Processing method for cadmium telluride laser high-density surface oxidation treatment

Abstract

The invention discloses a processing method for cadmium telluride laser high-density surface oxidation treatment, and relates to the technical field of cadmium telluride photovoltaic power generation glass processing, and the processing method specifically comprises the following steps: processing a substrate to obtain a plated light absorption layer, then carrying out activation and high-density laser surface treatment on the plated light absorption layer to form a surface oxidation film, and continuing to prepare a back contact layer; the back contact layer is subjected to laser etching to manufacture a back electrode layer, finally, the back electrode layer is subjected to laser edge cleaning, testing and packaging in sequence, and oxygen is introduced during high-density laser surface treatment. According to the invention, the processing method is changed, the cadmium telluride film surface is subjected to micro-oxidation treatment, and an oxidation film layer is formed between the back contact and the cadmium telluride, so that the potential barrier is reduced, the diffusion of doped copper elements is prevented, and the stability of the cadmium telluride battery is improved.

Description

Technical Field

[0001] The invention relates to the technical field of cadmium telluride photovoltaic power generation glass processing, and in particular to a processing method for cadmium telluride laser high-density surface oxidation treatment. Background Art

[0002] At present, cadmium telluride photovoltaic glass has been found to have a certain attenuation during its application. The main reason is that in the preparation process of cadmium telluride solar thin-film cells, in order to solve the back contact barrier problem and reduce the interface resistance, doping is carried out in the back contact material, mainly copper elements. However, because copper atoms are relatively small, and after cadmium telluride is treated, there are still certain defects in the grain boundaries, which causes copper atoms to diffuse, resulting in an increase in the back contact barrier and series resistance. At the same time, the diffusion of copper atoms will lead to an increase in composite defects and a decrease in battery performance.

[0003] At present, the surface of cadmium telluride is generally not treated or treated with acid before back contact. Usually, hydrochloric acid with a concentration of 30wt% is used, and a certain low solution concentration of 1-5wt% is configured in the solution tank. The surface is treated by immersion cleaning. However, this method has the following problems: (1) The surface parameters of solution etching are uncontrollable, difficult to monitor, and difficult to troubleshoot; (2) Affected by fluctuations in solution concentration or immersion time, the fluctuations are relatively large, which affects product consistency; (3) Acid solutions also have a relatively large impact on personnel safety and environmental safety; (4) Waste liquid can only be discharged after factory treatment, which increases costs; (5) The procedures for transportation and storage of acid solutions are cumbersome and costly. Therefore, further improvements are needed to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a processing method for high-density laser surface oxidation treatment of cadmium telluride.

[0005] The technical solution of the present invention is as follows:

[0006] A processing method for high-density laser surface oxidation treatment of cadmium telluride, wherein a light-plated absorption layer is obtained by processing a substrate, and then the light-plated absorption layer is activated and subjected to high-density laser surface treatment to form a surface oxide film, and then a back contact layer is prepared, and the back contact layer is laser-etched to form a back electrode layer, and finally the back electrode layer is sequentially laser-cleared, tested, and packaged, wherein oxygen is introduced while the high-density laser surface treatment is performed.

[0007] As a preferred embodiment of the present invention, the high-density laser surface treatment is specifically as follows:

[0008] It uses picosecond infrared laser processing with a wavelength of 1064 nanometers;

[0009] The laser power is 35-50W and the frequency is 150-200KHz;

[0010] The energy density is 200-350uj.

[0011] As a preferred embodiment of the present invention, the processing is carried out on the film surface after the activation of the plated light absorption layer, the processing speed is 3000-5000 mm / s, and the laser processing spot size is 0.9-1 mm.

[0012] As a preferred embodiment of the present invention, the flow rate of the oxygen gas is 500-1000 sccm.

[0013] As a preferred embodiment of the present invention, the thickness of the surface oxide film is 2-4 nm.

[0014] As a preferred solution of the present invention, the light-plating absorption layer is made of cadmium telluride.

[0015] As a preferred solution of the present invention, the back contact material is doped with copper.

[0016] As a preferred embodiment of the present invention, the activation is specifically performed using microwaves with a power of 300-500 W for 20-40 min.

[0017] The beneficial effects of the present invention are:

[0018] (1) The present invention can improve the photoelectric conversion efficiency after surface oxidation treatment by high-density laser. That is, after surface oxidation treatment, the light absorption capacity of the solar cell can be increased, thereby improving the photoelectric conversion efficiency.

[0019] (2) The present invention improves the stability of cadmium telluride glass cells after treatment. The oxide layer can provide a protective layer to prevent the back contact barrier from increasing due to the diffusion of copper atoms, thereby increasing the series resistance and significantly extending the service life of the battery.

[0020] (3) The present invention can improve current transmission through surface oxidation passivation treatment. Surface oxidation treatment can improve the transmission efficiency of electrons and holes inside the solar cell, thereby increasing current output.

[0021] (4) The present invention uses high-density laser to perform surface oxidation treatment, the process is controllable, the product consistency is improved, and it is safe and reliable.

[0022] (5) The present invention adopts high-density laser oxidation surface treatment to significantly improve the performance and stability of cadmium telluride thin film solar cells.

[0023] (6) The present invention combines microwave activation to provide more active sites on the surface of cadmium telluride, which is beneficial to the formation of oxide film and thus improves the stability of cadmium telluride. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the process flow of an embodiment of the present invention. DETAILED DESCRIPTION

[0025] Combine the following Figure 1 Embodiments of the present invention are described in detail. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0026] Example 1

[0027] A processing method for high-density laser surface oxidation treatment of cadmium telluride, wherein a light-plated absorption layer is obtained by processing a substrate, and then the light-plated absorption layer is activated and subjected to high-density laser surface treatment to form a surface oxide film, and then a back contact layer is prepared, and the back contact layer is laser-etched to form a back electrode layer, and finally the back electrode layer is sequentially laser-cleared, tested, and packaged, wherein oxygen is introduced while the high-density laser surface treatment is performed.

[0028] The high-density laser surface treatment is specifically as follows:

[0029] It uses picosecond infrared laser processing with a wavelength of 1064 nanometers;

[0030] The laser power is 35W and the frequency is 150KHz;

[0031] The energy density is 200uj.

[0032] The processing is carried out on the film surface after the activation of the plated light absorption layer, the processing speed is 3000 mm / s, and the laser processing spot size is 0.9-1 mm.

[0033] The flow rate of the oxygen gas is 500 sccm.

[0034] The thickness of the surface oxide film is 2 nm.

[0035] The light-plating absorption layer is made of cadmium telluride.

[0036] The back contact material is doped with copper, specifically copper-doped zinc telluride.

[0037] The activation is specifically carried out using microwaves with a power of 300 W for 20 minutes.

[0038] Example 2

[0039] A processing method for high-density laser surface oxidation treatment of cadmium telluride, wherein a light-plated absorption layer is obtained by processing a substrate, and then the light-plated absorption layer is activated and subjected to high-density laser surface treatment to form a surface oxide film, and then a back contact layer is prepared, and the back contact layer is laser-etched to form a back electrode layer, and finally the back electrode layer is sequentially laser-cleared, tested, and packaged, wherein oxygen is introduced while the high-density laser surface treatment is performed.

[0040] The high-density laser surface treatment is specifically as follows:

[0041] It uses picosecond infrared laser processing with a wavelength of 1064 nanometers;

[0042] The laser power is 40W and the frequency is 180KHz;

[0043] The energy density is 250uj.

[0044] The processing is carried out on the film surface after the activation of the plated light absorption layer, the processing speed is 4000mm / s, and the laser processing spot size is 0.9-1mm.

[0045] The flow rate of the oxygen gas is 6000 sccm.

[0046] The thickness of the surface oxide film is 2 nm.

[0047] The light-plating absorption layer is made of cadmium telluride.

[0048] The back contact material is doped with copper, specifically copper-doped zinc telluride.

[0049] The activation is specifically carried out using microwaves with a power of 400 W for 30 minutes.

[0050] Example 3

[0051] A processing method for high-density laser surface oxidation treatment of cadmium telluride, wherein a light-plated absorption layer is obtained by processing a substrate, and then the light-plated absorption layer is activated and subjected to high-density laser surface treatment to form a surface oxide film, and then a back contact layer is prepared, and the back contact layer is laser-etched to form a back electrode layer, and finally the back electrode layer is sequentially laser-cleared, tested, and packaged, wherein oxygen is introduced while the high-density laser surface treatment is performed.

[0052] The high-density laser surface treatment is specifically as follows:

[0053] It uses picosecond infrared laser processing with a wavelength of 1064 nanometers;

[0054] The laser power is 45W and the frequency is 180KHz;

[0055] The energy density is 300uj.

[0056] The processing is carried out on the film surface after the activation of the plated light absorption layer, the processing speed is 4000mm / s, and the laser processing spot size is 0.9-1mm.

[0057] The flow rate of the oxygen gas is 700 sccm.

[0058] The thickness of the surface oxide film is 3 nm.

[0059] The light-plating absorption layer is made of cadmium telluride.

[0060] The back contact material is doped with copper, specifically copper-doped zinc telluride.

[0061] The activation is specifically carried out using microwaves with a power of 400 W for 30 minutes.

[0062] Example 4

[0063] A processing method for high-density laser surface oxidation treatment of cadmium telluride, wherein a light-plated absorption layer is obtained by processing a substrate, and then the light-plated absorption layer is activated and subjected to high-density laser surface treatment to form a surface oxide film, and then a back contact layer is prepared, and the back contact layer is laser-etched to form a back electrode layer, and finally the back electrode layer is sequentially laser-cleared, tested, and packaged, wherein oxygen is introduced while the high-density laser surface treatment is performed.

[0064] The high-density laser surface treatment is specifically as follows:

[0065] It uses picosecond infrared laser processing with a wavelength of 1064 nanometers;

[0066] The laser power is 50W and the frequency is 200KHz;

[0067] The energy density is 350uj.

[0068] The processing is carried out on the film surface after the activation of the plated light absorption layer, the processing speed is 5000 mm / s, and the laser processing spot size is 0.9-1 mm.

[0069] The flow rate of the oxygen gas is 1000 sccm.

[0070] The thickness of the surface oxide film is 4 nm.

[0071] The light-plating absorption layer is made of cadmium telluride.

[0072] The back contact material is doped with copper, specifically copper-doped zinc telluride.

[0073] The activation is specifically carried out using microwaves with a power of 400 W for 30 minutes.

[0074] Example 5

[0075] A processing method for high-density laser surface oxidation treatment of cadmium telluride, wherein a light-plated absorption layer is obtained by processing a substrate, and then the light-plated absorption layer is activated and subjected to high-density laser surface treatment to form a surface oxide film, and then a back contact layer is prepared, and the back contact layer is laser-etched to form a back electrode layer, and finally the back electrode layer is sequentially laser-cleared, tested, and packaged, wherein oxygen is introduced while the high-density laser surface treatment is performed.

[0076] The high-density laser surface treatment is specifically as follows:

[0077] It uses picosecond infrared laser processing with a wavelength of 1064 nanometers;

[0078] The laser power is 45W and the frequency is 190KHz;

[0079] The energy density is 350uj.

[0080] The processing is carried out on the film surface after the activation of the plated light absorption layer, the processing speed is 5000 mm / s, and the laser processing spot size is 0.9-1 mm.

[0081] The flow rate of the oxygen gas is 1000 sccm.

[0082] The thickness of the surface oxide film is 4 nm.

[0083] The light-plating absorption layer is made of cadmium telluride.

[0084] The back contact material is doped with copper, specifically copper-doped zinc telluride.

[0085] The activation is specifically carried out using microwaves with a power of 500 W for 40 minutes.

[0086] Comparative Example 1

[0087] Different from Example 4, high-density laser surface treatment was not performed.

[0088] Comparative Example 2

[0089] The difference from Example 4 is that the activation step is 1 wt % hydrochloric acid cleaning for 20 min.

[0090] Comparative Example 3

[0091] Different from Example 4, high-density laser surface treatment was not performed, and the activation was performed by cleaning with 1 wt % hydrochloric acid for 20 min.

[0092] The performance of the above embodiments and comparative examples were tested, and the test results are shown in Table 1.

[0093]

[0094] It can be seen from Table 1 that the performance of the embodiment is better than that of the comparative example. The main reasons may be as follows: the embodiment adopts a method of changing the processing method to perform micro-oxidation treatment on the cadmium telluride film surface, forming an oxide film layer between the back contact and the cadmium telluride, which also reduces the potential barrier while preventing the diffusion of doped copper elements, thereby improving the stability of the cadmium telluride battery; in addition, it is combined with a microwave activation method to have more active sites on its surface, which is conducive to the formation of an oxide film, thereby improving the stability of the cadmium telluride.

[0095] The above-mentioned embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all these changes and deformations should fall within the scope of protection of the claims of the present invention.

Claims

1. A method for high-density laser surface oxidation treatment of cadmium telluride, characterized in that: The light-plated absorption layer is obtained by processing the substrate, and then the light-plated absorption layer is activated and subjected to high-density laser surface treatment to form a surface oxide film, and then the back contact layer is prepared, and the back contact layer is laser etched to form a back electrode layer. Finally, the back electrode layer is laser cleaned, tested, and packaged in sequence, wherein oxygen is introduced while the high-density laser surface treatment is performed.

2. The method for high-density laser surface oxidation treatment of cadmium telluride according to claim 1, characterized in that: The high-density laser surface treatment is specifically as follows: It uses picosecond infrared laser processing with a wavelength of 1064 nanometers; The laser power is 35-50W and the frequency is 150-200KHz; The energy density is 200-350uj.

3. The method for high-density laser surface oxidation treatment of cadmium telluride according to claim 2, characterized in that: The processing is carried out on the film surface after the activation of the plated light absorption layer, the processing speed is 3000-5000 mm / s, and the laser processing spot size is 0.9-1 mm.

4. The method for high-density laser surface oxidation treatment of cadmium telluride according to claim 1, characterized in that: The flow rate of the oxygen gas is 500-1000 sccm.

5. The method for high-density laser surface oxidation treatment of cadmium telluride according to claim 1, characterized in that: The thickness of the surface oxide film is 2-4 nm.

6. The method for high-density laser surface oxidation treatment of cadmium telluride according to claim 1, characterized in that: The light-plating absorption layer is made of cadmium telluride.

7. The method for high-density laser surface oxidation of cadmium telluride according to claim 1, characterized in that: The back contact material is doped with copper.

8. The method for high-density laser surface oxidation of cadmium telluride according to claim 1, characterized in that: The activation is specifically performed using microwaves with a power of 300-500 W for 20-40 min.

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