阅读说明：本技术 一种阵列异质结的自组装生长方法 (Self-assembly growth method of array heterojunction ) 是由 易庆华 丛姗 刘玉申 于 2020-08-31 设计创作，主要内容包括：本发明公开了一种阵列异质结的自组装生长方法,包括如下步骤：配置PSS溶液；将阵列基底置于PSS溶液中浸泡,形成PSS修饰的阵列基底,显负电性；配置聚乙烯亚胺辅助的金属离子前驱体溶液,形成带正电的离子团；将前驱体溶液滴加到PSS修饰的阵列基底上,正负基团的吸附作用将前驱体溶液吸附在阵列表面；热处理即可形成稳定牢固的异质结阵列。本发明首次公开了一种通过PSS修饰显负电性和PEI辅助形成的离子基团显正电性的金属离子前驱体溶液之间的正负吸引作用,将金属离子前驱体溶液与阵列表面相连热处理后形成稳定的异质结的自组装的生长方法,该方法形成的异质结表面均匀,可控性强,为异质结的生长提供了可选择的通用方法。(The invention discloses a self-assembly growth method of an array heterojunction, which comprises the following steps: preparing a PSS solution; soaking the array substrate in a PSS solution to form a PSS modified array substrate, and displaying electronegativity; preparing a polyethyleneimine-assisted metal ion precursor solution to form a positively charged ion group; dropwise adding the precursor solution onto the array substrate modified by the PSS, and adsorbing the precursor solution on the surface of the array by the adsorption action of the positive and negative groups; and (4) forming a stable and firm heterojunction array by heat treatment. The invention discloses a self-assembly growth method for forming a stable heterojunction after connecting a metal ion precursor solution with an array surface and performing heat treatment through positive and negative attraction between the PSS modified electronegativity and the PEI-assisted ionic group electropositivity-showing metal ion precursor solution.)

1. A method of forming a heterojunction on an array substrate by self-assembly of sodium polystyrene sulfonate and polyethyleneimine metal ion complexes, comprising the steps of:

a. preparing a sodium polystyrene sulfonate solution;

b. soaking the cleaned array substrate in a sodium polystyrene sulfonate solution to enable the sodium polystyrene sulfonate to be adsorbed on the surface of the array, so as to form the sodium polystyrene sulfonate modified array substrate, wherein the array substrate shows electronegativity;

c. utilizing a polymer auxiliary deposition technology to coordinate polyethyleneimine and derivatives thereof with metal ions to form a precursor solution containing the metal ions, wherein metal ion groups have positive electricity;

d. dripping a precursor solution containing metal ions onto a substrate soaked with the sodium polystyrene sulfonate solution, and adsorbing the precursor solution on the surface of the array by the adsorption action of positive and negative ions;

e. the metal ion precursor solution is converted into a metal oxide, a metal carbide, a metal nitride or a metal sulfide by heat treatment, thereby forming a heterojunction with the substrate array material.

2. The method of claim 1, wherein: in the step a, the mass concentration of the sodium polystyrene sulfonate solution is not more than 5%, and the solvent of the solution is ethanol.

3. The method of claim 1, wherein: and c, soaking in the step b at the temperature of 70-90 ℃ for 2 hours, wherein the substrate adopts a titanium dioxide array, a copper oxide array or a zinc oxide array.

4. The method of claim 1, wherein: the metal ions and the polyethyleneimine in the precursor solution in the step c can form a stable precursor solution; the metal ions are metal chloride or metal nitrate, the metal ions which are not complexed are ultrafiltered out through ultrafiltration after the metal ions react with polyethyleneimine, the viscosity of the solution is regulated and controlled according to different substrate arrays in experiments, and metal elements of the metal ions comprise Ni, Fe, Ti, Cu, Nb, Zn, Sb, Sn or Mo.

5. The method of claim 1, wherein: the metal ion precursor solution in the step d is Ni²⁺、Ti⁴⁺、Cu²⁺、Fe²⁺Or Zn²⁺A precursor solution mixed by any one kind of univalent metal ions and any two or more kinds of multivariate metal ions.

6. The method of claim 1, wherein: and e, performing heat treatment in different atmospheres, performing heat treatment in oxygen or air to obtain an oxide, obtaining a sulfide in a sulfur-containing atmosphere, obtaining a selenide in a selenium-containing atmosphere, obtaining a nitride in an ammonia atmosphere, and forming a heterojunction with a core-shell structure with the array.

Technical Field

The invention belongs to the technical field of semiconductor heterojunction, relates to a self-assembly growth method of an array heterojunction film, and particularly relates to a method for growing a heterojunction film on the surface of an array substrate by using a metal ion precursor solution formed by the assistance of sodium polystyrene sulfonate and polyethyleneimine.

Background

Nanoarrays such as TiO₂Compared with a planar film, the ZnO array and the like have the characteristics of unique structure, large specific surface area, higher capture efficiency on light, higher quantum effect and the like, and are widely applied to the fields of solar cells, light-emitting devices, photocatalysis and the like. However, a single material has its own defects, and growing another material on the surface of the array to form an array heterojunction can combine the advantages of the two, thereby making up for the deficiencies, and even exerting the novel characteristics that the original material does not have due to the unique coupling mechanism between the materials.

Recent studies have shown a wide range of applications based on array heterojunctions, and have also demonstrated excellent performance of array heterojunctions compared to single arrays. Xia topic of university in Zhejiang is TiO₂Growing Co on an array₉S₈Formation of TiO₂@Co₉S₈Array heterojunctions, used in oxygen/hydrogen evolution reactions as bifunctional catalysts with excellent performance, see adv. sci.2018, 5, 1700772. The Li topic of Shanghai university of transportation is in TiO₂ZnO is modified on the surface of the array to form a Z-type heterojunction photo-anode, and the photo-anode has high light absorption characteristic and high photoelectrochemical hydrolysis performance, which is shown in Appl. Catal. B-environ.2020,267, 118599. A ZnO/NiO heterojunction grows on the Fang topic group of the university of double denier and is successfully applied to a self-charging transparent ultraviolet detector, see J. Mater. chem. C2019,7 and 223. It can be known that the array heterojunction has important contribution in the fields of photoelectrocatalysis, photoelectric detection and the like, but the growth of the array heterojunction listed above mainly focuses on the growth of the heterojunction by a hydrothermal method, and the method is not strong in controllability. So far, there is no general method disclosed by which a controlled growth array heterojunction can be obtained.

Disclosure of Invention

In order to realize the formation of a uniform film on the surface of an array and the formation of a heterojunction with a core-shell structure by the array, the invention designs a method for forming the heterojunction by growing a semiconductor compound on the surface of an array substrate by a self-assembly method of a metal ion complex of sodium polystyrene sulfonate (PSS) and Polyethyleneimine (PEI), thereby realizing the generation of electron hole pairs after the heterojunction absorbs photons and the rapid separation of the electron hole pairs.

In order to achieve the purpose of the invention, the invention adopts the following technical scheme: a method of forming a heterojunction on an array substrate by self-assembly of sodium polystyrene sulfonate and polyethyleneimine metal ion complexes, comprising the steps of:

a. preparing a sodium polystyrene sulfonate (PSS) solution with a certain concentration;

b. soaking the cleaned array substrate in a sodium polystyrene sulfonate (PSS) solution to enable the sodium polystyrene sulfonate (PSS) to be adsorbed on the surface of the array, so that the array substrate modified by the sodium polystyrene sulfonate (PSS) is formed and shows electronegativity;

c. by utilizing a polymer auxiliary deposition technology, Polyethyleneimine (PEI) and derivatives thereof are coordinated with metal ions to form a precursor solution containing the metal ions, and the metal ion groups have electropositivity;

d. dripping a precursor solution containing metal ions onto a substrate soaked with a sodium polystyrene sulfonate (PSS) solution, and adsorbing the precursor solution on the surface of the array by the adsorption action of positive and negative ions;

e. the metal ion precursor solution is converted into metal oxide, metal carbide, metal nitride, metal sulfide, etc. by heat treatment, thereby forming a heterojunction with the substrate array material.

The invention discloses a self-assembly growth method for forming a stable heterojunction after connecting and heat treating a metal ion precursor solution and an array surface by positive and negative attraction between the PSS modified electronegativity and the PEI-assisted ionic group electropositivity-showing metal ion precursor solution.

Preferably, the mass concentration of the sodium polystyrene sulfonate (PSS) solution in step a is not more than 5%, and the solvent of the solution is ethanol.

Preferably, the soaking in step b is carried out at a temperature of 70-90 ℃ for 2 hours, and the substrate may be a titanium dioxide array, a copper oxide array, a zinc oxide array, or the like.

Preferably, the metal ions in the precursor solution in step c and the Polyethyleneimine (PEI) can form a stable precursor solution, generally, after the metal chlorides, metal nitrates, and the like react with the Polyethyleneimine (PEI), the uncomplexed metal ions are ultrafiltered out by ultrafiltration, and the viscosity of the solution can be controlled according to the difference of the substrate arrays in the experiment, wherein the metal ions including most of the metal elements in the periodic table, such as Ni, Fe, Ti, Cu, Nb, Zn, Sb, Sn, Mo, and the like, can form a uniform and stable precursor solution.

Preferably, the metal ion precursor solution in step d may be Ni²⁺、Ti⁴⁺、Cu²⁺、Fe²⁺、Zn²⁺The monovalent metal ion may also be Zn²⁺And Fe²⁺And a uniform coating state is formed between the precursor solution mixed by two or even multiple metal ions and the substrate modified by the sodium polystyrene sulfonate (PSS).

Preferably, in step e, heat treatment can be performed in different atmospheres, such as heat treatment in oxygen or air to obtain an oxide, in a sulfur-containing atmosphere to obtain a sulfide, in a selenium-containing atmosphere to obtain a selenide, and in an ammonia atmosphere to obtain a nitride and other compounds, so that the heterojunction with the core-shell structure is formed with the array.

The structural and performance characterization of the grown heterojunction is carried out, and the fact that the coating layer can be uniformly formed on the surface of the array through the method is obtained, so that the heterojunction is formed. The original array surface can be clearly seen to be smooth and in a cubic column structure under a scanning electron microscope, after the heterojunction is grown by the method, the surface is rough, obvious particles are uniformly distributed on the surface, and the electron holes can be smoothly led out compared with the array substrate without the heterojunction through the characterization of the performance.

The invention realizes the formation of heterojunction between the array and the film uniformly grown on the surface of the array substrate by a controllable method for the first time. The PSS-assisted method can uniformly and controllably form a uniform thin film on the surface of an irregular substrate, and compared with other methods, the PSS-assisted method has obvious characteristics and outstanding advantages that:

1. the key point of forming heterojunction with the substrate in the method is whether metal ions can form stable precursor solution with PEI and derivatives thereof, experimental experiments show that most of the metal ions in the periodic table can form mild precursors with the PEI and the derivatives thereof, and each precursor can form oxides, carbides, nitrides, sulfides, selenides and the like after heat treatment, so that the method has universality for forming heterojunction on the surface of the array substrate.

2. The thickness of the film of the heterojunction has important influence on the derivation of electrons and holes, the thickness of the heterojunction layer on the surface of the array can be different by regulating the viscosity, the ion concentration and the like of the precursor solution of metal ions, and the coating layers with different thicknesses can be grown according to actual requirements to obtain the array heterojunction with optimal performance.

Drawings

FIG. 1 is a schematic illustration of the growth of the heterojunction of the array of example 1;

FIG. 2 is a scanning electron microscope image of an embodiment, wherein (a) is a scanning electron microscope image of an array substrate and (b) is a scanning electron microscope image of a heterojunction formed;

FIG. 3 is a transmission electron microscope photograph of an embodiment, wherein (a) is a transmission electron microscope photograph of an array substrate and (b) is a transmission electron microscope photograph of a heterojunction formed;

FIG. 4 is SEM of array heterojunction of example, (a) is SEM of array heterojunction grown with PSS treatment, and (b) is SEM of array heterojunction grown without PSS treatment.

Detailed Description