Method for improving performance of CdTe solar cell device and CdTe solar cell device

Abstract

The invention provides a method for improving the performance of a CdTe solar cell device, which is characterized in that an Al2O3 layer is introduced into the back interface of a CdTe solar cell, and the method comprises the following steps: preparing a CdTe film semi-finished product; the CdTe thin film semi-finished product comprises a conductive substrate, and an electron transport layer and a CdTe absorption layer which are sequentially deposited on the conductive substrate; preparing an Al2O3 diluent; the CdTe absorption layer of the CdTe thin film semi-finished product is coated with the Al2O3 diluent in a spinning mode; then placing the CdTe thin film on a heating stage with the temperature of 100-200 DEG C for annealing to obtain a CdTe thin film structure covered with a thin layer of Al2O3; a back contact material is deposited on an Al2O3 layer of a CdTe thin film structure, and then a metal electrode layer CdTe solar cell is evaporated through thermal evaporation. According to the method for improving the performance of the CdTe solar cell device, the open-circuit voltage, the short-circuit current and the conversion efficiency of the cell are effectively improved by using the Al2O3 layer. The invention further provides a method for improving the performance of the CdTe solar cell device.

Description

Technical Field

[0001] The present invention belongs to the field of solar photovoltaic technology, and specifically relates to a method for improving the performance of a CdTe solar cell device and a CdTe solar cell device. More specifically, the present invention relates to a method for improving the performance of a CdTe solar cell device, a CdTe solar cell device, and a solar cell. Background Art

[0002] CdTe solar cells have shown great application potential in the photovoltaic field due to their high conversion efficiency and low cost. CdTe is a direct bandgap semiconductor material with a band gap of approximately 1.45 electron volts (eV). It has a high light absorption coefficient and can absorb most sunlight, making it one of the ideal solar cell materials. However, despite the significant progress made in the efficiency of CdTe solar cells, there are still many challenges to improving their device performance. Among them, the performance of the back interface has a crucial impact on the overall efficiency of CdTe solar cells. The back interface is the key area for the collection and transmission of photogenerated carriers in solar cells. Its quality and stability are directly related to the photoelectric conversion efficiency and long-term stability of the cell. Therefore, how to improve the device performance of CdTe solar cells by optimizing the back interface structure has always been a hot topic and difficulty in research in this field. Summary of the Invention

[0003] The present invention aims to provide a method for improving the performance of a CdTe solar cell device and a CdTe solar cell device, aiming to provide a solar cell device with higher photoelectric conversion efficiency.

[0004] To achieve the above object, the technical solution adopted by the present invention is: to provide a method for improving the performance of CdTe solar cell devices, introducing an Al2O3 layer on the back interface of the CdTe solar cell, comprising the following steps:

[0005] preparing a CdTe thin film semi-finished product; the CdTe thin film semi-finished product comprises a conductive substrate and an electron transport layer and a CdTe absorption layer sequentially deposited on the conductive substrate;

[0006] Prepare Al2O3 dilution solution;

[0007] Spin-coating a diluted Al2O3 solution on the CdTe absorption layer of the semi-finished CdTe film; then annealing it on a hot plate at 100-200°C to obtain a CdTe film structure covered with a thin layer of Al2O3;

[0008] The back contact material is deposited on the Al2O3 layer of the CdTe thin film structure, and then a metal electrode layer is deposited by thermal evaporation.

[0009] Preferably, the preparation of the Al2O3 dilution liquid comprises: using isopropyl alcohol as a diluent to dilute the Al2O3 solution, and the dilution ratio of the Al2O3 dilution liquid is Al2O3:isopropyl alcohol=1:20-50.

[0010] Preferably, the dilution ratio of the Al2O3 dilution solution is Al2O3:isopropanol=1:35.

[0011] A CdTe solar cell device comprises a product prepared based on any of the above methods for improving the performance of a CdTe solar cell device.

[0012] A CdTe solar cell device, comprising:

[0013] A conductive substrate, an electron transport layer, a CdTe absorption layer, an Al2O3 layer, a back contact material layer, and a metal electrode layer are stacked in sequence from one end to the other.

[0014] Preferably, the thickness of the CdTe absorption layer is 2-4 μm.

[0015] Preferably, the electron transport layer comprises one or more of SnO2, CdS and CdSe.

[0016] Preferably, the thickness of the metal electrode layer is 60-100 nm.

[0017] A solar cell comprises a product prepared based on any of the above methods for improving the performance of a CdTe solar cell device or / and any of the above CdTe solar cell devices.

[0018] The method for improving the performance of a CdTe solar cell device and the CdTe solar cell device provided by the present invention have the following beneficial effects: compared with the prior art, the method for improving the performance of a CdTe solar cell device and the CdTe solar cell device of the present invention effectively passivate the interface defects between the front electrode and the CdTe absorption layer of the CdTe solar cell by using an Al2O3 layer, reduce carrier recombination losses, and improve the open circuit voltage and short circuit current of the cell; the method of the present invention has a simple process, is easy to control, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, 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 paying any creative work.

[0020] Figure 1(a) Open circuit voltage (V) under different Al2O3 ratios OC )’s changing trend;

[0021] Figure 1 (b) Short-circuit current (J) under different Al2O3 ratios SC )’s changing trend;

[0022] Figure 1 (c) The changing trend of filling factor (FF) under different Al2O3 ratio conditions;

[0023] Figure 1 (d) The changing trend of photoelectric conversion efficiency (PCE) under different Al2O3 ratios;

[0024] Figure 2 The current density-voltage (JV) curves for the highest cell efficiency with no Al2O3 and the optimal Al2O3 ratio mentioned above;

[0025] Figure 3 (a) Surface morphology of the sample without Al2O3

[0026] Figure 3 (b) Surface morphology of the sample with an Al2O3 ratio of 1:50

[0027] Figure 3 (c) Surface morphology of the sample with an Al2O3 ratio of 1:35

[0028] Figure 3 (d) Surface morphology of the sample with an Al2O3 ratio of 1:20

[0029] Figure 3 (e) is a cross-sectional morphology of a sample without Al2O3 (this sample is a product prepared using existing technology)

[0030] Figure 3 (f) is the cross-sectional morphology of the sample with an Al2O3 ratio of 1:50

[0031] Figure 3 (g) is the cross-sectional morphology of the sample with an Al2O3 ratio of 1:35

[0032] Figure 3 (h) is the cross-sectional morphology of the sample with an Al2O3 ratio of 1:20

[0033] Figure 4 (a) is the contact angle test result of the sample surface without Al2O3

[0034] Figure 4 (b) The contact angle test results of the sample surface with an Al2O3 ratio of 1:50

[0035] Figure 4 (c) The contact angle test results of the sample surface with an Al2O3 ratio of 1:35

[0036] Figure 4 (d) is the surface contact angle test result of the sample with an Al2O3 ratio of 1:20. DETAILED DESCRIPTION

[0037] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] Please also refer to Figures 1 to 4 The present invention provides a CdTe solar cell device, which includes a conductive substrate, an electron transport layer, a CdTe absorption layer, an Al2O3 layer, a back contact material layer, and a metal electrode layer stacked in sequence from one end to the other.

[0039] As a specific embodiment of the present invention, a conductive substrate includes a substrate body and a conductive layer coated on a surface of the substrate body. Specifically, the conductive substrate includes one or more layers of quartz glass, soda-lime glass, and ultra-white glass. The conductive material used in the conductive layer is a transparent conductive oxide.

[0040] As a specific implementation of an embodiment of the present invention, the electron transport layer includes one or more of SnO2, CdS and CdSe.

[0041] As a specific implementation of the embodiment of the present invention, the back contact material layer includes one or more of anhydrous copper chloride and Cu-doped ZnTe.

[0042] As a specific implementation of the embodiment of the present invention, the thickness of the CdTe absorption layer is 2-4 μm.

[0043] A method for improving the performance of a CdTe solar cell device comprises the following steps:

[0044] Step S1, preparing a CdTe thin film semi-finished product; the CdTe thin film semi-finished product includes a conductive substrate and an electron transport layer and a CdTe absorption layer sequentially deposited on the conductive substrate;

[0045] Step S2, preparing an Al2O3 dilution solution. The specific implementation process of this step is: using isopropyl alcohol as a diluent to dilute the Al2O3 solution. The dilution ratio is Al2O3:isopropyl alcohol = 1:20-50.

[0046] Step S3, spin-coating the Al2O3 diluted solution on the CdTe absorption layer of the CdTe thin film semi-finished product at a rotation speed of 3000-4000 r / s for 25-30 s; then placing it on a hot plate at 100-200°C for annealing to obtain a CdTe thin film structure covered with a thin layer of Al2O3.

[0047] Step S4: Deposit a back contact material onto the Al2O3 layer of the CdTe thin film structure to form a back contact material layer. Then, a metal electrode layer is deposited by thermal evaporation. Specifically, the thickness of the metal electrode layer is 60nm-100nm, preferably 80nm. Gold is used as the material for the metal electrode layer.

[0048] In any achievable embodiment, the area size of each small battery can be defined by a mask, such as the area size is selected to be 0.105 cm 2 .

[0049] The present invention provides a method for improving the performance of a CdTe solar cell device and a CdTe solar cell device. Compared with the prior art, the use of an Al2O3 layer effectively passivates the interface defects between the front electrode and the CdTe absorption layer of the CdTe solar cell, reduces carrier recombination losses, and improves the open circuit voltage and short circuit current of the battery. The method of the present invention is simple and easy to control, and is suitable for large-scale industrial production. Specifically, the use of the Al2O3 layer can significantly improve the performance of the device. The Al2O3 layer can not only serve as an effective passivation layer, reduce the recombination centers at the back interface, and reduce the recombination rate of carriers, thereby improving the open circuit voltage (V OC ) and fill factor (FF), and can also act as a barrier layer to block the intrusion of harmful substances such as moisture and oxygen from the external environment, improving the long-term stability of the battery. By optimizing the deposition process and parameters of the Al2O3 layer, the interface defects between the front electrode and the CdTe absorber layer of the CdTe solar cell are effectively passivated, improving the cell's open circuit voltage, short circuit current, and conversion efficiency.

[0050] Example 1

[0051] A method for improving the performance of a CdTe solar cell device comprises the following steps:

[0052] Step S1, preparing a CdTe thin film semi-finished product; the CdTe thin film semi-finished product includes a conductive substrate and an electron transport layer and a CdTe absorption layer sequentially deposited on the conductive substrate;

[0053] Step S2: diluting the Al2O3 solution with isopropyl alcohol as a diluent. The dilution ratios are: Al2O3:isopropyl alcohol = 1:20; Al2O3:isopropyl alcohol = 1:35; and Al2O3:isopropyl alcohol = 1:50.

[0054] Step S3: Spin-coat the Al2O3 diluted solution obtained in the above step onto the CdTe absorption layer of the CdTe thin film semi-finished product at a rotation speed of 3000 r / s for 30 seconds; then place it on a hot plate at 200°C for annealing to obtain a CdTe thin film structure covered with a thin layer of Al2O3.

[0055] Step S4: Deposit a back contact material onto the Al2O3 layer of the CdTe thin film structure to form a back contact material layer. Then, a layer of gold is deposited by thermal evaporation to form a metal electrode layer. The thickness of the metal electrode layer is 80 nm.

[0056] Attachment Figure 1 The results show the trends in open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency of cells produced using different Al2O3 dilution concentrations. As the Al2O3 concentration increases, the open-circuit voltage and fill factor first increase and then decrease. The optimal Al2O3 ratio was determined to be Al2O3:isopropyl alcohol = 1:35. At this optimal ratio, CdTe solar cells with a maximum photoelectric conversion efficiency of 17.45% were produced.

[0057] Example 2

[0058] A method for improving the performance of a CdTe solar cell device comprises the following steps:

[0059] Step S1, preparing a CdTe thin film semi-finished product; the CdTe thin film semi-finished product includes a conductive substrate and an electron transport layer and a CdTe absorption layer sequentially deposited on the conductive substrate;

[0060] Step S2: dilute the Al2O3 solution using isopropyl alcohol as a diluent, with a dilution ratio of Al2O3:isopropyl alcohol = 1:35.

[0061] Step S3: spin-coat the Al2O3 diluted solution on the CdTe absorption layer of the CdTe thin film semi-finished product at a rotation speed of 3000 r / s for 30 seconds; then place it on a hot plate at 200°C for annealing to obtain a CdTe thin film structure covered with a thin layer of Al2O3.

[0062] Step S4: Deposit a back contact material onto the Al2O3 layer of the CdTe thin film structure to form a back contact material layer. Then, a layer of gold is deposited by thermal evaporation to form a metal electrode layer. The thickness of the metal electrode layer is 80 nm.

[0063] Attachment Figure 2The JV curves of the highest efficiency cells without Al2O3 and with the optimal Al2O3 ratio are shown. It can be seen that with the appropriate Al2O3 thickness, the efficiency of the cell can be effectively improved, with the highest efficiency reaching 17.45%.

[0064] Attachment Figure 3 The figure shows the CdTe surface treated with different Al2O3 ratios. It can be seen that as the Al2O3 concentration increases, the surface coverage of the CdTe increases. At a ratio of 1:20, the CdTe surface is completely covered, which is not conducive to carrier transport and thus leads to a decrease in device performance.

[0065] Attachment Figure 4 The contact angle test results of the CdTe surface obtained after treatment with different Al2O3 ratio conditions are shown. It can be seen that with the increase of Al2O3 concentration, the contact angle becomes smaller, which shows that the CdTe surface obtained after Al2O3 treatment is smoother, which helps to increase the battery fill factor.

[0066] The present invention also provides a solar cell, comprising any of the CdTe solar cell devices described above or a CdTe solar cell device prepared by any of the methods described above.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for improving the performance of a CdTe solar cell device, characterized in that: The introduction of an Al2O3 layer to the back interface of a CdTe solar cell includes the following steps: preparing a CdTe thin film semi-finished product; the CdTe thin film semi-finished product comprises a conductive substrate and an electron transport layer and a CdTe absorption layer sequentially deposited on the conductive substrate; Prepare Al2O3 dilution solution; Spin-coating a diluted Al2O3 solution on the CdTe absorption layer of the semi-finished CdTe film; then annealing it on a hot plate at 100-200°C to obtain a CdTe film structure covered with a thin layer of Al2O3; The back contact material is deposited on the Al2O3 layer of the CdTe thin film structure, and then a metal electrode layer is deposited by thermal evaporation.

2. A method for improving the performance of a CdTe solar cell device according to claim 2, characterized in that: The preparation of the Al2O3 dilution liquid includes: using isopropyl alcohol as a diluent to dilute the Al2O3 solution, and the dilution ratio of the Al2O3 dilution liquid is Al2O3:isopropyl alcohol=1:20-50.

3. A method for improving the performance of a CdTe solar cell device according to claim 2, characterized in that: The dilution ratio of the Al2O3 dilution solution is Al2O3:isopropyl alcohol=1:

35.

4. A solar cell device, characterized in that: The invention comprises a product prepared based on the method for improving the performance of a CdTe solar cell device according to any one of claims 1 to 3.

5. A solar cell device according to claim 4, characterized in that: A conductive substrate, an electron transport layer, a CdTe absorption layer, an Al2O3 layer, a back contact material layer, and a metal electrode layer are stacked in sequence from one end to the other.

6. A CdTe solar cell device according to claim 5, characterized in that: The thickness of the CdTe absorption layer is 2-4 μm.

7. A CdTe solar cell device according to claim 5, characterized in that: The electron transport layer includes one or more of SnO2, CdS and CdSe.

8. A CdTe solar cell device according to claim 5, characterized in that: The thickness of the metal electrode layer is 60-100 nm.

9. A solar cell, characterized in that: The invention comprises a product prepared based on the method for improving the performance of a CdTe solar cell device according to any one of claims 1 to 3 or / and a CdTe solar cell device according to any one of claims 5 to 8.

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