阅读说明：本技术 一种太阳能电池吸收层及其制备方法、太阳能电池 (Solar cell absorption layer, preparation method thereof and solar cell ) 是由 叶亚宽 郭逦达 杨立红 于 2018-06-11 设计创作，主要内容包括：本发明提供了一种太阳能电池吸收层及其制备方法、太阳能电池,该制备方法包括：在第一设定时长内,向放置有铜铟镓CIG预制膜的反应设备持续通入具有第一流量的硒蒸汽；在所述具有第一流量的硒蒸汽持续通入完成后,在第二设定时长内,向所述反应设备持续通入具有第二流量的硒蒸汽,其中,所述第二流量小于所述第一流量；利用通入硒蒸汽后的CIG预制膜形成铜铟镓硒CIGS薄膜太阳能电池吸收层。本发明提供的方案可以达到控制CIGS吸收层中Ga分布以及吸收层表面粗糙度的目的。(The invention provides a solar cell absorbing layer, a preparation method thereof and a solar cell, wherein the preparation method comprises the following steps: continuously introducing selenium steam with a first flow rate into a reaction device provided with the CIG prefabricated film within a first set time length; after the selenium steam with the first flow rate is continuously introduced, continuously introducing selenium steam with a second flow rate to the reaction equipment within a second set time period, wherein the second flow rate is smaller than the first flow rate; and forming an absorption layer of the CIG thin-film solar cell by using the CIG prefabricated film after the selenium steam is introduced. The scheme provided by the invention can achieve the purpose of controlling Ga distribution in the CIGS absorption layer and the surface roughness of the absorption layer.)

1. A method for preparing an absorption layer of a solar cell is characterized by comprising the following steps:

continuously introducing selenium steam with a first flow rate into a reaction device provided with the CIG prefabricated film within a first set time length;

after the selenium steam with the first flow rate is continuously introduced, continuously introducing selenium steam with a second flow rate to the reaction equipment within a second set time period, wherein the second flow rate is smaller than the first flow rate;

and forming an absorption layer of the CIG thin-film solar cell by using the CIG prefabricated film after the selenium steam is introduced.

2. The production method according to claim 1,

a ratio of the first flow rate to the second flow rate is equal to or greater than 5:1, or a pharmaceutically acceptable salt thereof.

3. The production method according to claim 2,

the ratio of the first flow rate to the second flow rate is 5: 1-20: 1.

4. The production method according to claim 2,

the first flow is any flow value which is greater than or equal to 5L/min;

the second flow is any flow value less than 2L/min.

5. The production method according to claim 4,

the first flow rate is 5L/min-15L/min.

6. The production method according to any one of claims 1 to 5,

in a first set duration, continuously introducing selenium steam with a first flow rate to reaction equipment provided with a copper indium gallium CIG prefabricated film, and the method comprises the following steps:

when the CIG prefabricated film is placed in the reaction equipment, selenium steam with a first flow rate is immediately introduced into the reaction equipment, and the duration of continuously introducing the selenium steam with the first flow rate is a first set duration.

7. The production method according to any one of claims 1 to 5,

after the selenium steam with the first flow rate is continuously introduced, continuously introducing selenium steam with a second flow rate to the reaction equipment within a second set time period, wherein the method comprises the following steps:

and when the continuous introduction time of the selenium steam with the first flow reaches the first set time, immediately introducing the selenium steam with the second flow into the reaction equipment, wherein the continuous introduction time of the selenium steam with the second flow is the second set time.

8. The production method according to any one of claims 1 to 5,

in a first set duration, continuously introducing selenium steam with a first flow rate to reaction equipment provided with a copper indium gallium CIG prefabricated film, and the method comprises the following steps:

when the CIG prefabricated film is placed in the reaction equipment, judging whether the current time reaches a preset first steam-through time or not;

if so, introducing selenium steam with a first flow rate into the reaction equipment, wherein the duration of continuously introducing the selenium steam with the first flow rate is a first set duration.

9. The production method according to any one of claims 1 to 5,

after the selenium steam with the first flow rate is continuously introduced, continuously introducing selenium steam with a second flow rate to the reaction equipment within a second set time period, wherein the method comprises the following steps:

when the continuous introduction time of the selenium steam with the first flow reaches the first set time, judging whether the current time reaches a preset second introduction time;

if so, introducing selenium steam with a second flow rate into the reaction equipment, wherein the duration of continuously introducing the selenium steam with the second flow rate is a second set duration.

10. The production method according to any one of claims 1 to 5,

the reaction equipment is graphite reaction equipment with the temperature of 500-700 ℃.

11. The production method according to claim 10,

the first set time is 15-120 s;

the second set time length is 15 s-480 s.

12. The production method according to claim 11,

the reaction equipment is graphite reaction equipment with the temperature of 500-580 ℃.

13. The production method according to claim 12,

the first set time is 30-120 s;

the second set time length is 270 s-480 s.

14. The production method according to claim 11,

the reaction equipment is graphite reaction equipment with the temperature of 620-700 ℃.

15. The method of claim 14,

the first set time is 15-25 s;

the second set time period is 15 s-35 s.

16. The production method according to any one of claims 1 to 15,

the CIG prefabricated film after the selenium steam is introduced is used for forming the CIGS thin-film solar cell absorption layer, and the CIGS thin-film solar cell absorption layer comprises the following components:

and (3) placing the CIG prefabricated film into which the selenium steam is introduced in an environment with the temperature of 500-590 ℃ for heat preservation for 5-30 min to form the CIGS thin-film solar cell absorption layer.

17. The production method according to any one of claims 1 to 15,

the selenium vapor is pure selenium vapor, or comprises hydrogen selenide H₂Selenium-rich gas of Se; wherein the selenium-rich gas comprises 10-15% of H₂Se。

18. The method of claim 17,

the pure selenium steam is formed by heating a solid selenium source to 250-500 ℃.

19. A solar cell absorber layer prepared by the method of any one of claims 1-18.

20. A solar cell, comprising:

the solar cell absorber layer of claim 19.

Technical Field

The invention relates to the technical field of solar cells, in particular to a solar cell absorption layer, a preparation method of the solar cell absorption layer and a solar cell.

Background

The CIGS (CIGS for short) thin-film solar cell has the advantages of high light absorption coefficient, high conversion efficiency, high stability, low cost, long service life, good low-light performance, strong radiation resistance and the like. Therefore, CIGS thin film solar cells are increasingly used in the market. The CIGS thin-film solar cell absorbing layer is the main structure in the CIGS thin-film solar cell, and the quality of the absorbing layer directly influences the performance of the CIGS thin-film solar cell.

At present, the preparation method of the CIGS thin-film solar cell absorption layer is mainly a two-step method. The process for preparing the CIGS thin-film solar cell absorption layer by adopting a two-step method generally comprises the following steps: the CIGS absorbing layer is generated by the next reaction In a saturated Se atmosphere, and the reaction process of Cu/In/Ga metal atoms and selenium Se molecules cannot be accurately controlled In the process. And because the reaction formation enthalpy of indium In, Cu and selenium Se is low, and the reaction rate is high, the Ga enrichment phenomenon appears at the bottom of the CIGS absorption layer, and small crystal grains at the bottom are formed. Alternatively, Cu/In/Ga interdiffusion is fast once selenium deficiency occurs, resulting In higher roughness of the CIGS absorber.

It is seen that the conventional method has low controllability of Ga distribution in the CIGS absorber and surface roughness of the absorber.

Disclosure of Invention

In view of the above, the present invention provides an absorber layer of a solar cell, a method for manufacturing the absorber layer, and a solar cell, and mainly aims to achieve the purpose of controlling Ga distribution in a CIGS absorber layer and roughness of the surface of the absorber layer.

In a first aspect, the present invention provides a method for preparing an absorber layer of a solar cell, the method comprising:

continuously introducing selenium steam with a first flow rate into a reaction device provided with the CIG prefabricated film within a first set time length;

after the selenium steam with the first flow rate is continuously introduced, continuously introducing selenium steam with a second flow rate to the reaction equipment within a second set time period, wherein the second flow rate is smaller than the first flow rate;

and forming an absorption layer of the CIG thin-film solar cell by using the CIG prefabricated film after the selenium steam is introduced.

Preferably, the first and second electrodes are formed of a metal,

a ratio of the first flow rate to the second flow rate is equal to or greater than 5:1, or a pharmaceutically acceptable salt thereof.

Preferably, the first and second electrodes are formed of a metal,

the ratio of the first flow rate to the second flow rate is 5: 1-20: 1.

Preferably, the first and second electrodes are formed of a metal,

the first flow is any flow value which is greater than or equal to 5L/min;

the second flow is any flow value less than 2L/min.

Preferably, the first and second electrodes are formed of a metal,

the first flow rate is 5L/min-15L/min.

Preferably, the first and second electrodes are formed of a metal,

in a first set duration, continuously introducing selenium steam with a first flow rate to reaction equipment provided with a copper indium gallium CIG prefabricated film, and the method comprises the following steps:

when the CIG prefabricated film is placed in the reaction equipment, selenium steam with a first flow rate is immediately introduced into the reaction equipment, and the duration of continuously introducing the selenium steam with the first flow rate is a first set duration.

Preferably, the first and second electrodes are formed of a metal,

after the selenium steam with the first flow rate is continuously introduced, continuously introducing selenium steam with a second flow rate to the reaction equipment within a second set time period, wherein the method comprises the following steps:

and when the continuous introduction time of the selenium steam with the first flow reaches the first set time, immediately introducing the selenium steam with the second flow into the reaction equipment, wherein the continuous introduction time of the selenium steam with the second flow is the second set time.

Preferably, the first and second electrodes are formed of a metal,

in a first set duration, continuously introducing selenium steam with a first flow rate to reaction equipment provided with a copper indium gallium CIG prefabricated film, and the method comprises the following steps:

when the CIG prefabricated film is placed in the reaction equipment, judging whether the current time reaches a preset first steam-through time or not;

if so, introducing selenium steam with a first flow rate into the reaction equipment, wherein the duration of continuously introducing the selenium steam with the first flow rate is a first set duration.

Preferably, the first and second electrodes are formed of a metal,

after the selenium steam with the first flow rate is continuously introduced, continuously introducing selenium steam with a second flow rate to the reaction equipment within a second set time period, wherein the method comprises the following steps:

when the continuous introduction time of the selenium steam with the first flow reaches the first set time, judging whether the current time reaches a preset second introduction time;

if so, introducing selenium steam with a second flow rate into the reaction equipment, wherein the duration of continuously introducing the selenium steam with the second flow rate is a second set duration.

Preferably, the first and second electrodes are formed of a metal,

the reaction equipment is graphite reaction equipment with the temperature of 500-700 ℃.

Preferably, the first and second electrodes are formed of a metal,

the first set time is 15-120 s;

the second set time length is 15 s-480 s.

Preferably, the first and second electrodes are formed of a metal,

the reaction equipment is graphite reaction equipment with the temperature of 500-580 ℃.

Preferably, the first and second electrodes are formed of a metal,

the first set time is 30-120 s;

the second set time length is 270 s-480 s.

Preferably, the first and second electrodes are formed of a metal,

the reaction equipment is graphite reaction equipment with the temperature of 620-700 ℃.

Preferably, the first and second electrodes are formed of a metal,

the first set time is 15-25 s;

the second set time period is 15 s-35 s.

Preferably, the first and second electrodes are formed of a metal,

the CIG prefabricated film after the selenium steam is introduced is used for forming the CIGS thin-film solar cell absorption layer, and the CIGS thin-film solar cell absorption layer comprises the following components:

placing the CIG prefabricated film which is introduced with the selenium steam in an environment with the temperature of 500-590 ℃ for heat preservation for 5-30 min to form the CIGS thin-film solar cell absorption layer

Preferably, the first and second electrodes are formed of a metal,

the selenium steam is pure selenium steam or selenium-rich gas containing hydrogen selenide H2 Se; wherein the selenium-rich gas comprises 10-15% of H2 Se.

Preferably, the first and second electrodes are formed of a metal,

the pure selenium steam is formed by heating a solid selenium source to 250-500 ℃.

In a second aspect, the invention provides a solar cell absorbing layer prepared by the preparation method of the solar cell absorbing layer.

In a third aspect, the present invention provides a solar cell comprising:

the solar cell absorption layer is described above.

The embodiment of the invention provides a solar cell absorbing layer, a preparation method thereof and a solar cell. And then after the selenium steam with the first flow rate is continuously introduced, continuously introducing the selenium steam with the second flow rate into the reaction equipment within a second set time period, so that the CIG prefabricated membrane reacts with the selenium steam with the second flow rate within the second set time period. It is noted that the second flow rate is less than the first flow rate. And finally, forming an absorption layer of the CIG thin-film solar cell by using the CIG prefabricated film into which the selenium steam is introduced. According to the scheme, the CIG prefabricated membrane placed in the reaction equipment is firstly introduced with the selenium steam with higher flow and then introduced with the selenium steam with lower flow. The selenium steam with higher flow rate is firstly introduced to form partial unsaturated chemical bonds on the surface of the CIG prefabricated film, and selenium atoms can diffuse to the bottom of the absorption layer through the unsaturated bonds. And then, introducing selenium steam with a lower flow rate, wherein the selenium steam with the lower flow rate does not quickly saturate unsaturated bonds, so that the loss of In and Ga elements In the CIG prefabricated film and the dispersion segregation phenomenon of the In and Ga elements are avoided. At the moment, the selenium atoms can also be rapidly diffused to the bottom of the absorption layer through unsaturated bonds, so that the phenomenon that Ga element is enriched to the bottom of the absorption layer is reduced. It can be seen that the CIG pre-fabricated film is treated with the selenium vapor at a higher flow rate and the selenium vapor at a lower flow rate, respectively. Not only can reduce the enrichment phenomenon of Ga element to the bottom of the absorption layer, but also can improve the grain size of the CIGS. Therefore, the scheme provided by the embodiment of the invention can achieve the purpose of controlling the Ga distribution in the CIGS absorption layer and the surface roughness of the absorption layer.

The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a flow chart illustrating a method for manufacturing an absorber layer of a solar cell according to an embodiment of the present invention;

fig. 2 is a flow chart illustrating a method for fabricating an absorber layer of a solar cell according to another embodiment of the present invention;

FIG. 3 is a flow chart illustrating a method for fabricating an absorber layer of a solar cell according to yet another embodiment of the present invention;

FIG. 4 is a flow chart illustrating a method for fabricating an absorber layer of a solar cell according to yet another embodiment of the present invention;

fig. 5 is a flowchart illustrating a method for manufacturing an absorber layer of a solar cell according to another embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

As shown in fig. 1, an embodiment of the present invention provides a method for preparing an absorption layer of a solar cell, where the method for preparing the absorption layer of the solar cell may include:

step 101: continuously introducing selenium steam with a first flow rate into a reaction device provided with the CIG prefabricated film within a first set time length;

step 102: after the selenium steam with the first flow rate is continuously introduced, continuously introducing selenium steam with a second flow rate to the reaction equipment within a second set time period, wherein the second flow rate is smaller than the first flow rate;

step 103: and forming an absorption layer of the CIG thin-film solar cell by using the CIG prefabricated film after the selenium steam is introduced.

According to the embodiment shown in fig. 1, selenium steam with a first flow rate is continuously introduced into a reaction device with a copper indium gallium CIG prefabricated film placed therein for a first set time period, so that the CIG prefabricated film reacts with the selenium steam with the first flow rate for the first set time period. And then after the selenium steam with the first flow rate is continuously introduced, continuously introducing the selenium steam with the second flow rate into the reaction equipment within a second set time period, so that the CIG prefabricated membrane reacts with the selenium steam with the second flow rate within the second set time period. It is noted that the second flow rate is less than the first flow rate. And finally, forming an absorption layer of the CIG thin-film solar cell by using the CIG prefabricated film into which the selenium steam is introduced. According to the scheme, the CIG prefabricated membrane placed in the reaction equipment is firstly introduced with the selenium steam with higher flow and then introduced with the selenium steam with lower flow. The selenium steam with higher flow rate is firstly introduced to form partial unsaturated chemical bonds on the surface of the CIG prefabricated film, and selenium atoms can diffuse to the bottom of the absorption layer through the unsaturated bonds. And then, introducing selenium steam with a lower flow rate, wherein the selenium steam with the lower flow rate does not quickly saturate unsaturated bonds, so that the loss of In and Ga elements In the CIG prefabricated film and the dispersion segregation phenomenon of the In and Ga elements are avoided. At the moment, the selenium atoms can also be rapidly diffused to the bottom of the absorption layer through unsaturated bonds, so that the phenomenon that Ga element is enriched to the bottom of the absorption layer is reduced. It can be seen that the CIG pre-fabricated film is treated with the selenium vapor at a higher flow rate and the selenium vapor at a lower flow rate, respectively. Not only can reduce the enrichment phenomenon of Ga element to the bottom of the absorption layer, but also can improve the grain size of the CIGS. Therefore, the scheme provided by the embodiment of the invention can achieve the purpose of controlling the Ga distribution in the CIGS absorption layer and the surface roughness of the absorption layer.

Each step and the important parameters involved therein are described in detail below.

With respect to step 101

In an embodiment of the present invention, the method for implementing step 101 in the flowchart shown in fig. 1 includes at least the following two methods:

the method comprises the following steps: when the CIG prefabricated film is placed in the reaction equipment, selenium steam with a first flow rate is immediately introduced into the reaction equipment, and the duration of continuously introducing the selenium steam with the first flow rate is a first set duration.

In this embodiment, the first set time duration may be determined according to a service requirement. For example, it may be 15s to 120 s.

In the present embodiment, the following are exemplified: when the CIG prefabricated film is placed in a reaction device, selenium steam is immediately introduced into the reaction device, the flow rate of the selenium steam is 10L/min, and the duration of the selenium steam introduction is 100 s.

In the present embodiment, the following are exemplified: when the CIG prefabricated film is placed in the reaction equipment, selenium steam is immediately introduced into the reaction equipment, the flow rate of the selenium steam is 7L/min, and the duration of continuously introducing the selenium steam is 35s of a first set duration.

According to the above embodiment, since the selenium vapor having the first flow rate is introduced into the reaction apparatus immediately when the CIG prefabricated film is placed in the reaction apparatus. The CIG prefabricated film has low probability of property change. Therefore, the quality of the prepared CIG prefabricated film is better.

The second method comprises the following steps: when the CIG prefabricated film is placed in the reaction equipment, judging whether the current time reaches a preset first steam-through time or not;

if so, introducing selenium steam with a first flow rate into the reaction equipment, wherein the duration of continuously introducing the selenium steam with the first flow rate is a first set duration.

In this embodiment, when the CIG prefabricated film is required to be left standing in the reaction equipment for a certain period of time, the first steam-through time may be set. For example, the first steam-passing time and the time of the CIG prefabricated film in the reaction equipment have a time interval of 0-3 min.

In this embodiment, when the CIG prefabricated film is placed in the reaction equipment, it is determined whether the current time reaches the first steam admission time. If not, the situation shows that the selenium steam with the first flow rate cannot be introduced into the reaction equipment at the current time. If so, indicating that the selenium steam with the first flow needs to be introduced into the reaction equipment at the current time, starting to introduce the selenium steam with the first flow into the reaction equipment, and setting the duration of continuously introducing the selenium steam with the first flow as a first set duration.

According to the embodiment, the first steam through time is set firstly, and then whether the current time reaches the first steam through time or not is judged when the CIG prefabricated film is placed into the reaction equipment. And when the current time is judged to reach the first steam introducing time, introducing selenium steam with a first flow rate into the reaction equipment. When the CIG prefabricated membrane is required to be kept still in the reaction equipment for a period of time, selenium steam with a first flow rate is automatically introduced according to the correlation between the current time and the set steam introducing time. Therefore, the service application is more flexible.

With respect to step 102

In one embodiment of the present invention, the method for implementing step 102 in the flowchart shown in fig. 1 includes at least the following two methods:

the method comprises the following steps: and when the continuous introduction time of the selenium steam with the first flow reaches the first set time, immediately introducing the selenium steam with the second flow into the reaction equipment, wherein the continuous introduction time of the selenium steam with the second flow is the second set time.

In this embodiment, the second set time duration may be determined according to the service requirement. For example, it may be 15s to 480 s.

In the present embodiment, the following are exemplified: when the continuous selenium steam feeding duration with the first flow reaches the first set duration 65s, selenium steam feeding with a second flow rate of 0.12L/min is immediately started to the reaction equipment. And the continuous introduction time period of the selenium steam with the second flow rate is a second set time period of '300 s'.

In the present embodiment, the following are exemplified: when the continuous selenium steam introducing time period with the first flow reaches 35s of the first set time period, selenium steam with the second flow of 1L/min is introduced into the reaction equipment immediately, and the continuous selenium steam introducing time period with the second flow of selenium steam is 20s of the second set time period.

According to the above embodiment, since the selenium vapor having the second flow rate is immediately started to be introduced into the reaction apparatus when the continuous introduction time period of the selenium vapor having the first flow rate reaches the first set time period. There is no time interval between the two kinds of flux selenium steam and the probability of CIG prefabricated film property change is lower. Therefore, the quality of the prepared CIG prefabricated film is better.

The second method comprises the following steps: when the continuous introduction time of the selenium steam with the first flow reaches the first set time, judging whether the current time reaches a preset second introduction time;

if so, introducing selenium steam with a second flow rate into the reaction equipment, wherein the duration of continuously introducing the selenium steam with the second flow rate is a second set duration.

In this embodiment, when the CIG prefabricated film is allowed to stand in the reaction equipment for a period of time after selenium steam with a first flow rate is introduced, a second flow time may be set. For example, the second steam flowing time and the stopping time for stopping flowing the steam with the first flow rate have a time interval of 0-3 min.

In this embodiment, when the continuous selenium steam with the first flow rate is continuously introduced for a long time reaching a first set time, the selenium steam with the first flow rate is stopped to be introduced, and meanwhile, whether the current time reaches a second preset steam introduction time is judged. If not, selenium steam with a second flow rate is not introduced into the reaction equipment. If so, introducing selenium steam with a second flow rate into the reaction equipment, wherein the duration of continuously introducing the selenium steam with the second flow rate is a second set duration.

According to the embodiment, the second ventilation time is set firstly, and then when the continuous ventilation time of the selenium steam with the first flow reaches the first set time, whether the current time reaches the second ventilation time is judged. And when the current time is judged to reach the second steam-venting time, introducing selenium steam with a second flow rate into the reaction equipment. When the CIG prefabricated film is required to be kept still in the reaction equipment for a period of time, selenium steam with a second flow rate is automatically introduced according to the correlation between the current time and the set steam introducing time. Therefore, the service application is more flexible.

With respect to the first flow rate and the second flow rate

The relationship between the first flow rate and the second flow rate in the flowchart shown in fig. 1 is at least three types:

the first method comprises the following steps: in one embodiment of the invention, the ratio of the first flow rate to the second flow rate is equal to or greater than 5:1, or a pharmaceutically acceptable salt thereof.

In the present embodiment, for example, the ratio of the first flow rate to the second flow rate is 30: 1.

And the second method comprises the following steps: in one embodiment of the present invention, the ratio of the first flow rate to the second flow rate is 5:1 to 20: 1.

In this embodiment, the first flow rate is greater than the second flow rate, and a ratio between the first flow rate and the second flow rate may be any ratio of 5:1 to 20: 1.

In this embodiment, for example, the ratio of the first flow rate to the second flow rate may be selected to be 7.5: 1. 8:1 and 11.3: 1.

In this embodiment, the first traffic and the second traffic may select any traffic according to the service requirement. However, it should be noted that the ratio between the first flow rate and the second flow rate is any ratio of 5:1 to 20: 1. For example, the following steps are carried out: and the ratio of the first flow rate to the second flow rate is 14:1, and the first flow rate is 30L/min, and then the second flow rate is determined to be 2.14L/min according to the ratio.

According to the embodiment, the ratio of the first flow rate to the second flow rate is any ratio of 5:1 to 20: 1. Therefore, no matter what specific flow value the first flow and the second flow are determined, the ratio of the first flow to the second flow can be any ratio of 5: 1-20: 1. Therefore, the service applicability is strong.

And the third is that: in one embodiment of the invention, the first flow rate is any flow rate value greater than or equal to 5L/min; the second flow is any flow value less than 2L/min. And the ratio of the first flow to the second flow is any ratio of 5: 1-20: 1.

In the present embodiment, the following are exemplified: the first flow rate is 5L/min-15L/min.

In the present embodiment, the following are exemplified: the ratio of the first flow rate to the second flow rate is determined to be 6:1, the first flow rate is 7L/min, and the second flow rate is 1.17L/min.

According to the above embodiment, since the first flow rate is any one of 5L/min to 15L/min, the second flow rate may be any one of less than 2L/min. And the ratio of the first flow to the second flow needs to be ensured to be any ratio of 5: 1-20: 1. Therefore, the determined first flow and the second flow can better meet the service requirement under the limiting conditions of the flow values and the ratio.

With respect to the first set duration and the second set durationSetting a time duration

In one embodiment of the present invention, the first set time period referred to in the above flowchart of fig. 1 is 15s to 120s, and the second set time period is 15s to 480 s.

In the present embodiment, the reaction rate between the CIG prefabricated film and the selenium vapor and the properties of the substrate on which the back electrode is disposed need to be fully considered when determining the first set time period and the second set time period. For example, when the melting point of the substrate on which the back electrode is located is low and the temperature in the reaction apparatus is high, the first set time period and the second set time period may each be selected to be shorter. If the temperature in the graphite reaction apparatus is low, the first set period of time and the second set period of time may each be selected to be longer for more complete reaction.

For example, the CIG prefabricated film is placed in a graphite reaction device with the temperature of 500-580 ℃, and the temperature of 500-580 ℃ is lower than the melting point of the glass substrate where the back electrode in the CIG prefabricated film is located, so that the first time period can be 30-120 s, and the second time period can be 270-480 s.

In the present embodiment, the following are exemplified: the temperature in the graphite reaction equipment is 513 ℃, and the temperature is lower than the melting point of the substrate on which the back electrode is arranged. The first duration may be 85s and the second duration may be 410 s.

In the present embodiment, the following are exemplified: the temperature in the graphite reaction equipment is 535 ℃, and the temperature is lower than the melting point of the glass substrate where the back electrode in the CIG prefabricated film is located. The first duration may be 100s and the second duration may be 370 s.

For another example, the CIG prefabricated film is placed in a graphite reaction device at a temperature of 620-700 ℃, and since the temperature of 620-700 ℃ is greater than or almost equal to the melting point of the glass substrate where the back electrode in the CIG prefabricated film is located, the first time period may be 15-25 s and the second time period may be 15-25 s in order to reduce the probability of substrate melting.

In the present embodiment, the following are exemplified: when the temperature in the graphite reaction equipment is 650 ℃, the temperature is higher than the melting point of the substrate where the back electrode in the CIG prefabricated film is located. The first time period may be 20s and the second time period may be 20 s.

In the present embodiment, the following are exemplified: when the temperature in the graphite reaction equipment is 663 ℃, the temperature is higher than the melting point of the glass substrate where the back electrode in the CIG prefabricated film is located. The first time period may be 18s and the second time period may be 23 s.

In the present embodiment, the following are exemplified: when the temperature in the graphite reaction equipment is 630 ℃, the temperature is higher than the melting point of the glass substrate where the back electrode in the CIG prefabricated film is located. The first duration may be 24s and the second duration may be 22 s.

CIG prefabricated film

In one embodiment of the present invention, the CIG prefabricated film referred to in the flowchart shown in fig. 1 may be prepared on a selected back electrode, and the method for preparing the CIG prefabricated film may include:

sputtering by using a copper gallium alloy CuGa target material, and depositing a CuGa alloy layer on the back electrode;

and sputtering by using an indium In target material, and depositing an In layer on the CuGa alloy layer to form the CIG prefabricated film.

In this example, the back electrode concerned is a molybdenum Mo layer deposited on a soda-lime glass substrate. Preferably, the thickness of the Mo layer is 300nm to 1000 nm. For example 700 nm. Also preferably, the soda lime glass substrate has a thickness of 2.0mm to 3.2 mm. Such as 2.8mm, 3 mm.

In the present embodiment, any method known In the art can be used for the method of sputtering using a copper gallium alloy target and the method of sputtering using an indium In target. For example, Direct Current (DC) magnetron sputtering, or intermediate frequency (MF) magnetron sputtering may be included, but is not limited thereto.

In this embodiment, the specific type of the In target material can also be determined according to the business requirements. For example, the target material may be an alloy target material containing In, or may be a pure In target material. Preferably, an In target may be selected.

In this embodiment, the thickness of the CuGa alloy layer can be adjusted by controlling parameters such as sputtering duration, sputtering current, target current, and sputtering ambient pressure. And the thickness of the CuGa alloy layer can be determined according to the service requirement. For example, the thickness of the CuGa alloy layer is preferably 200nm to 450 nm. For example, the following steps are carried out: the thickness of the CuGa alloy layer is 300 nm.

In the present embodiment, the thickness of the In layer can also be adjusted by controlling parameters such as sputtering duration, sputtering current, target current, sputtering ambient pressure, and the like. The thickness of the In layer can also be determined according to business requirements. For example, the thickness of the In layer is preferably 150nm to 400 nm. For example, the following steps are carried out: the thickness of the In layer was 250 nm.

In the present embodiment, it can be seen that the CIG prefabricated film includes a CuGa alloy layer and an In layer. Wherein the CuGa alloy layer covers the back electrode, and the In layer covers the CuGa alloy layer.

According to the above embodiment, a CuGa alloy layer is deposited on the back electrode by first sputtering using a copper-gallium-alloy target. And then, sputtering by using an In target, depositing an In layer on the formed CuGa alloy layer, and finally forming the CIG prefabricated film. The CIG prefabricated film is prepared by adopting a sputtering method, so that the prepared CIG prefabricated film has strong bonding force with the back electrode, and is more compact and uniform.

In the present embodiment, the atomic ratio in the CIG prefabricated film may be controlled during the process of manufacturing the CIG prefabricated film. For example, the target material type, sputtering time, sputtering current, target current, sputtering environment pressure and other parameters can be used for adjustment.

About a reaction device

In one embodiment of the present invention, the reaction apparatus in the flow chart shown in fig. 1 may be a graphite reaction apparatus with a temperature of 500 to 700 ℃.

In this embodiment, the temperature of the graphite reaction equipment can be determined according to the business requirements. For example, the temperature of the graphite reaction apparatus may be set to be a little higher when the melting point of the substrate on which the back electrode is located is higher. The temperature of the graphite reaction apparatus can be set to be a little lower when the melting point of the substrate on which the back electrode is located is low.

According to the embodiment, the reaction equipment is graphite reaction equipment with the temperature of 500-700 ℃. Therefore, the reaction between the CIG prefabricated film and the selenium steam is more facilitated.

In one embodiment of the present invention, the reaction apparatus according to the flow chart shown in FIG. 1 may be pre-charged with selenium vapor. The selenium steam can be uniformly filled in the space of the graphite reaction equipment for placing the CIG prefabricated film.

The selenium vapor is pure selenium vapor, or comprises hydrogen selenide H₂Se-rich gas, wherein the Se-rich gas contains 10-15% of H₂Se。

In this embodiment, when the selenium vapor is pure selenium vapor, the selenium vapor may be formed by heating a solid selenium source to 250 ℃ to 500 ℃. In the presence of selenium vapour comprising H₂When Se-rich gas is used, the Se-rich gas contains 10-15% of H₂And (5) Se. For example comprising 13% of H₂Se。

In the present embodiment, the following are exemplified: the solid selenium source is heated to 250-470 ℃ to form selenium vapor.

In the present embodiment, the following are exemplified: the solid selenium source is heated to 380-500 deg.c to form selenium vapor.

In one embodiment of the present invention, the pressure of the selenium vapor involved in the above-described flow chart shown in FIG. 1 is 1Pa to 1 atm. For example, the following steps are carried out: the pressure of the selenium steam is 5000 Pa.

According to the embodiment, since the graphite reaction device is pre-filled with selenium steam, the CIG prefabricated film is directly placed in the selenium atmosphere when being placed in the graphite reaction device. Therefore, the reaction between the CIG prefabricated film and the selenium steam is more facilitated. In addition, the selenium steam can be pure selenium steam or contain 10% -15% of H₂Se-rich gas. Therefore, the specific type of selenium steam can be flexibly selected according to the service requirement.

With respect to step 103

In an embodiment of the present invention, the step 103 in the flowchart shown in fig. 1, which forms the CIGs thin film solar cell absorber layer by using the CIG prefabricated film after selenium vapor is introduced, may include:

and placing the CIG prefabricated film into which the selenium steam is introduced in an environment with the temperature of 500-590 ℃, and preserving the heat for 5-30 min to form the CIGS thin-film solar cell absorption layer. In this embodiment, the ambient temperature and the holding time required for annealing can be determined according to the business requirements. For example, the temperature is 580 ℃ and the holding time is 25 min.

In the present embodiment, the following are exemplified: and (3) placing the CIG prefabricated film into which the selenium steam is introduced in an environment with the temperature of 520 ℃, and preserving the heat for 20 min.

In the present embodiment, the following are exemplified: and (3) placing the CIG prefabricated film into which the selenium steam is introduced in an environment with the temperature of 537 ℃, and preserving the heat for 6 min.

According to the embodiment, the CIG prefabricated film which is introduced with the selenium steam is placed in the environment with the temperature of 500-590 ℃ for heat preservation for 5-30 min, so that the aim of annealing is fulfilled. The CIG prefabricated film is subjected to annealing treatment. And in the annealing process, the particles in the CIG prefabricated film can be refined, and the residual internal stress in the CIG prefabricated film is eliminated. Therefore, the performance of the obtained CIGS thin-film solar cell absorption layer is good.

The following method for preparing the solar cell absorber layer is described in detail in examples 1 to 4: