Method for preparing graphical semitransparent cadmium telluride thin film solar cell

Abstract

The invention discloses a method for preparing a graphical semitransparent cadmium telluride thin film solar cell. Firstly, a window layer, an ultra-thin cadmium telluride absorption layer, a transparent back contact layer and a transparent back electrode are sequentially deposited on a transparent conductive glass substrate, and then the window layer, the ultra-thin cadmium telluride absorption layer, the transparent back contact layer and the transparent back electrode in different areas are selectively etched off by adopting a laser technology according to the requirements of graphic design, so that the substrate is exposed. Wherein the parts which are not etched form a plurality of miniature semitransparent cadmium telluride thin film solar cells, and the miniature thin film solar cells form a certain pattern. The technical scheme is convenient and fast, the graphical semitransparent thin film solar cell can be obtained without a complex process, the electricity generation function is achieved, meanwhile, the aesthetic pattern effect and the light transmission characteristic are achieved, and the application prospect is wide.

Description

Technical Field

[0001] The invention belongs to the technical field of photovoltaics, and in particular relates to a method for preparing a patterned semi-transparent cadmium telluride thin-film solar cell. Background Art

[0002] Cadmium telluride thin film solar cells have the advantages of low temperature coefficient, good weak light response, high absorption coefficient and stable performance at high temperature. In addition, they have simple preparation process, low production energy consumption, low cost and are suitable for large-scale production. In recent years, the shipment volume of cadmium telluride thin film solar cell modules has far exceeded the sum of other thin film solar cells. It is the most successful commercial thin film solar cell and also one of the most important photovoltaic technologies. If the thickness of the absorption layer of cadmium telluride thin film solar cells is reduced to less than 1 micron, forming an ultra-thin cadmium telluride absorption layer, then part of the long-wavelength sunlight can pass through the absorption layer to achieve a semi-transparent effect.

[0003] However, it is difficult to obtain a dense, uniform and continuous large-size film when preparing an ultra-thin cadmium telluride absorption layer. Various minor defects such as pinholes and cracks are prone to occur, which brings challenges to obtaining large-area ultra-thin cadmium telluride thin-film solar cells.

[0004] In view of the above problems, the present invention proposes a method for preparing a patterned semi-transparent cadmium telluride thin film solar cell. By laser technology, a large area of ​​ultra-thin cadmium telluride thin film solar cells are etched and subdivided to obtain independent micro-semi-transparent cadmium telluride thin film solar cells. These micro-semi-transparent thin film solar cells form an array to form the required pattern. This technical solution is not only convenient, fast, simple and easy to implement, but also can control the movement trajectory of the laser according to the needs to form different patterns and designs. This patterned semi-transparent cadmium telluride thin film solar cell can be used as a building component of windows, fences or roofs in the field of photovoltaic building integration. On the basis of both light transmission and aesthetics, it realizes the power generation function and has broad application prospects. Summary of the invention

[0005] The present invention provides a method for preparing a patterned semi-transparent cadmium telluride thin film solar cell, which is achieved by the following technical means: 1. First, clean the glass substrate coated with fluorine doped tin dioxide (FTO) or the glass substrate coated with indium doped tin dioxide (ITO) or the glass substrate coated with other transparent conductive films with deionized water, and then blow dry with nitrogen.

[0006] 2. After cleaning and drying, a layer of cadmium sulfide (CdS) or zinc magnesium oxide (MZO) or cadmium selenide (CdSe) n-type semiconductor film or a composite film composed of them is prepared on the substrate, that is, the window layer involved in the present invention, with a thickness of 50-70 nanometers, and the preparation method is magnetron sputtering or vacuum evaporation.

[0007] 3. Depositing an ultra-thin cadmium telluride absorption layer on the window layer, the thickness of which is 0.6-1.0 micrometers, the deposition method including close-space sublimation method, vapor transport deposition method, magnetron sputtering method or vacuum evaporation method.

[0008] 4. Depositing a transparent back contact layer CuBO on the ultra-thin cadmium telluride absorption layer x , with a thickness of 10-50 nm, and the preparation method is reactive plasma deposition or magnetron sputtering deposition.

[0009] 5. Deposit tungsten-doped tin dioxide (IWO) on the transparent back contact layer as a transparent back electrode, which is prepared by reactive plasma deposition or magnetron sputtering, with a thickness of 60-120 nanometers.

[0010] 6. Use a laser with a power of 20-200 watts and a wavelength of 532nm. The laser is incident from the direction of the transparent back electrode. The laser movement trajectory is controlled according to the pattern design. The high energy generated by the laser is used to vaporize the window layer, ultra-thin cadmium telluride absorption layer, transparent back contact layer, and transparent back electrode of the semi-transparent cadmium telluride thin film solar cell, so that they are etched away, so that part of the substrate is exposed, and a patterned micro-semi-transparent cadmium telluride thin film solar cell is formed. The area of ​​a single micro-semi-transparent cadmium telluride thin film solar cell is 1-20 square millimeters, and the spacing is 2-5 millimeters.

[0011] Through the implementation of the above invention, the problem of many defects in the ultra-thin cadmium telluride absorption layer in the prior art is effectively solved, and the semi-transparent cadmium telluride thin film solar cells are conveniently and quickly prepared. The movement trajectory of the laser can be controlled according to the pattern requirements to form different patterns and designs, which has great application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The present invention is a schematic diagram of a method for preparing a patterned semi-transparent cadmium telluride thin film solar cell, wherein: 1 is a glass substrate with a transparent conductive film, 2 is a micro cadmium telluride thin film solar cell, 3 is laser light emitted by a laser, and 4 is a laser.

[0013] Figure 2 It is a schematic diagram of the structure of a single micro-transparent cadmium telluride thin film solar cell, wherein: 1 is a glass substrate with a transparent conductive film, 21 is a window layer, 22 is a semi-transparent cadmium telluride absorption layer, 23 is a transparent back contact layer, and 24 is a transparent back electrode. DETAILED DESCRIPTION

[0014] In order to make the advantages, technical solutions and implementation effects of the present invention clearer and more feasible, the present invention is further described below. It should be understood that the specific embodiments provided herein are only used to better illustrate the present invention and do not limit the present invention.

[0015] The semi-transparent cell structure is, from bottom to top, a substrate 1, a window layer 21, an ultra-thin cadmium telluride absorption layer 22, a transparent back contact layer 23, and a transparent back electrode 24. A glass substrate coated with fluorine doped tin dioxide (FTO) or a glass substrate coated with indium doped tin dioxide (ITO) or a glass substrate coated with other transparent conductive films is cleaned with deionized water and then blown dry with nitrogen. After cleaning and drying, a layer of n-type semiconductor film such as cadmium sulfide (CdS) or magnesium zinc oxide (MZO) or cadmium selenide (CdSe) or a composite film composed of them is prepared on the substrate 1, which functions as a pn junction between the n-type layer and the p-type cadmium telluride absorption layer, and allows the incident solar photons to pass through as much as possible, which is the so-called window layer 21, which has a thickness of 70 nanometers and is prepared by magnetron sputtering or vacuum evaporation. An ultra-thin cadmium telluride film with a thickness of 0.6-1.0 microns is deposited on the window layer 21. Its function is to absorb solar photons transmitted through the window layer 21 and form photogenerated carriers to complete the conversion of solar energy into electrical energy. This is the so-called absorption layer 22, and its deposition method includes close-space sublimation method, gas phase transport deposition method, magnetron sputtering method or vacuum evaporation method. A layer of CuBO x , with a thickness of 10-50nm, and its function is to reduce the contact barrier between the cadmium telluride absorption layer and the back electrode. This is the so-called transparent back contact layer 23, and its preparation method is reactive plasma deposition or magnetron sputtering deposition. A transparent conductive film is deposited on the transparent back contact layer as the back electrode 24. The transparent back electrode 24 is tungsten doped tin dioxide (IWO), and its function is to collect current as a positive electrode and conduct it to the external circuit. It is prepared by reactive plasma deposition or magnetron sputtering, and its thickness is 60-120 nanometers.

[0016] After the preparation of the semi-transparent cadmium telluride thin film solar cell is completed, the laser 3 emitted by the laser 4 has a power of 20-200 watts and a wavelength of 532nm. The laser is incident from the direction of the transparent back electrode, and the laser motion trajectory is controlled according to the pattern design. The window layer, ultra-thin cadmium telluride absorption layer, transparent back contact layer, and transparent back electrode of the semi-transparent cadmium telluride thin film solar cell are vaporized by the high energy generated by the laser, so that they are etched away, so that part of the substrate is exposed, and a patterned micro-semi-transparent cadmium telluride thin film solar cell is formed. The area of ​​a single micro-semi-transparent cadmium telluride thin film solar cell is 1-20 square millimeters, and the spacing is 2-5 millimeters. Working principle of the present invention

[0017] After the semi-transparent cadmium telluride thin film solar cell is prepared, a laser is used to emit a certain power of laser, and the laser movement trajectory is controlled according to the pattern design to etch away the window layer, ultra-thin cadmium telluride absorption layer, transparent back contact layer, and transparent back electrode, so that the substrate is exposed. Among them, the unetched part forms micro cadmium telluride thin film solar cells, and these micro cells form an array to form a pattern. The sunlight can be transmitted from the exposed substrate part to form a patterned semi-transparent cadmium telluride thin film solar cell. This patterned semi-transparent cadmium telluride thin film solar cell can be used as a window, fence or roof building in the field of photovoltaic building integration, while absorbing most of the sunlight and realizing the power generation function.

Claims

1. A method for preparing a patterned semi-transparent cadmium telluride thin film solar cell, characterized in that: The semi-transparent cell structure is, from bottom to top, a substrate 1, a window layer 21, an ultra-thin cadmium telluride absorption layer 22, a transparent back contact layer 23, and a transparent back electrode 24. A laser 4 is used to emit a laser 3 of a certain power to etch away the window layer, the ultra-thin cadmium telluride absorption layer, the transparent back contact, and the transparent back electrode according to the pattern design requirements, so that the substrate is exposed. The unetched part is an independent micro-semi-transparent cadmium telluride thin film solar cell. These micro-semi-transparent cadmium telluride thin film solar cells form an array to form a pattern.

2. The method for preparing a patterned semi-transparent cadmium telluride thin film solar cell according to claim 1, characterized in that: The ultra-thin cadmium telluride absorption layer 22 has a thickness of 0.6-1.0 micrometers, and the transparent back contact layer 23 is CuBO x , with a thickness of 10-50 nm, and the transparent back electrode 24 is tin dioxide doped tungsten (IWO) with a thickness of 60-120 nanometers.

3. The method for preparing a patterned semi-transparent cadmium telluride thin film solar cell according to claim 1, characterized in that: The laser 3 emitted by the laser 4 has a power of 20-200 watts and a wavelength of 532 nm. The laser is incident from the direction of the transparent back electrode, and the movement trajectory of the laser is controlled to obtain different etching areas, thereby realizing an independent micro-transparent cadmium telluride thin film solar cell.

4. The method for preparing a patterned semi-transparent cadmium telluride thin film solar cell according to claim 1, characterized in that: The area of ​​the micro-transparent cadmium telluride thin film solar cell 2 is 1-20 square millimeters, and the spacing is 2-5 millimeters.

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