阅读说明：本技术 一种三步硫化工艺制备铜锌锡硫薄膜吸收层的方法 (Method for preparing copper-zinc-tin-sulfur film absorption layer by three-step vulcanization process ) 是由 申绪男 张超 冯洋 于 2019-11-21 设计创作，主要内容包括：本发明公开了一种三步硫化工艺制备铜锌锡硫薄膜吸收层的方法,属于高质量铜锌锡硫薄膜吸收层制备技术领域,其特征在于,包括如下步骤：S1、在真空退火炉中,放置热舟,在舟上方放置前驱体膜,热舟中放置5g硫粉,抽真空到10<Sup>-3</Sup>Pa后,对热舟进行快速加热,使其20秒到达800℃,而前驱体膜不加热,膜温度低于50℃,保持10分钟,使得硫原子能够均匀扩散到前驱体膜中；S2、将前驱体膜取出放入管式炉中,通入氩气,使得气压保持在1.2个大气压,加热管式炉到540℃-580℃,保持10分钟,降温；S3、将管式炉气压降至1个大气压,温度保持在250℃-300℃,保持10分钟,去除残留的硫,然后降至室温。(The invention discloses a method for preparing a copper-zinc-tin-sulfur film absorbing layer by a three-step vulcanization process, which belongs to the technical field of preparation of high-quality copper-zinc-tin-sulfur film absorbing layers and is characterized by comprising the following steps of: s1, placing a hot boat in a vacuum annealing furnace, placing a precursor film above the boat, placing 5g of sulfur powder in the hot boat, and vacuumizing to 10 DEG ‑3 After Pa, rapidly heating the heat boat to enable the heat boat to reach 800 ℃ in 20 seconds, and keeping the precursor film for 10 minutes without heating the precursor film, wherein the film temperature is lower than 50 ℃, so that sulfur atoms can be uniformly diffused into the precursor film; s2, taking out the precursor film, putting the precursor film into a tube furnace, introducing argon gas to keep the air pressure at 1.2 atmospheric pressures, heating the tube furnace to 540-580 DEG CKeeping the temperature for 10 minutes, and cooling; s3, reducing the pressure of the tube furnace to 1 atmosphere, keeping the temperature at 250-300 ℃, keeping the temperature for 10 minutes, removing residual sulfur, and then reducing the temperature to room temperature.)

1. A method for preparing a copper-zinc-tin-sulfur thin film absorption layer by a three-step vulcanization process is characterized in that a precursor film containing copper, zinc and tin elements is prepared on a double-layer Mo back electrode by a sputtering or coating method, and then annealing is carried out in a sulfur atmosphere to form a high-quality copper-zinc-tin-sulfur absorption layer thin film; the method comprises the following steps:

s1, placing a hot boat in a vacuum annealing furnace, placing a precursor film above the boat, placing 5g of sulfur powder in the hot boat, and vacuumizing to 10 DEG^-3After Pa, rapidly heating the heat boat to enable the heat boat to reach 800 ℃ in 20 seconds, and keeping the precursor film for 10 minutes without heating the precursor film, wherein the film temperature is lower than 50 ℃, so that sulfur atoms can be uniformly diffused into the precursor film;

s2, taking out the precursor film, placing the precursor film into a tube furnace, introducing argon gas to keep the air pressure at 1.2 atmospheric pressures, heating the tube furnace to 540-580 ℃, keeping the temperature for 10 minutes, and cooling;

s3, reducing the pressure of the tube furnace to 1 atmosphere, keeping the temperature at 250-300 ℃, keeping the temperature for 10 minutes, removing residual sulfur, and then reducing the temperature to room temperature.

2. The method for preparing a CZTS thin film absorption layer according to claim 1, wherein a hot tube furnace is heated to 540 ℃ in S2.

3. The method for preparing a CZTS thin film absorption layer according to claim 1, wherein a hot tube furnace is heated to 580 ℃ in S2.

4. The method for preparing a CZTS thin film absorption layer according to claim 1, wherein the temperature is maintained at 250 ℃ in S3.

5. The method for preparing a CZTS thin film absorption layer according to claim 1, wherein the temperature is maintained at 300 ℃ in S3.

Technical Field

The invention belongs to the technical field of preparation of high-quality copper-zinc-tin-sulfur thin film absorbing layers, and particularly relates to a method for preparing a copper-zinc-tin-sulfur thin film absorbing layer by a three-step vulcanization process.

Background

As fossil energy is often accompanied by serious environmental pollution problems, the demand and the emphasis of renewable energy is increasing. Solar cells have many advantages such as cleanness, renewability and inexhaustibility of energy, and have gradually become one of effective approaches to solving energy crisis and environmental crisis.

Among various solar cells, thin film solar cells are the hot point of research at present due to the advantages of few materials, ultrahigh light absorption coefficient of direct band gap materials, suitability for flexible substrate preparation and the like. Of these, Copper Indium Gallium Selenide (CIGS) and cadmium telluride (CdTe) materials are the most representative and have been developed. However, CdTe and CIGS and CdTe solar cells employ rare and toxic elements (mainly Cd), which largely limits the progress of industrialization of these two thin film solar cells. For the reasons, researchers have focused their research on materials that are non-toxic and rich in raw materials, copper-zinc-tin-sulfur (Cu)₂ZnSnS₄CZTS) solar cells have become a new research hotspot. Summarizing various methods for preparing CZTS absorbing layers, such as sputtering, nano-coating, sol-gel, etc., can be roughly divided into two steps. Firstly, preparing a precursor film containing elements such as copper, zinc, tin and the like, and then annealing in a sulfur atmosphere to form a CZTS absorption layer film meeting the requirements. Two common sources of elemental sulfur are used, one is high purity sulfur powder and the other is a sulfur powder containing a proportion of hydrogen sulfide (H)₂S) mixed gas. Because hydrogen sulfide is a toxic gas, the requirement on the use condition is high, and potential danger of environmental pollution exists, and patents about the preparation of the CZTS absorption layer and the thin film battery by adopting the process are as follows: patent application No. 201210135807.7 and application No. 201310277578.7. High-purity sulfur powder is used as a sulfur raw material source, and sulfur is sublimated at low temperature (below 200 ℃), so that the raw material loss is serious, and the raw material utilization rate is low; in addition, during the diffusion process of sulfur atoms into the precursor film, the sulfur atoms react with the precursor surface film to form a large crystal grain layer, so that the sulfur atoms are prevented from further diffusing to the deep part of the precursor film, and the lower crystal grains are fineFragmentation, affecting carrier transport, limiting cell efficiency, as typified by: patent application No. 201410326643.5 and application No. 201510550954.4. A typical scanning electron microscope cross-sectional view of a CZTS film prepared by a traditional vulcanization method is shown in FIG. 1.

Disclosure of Invention

The invention provides a method for preparing a high-quality copper-zinc-tin-sulfur absorption layer film by a three-step vulcanization process for solving the technical problems (fine grain at the lower layer and low raw material utilization rate) in the known technology, and the method aims to prepare the high-quality copper-zinc-tin-sulfur absorption layer film on the basis of improving the raw material utilization rate.

The invention aims to provide a method for preparing a copper-zinc-tin-sulfur film absorbing layer by a three-step vulcanization process, which comprises the steps of preparing a precursor film containing copper, zinc and tin elements on a double-layer Mo back electrode by a sputtering or coating method, and then annealing in a sulfur atmosphere to form a high-quality copper-zinc-tin-sulfur film absorbing layer; the method comprises the following steps:

s1, placing a hot boat in a vacuum annealing furnace, placing a precursor film above the boat, placing 5g of sulfur powder in the hot boat, and vacuumizing to 10 DEG^-3After Pa, rapidly heating the heat boat to enable the heat boat to reach 800 ℃ in 20 seconds, and keeping the precursor film for 10 minutes without heating the precursor film, wherein the film temperature is lower than 50 ℃, so that sulfur atoms can be uniformly diffused into the precursor film;

s2, taking out the precursor film, placing the precursor film into a tube furnace, introducing argon gas to keep the air pressure at 1.2 atmospheric pressures, heating the tube furnace to 540-580 ℃, keeping the temperature for 10 minutes, and cooling;

s3, reducing the pressure of the tube furnace to 1 atmosphere, keeping the temperature at 250-300 ℃, keeping the temperature for 10 minutes, removing residual sulfur, and then reducing the temperature to room temperature.

Further, in the S2, the heat pipe furnace was heated to 540 ℃.

Further, in the S2, the heat pipe furnace was heated to 580 ℃.

Further, in the S3, the temperature was maintained at 250 ℃.

Further, in the S3, the temperature was maintained at 300 ℃.

The invention has the advantages and positive effects that:

according to the invention, the crystallization quality of the film is improved through a three-step vulcanization process, the proportion of each element in the film is accurately controlled, and the utilization rate of raw materials is improved. According to the invention, the high-quality copper-zinc-tin-sulfur absorption layer film can be formed by preparing the precursor film containing copper, zinc and tin elements on the double-layer Mo back electrode by using a sputtering or coating method and then annealing in a sulfur atmosphere.

Drawings

FIG. 1 is a cross-sectional view of a scanning electron microscope for preparing a CZTS absorption layer film by a traditional vulcanization process;

FIG. 2 is a flow chart of a preferred embodiment of the present invention;

FIG. 3 is a scanning electron microscope cross-sectional view of a CZTS absorber layer film after the method of the present invention is adopted

Detailed Description

In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings:

aiming at the problems that the absorption layer film is divided into two layers of lower crystal grains which are easily broken, the components are uncontrollable and the utilization rate of raw materials is low by adopting the traditional vulcanization mode, the invention designs and develops a three-step vulcanization process to improve the crystallization quality of the film, accurately control the proportion of each element in the film and improve the utilization rate of the raw materials.

Please refer to fig. 1 to 3:

the invention prepares a precursor film containing copper, zinc and tin elements on a double-layer Mo back electrode by a sputtering or coating method, and then carries out annealing in a sulfur atmosphere to form a high-quality copper-zinc-tin-sulfur absorption layer film.

The method specifically comprises the following steps:

the first step is as follows: placing a hot boat in a vacuum annealing furnace, placing a precursor film above the boat, placing 5g of sulfur powder in the hot boat, and vacuumizing to 10 DEG^-3After Pa, rapidly heating the heat boat to 800 ℃ in 20 seconds, and keeping the heat boat for 10 minutes without heating the precursor film (the film temperature is lower than 50 ℃) so that sulfur atoms can be uniformly diffused into the precursor film;

secondly, taking out the precursor film, putting the precursor film into a tube furnace, introducing argon gas to keep the air pressure at 1.2 atmospheric pressures (the positive pressure can inhibit the loss of sulfur element), heating the tube furnace to 540-580 ℃, keeping the temperature for 10 minutes, and cooling;

and thirdly, reducing the air pressure of the tube furnace to 1 atmosphere, keeping the temperature at 250-300 ℃, keeping the temperature for 10 minutes, removing residual sulfur, and then reducing the temperature to room temperature, wherein a specific process flow chart is shown in fig. 2. The cross-sectional view of the CZTS absorption layer thin film prepared by the three-step vulcanization process is shown in FIG. 3.