Preparation method of n-type window layer doped with group III element or compound thereof and thin-film solar cell

Abstract

The invention relates to a preparation method of an n-type window layer doped with a group III element or a compound thereof and a thin-film solar cell. The preparation method comprises the following steps: obtaining a powder mixture composed of group III element powder and cadmium selenide powder; wherein the mass ratio of the group III element-containing powder to the powder mixture is 0.1-10 wt.%; the obtained powder mixture is put into a mold, then the mold containing the powder mixture is put into a vacuum hot pressing furnace, the temperature is increased to 300-500 DEG C, heat preservation is conducted for 30-60 min, and then the temperature continues to be increased to 550-1200 DEG C; keeping the temperature at 550-1200 DEG C for 30-100 minutes, and then stopping heating; and cooling to room temperature, and taking out a sample in the mold to obtain the III-group element doped cadmium selenide window layer material, so that the potential difference of a p-n junction can be improved, a built-in electric field can be increased, the extraction, separation and transmission of carriers can be promoted, the open-circuit voltage can be improved, and the photoelectric conversion efficiency of a cadmium telluride thin film battery can be further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of thin-film solar cell preparation, and in particular to a method for preparing an n-type window layer doped with a group III element or a compound thereof, and a thin-film solar cell. Background Art

[0002] With the rapid development of the economy, the existence of unbalanced energy supply, low per capita resource share, aggravated environmental pollution, and unstable primary energy has forced us to accelerate the transformation to cleaner, more efficient, and recyclable energy to achieve the goal of sustainable development. Among the green energy currently being developed, solar energy has attracted people's attention due to its inexhaustible characteristics. Among them, solar cells are a device that can directly utilize solar energy, relying on the photovoltaic effect to convert solar energy into electrical energy.

[0003] Cadmium telluride (CdTe) thin film solar cells are one of the few commercially available photovoltaic technologies. CdTe is an ideal photovoltaic material with a high light absorption coefficient and a direct band gap of 1.5 eV. The record efficiency of CdTe solar cells in the laboratory is above 23%. In addition, CdTe solar cells have a simple manufacturing process and low associated manufacturing costs, making them suitable for large-scale production and of great commercial value.

[0004] However, there is still a long way to go to achieve the theoretical limit efficiency (32.1%) of cadmium telluride solar cells. One of the challenges facing CdTe solar cells is to select a suitable window layer, which is crucial for the high transmittance of the CdTe absorption band and good absorption band alignment with the absorption layer to effectively separate photogenerated carriers. The present invention discloses a window layer doped with group III elements or their compounds and a preparation method thereof, a thin-film solar cell and a preparation method thereof. Using the window layer doped with group III elements or their compounds prepared according to the preparation method of the window layer doped with group III elements or their compounds as the n-type thin film layer in the cadmium telluride thin-film solar cell can increase the potential difference of the pn junction, increase the built-in electric field, promote the extraction, separation and transmission of carriers, improve the open circuit voltage and further improve the photoelectric conversion efficiency of the cadmium telluride thin-film battery. At the same time, the compound doped with group III elements, namely selenide, can provide excess Se without introducing other elements, forming Se-rich, and generating more cadmium vacancies (V Cd ), drive III Cd The formation of donors is beneficial to the full doping of group III elements, further improving the photoelectric conversion efficiency of battery devices. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a method for preparing an n-type window layer doped with group III elements or their compounds and a thin-film solar cell, which can improve the potential difference of the pn junction, increase the built-in electric field, promote the extraction, separation and transmission of carriers, improve the open circuit voltage and further improve the photoelectric conversion efficiency of the cadmium telluride thin film battery.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is a method for preparing an n-type window layer doped with a group III element or a compound thereof, comprising:

[0007] Obtaining a powder mixture consisting of Group III element powder and cadmium selenide powder; wherein the mass ratio of the Group III element powder to the mass ratio of the powder mixture is: 0.1-10wt.%;

[0008] The obtained powder mixture is placed in a mold, and then the mold containing the powder mixture is placed in a vacuum hot pressing furnace, heated to 300-500°C, kept warm for 30-60 minutes, and then continued to heat to 550-1200°C; kept warm at 550-1200°C for 30-100 minutes, and then stopped heating;

[0009] The vacuum hot pressing furnace is cooled down, and when the temperature drops to room temperature, the sample in the mold is taken out to obtain a window layer material of cadmium selenide doped with group III elements.

[0010] Furthermore, the Group III element in the Group III element-containing powder is one or more of aluminum, gallium, indium and thallium.

[0011] Furthermore, the material containing Group III element powder includes Al powder, Al 2 Se 3 Powder, Ga powder, Ga 2 Se 3 Powder,InPowder,In 2 Se 3 Powder, Tl powder and Tl 2 Se 3 One or more of powders.

[0012] Further, obtaining a powder mixture containing Group III element powder and cadmium selenide powder includes:

[0013] Obtaining a material containing a group III element and a cadmium selenide material, and crushing them respectively under a vacuum environment to obtain a powder containing a group III element and a cadmium selenide powder;

[0014] The obtained powder containing the group III element and the cadmium selenide powder are fully mixed under vacuum conditions to obtain a mixed powder, wherein the mass ratio of the group III element powder to the cadmium selenide powder is: (0.1:99.9)-(10:90).

[0015] Furthermore, the obtained powder mixture is placed in a mold, and the mold containing the powder mixture is placed in a vacuum hot pressing furnace at a rate of 8-15°C / min. When the temperature reaches 300-500°C, it is kept warm for 30-60 minutes and then continued to be heated at a rate of 5-12°C / min. When the temperature reaches 550-1200°C, the heating is stopped and kept warm for 30-100 minutes.

[0016] Furthermore, the obtained powder mixture is placed in a mold, and then the mold containing the powder mixture is placed in a vacuum hot pressing furnace at a rate of 9°C / min. When the temperature reaches 400°C, it is kept warm for 50 minutes and then continued to be heated at a rate of 5°C / min. When the temperature reaches 800°C, the heating is stopped and kept warm for 90 minutes.

[0017] A thin-film solar cell comprises an n-type window layer, which is made according to any preparation method of an n-type window layer doped with a III-group element or a compound thereof.

[0018] Furthermore, it also includes a substrate layer, a transparent conductive oxide layer, a high-resistance buffer layer, an n-type window layer, an absorption layer, a back contact layer and a back electrode layer arranged from bottom to top.

[0019] A method for preparing a thin-film solar cell, comprising:

[0020] Arranging a transparent conductive oxide layer on the substrate layer to form a FTO substrate, and completing cleaning of the obtained FTO base layer;

[0021] Depositing a high-resistance buffer layer on the FTO substrate by magnetron sputtering, wherein the thickness of the high-resistance buffer layer is 20-200 nm;

[0022] Depositing an n-type window layer on the high-resistance buffer layer by magnetron sputtering, wherein the thickness of the n-type window layer is 30-150 nm;

[0023] Depositing an absorption layer on the n-type window layer by using a space sublimation method, wherein the absorption layer has a thickness of 1-10 um;

[0024] A back base layer and a back electrode layer are sequentially deposited on the absorption layer to obtain a thin film solar cell.

[0025] Furthermore, the absorption layer deposited on the n-type window layer is a cadmium telluride absorption layer. After the deposition is completed, 5% CdCl is sprayed on the cadmium telluride absorption layer. 2The film was treated at 400° C. in a nitrogen atmosphere for 30 minutes and etched with a phosphorus nitric acid solution for 10 seconds, then rinsed with ultrapure water and dried with nitrogen.

[0026] The specific beneficial effects of the present invention are:

[0027] The window layer doped with group III elements or their compounds prepared by the method provided in the present application is used as the n-type thin film layer in the cadmium telluride thin film solar cell, which can increase the potential difference of the pn junction, increase the built-in electric field, promote the extraction, separation and transmission of carriers, improve the open circuit voltage and further improve the photoelectric conversion efficiency of the cadmium telluride thin film solar cell. At the same time, the compound doped with group III elements, i.e., selenide, can provide excess Se without introducing other elements, forming Se-rich, generating more cadmium vacancies (V Cd ), drive III Cd The formation of donors is beneficial to the full doping of group III elements, further improving the photoelectric conversion efficiency of battery devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiment of the present invention and its design scheme, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 It is a schematic diagram of the cross-sectional structure of a thin-film solar cell in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0031] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0032] Example 1

[0033] This embodiment provides a method for preparing an aluminum-doped n-type window layer, which is specifically carried out in the following steps:

[0034] Step 1. CdSe material and Al material are crushed in a vacuum environment to obtain CdSe powder and Al powder respectively;

[0035] Step 2. Mix CdSe powder and Al powder evenly under vacuum to obtain mixed powder, wherein the proportion of Al powder to the mixed powder is 0.1-10wt.%. In this embodiment, the proportion of Al powder to the mixed powder is 10wt.%;

[0036] Step 3. Put the mixed powder evenly into a special mold (i.e., a special mold for preparing the window layer material), and then put the special mold containing the mixed powder into a vacuum hot pressing furnace. The temperature in the vacuum hot pressing furnace is heated at a rate of 9°C / min. When the temperature reaches 400°C, keep it warm for 50 minutes; continue to heat at a rate of 5°C / min. When the temperature reaches 800°C, keep it warm for 90 minutes and then stop heating;

[0037] Step 4. The vacuum hot pressing furnace is then cooled down. When the temperature reaches room temperature (23° C.), the special mold is taken out from the vacuum hot pressing furnace to obtain the aluminum-doped cadmium selenide window layer material.

[0038] Example 2

[0039] This embodiment provides a method for preparing an aluminum selenide-doped n-type window layer, which is specifically carried out in the following steps:

[0040] Step 1. Mix CdSe material with Al 2 Se 3 The materials were crushed under vacuum to obtain CdSe powder and Al 2 Se 3 powder;

[0041] Step 2. Mix CdSe powder, Al 2 Se 3 The powders are fully and evenly mixed under vacuum conditions to obtain mixed powders, wherein Al 2 Se 3 The proportion of Al in the mixed powder is 0.1-10wt.%. 2 Se 3 The proportion of the powder to the mixed powder is 5wt.%;

[0042] Step 3. Put the mixed powder evenly into a special mold (i.e., a special mold for preparing the window layer material), and then put the special mold containing the mixed powder into a vacuum hot pressing furnace. The temperature in the vacuum hot pressing furnace is heated at a rate of 15°C / min. When the temperature reaches 500°C, keep it warm for 50 minutes; continue to heat at a rate of 12°C / min. When the temperature reaches 1200°C, keep it warm for 30 minutes and then stop heating;

[0043] Step 4. The vacuum hot pressing furnace is then cooled down. When the temperature reaches room temperature (23° C.), the special mold is taken out from the vacuum hot pressing furnace to obtain the aluminum selenide-doped cadmium selenide window layer material.

[0044] Example 3

[0045] This embodiment provides a method for preparing a gallium-doped n-type window layer, which is specifically carried out in the following steps:

[0046] Step 1. CdSe material and Ga material are crushed under vacuum to obtain CdSe powder and Ga powder respectively;

[0047] Step 2. CdSe powder and Ga powder are fully and evenly mixed under vacuum conditions to obtain a mixed powder, wherein the ratio of Ga powder to the mixed powder is 0.1-10wt.%, and in this embodiment, the ratio of Ga powder to the mixed powder is 0.1wt.%;

[0048] Step 3. Put the mixed powder into a special mold (i.e., a special mold for preparing the window layer material), and then put the special mold containing the mixed powder into a vacuum hot pressing furnace. The temperature in the vacuum hot pressing furnace is heated at a rate of 8°C / min. When the temperature reaches 300°C, keep it warm for 60 minutes; continue to heat at a rate of 5°C / min. When the temperature reaches 550°C, keep it warm for 100 minutes and then stop heating;

[0049] Step 4. The vacuum hot pressing furnace is then cooled down. When the temperature reaches room temperature (23° C.), the special mold is taken out from the vacuum hot pressing furnace to obtain a window layer material of gallium-doped cadmium selenide.

[0050] Example 4

[0051] This embodiment provides a method for preparing a gallium selenide-doped n-type window layer, comprising the following steps:

[0052] Step 1. Mix CdSe material with Ga 2 Se 3 The materials were crushed under vacuum to obtain CdSe powder and Ga 2 Se 3 powder;

[0053] Step 2. Mix CdSe powder, Ga 2 Se 3 The powders are fully and uniformly mixed under vacuum conditions to obtain mixed powders, wherein Ga 2 Se 3 The ratio of the powder to the mixed powder is 0.1-10wt.%. In this embodiment, Ga 2 Se 3 The proportion of powder to mixed powder is 6wt.%;

[0054] Step 3. Put the mixed powder evenly into a special mold (i.e., a special mold for preparing the window layer material), and then put the special mold containing the mixed powder into a vacuum hot pressing furnace. The temperature in the vacuum hot pressing furnace is heated at a rate of 10°C / min. When the temperature reaches 450°C, keep it warm for 40 minutes; continue to heat at a rate of 5°C / min. When the temperature reaches 1000°C, keep it warm for 50 minutes and then stop heating;

[0055] Step 4. The vacuum hot pressing furnace is then cooled down. When the temperature reaches room temperature (23° C.), the special mold is taken out from the vacuum hot pressing furnace to obtain a window layer material of gallium selenide doped with cadmium selenide.

[0056] Example 5

[0057] This embodiment provides a method for preparing an indium-doped n-type window layer, comprising the following steps:

[0058] Step 1. CdSe material and In material are crushed under vacuum to obtain CdSe powder and In powder respectively;

[0059] Step 2. Fully and uniformly mix CdSe powder and In powder under vacuum conditions to obtain mixed powder, wherein the ratio of In powder to the mixed powder is 0.1-10wt.%, and in this embodiment, the ratio of In powder to the mixed powder is 5wt.%;

[0060] Step 3. Put the mixed powder evenly into a special mold (i.e., a special mold for preparing the window layer material), and then put the special mold containing the mixed powder into a vacuum hot pressing furnace. The temperature in the vacuum hot pressing furnace is heated at a rate of 12°C / min. When the temperature reaches 350°C, keep it warm for 55 minutes; continue to heat at a rate of 10°C / min. When the temperature reaches 600°C, keep it warm for 100 minutes and then stop heating;

[0061] Step 4. The vacuum hot pressing furnace is then cooled down. When the temperature reaches room temperature (23° C.), the special mold is taken out from the vacuum hot pressing furnace to obtain the indium-doped cadmium selenide window layer material.

[0062] Example 6

[0063] This embodiment provides a method for preparing an indium selenide-doped n-type window layer, comprising the following steps:

[0064] Step 1. Mix CdSe material with In 2 Se 3 The materials were crushed under vacuum to obtain CdSe powder and In 2 Se 3 powder;

[0065] Step 2. Mix CdSe powder, In 2 Se 3 The powders are fully and evenly mixed under vacuum conditions to obtain mixed powders, wherein In 2 Se 3 The proportion of powder to mixed powder is 0.1-10wt.%. In this embodiment, In 2 Se 3 The proportion of powder to mixed powder is 7wt.%;

[0066] Step 3. Put the mixed powder evenly into a special mold (i.e., a special mold for preparing the window layer material), and then put the special mold containing the mixed powder into a vacuum hot pressing furnace. The temperature in the vacuum hot pressing furnace is heated at a rate of 14°C / min. When the temperature reaches 400°C, keep it warm for 50 minutes; continue to heat at a rate of 8°C / min. When the temperature reaches 800°C, keep it warm for 90 minutes and then stop heating;

[0067] Step 4. The vacuum hot pressing furnace is then cooled down. When the temperature reaches room temperature (23° C.), the special mold is taken out from the vacuum hot pressing furnace to obtain the indium selenide-doped cadmium selenide window layer material.

[0068] Example 7

[0069] This embodiment provides a method for preparing a thallium-doped n-type window layer, comprising the following steps:

[0070] Step 1. CdSe material and Tl material are crushed under vacuum to obtain CdSe powder and Tl powder respectively;

[0071] Step 2. CdSe powder and Tl powder are fully and evenly mixed under vacuum conditions to obtain a mixed powder, wherein the proportion of Tl powder to the mixed powder is 0.1-10wt.%, and in this embodiment, the proportion of Tl powder to the mixed powder is 10wt.%;

[0072] Step 3. Put the mixed powder evenly into a special mold (i.e., a special mold for preparing the window layer material), and then put the special mold containing the mixed powder into a vacuum hot pressing furnace. The temperature in the vacuum hot pressing furnace is heated at a rate of 9°C / min. When the temperature reaches 400°C, keep it warm for 50 minutes; continue to heat at a rate of 5°C / min. When the temperature reaches 800°C, keep it warm for 90 minutes and then stop heating;

[0073] Step 4. The vacuum hot pressing furnace is then cooled down. When the temperature reaches room temperature (23° C.), the special mold is taken out from the vacuum hot pressing furnace to obtain the thallium-doped cadmium selenide window layer material.

[0074] Example 8

[0075] This embodiment provides a method for preparing an n-type window layer doped with thallium selenide, comprising the following steps:

[0076] Step 1. Mix CdSe material with Tl 2 Se 3 The materials were crushed under vacuum to obtain CdSe powder and Tl 2 Se 3 powder;

[0077] Step 2. Mix CdSe powder, Tl 2 Se 3 The powders are fully and uniformly mixed under vacuum to obtain a mixed powder, wherein Tl 2 Se 3 The proportion of powder to mixed powder is 0.1-10wt.%, in this embodiment, Tl 2 Se 3 The proportion of powder to mixed powder is 4wt.%;

[0078] Step 3. Put the mixed powder evenly into a special mold (i.e., a special mold for preparing the window layer material), and then put the special mold containing the mixed powder into a vacuum hot pressing furnace. The temperature in the vacuum hot pressing furnace is heated at a rate of 13°C / min. When the temperature reaches 400°C, keep it warm for 50 minutes; continue to heat at a rate of 7°C / min. When the temperature reaches 800°C, keep it warm for 90 minutes and then stop heating;

[0079] Step 4. The vacuum hot pressing furnace is then cooled down. When the temperature reaches room temperature (23° C.), the special mold is taken out from the vacuum hot pressing furnace to obtain a window layer material of thallium selenide doped with cadmium selenide.

[0080] Example 9

[0081] This embodiment provides a thin film solar cell, such as Figure 1 As shown, the thin film solar cell includes a substrate layer, a transparent conductive oxide layer, a high resistance buffer layer, an n-type window layer, an absorption layer, a back contact layer and a back electrode layer arranged in sequence from bottom to top;

[0082] Wherein, the substrate layer is one or more of soda-lime glass or borosilicate glass layer;

[0083] The transparent conductive oxide layer is one or more of an F-doped tin oxide layer, an In-doped zinc oxide layer, and an Al-doped zinc oxide layer;

[0084] The high resistance buffer layer uses SnO 2 , ZnO, ZnO doped with element A or SnO doped with element A2 One or more of the layers, wherein the A element is one or more of Al, Zn, Mg, F, and Cd;

[0085] The n-type window layer adopts one or more window layer materials prepared in Examples 1 to 8;

[0086] The absorption layer is made of cadmium telluride layer;

[0087] The back contact layer is one or more of a copper-containing carbon paste layer, a copper-containing zinc telluride layer, a zinc telluride layer, a tellurium layer or a cadmium zinc telluride layer;

[0088] The material of the back electrode layer is selected from one or more of aluminum, silver, gold, copper, nickel and titanium.

[0089] This embodiment also provides a method for preparing a thin-film solar cell, the specific steps of which include:

[0090] Step S1, selecting the glass required for the substrate layer, and then arranging a transparent conductive oxide layer on the substrate layer to obtain an FTO substrate, cutting the FTO substrate into a suitable size, and then placing it in acetone, ethanol, and deionized water for ultrasonic treatment for 20 minutes, and then blowing it dry with high-purity nitrogen, and placing it in a 100° C. oven for drying for 20 minutes for use;

[0091] Step S2, preparation of high resistance buffer layer: deposit a layer of SnO on the FTO substrate by magnetron sputtering. 2 A high-resistance buffer layer is obtained, wherein the thickness of the high-resistance buffer layer is 20-200 nm, and preferably 40 nm in this embodiment;

[0092] Step S3, preparation of an n-type window layer: depositing a layer of an n-type window layer material prepared by any one of the methods in Examples 1 to 8 on the high-resistance buffer layer by magnetron sputtering to obtain an n-type window layer, wherein the thickness of the n-type window layer is 30-150 nm, and preferably 80 nm in this embodiment;

[0093] Step S4, preparation of p-type absorption layer: deposit a 1-10 μm cadmium telluride absorption layer on the n-type window layer by close-space sublimation method, preferably 3 μm in this embodiment. Then spray 5% CdCl 2 solution, treated at 400 °C in a nitrogen atmosphere for 30 min, then etched with a phosphorus nitric acid solution for 10 s, rinsed with ultrapure water, and dried with nitrogen;

[0094] Step S5, preparation of a back contact layer: depositing a back contact layer on the absorption layer;

[0095] Step S6, preparation of a metal back electrode: depositing a metal back electrode layer on the absorption layer to obtain a thin film.

[0096] In the process of preparing thin-film solar cells using the above-mentioned thin-film solar cell preparation method, the n-type window layer materials in Examples 1 to 8 are used respectively to obtain 8 different thin-film solar cells, that is, the thin-film solar cell obtained by the n-type window layer material prepared in Example 1 is battery 1, the thin-film solar cell obtained by the n-type window layer material prepared in Example 2 is battery 2, the thin-film solar cell obtained by the n-type window layer material prepared in Example 3 is battery 3, the thin-film solar cell obtained by the n-type window layer material prepared in Example 4 is battery 4, the thin-film solar cell obtained by the n-type window layer material prepared in Example 5 is battery 5, the thin-film solar cell obtained by the n-type window layer material prepared in Example 6 is battery 6, the thin-film solar cell obtained by the n-type window layer material prepared in Example 7 is battery 7, and the thin-film solar cell obtained by the n-type window layer material prepared in Example 8 is battery 8.

[0097] Comparative Example

[0098] This embodiment provides a method for preparing a cadmium telluride thin film solar cell:

[0099] Step S1, cleaning of FTO substrate: cut the glass into appropriate sizes, and then place it in acetone, ethanol, and deionized water for 20 minutes in sequence, then blow dry with high-purity nitrogen, and place it in a 100°C oven to dry for 20 minutes for use.

[0100] Step S2, preparation of high-resistance buffer layer: deposit a layer of SnO by magnetron sputtering 2 , the thickness is 20-200nm, and the preferred thickness in this embodiment is 40nm;

[0101] Step S3, preparation of n-type window layer: depositing a layer of undoped CdSe window layer by magnetron sputtering, with a thickness of 30-150 nm, preferably 80 nm in this embodiment;

[0102] Step S4, preparation of p-type absorption layer: deposit a 1-10 μm cadmium telluride absorption layer on the n-type window layer by close-space sublimation method, preferably 3 μm in this embodiment. Then spray 5% CdCl on the cadmium telluride film. 2 solution, treated at 400 °C in a nitrogen atmosphere for 30 min, then etched with phosphorus nitric acid solution for 10 s, rinsed with ultrapure water, and dried with nitrogen;

[0103] Step S5, preparation of a back contact layer: depositing a back contact layer on the absorption layer;

[0104] Step S6, preparation of a metal back electrode: depositing a metal back electrode layer on the absorption layer to obtain a comparison cell.

[0105] The following are battery performance tests for Battery 1 to Battery 8 and the comparison battery, during which open circuit voltage, short circuit current, fill factor and photoelectric conversion efficiency were tested.

[0106] The following table is a comparison table of performance parameters of thin-film solar cells that have completed the test;

[0107]

[0108] It can be seen from the above-mentioned battery performance test that the n-type window layer material prepared by doping Group III elements or their compounds as the n-type window layer in the thin-film solar cell in the present application can generate a larger built-in electric field between the p-type cadmium telluride absorption layer in the thin-film battery, significantly improve the open circuit voltage of the battery, and ultimately improve the photoelectric conversion efficiency of the thin-film solar cell.

[0109] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for preparing an n-type window layer doped with a group III element or a compound thereof, characterized in that: include: Obtaining a powder mixture consisting of Group III element powder and cadmium selenide powder; wherein the mass ratio of the Group III element powder to the mass ratio of the powder mixture is: 0.1-10wt.%; The obtained powder mixture is placed in a mold, and then the mold containing the powder mixture is placed in a vacuum hot pressing furnace, heated to 300-500°C, kept warm for 30-60 minutes, and then continued to heat to 550-1200°C; and kept warm at 550-1200°C for 30-100 minutes before stopping heating; The vacuum hot pressing furnace is cooled down, and when the temperature drops to room temperature, the sample in the mold is taken out to obtain a window layer material of cadmium selenide doped with group III elements.

2. The method for preparing an n-type window layer doped with a group III element or a compound thereof according to claim 1, characterized in that: The group III element in the powder containing group III elements is one or more of aluminum, gallium, indium and thallium.

3. The method for preparing an n-type window layer doped with a group III element or a compound thereof according to claim 1, characterized in that: The material containing Group III element powder includes one or more of Al powder, Al2Se3 powder, Ga powder, Ga2Se3 powder, In powder, In2Se3 powder, Tl powder and Tl2Se3 powder.

4. The method for preparing an n-type window layer doped with a group III element or a compound thereof according to claim 1, characterized in that: Obtaining a powder mixture containing Group III element powder and cadmium selenide powder includes: Obtaining a material containing a group III element and a cadmium selenide material, and crushing them respectively under a vacuum environment to obtain a powder containing a group III element and a cadmium selenide powder; The obtained powder containing the group III element and the cadmium selenide powder are fully mixed under vacuum conditions to obtain a mixed powder, wherein the mass ratio of the group III element powder to the cadmium selenide powder is: (0.1:99.9)-(10:90).

5. The method for preparing an n-type window layer doped with a group III element or a compound thereof according to claim 1, characterized in that: The obtained powder mixture is placed in a mold, and the mold containing the powder mixture is placed in a vacuum hot pressing furnace at a rate of 8-15°C / min. When the temperature reaches 300-500°C, keep it warm for 30-60 minutes and then continue to heat it at a rate of 5-12°C / min. When the temperature reaches 550-1200°C, stop heating and keep it warm for 30-100 minutes.

6. The method for preparing an n-type window layer doped with a group III element or a compound thereof according to claim 1 or 5, characterized in that: The obtained powder mixture is placed in a mold, and then the mold containing the powder mixture is placed in a vacuum hot pressing furnace at a rate of 9°C / min. When the temperature reaches 400°C, it is kept warm for 50 minutes and then continued to be heated at a rate of 5°C / min. When the temperature reaches 800°C, the heating is stopped and kept warm for 90 minutes.

7. A thin film solar cell, characterized in that: The invention comprises an n-type window layer, which is made according to the method for preparing an n-type window layer doped with a group III element or a compound thereof according to any one of claims 1 to 6.

8. The thin film solar cell according to claim 7, characterized in that: The invention also includes a substrate layer, a transparent conductive oxide layer, a high-resistance buffer layer, an n-type window layer, an absorption layer, a back contact layer and a back electrode layer arranged from bottom to top.

9. A method for preparing a thin film solar cell, characterized in that: include: Arranging a transparent conductive oxide layer on the substrate layer to form a FTO substrate, and completing cleaning of the obtained FTO base layer; Depositing a high-resistance buffer layer on the FTO substrate by magnetron sputtering, wherein the thickness of the high-resistance buffer layer is 20-200 nm; Depositing an n-type window layer on the high-resistance buffer layer by magnetron sputtering, wherein the thickness of the n-type window layer is 30-150 nm; Depositing an absorption layer on the n-type window layer by using a space sublimation method, wherein the absorption layer has a thickness of 1-10 um; A back base layer and a back electrode layer are sequentially deposited on the absorption layer to obtain a thin film solar cell.

10. The method for preparing a thin film solar cell according to claim 9, characterized in that: The absorption layer deposited on the n-type window layer is a cadmium telluride absorption layer. After the deposition is completed, a 5% CdCl2 solution is sprayed on the cadmium telluride absorption layer, treated in a nitrogen atmosphere at 400°C for 30 minutes, and etched with a phosphorus nitric acid solution for 10 seconds, then rinsed with ultrapure water and blown dry with nitrogen.

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