阅读说明：本技术 一种以四苯基联苯二胺衍生物为空穴传输材料的钙钛矿电池 (Perovskite battery with tetraphenylbiphenyldiamine derivative as hole transport material ) 是由 原秀玲 于 2019-04-04 设计创作，主要内容包括：本发明涉及一种以四苯基联苯二胺衍生物为空穴传输材料的钙钛矿太阳能电池,该电池采用p-i-n结构,包括ITO玻璃、空穴输运层、钙钛矿结构吸收层、电子输运层、背电极,所述空穴传输层所采用的空穴传输材料为四苯基联苯胺衍生物,其外围四个苯环已经被甲氧基和膦酸根官能团化,可与ITO形成牢固的化学键,且有效钝化与钙钛矿接触的界面缺陷；同时采用精确控制含水量和特定气氛退火的条件下制备了高质量的钙钛矿薄膜,得到了性能优异的钙钛矿太阳能电池器件。(The invention relates to a perovskite solar cell taking tetraphenyl biphenyl diamine derivatives as hole transport materials, which adopts a p-i-n structure and comprises ITO glass, a hole transport layer, a perovskite structure absorption layer, an electron transport layer and a back electrode, wherein the hole transport material adopted by the hole transport layer is tetraphenyl biphenyl diamine derivatives, four benzene rings on the periphery of the tetraphenyl biphenyl diamine derivatives are functionalized by methoxy and phosphonate groups, a firm chemical bond can be formed with ITO, and interface defects in contact with perovskite are effectively passivated; meanwhile, the high-quality perovskite thin film is prepared under the conditions of accurately controlling the water content and annealing in a specific atmosphere, and the perovskite solar cell device with excellent performance is obtained.)

1. A perovskite solar cell taking tetraphenylbiphenyldiamine derivatives as hole transport materials adopts a p-i-n structure, comprises ITO glass, a hole transport layer, a perovskite structure absorption layer, an electron transport layer and a back electrode, and is characterized in that: the hole transport material adopted by the hole transport layer is tetraphenyl biphenyl diamine derivative, four benzene rings on the periphery of the tetraphenyl biphenyl diamine derivative are functionalized by methoxy and phosphonate, and the molecular structural formula of the tetraphenyl biphenyl diamine derivative is as follows:

the absorption layer of the perovskite structure is CH₃NH₃PbI₃The electron transport layer is doped fullerene derivative PCBM, and the preparation steps of the battery are as follows:

firstly, cleaning ITO glass: using ITO glass as a substrate, respectively ultrasonically cleaning the ITO glass for 3-5min by sequentially adopting deionized water, acetone and isopropanol, blow-drying the ITO glass by using nitrogen, and then cleaning the ITO glass for 5-10min by using ozone plasma for later use;

step two, growing a hole transport layer: immersing the sample obtained in the first step into 0.001mol/L tetrahydrofuran/ethanol (volume ratio is 1: 1) solution mixed by tetraphenylbenzidine derivatives and n-butyl phosphonic acid, standing for 20h, taking out, annealing at 140 ℃ for 1h, and then washing with deionized water;

step three, preparation of a perovskite absorption layer: preheating the sample obtained in the second step to 100 ℃, and dripping 1mol/L PbI at 85 ℃ by spin coating at 2000rpm₂The solution of dimethyl formamide/water precursor is kept stand for 1min for 30 s; then 0.5mol/L CH with the temperature of 80 ℃ is added in a drop-wise manner at the rotating speed of 2000rpm₃NH₃I/isopropanol/water precursor solution for 20s, and standing for 1 min; then keeping the substrate temperature at 60 ℃ and annealing for 10min in the dimethyl formamide atmosphere, and then heating the substrate temperature to 100 ℃ and annealing for 10min in the atmosphere to obtain a perovskite absorption layer;

step four, preparing an electron transport layer: spin-coating the sample obtained in the third step at the rotating speed of 1000rpm, dropwise adding PCBM chlorobenzene solution with the mass fraction of 2% for 30s, and then standing for 12h in chlorobenzene atmosphere;

step five, back electrode deposition: and depositing a copper film back electrode on the perovskite absorption layer by adopting an electron beam evaporation method to obtain the perovskite solar cell.

2. The perovskite solar cell with the tetraphenylbiphenyldiamine derivative as the hole transport material according to claim 1, wherein: the mass ratio of tetraphenylbenzidine derivatives to n-butylphosphonic acid in the second step was 1: 10.

3. The perovskite solar cell with the tetraphenylbiphenyldiamine derivative as the hole transport material according to claim 1, wherein: PbI in the third step₂In the/dimethylformamide/aqueous precursor solution, the mass fraction of water relative to dimethylformamide was 2%.

4. The perovskite solar cell with the tetraphenylbiphenyldiamine derivative as the hole transport material according to claim 1, wherein: CH in the third step₃NH₃In the I/isopropanol/water precursor solution, the volume fraction of water relative to isopropanol was 0.5%.

Technical Field

The invention relates to a perovskite solar cell taking tetraphenyl biphenyl diamine derivatives as hole transport materials, belonging to the technical field of solar photovoltaic manufacturing.

Background

Since 2009 organic and inorganic hybrid halide perovskite materials are used for solar photovoltaic cells, the conversion efficiency is rapidly improved, and the small-area efficiency of a laboratory at present exceeds 23%, so that the organic and inorganic hybrid halide perovskite materials show great development potential different from conventional crystalline silicon and thin film cells. According to the sequence of light receiving, a conventional perovskite cell is generally of an n-i-p structure and sequentially comprises a TCO conductive substrate, an electron transmission layer, a perovskite absorption layer, a hole transmission layer and a back electrode, and an n-i-p structure device has some problems, for example, the electron transmission layer is generally made of compact TiO2, and the preparation process needs high-temperature heating and is not beneficial to preparing a flexible device; the voltage and current of the device have hysteresis phenomenon; hole transport layer materials are expensive and unstable, and the back electrode requires noble metals such as Au or Ag. Therefore, scientists have developed a p-i-n perovskite battery device, which sequentially comprises a TCO conductive substrate, a hole transport layer, a perovskite absorption layer, an electron transport layer, and a back electrode, wherein the hole transport layer is made of a hole transport material, usually PEDOT: PSS or PTAA, whereas PEDOT: PSS has a certain hygroscopicity and acidity, which is disadvantageous to the stability of devices, PTAA is expensive, has absorption at visible short wavelengths, and is greatly affected by the subsequent processes. In order to improve the performance of the p-i-n perovskite cell, on one hand, a proper hole transport material needs to be selected, and not only needs to be completely covered and firmly combined with a TCO substrate, but also the open-circuit voltage of the device is reduced; the thickness cannot be too thick, otherwise, the self absorption greatly influences the transmittance; the energy level of the material is matched with that of perovskite and TCO, and the material has high-efficiency hole extraction and transmission capability and the like; on the other hand, the perovskite absorption layer thin film has high preparation quality, needs large crystal grains and low defects, and thus improves the photoelectric conversion efficiency.

Disclosure of Invention

The invention aims to select a proper hole transport material and manufacture a high-performance and high-quality perovskite solar cell through a well-designed preparation step.

The technical scheme of the scheme is as follows: a perovskite solar cell taking tetraphenylbiphenyldiamine derivatives as hole transport materials adopts a p-i-n structure, comprises ITO glass, a hole transport layer, a perovskite structure absorption layer, an electron transport layer and a back electrode, the hole transport materials adopted by the hole transport layer are tetraphenylbenzidine derivatives, four benzene rings on the periphery of the tetraphenylbenzidine derivatives are functionalized by methoxy and phosphonate, and the molecular structural formula of the perovskite solar cell is as follows:

the absorption layer of the perovskite structure is CH₃NH₃PbI₃The electron transport layer is doped fullerene derivative PCBM, and the preparation steps of the battery are as follows:

firstly, cleaning ITO glass: using ITO glass as a substrate, respectively ultrasonically cleaning the ITO glass for 3-5min by sequentially adopting deionized water, acetone and isopropanol, blow-drying the ITO glass by using nitrogen, and then cleaning the ITO glass for 5-10min by using ozone plasma for later use;

step two, growing a hole transport layer: immersing the sample obtained in the first step into 0.001mol/L tetrahydrofuran/ethanol (volume ratio is 1: 1) solution mixed by tetraphenylbenzidine derivatives and n-butyl phosphonic acid, standing for 20h, taking out, annealing at 140 ℃ for 1h, and then washing with deionized water;

step three, preparation of a perovskite absorption layer: preheating the sample obtained in the second step to 100 ℃, and dripping 1mol/L PbI at 85 ℃ by spin coating at 2000rpm₂The solution of dimethyl formamide/water precursor is kept stand for 1min for 30 s; then 0.5mol/L CH with the temperature of 80 ℃ is added in a drop-wise manner at the rotating speed of 2000rpm₃NH₃I/isopropanol/water precursor solution for 20s, and standing for 1 min; then keeping the substrate temperature at 60 ℃ and annealing for 10min in a DMF atmosphere, and then heating the substrate temperature to 100 ℃ and annealing for 10min in an atmospheric atmosphere to obtain a perovskite absorption layer;

step four, preparing an electron transport layer: spin-coating the sample obtained in the third step at the rotating speed of 1000rpm, dropwise adding PCBM chlorobenzene solution with the mass fraction of 2% for 30s, and then standing for 12h in chlorobenzene atmosphere;

step five, back electrode deposition: and depositing a copper film back electrode on the perovskite absorption layer by adopting an electron beam evaporation method to obtain the perovskite solar cell.

Further, the mass ratio of the tetraphenylbenzidine derivative and the n-butylphosphonic acid in the second step is 1: 10.

Further, PbI in the third step₂In the/dimethylformamide/aqueous precursor solution, the mass fraction of water relative to dimethylformamide was 2%.

Further, CH in the third step₃NH₃In the I/isopropanol/water precursor solution, the volume fraction of water relative to isopropanol was 0.5%.

The invention has the beneficial effects that: the hole transport layer is prepared on the surface of the ITO by adopting the tetraphenylbenzidine derivative functionalized by phosphonate and methoxyl groups, the preparation growth condition is mild, on one hand, the phosphonate functional group and an oxygen atom on the surface of the ITO can form a firm P-O chemical bond, and a large conjugated system of the tetraphenylbenzidine derivative can effectively extract and transport a hole, so that the hole transport material can completely and uniformly cover the ITO with the minimum use amount and thickness, the material use amount is saved, the absorption of incident light by the hole transport material is reduced to the minimum, and the hole transport material and the ITO are combined very firmly in a P-O covalent bond mode and are hardly influenced by a solvent used in the subsequent preparation of a perovskite absorption layer; on the other hand, the existence of the methoxy functional group not only provides electrons and a conjugated system consisting of large pi bonds of benzene rings of the methoxy functional group, but also directly contacts with the perovskite as Lewis base, thereby increasing the capacity of extracting holes from the perovskite, effectively passivating the defect center between the perovskite layer and the hole transport layer interface and reducing the hole recombination chance. As a hole transport material, compared with perovskite, the shallow HOMO and LUMO energy levels of the perovskite are beneficial to hole transport, so that electron transport is inhibited, and the performance of a battery device is improved.

The perovskite absorption layer is prepared by a two-step method, firstly PbI is adopted₂And controlling the water content to prepare PbI₂Film and then CH is used₃NH₃Growth of CH in isopropanol solution with controlled water content₃NH₃PbI₃Perovskite thin films, small amounts of water favoring CH due to precise control of water content₃NH₃I direction PbI₂Penetration of the film, thereby favoring CH₃NH₃PbI₃The growth of perovskite crystal grains enables the diameter of polycrystalline grains in the perovskite film to reach the micron order; meanwhile, through annealing in the dimethyl formamide atmosphere, gaps among polycrystalline particles become small, the surface of the perovskite thin film becomes smoother, and therefore the improvement of the photoelectric performance of a battery device is greatly promoted.

Drawings

FIG. 1 is a schematic view of chemical bonding of a hole transport layer to an ITO surface.

FIG. 2 SEM of perovskite thin films prepared without aqueous solution.

FIG. 3 SEM of perovskite thin films prepared from solutions of specific moisture content.

FIG. 4 SEM of annealed perovskite thin film under specific atmosphere.

Average IV curve test plots for the devices of fig. 5.

Fig. 6 external quantum efficiency spectrum of the device.

Detailed Description

The technical solution of the present invention is specifically described below with reference to the accompanying drawings and examples.