catalysed, which provides a reasonable explanation for the extensive photo-brightening observed when acidic compounds are used as perovskite precursors (such as in the "acetate route"). The pKa dependence of this reaction and the stronger acidity of MA also explain why the process of photo-brightening has so far been observed only in perovskites with MA as the a-site cation, and previous reports on photo-brightening failed to explain this observation.

Then can take electrons through the peroxyl radicalReaction with another hydroperoxyl radical or reaction of superoxide with water to produce hydrogen peroxide. Improvement of PLQE measurement moving from dry to humid air and subsequent loss due to MA (and PbI)₂Formation of (b) indicates that all of these processes may be functional upon light soaking.

HO₂ ^·+e^-→HO₂ ^-

O₂ ^-+H₂O→¹/₂O₂+H₂O₂

The introduction of oxygen for the production of superoxide species will then produce hydrogen peroxide as a strong oxidant in close proximity to the lead-rich surface. Pb and H₂O₂Reaction to form Pb (OH)₂. It is concluded that this reactivity can be applied to the generation of atomic lead on the perovskite surface, as shown in the above formula.

Pb+H₂O₂→Pb(OH)₂

PbO can be formed by reaction of peroxide anions with lead octahedra in the perovskite lattice to form two covalent Pb-O bonds. The distorted octahedra are subsequently broken up to form PbO degradation products. Similarly, atomic lead on the surface of the perovskite may react with peroxide to generate localized PbO structures. The following formula outlines this reaction behavior.

Pb+H₂O₂→PbO+H₂O

In summary, the mechanism proposes MAPbI under ambient conditions₃Provides a thorough understanding of the origin of the instability of metal halide perovskites. This entire process may occur within hours and is strictly dependent on the humidity conditions and light intensity conditions in the air.

Oxidation of hydrogen peroxide

To investigate the proposed mechanism, hydrogen peroxide was applied directly to the perovskite as a post-treatment. It was found that the photo-brightening process could be simulated and that the passivated lead oxide species could be reproducibly generated. Similar improvements in the photoelectric properties of the materials were observed. Furthermore, by not generating hydrogen peroxide in situ, a series of degradation reactions leading to its formation can be avoided. This means that the presence of methylammonium as a proton source is no longer required and can be replaced by other less acidic cations such as Formamidine (FA) which, when combined with small amounts of cesium and mixed halide stoichiometry, can form stable perovskite thin films with reported n-i-p device efficiencies in excess of 20%.

Two kinds of H were developed₂O₂The deposition method comprises the following steps: one based on solvent and the other in the gas phase, as detailed in the process section. The wet deposition process involves briefly immersing a thin film perovskite in H₂O₂And vapor deposition processes using urea peroxide (UHP) to produce pure H₂O₂An atmosphere of gas to which the perovskite is exposed in the chamber. FA_0.83Cs_0.17Pb(Br_0.1I_0.9)₃The film uses a solvent quenching route (see methods).

PL Spectroscopy for study H₂O₂The effect of post-processing on perovskite photoelectric properties. In FIG. 2, FA treated via wet deposition is shown_0.83Cs_0.17Pb(I_0.83Br_0.17)₃Steady-State PL measurement of thin films, where thin film perovskites are briefly immersed in H₂O₂To a low concentration isopropyl alcohol (IPA) solution.

To compare the different PL decays, the time τ 1/e required for the normalized intensity to reach 1/e was taken as an indicator of the radiation lifetime. An increase in lifetime indicates a decrease in non-radiative recombination and generally indicates an improvement in material quality due to a decrease in defect density. For the application of 0.013M and 0.026M H₂O₂The observed radiative lifetimes for the solution-treated membranes were 140ns and 281ns, respectively, which represents a significant increase compared to the average untreated control value of 40 ± 5 ns. Steady state measurements showed a more than 10 fold increase in relative PL, which isMeasured by integrating the area under each curve. Both findings indicate a substantial reduction in non-radiative pathways, consistent with passivation of surface defects. Interestingly, the initial fast component of decay observed in the first 50ns is at high concentrations of H₂O₂Almost completely eliminated under treatment. Low excitation flux (carrier density 10) as used herein¹⁵cm^-3) This initial decay is likely to be associated with rapid trapping that is detrimental to device performance. To rule out the possibility that the improvement was due to the presence of water in the peroxide solution, a control measurement was performed using an equivalent water concentration in IPA and no improvement in PL was observed.

Next, PL quantum efficiency was measured as a function of irradiance for the perovskite film, which was processed through the gas deposition method at different times between 0s and 180s, with the results shown in fig. 3. The treated film was at 1W/cm within 180s, compared to 4.4% of the untreated control film²The lower maximum PLQE was 22.1%. PLQE was found to have a strong dependence on excitation power for all samples, consistent with the trap filling mechanism. However, the processed film will reach its maximum efficiency faster, and eventually the steady state efficiency increases significantly, consistent with the increased radiation efficiency due to passivation.

Interestingly, for the membrane treated with higher concentrations of hydrogen peroxide, a slight color change was observed at the membrane surface. The UV-Vis absorption spectrum shows that the initial absorption remains constant after treatment, indicating that no chemical change has occurred. While the color change is due to optical interference caused by the presence of a new layer with a different refractive index formed on top of the perovskite surface. This is consistent with the proposed mechanism of lead oxide species formation when coating surfaces. Furthermore, the X-ray diffraction spectrum shown in fig. 4 confirms that no change has occurred in the host perovskite crystal structure, and that the treatment is only a surface effect.

To use H₂O₂Benchmark tests of PLQE improvement with other passivation treatments were performed, comparing measurements of currently most advanced passivation treatments phenethyl ammonium iodide (PEAI) and Butyl Ammonium Iodide (BAI). FIG. 5 shows the use of different passivating agents at 1 solar irradiancePLQE of treated film. For with H₂O₂The PLQE measured under 1 sun exposure for 60s of treated film was 6.4%, compared to 1.4% for untreated film, 1.7% for BAI and 2.3% for PEAI. In reducing the concentration of defects causing non-radiative recombination, H₂O₂The treatment is more effective than some of the currently best performing passivates.

Also for pure inorganic perovskites CsPb (Br)_0.9I_0.1)₃The potential use of oxidative passivation was investigated. According to the proposed mechanism, H is generated in situ₂O₂A proton source (e.g., MA cation or FA cation) is required. Exposing the perovskite to hydrogen peroxide should avoid this dependence on the presence of a proton source. When CsPb (Br)_0.9I_0.1)₃This was confirmed by the observation that five times the steady state PL measurement was increased compared to the control by the gas deposition method for five minutes (fig. 6).

In order to gain insight into the chemistry of the perovskite surface before and after the oxidation treatment, X-ray photoelectron emission spectroscopy (XPS) measurements were performed. No significant changes in Br, I and Cs environments were observed in both the original and treated films.

The Pb 4f scan shows that the respective Pb is attributed to²⁺And Pb⁰The peaks observed at 138.7eV and 137 eV. These peaks were observed for all samples except those treated for 10 minutes, in which case only one peak at 138.7eV was observed. Corresponding to Pb in the film treated for the longest time⁰The disappearance of the peak of (a) is accompanied by a significant broadening of the peak. This indicates the Pb that was previously observed in the film⁰Is oxidized into Pb²⁺The observed peak broadening is a typical feature of metal oxide species. The O1s scan of all samples showed the presence of three oxygen species within the surface of all films. These species were observed at-533 eV, 531eV and 530eV, with slightly different exact peak positions between samples, and were attributed to organic C ═ O (533eV), peroxide O (533eV), and₂ ^2-hydroxide OH^-(531eV) and oxide O^2-(530 eV). The binding energies of the peroxide and hydroxide O1s peak positions were very similar, and it is likely that the two would beSpecies contribute to the 531eV peak, consistent with the proposed mechanism. Although all three oxygen species were observed in the original film, the relative proportions of the different species differed between the original and treated films. It is important to note that there is a signal corresponding to PbO in the O1s scan of the original film, which is due to the sample being prepared and stored in air. However, a significant increase in the signal for PbO was observed in the treated samples. This finding is due to Pb in the Pb 4f scan⁰The combined disappearance of the peaks indicates that hydrogen peroxide is the reactant responsible for the formation of lead oxide on the perovskite surface, an observation that is in good agreement with the proposed mechanism.

From these findings, it can be concluded that hydrogen peroxide "oxidatively passivates" the surface of the perovskite with atomic lead for charge trapping, forming covalent lead-oxygen bonds. Encouraging this behavior is reactively matched to the photo-brightening mechanism set forth in the above formula.

Use of ozone treatment and oxygen plasma treatment

The effect of oxygen plasma and ozone on perovskites was also investigated.

For oxygen plasma treatment, FA was prepared_0.83Cs_0.17Pb(I_0.83Br_0.17)₃The membrane is then treated in a low pressure oxygen plasma system for a short period of time. It was found that exposure to oxygen plasma increased the radiative lifetime of the film compared to the control. In particular, FA compared to control_0.83Cs_0.17Pb(I_0.83Br_0.17)₃Time-resolved photoluminescence measurements of the films after exposure to oxygen plasma 2s and 5s treatment resulted in observed radiative lifetimes of: tau is_1/e(control) ═ 40ns,. tau_1/e(“2s”)＝118ns，τ_1/e("5 s") -226 ns. The steady state PL measurements are shown in fig. 7. A large increase in PL lifetime and strength was observed accordingly.

MAPbI will also be₃The perovskite film is exposed to an oxygen atmosphere containing-30% ozone. The steady state PL measurements are shown in fig. 8. A large increase in PL intensity was observed.

H of photovoltaic device₂O₂Treatment of

By direct use of H₂O₂As an oxidation passivating agent, a scalable and efficient post-treatment is proposed. Practical uses of the vapor phase treatment in photovoltaic devices of both n-i-p and p-i-n configurations are as follows.

Fabricating a planar heterojunction (heterojunction) solar cell on a glass substrate, having the following structure:

·FTO/SnO₂/FA_0.83Cs_0.17Pb(I_0.83Br_0.17)₃perovskite/spiro-OMeTAD/Ag (n-i-p); and

FTO/Poly TPD/FA_0.83Cs_0.17Pb(Br_0.1I_0.9)₃perovskite/PCBM/BCP/Ag (p-i-n).

The current-voltage (J-V) curves for the control device and the device treated with hydrogen peroxide via the gas deposition method are shown in fig. 9. FA_0.83Cs_0.17Pb(I_0.9Br_0.1)₃The Champion n-i-p device of the control film had the following scan parameters: j. the design is a square_sc＝22.9mA/cm²，V_oc1.11V, FF 0.78, PCE 19.8%. Champion devices using urea peroxide treated devices show V_ocThe PCE increased to 20.4% from 60mV to 1.17V. FF slightly changed and Jsc slightly decreased. The Champion inverted p-i-n device shows similar improvement on open circuit voltage, and for the best performance device, the power conversion efficiency is increased by almost one percent to 19.8 percent, usually from 1.06V to 1.09V. The average values of these parameters for several control devices and devices treated with urea peroxide are summarized in table 1. The steady state power output of the inverted p-i-n device is shown at H₂O₂The treatment rate is improved from 18.5% to 19.2%. The same increase was not observed for n-i-p devices with slightly lower photocurrents, probably due to the inhibition of charge extraction by the lead oxide layer in the device construction. Encouraging, the degree of hysteresis appeared to decrease after treatment. Box plots of device performance for the n-i-p device and the p-i-n device are shown in fig. 10 and 11, respectively.

TABLE 1-comparison with the control via gas depositionProduct method of n-i-p and inverted p-i-n FA treated with hydrogen peroxide_0.83Cs_0.17Pb(Br_0.1I_0.9)₃Device performance parameters of the device.

	Jsc(mA/cm2)	PCE(％)	Voc(V)	FF
					Control n-i-p	22.3±0.4	18.5±0.7	1.10±0.02	0.76±0.02
Treated n-i-p	22.0±0.6	19.4±0.6	1.15±0.02	0.76±0.01
					Control p-i-n	21.9±0.7	16.5±1.2	-1.04±0.01	0.70±0.5
Treated p-i-n	22.1±0.6	17.4±1.1	-1.06±0.01	0.71±0.5

Conclusion

In summary, H₂O₂And other oxygen-based passivating agents have been used as a rapid, non-toxic, scalable and effective post-treatment of perovskite surfaces to simulate the photo-brightening process that occurs over several hours. The same significant improvement in photoluminescence was observed after this treatment and a series of experimental techniques were used on these samples to verify our mechanism and gain a better understanding of the process of brightening. This mechanism highlights the instability of methylammonium cations and the degradation route of perovskites upon exposure to light under ambient conditions. By direct use of H₂O₂As a post-treatment of metal halide perovskites with less acidic a-site cations (e.g., formamidine and cesium), passivation can be applied to stable, efficient perovskite compositions without the need for light soaking. This results in a significant increase in open circuit voltage and power conversion efficiency, demonstrating that oxidative passivation is a valuable technique for seeking high luminescence and excellent charge transport. The technology possibly opens up a new way for perovskite chemical passivation, and the technology is used as a substitute for molecular passivation to promote the development of the perovskite chemical passivation in the aspects of next-generation photovoltaics, LEDs and other photoelectric devices.

Example 2 Effect of annealing on PLQE

To FA_0.83Cs_0.17Pb(I_0.83Br_0.17)₃The layer was exposed to hydrogen peroxide gas generated from UHP for 60 seconds. The passivated perovskites were then maintained at various temperatures ranging from 25 ℃ (unannealed) to 180 ℃ and photoluminescence quantum efficiency (PLQE) values were measured. As shown in fig. 12, the highest PLQE was found to be observed without annealing. The solid line in FIG. 12 is the crystallization without post annealingPLQE of control film.

Example 3 Effect of different Hydrogen peroxide concentrations on UV-Vis absorption

With different H via wet deposition₂O₂Concentration of H₂O₂Handling FA_0.83Cs_0.17Pb(I_0.83Br_0.17)₃And (3) a layer. Fig. 13 shows the UV-Vis absorption spectrum. The onset of absorption remained constant, indicating that the treatment had no effect on the host perovskite material, but only on the surface. The relatively small change in the optical absorption spectrum is due to a change in reflection due to a change in the surface. This is further indicated by the change in the interference pattern visible below the band edge.

Example 4 Performance parameters of n-i-p device

24 pieces of FTO/SnO were produced₂/FA_0.83Cs_0.17Pb(I_0.83Br_0.17)₃An n-i-p device of perovskite/spiro-OMeTAD/Ag structure. The 24 devices were located on four separate substrates. These devices were treated with gaseous hydrogen peroxide. The treated devices were compared to control devices and the performance parameters are shown in table 2 below.

TABLE 2	Jsc(mA/cm2)	PCE(％)	Voc(V)	FF	SPO(％)
						Control n-i-p	21.9±0.4	17.6±0.4	1.09±0.01	0.73±0.03	17.1
Treated n-i-p	21.7±0.6	18.6±1.0	1.13±0.01	0.75±0.03	17.8