Photovoltaic cell and preparation method thereof

Abstract

The present invention provides a photovoltaic cell and a preparation method thereof, the preparation method comprising providing a substrate, the substrate having a first surface and a second surface arranged opposite to each other; forming a hydrogenated transparent conductive layer on the first surface and the second surface of the substrate respectively, performing an activation treatment on the hydrogenated transparent conductive layer, applying an epoxy-based conductive paste on the surface of the hydrogenated transparent conductive layer after the activation treatment, and then performing a sintering treatment to form a conductive electrode to obtain a photovoltaic cell. The method can improve the adhesion between the conductive electrode and the hydrogenated transparent conductive layer, and improve the performance of the photovoltaic cell in terms of open circuit voltage, fill factor and conversion efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cell preparation, and in particular to a photovoltaic cell and a preparation method thereof. Background Art

[0002] Photovoltaic cells convert light energy into electrical energy and use metal electrodes to collect current and guide it to external circuits. Photovoltaic cells have the advantages of simple process, high efficiency, high stability, and double-sided power generation, and have become the focus of current research on high-efficiency solar cells.

[0003] In the related art, low-temperature silver paste (<200°C) is usually used for screen printing and sintering to form grid lines, which are directly connected to transparent conductive films as conductive electrodes. The low-temperature silver paste is composed of silver powder, resin, additives, curing agent and solvent. However, the adhesion between the resin in the low-temperature silver paste and the transparent conductive film is poor, resulting in an increase in the contact resistance between the conductive electrode and the transparent conductive film, which reduces the open circuit voltage, fill factor and conversion efficiency of the photovoltaic cell.

[0004] Therefore, it is necessary to make technical improvements to photovoltaic cells and their preparation methods to ensure and improve the electrical performance of photovoltaic cells. Summary of the invention

[0005] The present invention provides a method for preparing a photovoltaic cell, which can increase the bonding force between a conductive electrode and a transparent conductive layer, thereby preparing a high-performance photovoltaic cell. The method is simple and efficient, and is suitable for wide promotion and application.

[0006] The present invention also provides a photovoltaic cell prepared by the above preparation method, and the photovoltaic cell has the advantages of high open circuit voltage, high fill factor and high conversion efficiency.

[0007] The present invention provides a method for preparing a photovoltaic cell, comprising: providing a substrate, wherein the substrate has a first surface and a second surface arranged opposite to each other, and the method further comprises:

[0008] forming a hydrogenated transparent conductive layer on the first surface and the second surface of the substrate respectively;

[0009] Performing an activation treatment on the hydrogenated transparent conductive layer to at least disconnect the hydroxyl groups on the surface of the hydrogenated transparent conductive layer to form oxygen-deficient dangling bonds;

[0010] Applying epoxy conductive paste on the surface of the hydrogenated transparent conductive layer after the activation treatment, the oxygen-containing bonds in the epoxy conductive paste and the oxygen-losing dangling bonds on the surface of the hydrogenated transparent conductive layer form chemical bonds to obtain an initial conductive electrode;

[0011] The initial conductive electrode is sintered to form a conductive electrode, thereby obtaining the photovoltaic cell.

[0012] In the preparation method as described above, the step of forming the hydrogenated transparent conductive layer comprises:

[0013] A magnetron sputtering process is adopted to deposit a transparent conductive film on the first doped layer side away from the substrate and the second doped layer side away from the substrate, and hydrogen is doped during the deposition process to obtain the hydrogenated transparent conductive layer.

[0014] In the preparation method as described above, the molar percentage of hydrogen element in the hydrogenated transparent conductive layer is 1% to 1.5%.

[0015] In the preparation method as described above, the step of performing activation treatment on the hydrogenated transparent conductive layer comprises:

[0016] Laser activation treatment is performed on the surface of at least one of the hydrogenated transparent conductive layers to obtain a first activation region containing oxygen-deficient dangling bonds; wherein the depth of the first activation region is comprised between 0.1 nm and 20 nm.

[0017] The preparation method as described above, wherein in the laser activation treatment, the laser irradiation intensity includes: 20kW / m 2 ~100kW / m 2 ; Laser irradiation duration includes: 5s ~ 120s.

[0018] In the preparation method as described above, the step of performing activation treatment on the hydrogenated transparent conductive layer comprises:

[0019] A plasma activation treatment is performed on the surface of at least one of the hydrogenated transparent conductive layers to obtain a second activation region containing oxygen-deficient dangling bonds; wherein the depth of the second activation region is comprised between 0.1 nm and 20 nm.

[0020] In the preparation method as described above, in the plasma activation treatment, an inert gas source is used as the plasma gas; the gas source introduction pressure includes: 0.05mbar~0.5mbar; the plasma discharge power includes: 10W~100W; the plasma bombardment time includes: 5s~50s.

[0021] The preparation method as described above, wherein, before performing the activation treatment, the method further comprises:

[0022] Micro-etching is performed on the surface of the hydrogenated transparent conductive layer to obtain a surface region with a preset roughness; wherein the preset roughness includes: 0.738nm-0.8nm.

[0023] In the preparation method as described above, forming the hydrogenated transparent conductive layer on the first surface and the second surface of the substrate respectively comprises: performing a texturing treatment on the first surface and / or the second surface of the substrate to form a surface textured structure;

[0024] Forming a first passivation layer and a first doping layer of a first conductivity type stacked in sequence on the first surface side of the substrate;

[0025] forming a second passivation layer and a second doping layer of a second conductivity type stacked in sequence on the second surface side of the substrate;

[0026] A hydrogenated transparent conductive layer is formed on the first doping layer and the second doping layer respectively at the side facing away from the substrate.

[0027] The present invention also provides a photovoltaic cell obtained by the above-mentioned preparation method, comprising: a substrate having a first surface and a second surface arranged opposite to each other;

[0028] Also includes:

[0029] A hydrogenated transparent conductive layer is disposed on the first surface and the second surface of the substrate respectively;

[0030] A conductive electrode, disposed on the side of the hydrogenated transparent conductive layer facing away from the substrate;

[0031] The oxygen-containing bonds of the conductive electrode form chemical bonds with the oxygen-depleted dangling bonds on the surface of the hydrogenated transparent conductive layer.

[0032] The preparation method of the photovoltaic cell of the present invention performs an activation treatment on the hydrogenated transparent conductive layer, at least causing the chemical bonds on the surface of the hydrogenated transparent conductive layer to break, generating more oxygen vacancy defects, so that the surface of the hydrogenated transparent conductive layer is acidified and hydrophilized, thereby showing a strong tendency to chemically recombine with free carboxyl groups, oxygen ions and hydroxide ions. Based on this, an epoxy conductive paste is provided, and the epoxy ring is opened by means of hydrogen elements in the transparent conductive layer, thereby forming free carboxyl groups, oxygen ions and hydroxide ions. In this way, the free carboxyl groups, oxygen ions and hydroxide ions in the conductive paste form a relatively stable chemical bond with the oxygen vacancies on the surface of the hydrogenated transparent conductive layer (i.e., a fixed phase of a specific group is bonded to the surface of the carrier through a chemical reaction), and then sintered, so that the hydrogenated transparent conductive layer and the conductive electrode interface are cross-linked at the macro level to form a dense cross-linked network structure. Thereby significantly improving the bonding effect between the conductive electrode and the hydrogenated transparent conductive layer, it is beneficial to obtain a photovoltaic cell with high open circuit voltage, high fill factor and high conversion efficiency. The method has simple and efficient process and is suitable for popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1A schematic diagram of a process for preparing a photovoltaic cell provided in some embodiments of the present invention;

[0034] Figure 2 A schematic diagram of the structure of a photovoltaic cell provided in some embodiments of the present invention;

[0035] Figure 3 A schematic diagram of the structure of a photovoltaic cell provided in some embodiments of the present invention;

[0036] Figure 4 Schematic diagram of the structure of a hydrogenated transparent conductive layer obtained after micro-etching treatment provided in some embodiments of the present invention.

[0037] Description of reference numerals:

[0038] 1- substrate;

[0039] 2- first passivation layer;

[0040] 3- second passivation layer;

[0041] 4- first doping layer;

[0042] 5- second doping layer;

[0043] 6-Hydrogenated transparent conductive layer;

[0044] 7- Conductive electrodes. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] Figure 1 A schematic diagram of a process for preparing a photovoltaic cell provided in some embodiments of the present invention; Figure 2 A schematic diagram of the structure of a photovoltaic cell provided in some embodiments of the present invention is shown in FIG. Figure 1-2 As shown, the present invention provides a method for preparing a photovoltaic cell, comprising:

[0047] Providing a substrate 1, wherein the substrate 1 has a first surface and a second surface arranged opposite to each other;

[0048] Forming a hydrogenated transparent conductive layer 6 on the first surface and the second surface of the substrate 1 respectively;

[0049] Performing an activation treatment on the hydrogenated transparent conductive layer 6 to at least disconnect the hydroxyl groups on the surface of the hydrogenated transparent conductive layer to form oxygen-deficient dangling bonds;

[0050] Applying epoxy conductive paste on the surface of the hydrogenated transparent conductive layer 6 after the activation treatment, the oxygen-containing bonds in the epoxy conductive paste form chemical bonds with the oxygen-losing dangling bonds on the surface of the hydrogenated transparent conductive layer to obtain an initial conductive electrode;

[0051] The initial conductive electrode is subjected to a sintering process to form a conductive electrode 7, thereby obtaining a photovoltaic cell.

[0052] The substrate of the present invention has two surfaces with the largest area and arranged opposite to each other, which are respectively called the first surface and the second surface. The present invention does not limit the material, shape, size, and thickness of the substrate, which can be selected according to actual needs.

[0053] The present invention forms a hydrogenated transparent conductive layer on both the first surface and the second surface of the substrate; then, the surface of the hydrogenated transparent conductive layer is activated to disconnect the hydroxyl groups on the surface of the hydrogenated transparent conductive layer to form oxygen-depleted dangling bonds; an epoxy-based conductive paste is applied on the surface of the hydrogenated transparent conductive layer after the activation treatment, so that the oxygen-containing bonds in the epoxy-based conductive paste and the oxygen-depleted dangling bonds on the surface of the hydrogenated transparent conductive layer form chemical bonds to obtain an initial conductive electrode; finally, the initial conductive electrode is sintered to form a conductive electrode, thereby significantly improving the bonding effect between the conductive electrode and the hydrogenated transparent conductive layer, and facilitating the obtaining of a photovoltaic cell with high open circuit voltage, high fill factor and high conversion efficiency.

[0054] The epoxy-based conductive paste of the present invention is a commercially available product, such as Dico Electronic Materials Co., Ltd. and Suzhou Jingyin New Materials Technology Co., Ltd.

[0055] In some embodiments, the step of forming the hydrogenated transparent conductive layer includes: using a magnetron sputtering process to deposit a transparent conductive film on both the first doped layer side away from the substrate and the second doped layer side away from the substrate to form a transparent conductive film, and doping hydrogen elements during the deposition process to obtain a hydrogenated transparent conductive layer. That is, using a magnetron sputtering process to deposit a transparent conductive film on the first doped layer side away from the substrate, doping hydrogen elements during the deposition process, and obtaining a hydrogenated transparent conductive layer on the first doped layer side away from the substrate; and simultaneously using a magnetron sputtering process to deposit a transparent conductive film on the second doped layer side away from the substrate, doping hydrogen elements during the deposition process, and obtaining a hydrogenated transparent conductive layer on the second doped layer side away from the substrate.

[0056] Here, by doping hydrogen elements in the transparent conductive layer, in the subsequent step, the epoxy groups on the epoxy resin in the conductive electrode can be opened by means of the hydrogen elements in the hydrogenated transparent conductive layer, thereby forming negatively charged ions and groups; furthermore, these negatively charged ions and groups are easily chemically bonded with oxygen vacancies on the surface of the hydrogenated transparent conductive layer, thereby improving the bonding effect between the conductive paste and the transparent conductive layer.

[0057] According to the technical solution of the present invention, the molar percentage of hydrogen element in the hydrogenated transparent conductive layer is 1% to 1.5%, for example, it can be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, which can make the hydrogenated transparent conductive layer have better adhesion with the conductive electrode, thereby further improving the open circuit voltage, fill factor and conversion efficiency of the photovoltaic cell.

[0058] In the present invention, the step of performing activation treatment on the hydrogenated transparent conductive layer comprises:

[0059] Laser activation treatment is performed on the surface of at least one of the hydrogenated transparent conductive layers to obtain a first activated region containing oxygen-deficient dangling bonds; that is, laser activation treatment can be performed on the surface of the hydrogenated transparent conductive layer on the first doped layer side; laser activation treatment can also be performed on the surface of the hydrogenated transparent conductive layer on the second doped layer side, and laser activation treatment can also be performed on the surface of the hydrogenated transparent conductive layer on the first doped layer side and the surface of the hydrogenated transparent conductive layer on the second doped layer side.

[0060] Among them, the depth of the first activation zone includes: 0.1nm-20nm, for example, it can be 0.1nm, 0.5nm, 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, 16nm, 17nm, 18nm, 19nm, 20nm.

[0061] The depth of the first activation zone in the present invention refers to the thickness of the oxygen-deficient dangling bond region formed after the hydrogenated transparent conductive layer is treated by laser activation.

[0062] When the depth of the first activation zone is within the above range, the hydrogenated transparent conductive layer can be fully laser activated while reducing damage and thermal damage to the hydrogenated transparent conductive layer to obtain more oxygen-lost dangling bonds, thereby further increasing the adhesion between the conductive electrode and the hydrogenated transparent conductive layer.

[0063] The present invention does not particularly limit the specific type of laser. In some embodiments, the laser can be one of red light, green light, and ultraviolet light.

[0064] In some embodiments, during the laser activation process, the laser irradiation intensity includes: 20 kW / m2 ~100kW / m 2 , for example, it can be 20kW / m 2 、30kW / m 2 , 40kW / m 2 、50kW / m 2 、60kW / m 2 、70kW / m 2 、80kW / m 2 、90kW / m 2 , 100kW / m 2 The laser irradiation time includes: 5s to 120s, for example, 5s, 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 110s, 120s. It is beneficial to the fine processing of the hydrogenated transparent conductive layer, while breaking the oxygen bonds on the surface of the hydrogenated transparent conductive layer to form hanging bonds, and reducing the damage and thermal damage to the hydrogenated transparent conductive layer.

[0065] In the present invention, the step of performing activation treatment on the hydrogenated transparent conductive layer comprises:

[0066] Plasma activation treatment is performed on at least one surface of the hydrogenated transparent conductive layer to obtain a second activated region containing oxygen-deficient dangling bonds; that is, plasma activation treatment can be performed on the surface of the hydrogenated transparent conductive layer on the first doping layer side; plasma activation treatment can also be performed on the surface of the hydrogenated transparent conductive layer on the second doping layer side; plasma activation treatment can also be performed on the surface of the hydrogenated transparent conductive layer on the first doping layer side and the surface of the hydrogenated transparent conductive layer on the second doping layer side.

[0067] The depth of the second activation zone includes: 0.1nm-20nm, for example, it can be 0.1nm, 0.5nm, 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, 16nm, 17nm, 18nm, 19nm, 20nm.

[0068] The depth of the second activated region in the present invention refers to the thickness of the region containing oxygen-deficient dangling bonds formed after the hydrogenated transparent conductive layer is treated by plasma activation.

[0069] When the depth of the second activation zone is within the above range, the hydrogenated transparent conductive layer can be fully plasma activated while reducing damage and thermal damage to the hydrogenated transparent conductive layer to obtain more oxygen-losing dangling bonds, thereby further enhancing the interface bonding force between the conductive electrode and the hydrogenated transparent conductive layer.

[0070] According to the technical solution of the present invention, in plasma activation treatment, an inert gas source is used as plasma gas, and the inert gas source includes argon, helium, etc. These gases will not chemically react with the material in the plasma state, and only activate the surface through physical bombardment.

[0071] The gas source input pressure includes: 0.05mbar~0.5mbar, for example, it can be 0.05mbar, 0.1mbar, 0.15mbar, 0.2mbar, 0.25mbar, 0.3mbar, 0.4mbar, 0.5mbar. The pressure in this range can ensure the stability and uniformity of the plasma while avoiding excessive bombardment and material damage caused by excessive pressure.

[0072] The plasma discharge power includes: 10W~100W, for example, 10W, 30W, 50W, 70W, 100W, and the plasma bombardment time includes: 5s~50s, for example, 5s, 10s, 15s, 25s, 35s, 50s, which can fully plasma activate the hydrogenated transparent conductive layer while saving energy.

[0073] In the present invention, a micro-etching process is performed on the surface of the hydrogenated transparent conductive layer to obtain a surface region with a preset roughness. Figure 4 FIG. 1 is a schematic diagram of the structure of a hydrogenated transparent conductive layer obtained after micro-etching treatment provided in some embodiments of the present invention. Figure 4 As shown, Figure 4 The depth in refers to the depth of micro-etching on the surface of the hydrogenated transparent conductive layer after micro-etching treatment. By increasing the roughness of the hydrogenated transparent conductive layer, the contact area between the hydrogenated transparent conductive layer and the conductive electrode is increased, thereby further improving the adhesion between the hydrogenated transparent conductive layer and the conductive electrode. In some embodiments, the micro-etching treatment includes laser etching, dilute acid solution corrosion and acid solution corrosion containing ferrous ions. Laser etching refers to the technology of surface modification of the hydrogenated transparent conductive layer using a high-energy laser beam. By adjusting the wavelength, pulse width and energy density of the laser, the depth and shape of the etching can be precisely controlled. Dilute acid solution corrosion is a technology that uses acidic chemical solutions to treat and remove materials through chemical reactions. Commonly used acidic solutions include nitric acid (HNO3), hydrochloric acid (HCl), sulfuric acid (H2SO4) and hydrofluoric acid (HF), which have the advantages of low cost and simple process. Acid solution corrosion containing ferrous ions is a special chemical corrosion technology that uses ferrous ions (Fe 2+ ) uses the chemical reaction characteristics in an acidic environment to achieve etching and surface treatment of the hydrogenated transparent conductive layer, with a high corrosion rate and good selectivity.

[0074] Generally, the preset roughness of the micro-etching treatment includes: 0.738nm~0.8nm, for example, it can be 0.738nm, 0.74nm, 0.75nm, 0.76nm, 0.77nm, 0.78nm, 0.79nm, 0.8nm, which further increases the contact area between the hydrogenated transparent conductive layer and the conductive electrode and enhances the adhesion between the hydrogenated transparent conductive layer and the conductive electrode.

[0075] Figure 3 This is a schematic diagram of the structure of a photovoltaic cell provided in some embodiments of the present invention.

[0076] In some embodiments, Figure 3 As shown, forming a hydrogenated transparent conductive layer 6 on the first surface and the second surface of the substrate 1 respectively includes:

[0077] Performing a texturing treatment on the first surface and / or the second surface of the substrate 1 to form a surface textured structure;

[0078] A first passivation layer 2 and a first doping layer 4 of a first conductivity type are sequentially stacked on the first surface side of the substrate;

[0079] A second passivation layer 3 and a second doping layer 5 of a second conductivity type are formed on the second surface side of the substrate and stacked in sequence;

[0080] A hydrogenated transparent conductive layer 6 is formed on the first doping layer 4 and the second doping layer 5 respectively on the side facing away from the substrate.

[0081] It can be understood that the texturing treatment can be performed on the first surface of the substrate, the second surface of the substrate, or both the first and second surfaces of the substrate. The texturing surface has the advantage of low reflectivity and improves the light absorption efficiency.

[0082] The present invention forms a first passivation layer on the first surface of a substrate, forms a first doped layer of a first conductivity type on a surface of the first passivation layer away from the substrate; forms a second passivation layer on the second surface of the substrate, forms a second doped layer of a second conductivity type on a surface of the second passivation layer away from the substrate; and then forms a hydrogenated transparent conductive layer on both the surface of the first doped layer away from the first passivation layer and the surface of the second doped layer away from the second passivation layer.

[0083] The present invention does not limit the method for preparing the first passivation layer, the second passivation layer, the first doping layer, and the second doping layer, which can be selected according to actual conditions. Generally, the first passivation layer, the second passivation layer, the first doping layer, and the second doping layer can be prepared by plasma enhanced chemical vapor deposition (PECVD) or hot wire chemical vapor deposition (HWCVD).

[0084] In some embodiments, the first conductivity type is selected from one of P type and N type; and the second conductivity type is selected from the other of P type and N type.

[0085] The present invention also provides a photovoltaic cell obtained by the above-mentioned preparation method, comprising:

[0086] A substrate 1 having a first surface and a second surface arranged opposite to each other;

[0087] It also includes a hydrogenated transparent conductive layer 6, which is disposed on the first surface and the second surface of the substrate 1 respectively;

[0088] A conductive electrode 7 is arranged on the side of the hydrogenated transparent conductive layer facing away from the substrate;

[0089] The oxygen-containing bonds in the conductive electrode 7 form chemical bonds with the oxygen-deficient dangling bonds on the surface of the hydrogenated transparent conductive layer 6 .

[0090] Specifically, the photovoltaic cell of the present invention comprises: a substrate 1 having a first surface and a second surface arranged opposite to each other, a hydrogenated transparent conductive layer 6 arranged on the first surface of the substrate 1, a hydrogenated transparent conductive layer 6 arranged on the second surface of the substrate, and a conductive electrode 7 arranged on the side of the hydrogenated transparent conductive layer 6 facing away from the substrate.

[0091] The conductive electrode and the hydrogenated transparent conductive layer in the photovoltaic cell have excellent adhesion, which can make the photovoltaic cell have low short-circuit current density, high open-circuit voltage, high filling factor and high conversion efficiency.

[0092] Hereinafter, the present invention will be further described in detail through specific examples.

[0093] Example 1

[0094] The method for preparing the photovoltaic cell of this embodiment comprises the following steps:

[0095] 1) performing a texturing process on the first surface and the second surface of the substrate so that both the first surface and the second surface of the substrate form a texturing surface;

[0096] 2) forming a first passivation layer and a first doping layer of a first conductivity type stacked in sequence on the first surface side of the substrate;

[0097] 3) forming a second passivation layer and a second doping layer of a second conductivity type stacked in sequence on the second surface side of the substrate,

[0098] 4) using a magnetron sputtering process to deposit a transparent conductive film on the first doped layer side facing away from the substrate and the second doped layer side facing away from the substrate, and doping hydrogen during the deposition process to obtain a hydrogenated transparent conductive layer;

[0099] The molar percentage of hydrogen in the hydrogenated transparent conductive layer is 1.2%;

[0100] 5) performing laser etching on the surface of the hydrogenated transparent conductive layer on the side of the first doped layer facing away from the substrate and the surface of the hydrogenated transparent conductive layer on the side of the second doped layer facing away from the substrate to obtain a hydrogenated transparent conductive layer with a surface roughness of 0.749 nm;

[0101] During laser etching, the irradiation intensity is 60kW / m 2 , the laser etching treatment time is 15s;

[0102] 6) performing laser activation treatment on the surface of the hydrogenated transparent conductive layer on the surface of the first doping layer to obtain a first activation area containing oxygen-deficient dangling bonds;

[0103] The depth of the first activation zone is 3.12 nm. During the laser activation process, the laser irradiation intensity is 60 kW / m 2 , the duration of laser irradiation is 30s;

[0104] 7) performing plasma activation treatment on the surface of the hydrogenated transparent conductive layer on the surface of the second doping layer to obtain a second activation region containing oxygen-deficient dangling bonds;

[0105] The depth of the second activation zone is 4.25 nm, the plasma gas is argon, the gas source pressure is 0.15 mbar, the plasma discharge power is 50 W, and the plasma bombardment time is 25 s;

[0106] 8) An epoxy conductive paste (DiKe Electronic Materials) was applied on the surface of the hydrogenated transparent conductive layer subjected to laser activation treatment and the hydrogenated transparent conductive layer subjected to plasma activation treatment, and then sintered at 170° C. for 4 minutes to form a conductive electrode to obtain a photovoltaic cell.

[0107] Example 2

[0108] The method for preparing the photovoltaic cell provided in this embodiment is basically the same as that in embodiment 1, except that:

[0109] 5) performing laser etching on the surface of the hydrogenated transparent conductive layer on the side of the first doped layer facing away from the substrate and the surface of the hydrogenated transparent conductive layer on the side of the second doped layer facing away from the substrate to obtain a hydrogenated transparent conductive layer with a surface roughness of 0.756 nm;

[0110] During laser etching, the irradiation intensity is 60kW / m 2 , the laser etching treatment time is 50s;

[0111] 6) performing laser activation treatment on the surface of the hydrogenated transparent conductive layer on the surface of the first doping layer to obtain a first activation area containing oxygen-deficient dangling bonds;

[0112] The depth of the first activation zone is 5.65 nm. During the laser activation process, the irradiation intensity is 60 kW / m 2 , the duration of laser irradiation is 80s;

[0113] 7) performing plasma activation treatment on the surface of the hydrogenated transparent conductive layer on the surface of the second doping layer to obtain a second activation region containing oxygen-deficient dangling bonds;

[0114] The depth of the second activation zone is 8.93 nm, the plasma gas is argon, the gas source pressure is 0.3 mbar, the plasma discharge power is 60 W, and the plasma bombardment time is 35 s.

[0115] Example 3

[0116] The method for preparing the photovoltaic cell provided in this embodiment is basically the same as that in embodiment 1, except that:

[0117] 5) performing laser etching on the surface of the hydrogenated transparent conductive layer on the side of the first doped layer facing away from the substrate and the surface of the hydrogenated transparent conductive layer on the side of the second doped layer facing away from the substrate to obtain a hydrogenated transparent conductive layer with a surface roughness of 0.761 nm;

[0118] During laser etching, the irradiation intensity is 70kW / m 2 , the laser etching treatment time is 50s;

[0119] 6) performing laser activation treatment on the hydrogenated transparent conductive layer on the surface of the first doping layer to obtain a first activation region containing oxygen-deficient dangling bonds;

[0120] The depth of the first activation zone is 6.45 nm. During the laser activation process, the irradiation intensity is 80 kW / m 2 , the duration of laser irradiation is 50s;

[0121] 7) performing plasma activation treatment on the surface of one of the hydrogenated transparent conductive layers on the surface of the second doping layer to obtain a second activation region containing oxygen-deficient dangling bonds;

[0122] The depth of the second activation zone is 10.67 nm, the plasma gas is argon, the gas source pressure is 0.4 mbar, the plasma discharge power is 80 W, and the plasma bombardment time is 50 s.

[0123] Comparative Example

[0124] The preparation method of the photovoltaic cell of this comparative example comprises the following steps:

[0125] 1) performing a texturing process on the first surface and the second surface of the substrate so that both the first surface and the second surface of the substrate form a texturing surface;

[0126] 2) forming a first passivation layer and a first doping layer of a first conductivity type stacked in sequence on the first surface side of the substrate;

[0127] 3) forming a second passivation layer and a second doping layer of a second conductivity type stacked in sequence on the second surface side of the substrate,

[0128] 4) using a magnetron sputtering process to deposit a transparent conductive film on the first doped layer side facing away from the substrate and the second doped layer side facing away from the substrate, and doping hydrogen during the deposition process to obtain a hydrogenated transparent conductive layer;

[0129] The molar percentage of hydrogen in the hydrogenated transparent conductive layer is 1.2%;

[0130] 5) An epoxy-based conductive paste (DiKe Electronic Materials) was applied on the surface of the hydrogenated transparent conductive layer on the surface of the first doping layer and the surface of the hydrogenated transparent conductive layer on the surface of the second doping layer, and then sintered at 170° C. for 4 minutes to form a conductive electrode to obtain a photovoltaic cell.

[0131] Performance Testing

[0132] (1) Adhesion test

[0133] The adhesion between the conductive electrode and the hydrogenated transparent conductive layer in the photovoltaic cell of Example 1 and the adhesion between the conductive electrode and the hydrogenated transparent conductive layer in the photovoltaic cell of the comparative example were respectively subjected to tensile tests. The conductive electrode was divided into 10 sections from one end to the other end, and each section was subjected to three tensile tests using a grid line tensile testing machine. The tensile test data results are shown in Table 1.

[0134] Table 1 Tensile test data results

[0135]

[0136]

[0137] It can be seen from Table 1 that the adhesion between the conductive electrode and the hydrogenated transparent conductive film in the photovoltaic cells of Examples 1-3 is greater than the adhesion between the conductive electrode and the hydrogenated transparent conductive layer in the photovoltaic cells of the comparative example, indicating that the method of the present invention can effectively increase the adhesion between the conductive electrode and the hydrogenated transparent conductive layer.

[0138] (2) Photovoltaic cell performance test

[0139] The photovoltaic cells of the embodiment and the comparative example were subjected to IV tests to obtain short-circuit current density (Jsc), open-circuit voltage (Uoc), fill factor (FF), and conversion efficiency (Eta). The results are shown in Table 2.

[0140] Table 2 Electrical parameter measurement results

[0141] sample <![CDATA[Jsc(mA / cm 2 )]]> Uoc(mV) FF(%) Eta(%) Comparative Example 39.9659 0.7472 83.80 25.03 Example 1 39.8487 0.7478 85.94 25.61 Example 2 39.7094 0.7480 86.75 25.77 Example 3 39.6650 0.7496 86.84 25.82

[0142] It can be seen from Table 2 that, compared with the photovoltaic cells prepared in the comparative example, although the short-circuit current density Jsc of the photovoltaic cells prepared in the present invention is slightly reduced to a certain extent, it has the advantages of high open circuit voltage Uoc, high fill factor FF and high conversion efficiency Eta, which shows that the method of the present invention can be used to prepare high-performance photovoltaic cells.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a photovoltaic cell, comprising: A substrate is provided, wherein the substrate has a first surface and a second surface arranged opposite to each other, wherein the method further comprises: forming a hydrogenated transparent conductive layer on the first surface and the second surface of the substrate respectively; Performing an activation treatment on the hydrogenated transparent conductive layer to at least disconnect the hydroxyl groups on the surface of the hydrogenated transparent conductive layer to form oxygen-deficient dangling bonds; Applying epoxy conductive paste on the surface of the hydrogenated transparent conductive layer after the activation treatment, the oxygen-containing bonds in the epoxy conductive paste and the oxygen-losing dangling bonds on the surface of the hydrogenated transparent conductive layer form chemical bonds to obtain an initial conductive electrode; The initial conductive electrode is subjected to a sintering process to form a conductive electrode, thereby obtaining the photovoltaic cell.

2. The preparation method according to claim 1, characterized in that: The steps of forming the hydrogenated transparent conductive layer include: A magnetron sputtering process is adopted to deposit a transparent conductive film on the first doped layer side away from the substrate and the second doped layer side away from the substrate, and hydrogen is doped during the deposition process to obtain the hydrogenated transparent conductive layer.

3. The preparation method according to claim 2, characterized in that: In the hydrogenated transparent conductive layer, the molar percentage of hydrogen element is 1% to 1.5%.

4. The preparation method according to any one of claims 1 to 3, characterized in that The step of performing activation treatment on the hydrogenated transparent conductive layer comprises: A laser activation treatment is performed on the surface of at least one of the hydrogenated transparent conductive layers to obtain a first activated region containing oxygen-deficient dangling bonds; wherein, The depth of the first activation zone includes: 0.1nm-20nm.

5. The preparation method according to claim 4, characterized in that: In the laser activation process, the laser irradiation intensity includes: 20kW / m 2 ~100kW / m 2 ; Laser irradiation duration ranges from 5s to 120s.

6. The preparation method according to any one of claims 1 to 3, characterized in that: The step of performing activation treatment on the hydrogenated transparent conductive layer comprises: A plasma activation treatment is performed on the surface of at least one of the hydrogenated transparent conductive layers to obtain a second activated region containing oxygen-deficient dangling bonds; wherein, The depth of the second activation zone includes: 0.1nm-20nm.

7. The preparation method according to claim 6, characterized in that: In the plasma activation process, an inert gas source is used as the plasma gas; The gas source input pressure includes: 0.05mbar~0.5mbar; Plasma discharge power includes: 10W~100W; The plasma bombardment duration ranges from 5s to 50s.

8. The preparation method according to claim 1, characterized in that: Before performing the activation treatment, the method further comprises: The surface of the hydrogenated transparent conductive layer is micro-etched to obtain a surface area with a preset roughness; wherein, The preset roughness includes: 0.738nm~0.8nm.

9. The preparation method according to claim 1, characterized in that: Forming a hydrogenated transparent conductive layer on the first surface and the second surface of the substrate respectively comprises: Performing a texturing process on the first surface and / or the second surface of the substrate to form a surface textured structure; Forming a first passivation layer and a first doping layer of a first conductivity type stacked in sequence on the first surface side of the substrate; forming a second passivation layer and a second doping layer of a second conductivity type stacked in sequence on the second surface side of the substrate; A hydrogenated transparent conductive layer is formed on the first doping layer and the second doping layer respectively at the side facing away from the substrate.

10. A photovoltaic cell, comprising a substrate, wherein the substrate has a first surface and a second surface arranged opposite to each other; characterized in that: Also includes: A hydrogenated transparent conductive layer is disposed on the first surface and the second surface of the substrate respectively; A conductive electrode, disposed on the side of the hydrogenated transparent conductive layer facing away from the substrate; The oxygen-containing bonds of the conductive electrode form chemical bonds with the oxygen-depleted dangling bonds on the surface of the hydrogenated transparent conductive layer.

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