WO2019196025A1

WO2019196025A1 - Azo transparent conductive thin film, and preparation method therefor and application thereof

Info

Publication number: WO2019196025A1
Application number: PCT/CN2018/082599
Authority: WO
Inventors: 刘荣跃; 丁庆; 冯军正; 杨旻蔚; 张翠; 许奔; 孙竹
Original assignee: 深圳市太赫兹科技创新研究院; 深圳市太赫兹科技创新研究院有限公司
Priority date: 2018-04-11
Filing date: 2018-04-11
Publication date: 2019-10-17

Abstract

A preparation method for an AZO transparent conductive thin film, comprising the following steps: providing a substrate and performing cleaning treatment on the surface of the substrate; providing a zinc oxide seed solution, and depositing the zinc oxide seed solution on the substrate to prepare a zinc oxide seed layer combined on the surface of the substrate; providing a zinc oxide deposition solution, placing the substrate deposited with the zinc oxide seed layer in the zinc oxide deposition solution, and enabling the substrate to be completely immersed in the zinc oxide deposition solution, wherein the surface of the substrate deposited with the zinc oxide seed layer is not adhered to wall; under a heating condition, introducing aluminum ions to the zinc oxide deposition solution continuously and stirring to grow and prepare an AZO pre-fabricated thin film on the surface of the zinc oxide seed layer; and performing ultraviolet radiation treatment on the AZO pre-fabricated thin film to prepare the AZO transparent conductive thin film.

Description

AZO transparent conductive film and preparation method and application thereof

Technical field

The invention belongs to the field of new energy, and particularly relates to an AZO transparent conductive film and a preparation method and application thereof.

Background technique

Photovoltaic solar cells have the advantages of clean energy, renewable energy and inexhaustible energy. In addition, their industrialized manufacturing is becoming more and more mature and the cost is getting lower and lower, which makes it gradually become an effective way to solve the energy crisis and environmental crisis. At present, research on solar cells is mainly focused on improving the conversion efficiency of batteries and saving manufacturing costs, as well as improving the effective use time of batteries. There are two main ways to improve the efficiency of photovoltaic solar cells: one is to make full use of the solar spectrum energy of each band; the other is to improve the collection efficiency of photogenerated carriers. Among them, the transparent conductive film is one of the key materials in the solar cell. By increasing the transmittance of the transparent conductive film, more sunlight can be reached to the absorption layer of the battery, thereby generating more photo-generated carriers; by reducing the resistivity of the transparent conductive film, more photo-generated carriers can be made. By passing through the film, the energy conversion efficiency is effectively improved; by optimizing the structure of the transparent conductive film, the chemical and mechanical stability of the solar cell can be improved. Therefore, the development of transparent conductive film materials must be oriented in a direction of lower cost, higher transmittance, lower resistivity, and better chemical stability.

At present, the commercial transparent conductive film is mainly made of indium-doped tin oxide (ITO), but due to its high production cost, limited raw materials and toxic reasons, it is urgent to develop a new transparent conductive film substitute material. Aluminum-doped zinc oxide (AZO) film raw materials are widely used, non-toxic, and good photoelectric properties, and have gradually become an ideal substitute for ITO transparent conductive film materials. At present, AZO transparent conductive films with excellent photoelectric properties can be prepared by vacuum method and solution method, and have been widely applied. However, the area of the AZO film prepared by the vacuum method is limited by the size of the vacuum chamber, and the complicated vacuum equipment greatly increases the film production cost. The AZO film prepared by the solution method needs to be annealed at a high temperature of 600 ° C or higher for a long time, and then post-annealed under a hydrogen atmosphere of 550 ° C to obtain a resistivity of 1.7 × 10 ^-3 to 7.2 × 10 ^-3 Ω. · AZO film between cm. For thin-film solar cells, such as copper indium gallium selenide (CIGS) or copper-zinc-tin-sulfur (CZTS) thin-film solar cells, AZO transparent conductive films are deposited on top of the cell, and excessive annealing temperatures cause excessive cadmium or zinc. Diffusion into the absorption layer of the battery (excessive element diffusion at the pn junction interface, thereby destroying the pn junction), causing various defects in the battery absorption layer, increasing carrier recombination opportunities, deteriorating battery performance, thereby reducing battery photoelectric conversion efficiency. Therefore, reducing the annealing temperature of the window layer, developing a non-vacuum, low temperature, low cost, and mass production of a transparent conductive film has become a current development trend.

technical problem

The object of the present invention is to provide an AZO transparent conductive film and a preparation method thereof, aiming at solving the high cost of the preparation method of the existing AZO film, and the diffusion of metal atoms in the deposited film due to the high annealing temperature, which affects the device. It is a problem of thin film solar cell performance (especially photoelectric conversion efficiency).

Another object of the present invention is to provide a thin film solar cell comprising an AZO transparent conductive film.

Technical solution

In order to achieve the above object, the technical solution adopted by the present invention is as follows:

An aspect of the invention provides a method for preparing an AZO transparent conductive film, comprising the following steps:

Providing a substrate, and performing surface cleaning treatment on the substrate;

Providing a zinc oxide seed solution, depositing the zinc oxide seed solution on the substrate to prepare a zinc oxide seed layer bonded to the surface of the substrate;

Providing a zinc oxide deposition solution, placing a substrate on which the zinc oxide seed layer is deposited in the zinc oxide deposition solution, immersing the zinc oxide deposition solution in the substrate, and depositing zinc oxide seeds in the substrate The surface of the layer is not adhered to the wall, and under the heating condition, aluminum ions are continuously introduced into the zinc oxide deposition solution and stirred to form an AZO pre-formed film on the surface of the zinc oxide seed layer;

The AZO pre-formed film is subjected to ultraviolet irradiation treatment to prepare an AZO transparent conductive film.

Another aspect of the present invention provides an AZO transparent conductive film comprising a zinc oxide seed layer, and an array of AZO thin films bonded to the surface of the zinc oxide seed layer.

According to still another aspect of the present invention, a thin film solar cell comprising the above AZO transparent conductive film or an AZO transparent conductive film prepared by the above method is provided.

Beneficial effect

The method for preparing an AZO transparent conductive film provided by the invention adopts an aqueous solution method, first preparing a zinc oxide seed layer on a substrate, then depositing aluminum-doped zinc oxide on the zinc oxide seed layer, and finally performing ultraviolet irradiation treatment. An AZO transparent conductive film was prepared.

Firstly, the method uses an aqueous solution method to deposit a film, and does not require high-temperature annealing treatment. Therefore, the diffusion of metal atoms in the deposited functional layer during high-temperature annealing can be avoided, and the influence on other functional layers can be avoided. In particular, when the AZO transparent conductive film is used in a thin film solar cell, cadmium or zinc in the functional layer can be prevented from diffusing into the absorption layer of the thin film solar cell during high temperature annealing, thereby improving the photoelectric conversion efficiency of the battery. The AZO transparent conductive film is used as a conductive window layer of a copper zinc tin sulfide (CZTS) thin film solar cell, and the photoelectric conversion efficiency of the battery can reach 5.47%.

Next, the AZO transparent conductive film provided by the present invention can remove excess carbon impurities in the film by ultraviolet irradiation treatment of the AZO pre-formed film, improve carrier concentration and conductivity of the film, and obtain AZO transparent excellent in electrical conductivity. Conductive film.

Further, in the present invention, the conditions for preparing the AZO transparent conductive film are mild, and it is not necessary to use complicated and expensive equipment, which is advantageous for reducing the production cost of the AZO transparent conductive film.

The AZO transparent conductive film provided by the invention has excellent electrical conductivity and low manufacturing cost, and is an ideal substitute for the ITO transparent conductive film, and can be widely used in CIGS and CZTS thin film solar cells, and has better photoelectric conversion efficiency of the battery.

The thin film solar cell provided by the present invention can not only reduce the cost but also improve the photoelectric conversion efficiency of the battery because the AZO transparent conductive film is contained.

First, an aqueous solution of zinc oxide seed layer is prepared, a zinc oxide seed layer is uniformly deposited on the surface of the glass, and then an aqueous solution of aluminum-doped zinc oxide is prepared, and a dense and uniform columnar aluminum-doped zinc oxide nano-array is deposited on the surface of the seed layer, followed by UV. When the lamp is irradiated, an aluminum-doped zinc oxide transparent conductive film excellent in photoelectric properties can be obtained.

DRAWINGS

1 is a flow chart of a process for preparing an AZO transparent conductive film according to an embodiment of the present invention;

2 is a plan view showing an AZO transparent conductive film provided in Embodiment 1 of the present invention;

Figure 3 is a cross-sectional view showing an AZO transparent conductive film provided in Example 1 of the present invention;

4 is a view showing the effect of detecting light transmittance of the AZO transparent conductive film provided in Example 1 of the present invention;

5 is a schematic structural view of a CZTA thin film solar cell according to Embodiment 2 of the present invention;

6 is a cross-sectional view showing the structure of a CZTA thin film solar cell according to Embodiment 2 of the present invention;

7 is a graph showing current and voltage curves of a CZTA thin film solar cell structure according to Embodiment 2 of the present invention.

Embodiments of the invention

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear, the present invention will be further described in detail below with reference to the embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the description of the present invention, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include one or more of the features either explicitly or implicitly. In the description of the present invention, the meaning of "a plurality" is two or more unless specifically and specifically defined otherwise.

With reference to FIG. 1, an embodiment of the present invention provides a method for preparing an AZO transparent conductive film, which includes the following steps:

S01. Providing a substrate, and performing surface cleaning treatment on the substrate;

S02. Providing a zinc oxide seed solution, depositing the zinc oxide seed solution on the substrate to prepare a zinc oxide seed layer bonded to the surface of the substrate;

S03. Providing a zinc oxide deposition solution, placing a substrate on which the zinc oxide seed layer is deposited in the zinc oxide deposition solution, immersing the zinc oxide deposition solution in the substrate, and depositing oxidation in the substrate The surface of the zinc seed layer is not adhered to the wall, and under the heating condition, aluminum ions are continuously introduced into the zinc oxide deposition solution and stirred to form an AZO pre-formed film on the surface of the zinc oxide seed layer;

S04. The AZO pre-formed film is subjected to ultraviolet irradiation treatment to prepare an AZO transparent conductive film.

The method for preparing an AZO transparent conductive film provided by the embodiment of the invention adopts an aqueous solution method, first preparing a zinc oxide seed layer on a substrate, then depositing aluminum-doped zinc oxide on the zinc oxide seed layer, and finally passing ultraviolet irradiation. The AZO transparent conductive film was prepared by treatment.

The AZO transparent conductive film provided by the embodiment of the present invention can remove excess carbon impurities in the film by ultraviolet irradiation treatment on the AZO pre-formed film, improve carrier concentration and conductivity of the film, and obtain excellent electrical conductivity. AZO transparent conductive film.

Further, in the embodiment of the present invention, the conditions for preparing the AZO transparent conductive film are mild, and it is not necessary to use complicated and expensive equipment, which is advantageous for reducing the production cost of the AZO transparent conductive film.

Specifically, in the above step S01, the substrate used as the AZO transparent conductive film is not strictly limited, and a substrate commonly used in the art, such as ultra-white glass, may be selected. In order to improve the adhesion of the material on the substrate, the substrate needs to be surface cleaned prior to deposition of the zinc oxide seed solution.

As a preferred embodiment, the method of surface cleaning treatment is as follows:

After preliminarily cleaning the surface surface stain with the decontamination powder, clean it with a glass cleaner (preferably an aqueous alkaline detergent solution having a volume concentration of 5%, an alkaline detergent and deionized water at a volume ratio of 5:95). Remove the oil that is difficult to remove on the glass surface.

Next, the substrate was rinsed in clean deionized water, placed in acetone, and the organic impurities on the surface of the glass were removed, followed by ultrasonic cleaning in isopropanol for 10 min.

Then, the substrate is washed in a low-concentration glass cleaning agent to remove particulate impurities on the surface of the substrate, washed again with deionized water, and finally ultrasonically cleaned in anhydrous ethanol. Min after use.

The surface of the substrate after the surface cleaning treatment by the above method is as clean as new, which is advantageous for deposition of an aqueous zinc oxide solution.

In the embodiment of the present invention, a large substrate can be cut and cut according to the specifications of the formed AZO transparent conductive film to obtain a desired substrate size, such as 25 mm × 25 mm. It should be understood that the large substrate may be first cut and then subjected to surface cleaning; or the large substrate may be surface-cleaned before cutting and cutting. Preferably, in order to avoid the introduction of impurities or dirt during the cutting and cutting process, it is preferred to cut the cutting after the surface cleaning treatment.

In the above step S02, since the bonding strength of the aluminum-doped zinc oxide to the surface of the substrate, particularly the glass substrate, is not strong, the bonding is not strong, and it is even difficult to nucleate the surface of the substrate, and therefore, the aluminum-doped zinc oxide is deposited. Previously, a layer of zinc oxide seed was deposited on the substrate for subsequent formation and growth of zinc oxide nanoarrays. Specifically, a zinc oxide seed solution is used to nucleate the surface of the substrate to form a transition layer, that is, a zinc oxide seed layer. Further, aluminum-doped zinc oxide is deposited on the substrate by using the zinc oxide seed layer as a medium.

In the embodiment of the invention, the zinc oxide seed solution is an aqueous solution of zinc oxide added with excess ammonia water, and the addition of excess ammonia water is beneficial to increase the solubility of zinc oxide. As a specific embodiment, the zinc oxide seed solution is prepared by dispersing zinc oxide powder in deionized water, and then adding ammonia water to stir well to promote dissolution of the oxidative powder. Further, the dissolved solution is subjected to a filtration treatment to remove excess zinc oxide impurities, and the clear solution remains. Specifically, the filtration treatment was carried out by using a filter having a diameter of 0.45 μm.

Specifically, the zinc oxide seed solution is deposited on the substrate, and as the ammonia water in the zinc oxide seed solution is volatilized, the dissolution property of the zinc oxide is lowered, and further adhered to the surface of the substrate to form a film layer. Preferably, the concentration of zinc oxide in the zinc oxide seed solution is 20-50 mmol/L to form a dense and uniform zinc oxide seed layer. If the concentration of zinc oxide in the zinc oxide seed solution is too low, the formed film layer is not dense. If the concentration of zinc oxide in the zinc oxide seed solution is too high, the zinc oxide particles deposited on the substrate are not uniform, and the obtained surface film layer is not uniform in thickness, which affects the thickness of the subsequent deposition of the zinc oxide film. Uniformity further affects the stability of film properties. In addition, if the concentration of zinc oxide in the zinc oxide seed solution is too high, the thickness of the obtained zinc oxide seed layer is too thick, which affects the performance of the AZO transparent conductive film. Further preferably, the concentration of zinc oxide in the zinc oxide seed solution is 30-40 mmol/L.

A method of depositing the zinc oxide seed solution on the substrate to prepare a zinc oxide seed layer bonded to the surface of the substrate, preferably using a spin coating method. As a specific embodiment, the method for preparing a zinc oxide seed layer by spin coating is as follows:

The cleaned substrate was taken out, blown under a nitrogen stream, and placed on the sample stage of the homogenizer. Set the pre-rotation number and pre-rotation time, rotation rotation number and rotation time of the homogenizer, absorb the zinc oxide ammonia aqueous solution and drip it onto the first surface to ensure that the zinc oxide seed layer solution completely covers the sample surface. , then turn on the vacuum pump and the vacuum control vacuum control switch, press the start button to spin. The spin-coated substrate is placed on a thermostatic table, and heated at a constant temperature for a certain period of time to be cooled in the air to form a zinc oxide seed layer.

In the above step S03, the embodiment of the present invention prepares an AZO transparent conductive film by a solution method. Specifically, a zinc oxide deposition solution for deposition is first provided. The zinc oxide deposition solution contains zinc oxide, ammonia water and deionized water, wherein the ammonia water is used to increase the solubility of the zinc oxide, and at the same time, in the preparation of the AZO pre-formed film, zinc oxide is realized by volatilization of ammonia water. Deposition. Preferably, the ammonia water is added in an amount such that the pH of the zinc oxide deposition solution is 9-12. In this pH range, the solubility of zinc oxide in deionized water can be improved, the deposition rate of zinc oxide can be controlled, and the density of the obtained film layer can be improved. At the same time, the present invention reduces the solubility of zinc oxide by the evaporation of ammonia water, and further the growth of zinc oxide after aluminum doping on the surface of the zinc oxide seed layer.

Further preferably, the zinc oxide deposition solution further contains ammonium citrate and ammonium nitrate. The ammonium citrate and ammonium nitrate can control the crystal structure and morphology of the aluminum-doped zinc oxide on the surface of the zinc oxide seed layer, thereby obtaining an AZO transparent conductive film of an array structure. Specifically, the array structure is a columnar structure. Compared with the AZO transparent conductive film which does not have the array structure, the AZO transparent conductive film of the array structure transmits electrons directly along the array during charge, such as electron transport, which can reduce the barrier effect of the grain boundary and thereby improve the photoelectric effect.

Further, in the zinc oxide deposition solution, the concentration of each constituent substance is preferably:

Zinc oxide 20~60 mmol/L;

Ammonium citrate 0.01~4 mmol/L;

The concentration of ammonium nitrate is 0.01~2 mmol/L.

A suitable concentration of the above substances can be doped with an aluminum zinc oxide nano-array, and the aluminum-doped zinc oxide nano-array is uniformly dense. Specifically, if the concentration of the zinc oxide is too high, the growth rate of the zinc oxide is fast, and the doping speed of the aluminum cannot keep up with the growth rate of the zinc oxide, so that the aluminum doping content of the finally obtained AZO transparent conductive film does not meet the requirements. . In addition, the concentration of zinc oxide is too high, the zinc oxide particles formed during the deposition process are coarse, and pores are formed between the zinc oxide particles, thereby lowering the properties of the finally obtained AZO transparent conductive film. If the concentration of the zinc oxide is too low, the growth rate of zinc oxide is slow. The content of the ammonium citrate and ammonium nitrate is related to the formation of the aluminum-doped zinc oxide nano-array, that is, whether the AZO transparent conductive film has an array structure. The ammonium citrate and ammonium nitrate are used as an additive in the form of citrate ions, nitrate ions and ammonium ions in an aqueous solution. Due to electrostatic attraction, citrate ions and nitrate ions are strongly adsorbed to the oxidation. The crystal plane of zinc, which occupies most of the growth position of zinc and oxygen, inhibits the growth of zinc oxide nanorods along the c-axis direction, while the lateral growth of nanorods is less affected, so the nanorods tend to grow laterally. The aspect ratio is reduced, and the nanorods can contact each other to form a dense film. At the same time, the introduced ammonium ions are present in the solution itself and therefore do not affect the chemical properties of the solution. If the concentration of the ammonium citrate and the ammonium nitrate is too high, the longitudinal growth limitation of the zinc oxide nanorods is severe, and the rod-shaped zinc oxide will grow into a sheet shape, which is disadvantageous to the increase of carrier mobility, resulting in thin film electrical power. Reduced performance. As a specific embodiment, the zinc oxide deposition solution is prepared by taking a clean container such as a beaker, weighing a certain amount of deionized water, and adding the desired ammonium citrate, ammonium nitrate, and oxidation to the beaker. Zinc powder and ammonia reagent. After stirring for 24 h at room temperature, excess zinc oxide impurities in the solution were removed by filtration using a filter having a diameter of 0.45 μm, leaving a clear solution for use.

In an embodiment of the invention, a substrate on which a zinc oxide seed layer is deposited is placed in the zinc oxide deposition solution, the zinc oxide deposition solution is immersed in the substrate, and zinc oxide seeds are deposited in the substrate. The surface of the layer is not adhered to grow aluminum-doped zinc oxide on the surface of the zinc oxide seed layer. Preferably, the substrate is placed vertically in the zinc oxide deposition solution. When the substrate is placed vertically on the zinc oxide deposition solution, impurities may be prevented from falling into the surface of the zinc oxide seed layer during sedimentation, and space saving is facilitated, and deposition of a plurality of substrates is simultaneously achieved. Further preferably, a plurality of substrates are simultaneously placed in the zinc oxide deposition solution to prepare an AZO transparent conductive film. The substrate is placed vertically in the zinc oxide deposition solution, which can be realized by means of a mold, and the selection of the mold is not specifically required.

In the process of preparing the AZO transparent conductive film by the aqueous solution method, the zinc oxide is deposited by heating (volatile ammonia water to supersaturate the zinc oxide in the solution); at the same time, the aluminum ion is continuously introduced into the zinc oxide deposition solution. Doping with deposited zinc oxide. Specifically, a peristaltic pump is used to continuously add aluminum nitrate nonahydrate or immersed in an aluminum flake to the zinc oxide deposition solution, and aluminum ions are continuously introduced into the zinc oxide deposition solution to achieve uniform doping. As a specific preferred embodiment, the step of introducing aluminum nitrate into the aluminum oxide by continuously adding the aluminum nitrate nonahydrate in the zinc oxide deposition solution by using a peristaltic pump satisfies the introduction condition of the aluminum ion: the rotational speed of the peristaltic pump is ≥0.1 rpm. The concentration of aluminum nitrate in the zinc oxide deposition solution is 10 to 300 mmol/L. As another specific preferred embodiment, the step of continuously immersing the aluminum sheet into the aluminum ion in the zinc oxide deposition solution by using a peristaltic pump, the introduction condition of the aluminum ion is satisfied: the rotational speed of the peristaltic pump is ≥0.1 rpm, The immersion area of the aluminum sheet is 1 to 10 cm ² . During the growth of zinc oxide columnar grains, the columnar surface of zinc oxide is positively charged, and its top surface is negatively charged. Therefore, under the action of electrostatic adsorption, different surfaces may have different attracting abilities to ions in the solution. The aluminum ion will exist in the form of [Al(OH) ₄ ] ⁻ in the alkaline solution, so most of it will adsorb to the crystal plane of the zinc oxide columnar crystal, which will cause the columnar surface to accept a large decrease in the position of zinc. The growth of the columnar crystal lateral direction is suppressed, resulting in a decrease in grain size and an increase in aspect ratio. Therefore, if the concentration of the aluminum nitrate nonahydrate is too high or the area of the immersed aluminum sheet is too large, the growth of the zinc oxide columnar grain is limited, the film cannot grow on the substrate; if the concentration of the aluminum nitrate nonahydrate is too low Or the area of the immersed aluminum sheet is too small, the aluminum doping concentration in the zinc oxide is decreased, and the conductive property of the zinc oxide film is decreased.

In the embodiment of the present invention, the purpose of the heating is to volatilize the ammonia water in the zinc oxide deposition solution, and the heating temperature has a great influence on the preparation of the AZO pre-formed film in the embodiment of the invention. Preferably, the zinc oxide deposition solution contains zinc oxide, ammonia water and deionized water, the zinc oxide deposition solution has a pH of 9-12, and the heating temperature is 60-90 °C. In the temperature range again, the ammonia water can ensure a proper evaporation rate, which is beneficial to the formation of AZO prefabricated film with good crystal structure. If the heating temperature is too low, the volatilization speed is slow; if the heating temperature is too high, the ammonia water volatilizes too fast, the zinc oxide grows fast, and the doping speed of aluminum cannot keep up with the growth rate of zinc oxide. The aluminum doping content in the finally obtained AZO transparent conductive film is not satisfactory. In addition, the zinc oxide particles formed by the deposition are coarse, and pores are formed between the zinc oxide particles, thereby lowering the properties of the finally obtained AZO transparent conductive film.

As a preferred embodiment, the zinc oxide deposition solution is added to the heating vessel, and the substrate on which the zinc oxide seed layer is deposited is placed in the zinc oxide deposition solution, and the zinc oxide deposition solution is immersed in the lining. a bottom, and a surface of the substrate in which the zinc oxide seed layer is deposited is not adhered; the heating vessel is placed in a water bath, and aluminum ions are continuously introduced into the zinc oxide deposition solution under heating The AZO pre-formed film was prepared by growing on the surface of the zinc oxide seed layer by stirring. By heating the zinc oxide deposition solution by a water bath, the reaction temperature can be better controlled, and deposition can occur at a uniform rate.

The sample from which the AZO pre-formed film was grown was taken out from the aqueous solution, rinsed with a large amount of deionized water, and then blown dry under a nitrogen stream.

In the above step S04, the AZO pre-formed film is subjected to ultraviolet irradiation treatment, and then the surface of the sample is irradiated with a UV irradiation lamp for 5 to 10 minutes to complete preparation of the AZO film sample. Excess carbon impurities in the film are removed to increase the carrier concentration and conductivity of the film. Preferably, the ultraviolet irradiation treatment condition is: the UV lamp has an effective area of 100 cm ² and a radiation time of 1 to 20 min.

Embodiments of the present invention provide an AZO transparent conductive film, including a zinc oxide seed layer, and an array of AZO thin films bonded to the surface of the zinc oxide seed layer.

The AZO transparent conductive film provided by the embodiment of the invention has excellent electrical conductivity and low manufacturing cost, and is an ideal substitute for the ITO transparent conductive film, and can be widely used in CIGS and CZTS thin film solar cells, and has better photoelectric conversion efficiency of the battery. The AZO transparent conductive film provided by the embodiment of the invention can be obtained by the above method.

Compared with the AZO transparent conductive film without the array structure, the AZO transparent conductive film of the array structure transmits electrons directly along the array during charge, such as electron transport, which can reduce the barrier effect of the grain boundary and is beneficial to the collection of carriers. , thereby improving the photoelectric conversion efficiency of the solar cell. Preferably, the array of the array of AZO thin films is a columnar nano array.

The thin film solar cell provided by the embodiment of the invention can not only reduce the cost but also improve the photoelectric conversion efficiency of the battery because the AZO transparent conductive film is contained.

The thin film solar cell may be a copper indium gallium selenide (CIGS) or a copper zinc tin sulfide (CZTS) thin film solar cell. As a particularly preferred embodiment, the thin film solar cell is a CZTA thin film solar cell, including a glass substrate, and a molybdenum metal layer, a CATS light absorbing layer, a cadmium sulfide buffer layer, and an AZO transparent layer sequentially disposed on the glass substrate. Conductive film and silver electrode. The CZTA thin film solar cell can be prepared by the following method:

Cleaning the soda lime glass deposited with metal Mo, the cleaning method can refer to the surface cleaning treatment method of the substrate, and then continuously adopting the sol-gel technique and the high-temperature tempering two-step method to prepare the CZTS light absorbing layer, and chemical bath deposition vulcanization The cadmium buffer layer is tempered at 200 ° C for 10 min, and then the AZO transparent conductive film is prepared on the surface of the sample by using the preparation method of the AZO transparent conductive film, and the top electrode (wiring electrode) is prepared by using the conductive silver paste to complete the CZTS thin film solar energy. Battery preparation.

The following description will be made in conjunction with specific embodiments.

Example 1

A method for preparing an AZO transparent conductive film, comprising the steps of:

S11. Providing a substrate, and performing surface cleaning treatment on the substrate;

S12. Providing a zinc oxide seed solution, spin-depositing the zinc oxide seed solution on the substrate to prepare a zinc oxide seed layer bonded to a surface of the substrate, wherein a solution composition of the zinc oxide seed solution is : zinc oxide nanoparticles, high purity water, excess ammonia water, wherein the concentration of zinc oxide is 20~50 Mmmol/L;

S13. Providing a zinc oxide deposition solution, placing a substrate on which the zinc oxide seed layer is deposited in the zinc oxide deposition solution, immersing the zinc oxide deposition solution in the substrate, and depositing oxidation in the substrate The surface of the zinc seed layer is not attached to the wall, and the aluminum ion is continuously introduced into the zinc oxide deposition solution under stirring at 60 ° C to 90 ° C, and the mixture is stirred and deposited 40 ~80 min, preparing AZO pre-formed film on the surface of the zinc oxide seed layer, wherein the pH of the zinc oxide deposition solution is 9-12, and the solution composition is: zinc oxide concentration 20~60 mmol/L, ammonium citrate Concentration 0~4 mmol/L, ammonium nitrate concentration 0~2 Mmmol/L, excess ammonia water;

S14. The AZO pre-formed film is subjected to ultraviolet irradiation treatment under the following conditions: the UV lamp has an effective area of 100 cm ² and the irradiation time is 1 to 20 min, and an AZO transparent conductive film is prepared.

The plan view and the cross-sectional view of the AZO transparent conductive film prepared in the first embodiment of the present invention are as shown in FIG. 2 and FIG. 3, and the AZO transparent conductive film prepared in the first embodiment of the present invention is tested for light transmittance, and the result is shown in FIG. The light rate is 85%-95%.

Example 2

A method for preparing a CZTA thin film solar cell, comprising the steps of:

The soda lime glass deposited with metal Mo is cleaned, and then the CZTS light absorbing layer is prepared by a sol gel technique and a high temperature tempering two-step method, and the cadmium sulfide buffer layer is deposited by a chemical bath, tempered at 200 ° C for 10 min, and then The method of Example 1 prepared an AZO transparent conductive film on the surface of the sample, and prepared a top electrode (wiring electrode) using a conductive silver paste to complete the preparation of the CZTS thin film solar cell.

The structure of the CZTA thin film solar cell prepared in Example 2 is shown in Fig. 5, and a cross-sectional view of the structure of the CZTA thin film solar cell is shown in Fig. 6.

The CZTA thin film solar cell prepared in Example 2 and the AZO thin film prepared by high temperature annealing were subjected to long-time annealing at a high temperature of 600 ° C or higher, followed by post-annealing under a hydrogen atmosphere at 550 ° C to obtain a resistivity of 1.7×10 ^{-3 .} The CZTS thin film solar cell obtained by the AZO thin film of ~7.2×10 ^-3 Ω·cm and the other layer method is the same) is subjected to photoelectric performance test, and the current-voltage curve obtained by the test is shown in Fig. 7. Since the AZO thin film prepared by high temperature annealing is deposited on the surface of the CZTS thin film solar cell, an excessive element diffusion at the pn junction interface is caused, thereby destroying the pn junction, and thus the battery conversion efficiency is seriously degraded. The photoelectric conversion efficiency of the CZTA thin film solar cell prepared in Example 2 was significantly improved compared to the CZTS thin film solar cell obtained by the AZO film prepared by high temperature annealing.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

A method for preparing an AZO transparent conductive film, comprising the steps of:

Providing a substrate, and performing surface cleaning treatment on the substrate;

Providing a zinc oxide seed solution, depositing the zinc oxide seed solution on the substrate to prepare a zinc oxide seed layer bonded to the surface of the substrate;

Providing a zinc oxide deposition solution, placing a substrate on which the zinc oxide seed layer is deposited in the zinc oxide deposition solution, immersing the zinc oxide deposition solution in the substrate, and depositing zinc oxide seeds in the substrate The surface of the layer is not adhered to the wall, and under the heating condition, aluminum ions are continuously introduced into the zinc oxide deposition solution and stirred to form an AZO pre-formed film on the surface of the zinc oxide seed layer;

The AZO pre-formed film is subjected to ultraviolet irradiation treatment to prepare an AZO transparent conductive film.
The method for preparing an AZO transparent conductive film according to claim 1, wherein the zinc oxide deposition solution contains zinc oxide, ammonia water and deionized water, and the pH of the zinc oxide deposition solution is 9-12. And the heating temperature is 60-90 °C.
The method for producing an AZO transparent conductive film according to claim 2, wherein the zinc oxide deposition solution further contains ammonium citrate or ammonium nitrate.
The method for preparing an AZO transparent conductive film according to claim 3, wherein the concentration of each constituent substance in the zinc oxide deposition solution is:

Zinc oxide 20~60 mmol/L;

Ammonium citrate 0.01~4 mmol/L;

Ammonium nitrate concentration 0.01~2 mmol/L.
The method for preparing an AZO transparent conductive film according to any one of claims 1 to 4, wherein a peristaltic pump is used to continuously add aluminum nitrate nonahydrate or immersed in an aluminum sheet to the zinc oxide deposition solution. The aluminum ion is continuously introduced into the zinc oxide deposition solution.
The method for preparing an AZO transparent conductive film according to claim 5, wherein a step of introducing aluminum ions into the aluminum oxide non-aqueous solution in the zinc oxide deposition solution by using a peristaltic pump is performed, and the introduction condition of the aluminum ions is satisfied: The rotational speed of the peristaltic pump is ≥0.1 rpm, and the concentration of aluminum nitrate nonahydrate in the zinc oxide deposition solution is 10~300 mmol/L; or

In the step of continuously immersing the aluminum sheet into the aluminum oxide by the peristaltic pump in the zinc oxide deposition solution, the introduction condition of the aluminum ion is satisfied: the rotational speed of the peristaltic pump is ≥0.1 rpm, and the immersion area of the aluminum sheet is 1~ 10 cm 2 .
The method for preparing an AZO transparent conductive film according to any one of claims 1 to 4, wherein the zinc oxide deposition solution is added to the heating container, and the substrate on which the zinc oxide seed layer is deposited is placed in the In the zinc oxide deposition solution, the zinc oxide deposition solution is immersed in the substrate, and a surface of the substrate in which the zinc oxide seed layer is deposited is not attached; the heating container is placed in a water bath and heated Under the condition, aluminum ions are continuously introduced into the zinc oxide deposition solution and stirred, and an AZO pre-formed film is prepared by growing on the surface of the zinc oxide seed layer.
The method for producing an AZO transparent conductive film according to any one of claims 1 to 4, wherein the zinc oxide seed solution is an aqueous zinc oxide solution to which an excess amount of aqueous ammonia is added.
The method for producing an AZO transparent conductive film according to claim 8, wherein the zinc oxide seed solution has a zinc oxide concentration of 20 to 50 mmol/L.
The method of producing an AZO transparent conductive film according to any one of claims 1 to 4, wherein the substrate is placed vertically in the zinc oxide deposition solution.
The method of producing an AZO transparent conductive film according to claim 10, wherein a plurality of substrates are simultaneously placed in the zinc oxide deposition solution to prepare an AZO transparent conductive film.
An AZO transparent conductive film characterized by comprising a zinc oxide seed layer, and an array of AZO thin films bonded to the surface of the zinc oxide seed layer.
The AZO transparent conductive film according to claim 12, wherein the array of the array-shaped AZO thin films is a columnar nano-array.
A thin film solar cell comprising the AZO transparent conductive film according to any one of claims 12 to 13, or the AZO transparent conductive film prepared by the method according to any one of claims 1 to 11.
The thin film solar cell according to claim 14, wherein the thin film solar cell is a CZTA thin film solar cell comprising a glass substrate, and a molybdenum metal layer and a CATS light absorbing layer sequentially disposed on the glass substrate. , cadmium sulfide buffer layer, AZO transparent conductive film and silver electrode.