Solar cell

Abstract

The utility model discloses a solar cell which comprises the following components: a photoelectric conversion unit which comprises a light receiving surface and a backlight surface which are oppositely arranged; the transparent conducting layer comprises a first transparent conducting layer located on the light receiving surface of the photoelectric conversion unit and a second transparent conducting layer located on the backlight surface of the photoelectric conversion unit; the electrodes comprise a first electrode electrically contacted with the first transparent conductive layer and a second electrode electrically contacted with the second transparent conductive layer; wherein the first transparent conductive layer comprises a first optical dominant layer and a first electrode contact layer which are sequentially stacked on the light receiving surface of the photoelectric conversion unit, the thickness of the first optical dominant layer is larger than or equal to 30 nm, and the mobility of the first electrode contact layer is larger than that of the first optical dominant layer. By optimizing the structure, the thickness, the mobility and the like of the transparent conducting layer on the front surface of the cell, higher optical gain and electrical gain can be obtained, and the photoelectric conversion efficiency of the solar cell is effectively improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of solar energy, and in particular relates to a solar cell. Background Art

[0002] Heterojunction cell (HJT) is a hybrid solar cell made of crystalline silicon substrate and amorphous silicon thin film. It has many advantages such as simple preparation process, low process temperature, high open circuit voltage, high photoelectric conversion efficiency and low temperature coefficient. It is one of the most widely used high-efficiency crystalline silicon solar energy technologies.

[0003] With the introduction of microcrystalline technology in heterojunction cells, the doping concentration of the microcrystalline silicon layer has increased, so the demand for high carrier concentration in the transparent conductive layer (TCO layer) has decreased, and a wider optical window can be obtained under the same electrical contact conditions. Therefore, increasing the front mobility and increasing the thickness of the optical advantage layer has become an effective means of improving efficiency.

[0004] Adding H to the TCO layer can effectively improve the mobility of the TCO layer, and at the same time has little effect on the carrier concentration within a certain concentration range, especially for high In content hydrogen doping effect is better (In 2 O 3 wt%: 99.5%>97%>90%), but the introduction of H often brings negative effects on the stability and passivation effect of the front N-type amorphous or microcrystalline silicon layer.

[0005] Therefore, in view of the above technical problems, it is necessary to provide a solar cell. Utility Model Content

[0006] In view of this, the purpose of the utility model is to provide a solar cell, which improves the photoelectric conversion efficiency of the cell by optimizing the thickness and mobility of the transparent conductive layer of the cell.

[0007] In order to achieve the above purpose, the technical solution provided by an embodiment of the present utility model is as follows:

[0008] A solar cell, comprising:

[0009] The photoelectric conversion unit comprises a light receiving surface and a backlight surface which are arranged opposite to each other;

[0010] The transparent conductive layer includes a first transparent conductive layer located on the light-receiving surface of the photoelectric conversion unit and a second transparent conductive layer located on the backlight surface of the photoelectric conversion unit;

[0011] Electrodes, including a first electrode electrically contacting the first transparent conductive layer and a second electrode electrically contacting the second transparent conductive layer;

[0012] Among them, the first transparent conductive layer includes a first optical advantage layer and a first electrode contact layer stacked in sequence on the light-receiving surface of the photoelectric conversion unit, the thickness of the first optical advantage layer is greater than or equal to 30nm, and the mobility of the first electrode contact layer is greater than the mobility of the first optical advantage layer.

[0013] In one embodiment, the thickness of the first transparent conductive layer is 80nm-120nm, the thickness of the first optically advantageous layer is 30nm-100nm, and the thickness of the first electrode contact layer is 15nm-50nm; and / or,

[0014] The first transparent conductive layer comprises one or more first optically advantageous layers.

[0015] In one embodiment, the ratio of the mobility of the first optically advantageous layer to the mobility of the first electrode contact layer is (0.7-0.9):1; and / or,

[0016] The mobility of the first optically advantageous layer is 25 cm 2 / V·s~60cm 2 / V·s, the mobility of the first electrode contact layer is 35cm 2 / V·s~80cm 2 / V·s.

[0017] In one embodiment, the first transparent conductive layer is doped with H, the H doping concentration in the first electrode contact layer is greater than the H doping concentration in the first optically advantageous layer, and the H doping concentration in the first electrode contact layer is 0.9E21 / cm 3 ~5E21 / cm 3 .

[0018] In one embodiment, the carrier concentration of the first electrode contact layer is greater than the carrier concentration of the first optically advantageous layer.

[0019] In one embodiment, the carrier concentration of the first electrode contact layer is 2.0E20 / cm 3 ~4.0E20 / cm 3 The carrier concentration of the first optically advantageous layer is 0.2E20 / cm 3 ~2.0E20 / cm 3 .

[0020] In one embodiment, the first transparent conductive layer is any one of an ITO layer, an IWO layer, an IMO layer, an AZO layer, and a GZO layer.

[0021] In one embodiment, the first transparent conductive layer is doped with metal and / or metal oxide, and the doping amount is 0.5 wt % to 10 wt %.

[0022] In one embodiment, the thickness of the second transparent conductive layer is 80 nm to 120 nm; and / or,

[0023] The mobility of the second transparent conductive layer is 40 cm 2 / V·s~80cm 2 / V·s; and / or,

[0024] The carrier concentration of the second transparent conductive layer is 0.2E20 / cm 3 ~4.0E20 / cm 3 .

[0025] In one embodiment, the solar cell is a heterojunction cell, and the photoelectric conversion unit includes:

[0026] A substrate, comprising a first surface and a second surface arranged opposite to each other, wherein the substrate is N-type doped or P-type doped;

[0027] A first intrinsic layer, located on a first surface of the substrate, wherein the first intrinsic layer is an intrinsic amorphous silicon layer and / or an intrinsic microcrystalline silicon layer;

[0028] A first doped layer, located on the first intrinsic layer, wherein the first doped layer is an amorphous silicon layer and / or a microcrystalline silicon layer, and the doping type is the same as the doping type of the substrate;

[0029] A second intrinsic layer, located on the second surface of the substrate, wherein the second intrinsic layer is an intrinsic amorphous silicon layer and / or an intrinsic microcrystalline silicon layer;

[0030] The second doped layer is located on the second intrinsic layer. The second doped layer is an amorphous silicon layer and / or a microcrystalline silicon layer. The doping type of the second doped layer is opposite to that of the substrate.

[0031] The utility model has the following beneficial effects:

[0032] The utility model can obtain higher optical gain and electrical gain by optimizing the structure, thickness and mobility of the transparent conductive layer on the front side of the battery, thereby effectively improving the photoelectric conversion efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 It is a schematic diagram of the structure of the solar cell in the utility model;

[0035] Figure 2 It is a schematic structural diagram of another solar cell in the utility model. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0037] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0038] Ginseng Figure 1 The structure diagram of the solar cell in the utility model is shown, which includes:

[0039] The photoelectric conversion unit 100 includes a light receiving surface and a backlight surface which are arranged opposite to each other;

[0040] The transparent conductive layer includes a first transparent conductive layer (TCO1) 21 located on the light-receiving surface of the photoelectric conversion unit 100 and a second transparent conductive layer (TCO2) 22 located on the backlight surface of the photoelectric conversion unit 100;

[0041] The electrodes include a first electrode 31 electrically contacting the first transparent conductive layer 21 and a second electrode 32 electrically contacting the second transparent conductive layer 22 .

[0042] The first transparent conductive layer 21 in the present invention includes a first optical advantage layer 211 (i.e., an inner transparent conductive layer) electrically contacting the light-receiving surface of the photoelectric conversion unit 100, and a first electrode contact layer 212 (i.e., an outer transparent conductive layer) electrically contacting the first electrode 31, and the first electrode contact layer 212 is stacked on the first optical advantage layer 211.

[0043] The thickness of the first optically advantageous layer 211 is greater than or equal to 30 nm, and the mobility of the first electrode contact layer 212 is greater than the mobility of the first optically advantageous layer 211 .

[0044] Preferably, the thickness of the first transparent conductive layer 21 (ie, the sum of the thickness of the first electrode contact layer 212 and the first optical advantage layer 211 ) is 80nm-120nm, the thickness of the first optical advantage layer 211 is 30nm-100nm, and the thickness of the first electrode contact layer 212 is 15nm-50nm.

[0045] Preferably, the ratio of the mobility of the first optically advantageous layer 211 to the mobility of the first electrode contact layer 212 is (0.7-0.9):1, and the mobility of the first optically advantageous layer 211 is 25 cm 2 / V·s~60cm 2 / V·s, and the mobility of the first electrode contact layer 212 is 35cm 2 / V·s~80cm 2 / V·s.

[0046] Furthermore, in the present invention, the carrier concentration of the first electrode contact layer 212 is greater than the carrier concentration of the first optical advantage layer 211 .

[0047] Preferably, the carrier concentration of the first electrode contact layer 212 is 2.0E20 / cm 3 ~4.0E20 / cm 3 , the carrier concentration of the first optical advantage layer 211 is 0.2E20 / cm 3 ~2.0E20 / cm 3 .

[0048] The first optical advantage layer 211 and the first electrode contact layer 212 in the first transparent conductive layer 21 of the present invention are made of the same transparent conductive oxide material. The transparent conductive layer can be any one of an ITO layer, an IWO layer, an IMO layer, an AZO layer, a GZO layer, etc.

[0049] In order to further improve the conductivity of the transparent conductive layer, metal or metal oxide is doped into the transparent conductive layer, and the doping amount may be 0.5 wt % to 10 wt %.

[0050] For example, the ITO layer can be 2 O 3 SnO doped in substrate 2 、TiO 2 、CeO 2 、 2 O 5 , Ga 2 O 3 、ZrO 2 、MoO 3 The IWO layer is doped with WO 2, the IMO layer is doped with MoO 3 AZO layer is made by doping Al in ZnO substrate 2 O 3 ; GZO is Ga doped in ZnO substrate 2 O 3 .

[0051] Preferably, the first transparent conductive layer in the present invention is an ITO layer (In 2 O 3 SnO doped 2 ), the doping amount is 0.5wt%~3wt%

[0052] The above-mentioned transparent conductive layer only lists some materials. The transparent conductive layer in the present utility model is not limited to the above-mentioned materials. All doped / undoped oxides that can achieve both conductivity and transparency belong to the scope of protection of the present utility model.

[0053] More importantly, the first transparent conductive layer of the present invention is doped with H, and the H doping concentration in the first electrode contact layer 212 is greater than the H doping concentration in the first optical advantage layer 211. Preferably, the H doping concentration in the first electrode contact layer 212 is 0.9E21 / cm 3 ~5E21 / cm 3 .

[0054] By increasing the H doping concentration in the first electrode contact layer, the mobility of the first electrode contact layer can be increased.

[0055] The thickness of the second transparent conductive layer 22 in the present invention is 80nm to 120nm, and the mobility is 40cm 2 / V·s~80cm 2 / V·s, carrier concentration is 0.2E20 / cm 3 ~4.0E20 / cm 3 .

[0056] The material of the second transparent conductive layer is the same as that of the first transparent conductive layer, and will not be described in detail here.

[0057] Ginseng Figure 2 As shown, the second transparent conductive layer 22 in the present invention may also include a second optical advantage layer 221 electrically contacting the backlight surface of the photoelectric conversion unit 100 , and a second electrode contact layer 222 electrically contacting the second electrode 32 , and the second electrode contact layer 222 is stacked on the second optical advantage layer 221 .

[0058] The first transparent conductive layer of the present invention is described by taking a first optical advantage layer and a first electrode contact layer as an example. In some embodiments, the first optical advantage layer can also be set as a multilayer, which will not be described in detail in the present invention.

[0059] Exemplarily, the solar cell in the present invention is described by taking a heterojunction cell (HJT) as an example, the photoelectric conversion unit 100 is the cell body of the heterojunction cell, the light-receiving surface is the front side (or upper surface) of the cell body, and the backlight surface is the back side (or lower surface) of the cell body.

[0060] Specifically, the photoelectric conversion unit 100 includes:

[0061] The substrate 11 includes a first surface (i.e., a front surface or an upper surface) and a second surface (i.e., a back surface or a lower surface) that are arranged opposite to each other, and the substrate is N-type doped or P-type doped;

[0062] A first intrinsic layer 121, located on the first surface of the substrate 11, and the first intrinsic layer 121 may be an intrinsic amorphous silicon layer or an intrinsic microcrystalline silicon layer;

[0063] A first doping layer 131 is located on the first intrinsic layer 121. The first doping layer 131 may be an amorphous silicon layer or a microcrystalline silicon layer, and the doping type is the same as that of the substrate;

[0064] A second intrinsic layer 122, located on the second surface of the substrate 11, and the second intrinsic layer 122 may be an intrinsic amorphous silicon layer or an intrinsic microcrystalline silicon layer;

[0065] The second doping layer 132 is located on the second intrinsic layer 122 . The second doping layer 132 may be an amorphous silicon layer or a microcrystalline silicon layer, and the doping type of the second doping layer 132 is opposite to the doping type of the substrate.

[0066] Taking an N-type heterojunction battery as an example, the substrate 11 is an N-type substrate, the first doping layer 131 is N-type doped, and the second doping layer 132 is P-type doped.

[0067] The structure and principle of the photoelectric conversion unit in the heterojunction battery are prior art and will not be described in detail here.

[0068] Taking a heterojunction solar cell as an example, the method for preparing the solar cell in the utility model comprises the following steps:

[0069] 1. Prepare the photoelectric conversion unit in the solar cell.

[0070] 1.1. Provide silicon wafers.

[0071] The silicon wafer in the present invention is preferably an N-type single crystal silicon wafer with a resistivity of 0.5Ω.cm to 3Ω.cm, a thickness of 150μm to 200μm, and a size of 182mm.

[0072] 1.2. Cleaning and velveting.

[0073] The oxide layer on the surface of the silicon wafer is removed by using a diluted HF solution with a solubility of 5%, and a shallow pyramid velvet structure is formed on the surface by using a method of KOH or NaOH or tetramethylammonium hydroxide (TMAH) plus alcohol and utilizing anisotropic etching of single crystal silicon.

[0074] 1.3. Deposit an amorphous silicon layer.

[0075] First, SiH 4 (Silane) gas is introduced into the vacuum chamber, and a first intrinsic amorphous silicon layer is formed on the entire area of ​​the first surface of the N-type single crystal silicon wafer by a plasma CVD process; and then SiH 4 Gas, H 2 Gas and pH 3 (phosphine) gas is introduced into the vacuum chamber, and an N-type doped amorphous silicon layer is formed on the first intrinsic amorphous silicon layer by a plasma CVD process;

[0076] Next, turn it over, change the tray, and then place the SiH 4 (Silane) gas is introduced into the vacuum chamber, and a second intrinsic amorphous silicon layer is formed on the entire area of ​​the second surface of the N-type single crystal silicon wafer by a plasma CVD process; and then SiH 4 Gas, H 2 Gas and pH 3 (Phosphine) gas is introduced into the vacuum chamber, and a P-type doped amorphous silicon layer is formed on the second intrinsic amorphous silicon layer by a plasma CVD process.

[0077] 2. Depositing a first transparent conductive layer on the light-receiving surface of the photoelectric conversion unit, and depositing a second transparent conductive layer on the backlight surface of the photoelectric conversion unit.

[0078] The amorphous silicon layer on the front and back sides is coated by a physical vapor deposition (PVD) process, which may be a reactive plasma deposition (RPD) process or a magnetron sputtering process. The back side is shielded by the edge of the carrier design (or by a mask), and the specific shielding area around it is ~0.8 mm.

[0079] When preparing the first transparent conductive layer, different transparent conductive layers, namely the first optical advantage layer (inner transparent conductive layer) and the first electrode contact layer (outer transparent conductive layer), are sequentially deposited on the substrate after depositing the front amorphous silicon layer.

[0080] The specific method is:

[0081] PVD mass production equipment has at least 4 non-contaminating coating targets, with different target materials installed on the targets; the substrate is placed on a carrier and sequentially subjected to coating at different targets to obtain the desired film design. The process parameters are adjusted at different targets to adjust the thickness, mobility, carrier concentration, etc. of the first transparent conductive layer to within the preset range.

[0082] The physical vapor deposition process uses a certain amount of energy to bombard the material in the target material, while introducing the corresponding gas (oxygen O 2 、H 2 and argon Ar) to form a certain atmosphere. Different process parameters are selected for different transparent conductive layers, including deposition temperature, deposition time, flow ratio of each gas in the gas, pressure in the deposition chamber, temperature in the deposition chamber, etc.

[0083] 3. Form a first electrode and a second electrode on the first transparent conductive layer and the second transparent conductive layer respectively.

[0084] A layer of low-temperature conductive silver paste is printed on the transparent conductive layer on the front and back sides respectively by screen printing technology, and then sintered and cured at a low temperature of 150°C to 300°C to form a good ohmic contact electrode.

[0085] The first optical advantage layer and the first electrode contact layer in the utility model adopt the same TCO material, and the two-layer structure can be carried out in the PVD deposition process, and only different process conditions need to be controlled, and no new deposition steps will be added.

[0086] The present invention is further described below in conjunction with specific embodiments.

[0087] Comparative Example:

[0088] Ginseng Figure 1 As shown, the solar cell in this comparative example is a heterojunction cell, which includes:

[0089] The substrate 11 comprises a first surface and a second surface which are arranged opposite to each other, and the substrate is N-type doped;

[0090] A first intrinsic layer 121 is located on the first surface of the substrate 11, and the first intrinsic layer 121 is an intrinsic amorphous silicon layer;

[0091] A first doped layer 131 is located on the first intrinsic layer 121 , and the first doped layer 131 is an N-type doped amorphous silicon layer;

[0092] A second intrinsic layer 122, located on the second surface of the substrate 11, and the second intrinsic layer 122 is an intrinsic amorphous silicon layer;

[0093] A second doped layer 132 , located on the second intrinsic layer 122 , the second doped layer 132 is a P-type doped amorphous silicon layer;

[0094] The first transparent conductive layer 21 includes a first optically advantageous layer (inner transparent conductive layer) 211 stacked on the first doping layer 131 and a first electrode contact layer (outer transparent conductive layer) 212 stacked on the first optically advantageous layer, wherein the first optically advantageous layer 211 is SnO 2 Doped ITO layer, doping amount is 0.5wt%, carrier concentration is 1.1E20 / cm 3 , the mobility is 55cm 2 / V·s, a thickness of 47.5nm, and the first electrode contact layer 212 is SnO 2 Doped ITO layer, doping amount is 0.5wt%, carrier concentration is 3E20 / cm 3 , the mobility is 50cm 2 / V·s, thickness is 47.5nm;

[0095] The second transparent conductive layer 22 is SnO 2 Doped ITO layer, doping amount is 0.5wt%, carrier concentration is 3.0E20 / cm 3 , thickness is 90nm;

[0096] A first electrode 31, located on the first transparent conductive layer 21 and electrically contacting therewith;

[0097] The second electrode 32 is located on the second transparent conductive layer 22 and is in electrical contact with the second transparent conductive layer 22 .

[0098] In the process of PVD deposition of the first optical advantage layer 211 and the first electrode contact layer 212 in this comparative example, the gas introduced into the chamber includes hydrogen gas with a flow rate of 1%. The H doping concentration in the first electrode contact layer is 1E21 / cm 3 The H doping concentration in the first optical advantage layer 211 is 1E21 / cm 3

[0099] Embodiment 1:

[0100] Ginseng Figure 1 As shown, the solar cell in this embodiment is a heterojunction cell, which includes:

[0101] The substrate 11 comprises a first surface and a second surface which are arranged opposite to each other, and the substrate is N-type doped;

[0102] A first intrinsic layer 121 is located on the first surface of the substrate 11, and the first intrinsic layer 121 is an intrinsic amorphous silicon layer;

[0103] A first doped layer 131 is located on the first intrinsic layer 121 , and the first doped layer 131 is an N-type doped amorphous silicon layer;

[0104] A second intrinsic layer 122 is located on the second surface of the substrate 11, and the second intrinsic layer 122 is an intrinsic amorphous silicon layer;

[0105] A second doped layer 132, located on the second intrinsic layer 122, the second doped layer 132 is a P-type doped amorphous silicon layer;

[0106] The first transparent conductive layer 21 includes a first optically advantageous layer (inner transparent conductive layer) 211 stacked on the first doping layer 131 and a first electrode contact layer (outer transparent conductive layer) 212 stacked on the first optically advantageous layer, wherein the first optically advantageous layer 211 is SnO 2 Doped ITO layer, doping amount is 0.5wt%, carrier concentration is 1.1E20 / cm 3 , the mobility is 70cm 2 / V·s, a thickness of 47.5nm, and the first electrode contact layer 212 is SnO 2 Doped ITO layer, doping amount is 0.5wt%, carrier concentration is 3E20 / cm 3 , the mobility is 65cm 2 / V·s, thickness is 47.5nm;

[0107] The second transparent conductive layer 22 is SnO 2 Doped ITO layer, doping amount is 0.5wt%, carrier concentration is 3.0E20 / cm 3 , thickness is 90nm;

[0108] A first electrode 31, located on the first transparent conductive layer 21 and electrically contacting therewith;

[0109] The second electrode 32 is located on the second transparent conductive layer 22 and is in electrical contact with the second transparent conductive layer 22 .

[0110] In the process of PVD deposition of the first optical advantage layer 211 and the first electrode contact layer 212 in this comparative example, the gas introduced into the chamber includes hydrogen gas with a flow rate of 3.5%, which is 2.5% higher than that in the comparative example. The H doping concentration in the first electrode contact layer is 3E21 / cm 3 The H doping concentration in the first optical advantage layer 211 is 3E21 / cm 3 .

[0111] Embodiment 2:

[0112] Ginseng Figure 1 As shown, the solar cell in this embodiment is a heterojunction cell, which includes:

[0113] The substrate 11 comprises a first surface and a second surface which are arranged opposite to each other, and the substrate is N-type doped;

[0114] A first intrinsic layer 121 is located on the first surface of the substrate 11, and the first intrinsic layer 121 is an intrinsic amorphous silicon layer;

[0115] A first doped layer 131 is located on the first intrinsic layer 121 , and the first doped layer 131 is an N-type doped amorphous silicon layer;

[0116] A second intrinsic layer 122 is located on the second surface of the substrate 11, and the second intrinsic layer 122 is an intrinsic amorphous silicon layer;

[0117] A second doped layer 132, located on the second intrinsic layer 122, the second doped layer 132 is a P-type doped amorphous silicon layer;

[0118] The first transparent conductive layer 21 includes a first optically advantageous layer (inner transparent conductive layer) 211 stacked on the first doping layer 131 and a first electrode contact layer (outer transparent conductive layer) 212 stacked on the first optically advantageous layer, wherein the first optically advantageous layer 211 is SnO 2 Doped ITO layer, doping amount is 0.5wt%, carrier concentration is 1.1E20 / cm 3 , the mobility is 55cm 2 / V·s, a thickness of 47.5nm, and the first electrode contact layer 212 is SnO 2 Doped ITO layer, doping amount is 0.5wt%, carrier concentration is 3E20 / cm 3 , the mobility is 65cm 2 / V·s, thickness is 47.5nm;

[0119] The second transparent conductive layer 22 is SnO 2 Doped ITO layer, doping amount is 0.5wt%, carrier concentration is 3.0E20 / cm 3 , thickness is 90nm;

[0120] A first electrode 31, located on the first transparent conductive layer 21 and electrically contacting therewith;

[0121] The second electrode 32 is located on the second transparent conductive layer 22 and is in electrical contact with the second transparent conductive layer 22 .

[0122] In the process of PVD deposition of the first optical advantage layer 211 in this comparative example, the gas introduced into the chamber includes hydrogen gas with a flow rate of 1%, which is the same as in the comparative example; however, in the process of PVD deposition of the first electrode contact layer 212, the gas introduced into the chamber includes hydrogen gas with a flow rate of 3.5%, which is 2.5% higher than that in the comparative example. The H doping concentration in the first electrode contact layer is ~3E21 / cm 3 The H doping concentration in the first optical advantage layer 211 is 1E21 / cm 3 .

[0123] After testing, the performance parameters of the heterojunction battery in the comparative example and the embodiment are as follows:

[0124]

[0125] It can be seen that the front TCO layer in Example 1 is prepared by the H-adding process. Compared with the comparative example, the current density Jsc and the fill factor FF are improved, but the open circuit voltage Voc (passivation performance) is greatly reduced, and the efficiency Eta is basically the same.

[0126] In Example 2, only the electrode contact layer of the front TCO layer is prepared by the H addition process. Compared with the comparative example, the open circuit voltage Voc, the fill factor FF, and the current density Jsc all have certain gains, and the efficiency Eta is improved by 0.08%.

[0127] It can be seen from the above technical solutions that the utility model has the following beneficial effects:

[0128] The utility model can obtain higher optical gain and electrical gain by optimizing the structure, thickness and mobility of the transparent conductive layer on the front side of the battery, thereby effectively improving the photoelectric conversion efficiency of the solar cell.

[0129] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0130] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A solar cell, characterized in that: The solar cell comprises: The photoelectric conversion unit comprises a light receiving surface and a backlight surface which are arranged opposite to each other; The transparent conductive layer includes a first transparent conductive layer located on the light-receiving surface of the photoelectric conversion unit and a second transparent conductive layer located on the backlight surface of the photoelectric conversion unit; Electrodes, including a first electrode electrically contacting the first transparent conductive layer and a second electrode electrically contacting the second transparent conductive layer; Among them, the first transparent conductive layer includes a first optical advantage layer and a first electrode contact layer stacked in sequence on the light-receiving surface of the photoelectric conversion unit, the thickness of the first optical advantage layer is greater than or equal to 30nm, and the mobility of the first electrode contact layer is greater than the mobility of the first optical advantage layer.

2. The solar cell according to claim 1, characterized in that: The thickness of the first transparent conductive layer is 80nm to 120nm, the thickness of the first optically advantageous layer is 30nm to 100nm, and the thickness of the first electrode contact layer is 15nm to 50nm; and / or, The first transparent conductive layer comprises one or more first optically advantageous layers.

3. The solar cell according to claim 1, characterized in that The ratio of the mobility of the first optically advantageous layer to the mobility of the first electrode contact layer is (0.7-0.9):1; and / or, The mobility of the first optically advantageous layer is 25 cm 2 / V·s~60cm 2 / V·s, the mobility of the first electrode contact layer is 35cm 2 / V·s~80cm 2 / V·s.

4. The solar cell according to claim 1, characterized in that The carrier concentration of the first electrode contact layer is greater than the carrier concentration of the first optically advantageous layer.

5. The solar cell according to claim 4, characterized in that: The carrier concentration of the first electrode contact layer is 2.0E20 / cm 3 ~4.0E20 / cm 3 The carrier concentration of the first optically advantageous layer is 0.2E20 / cm 3 ~2.0E20 / cm 3 .

6. The solar cell according to claim 1, characterized in that The first transparent conductive layer is any one of an ITO layer, an IWO layer, an IMO layer, an AZO layer, and a GZO layer.

7. The solar cell according to claim 1, characterized in that The thickness of the second transparent conductive layer is 80 nm to 120 nm; and / or, The mobility of the second transparent conductive layer is 40 cm 2 / V·s~80cm 2 / V·s; and / or, The carrier concentration of the second transparent conductive layer is 0.2E20 / cm 3 ~4.0E20 / cm 3 .

8. The solar cell according to claim 1, characterized in that The solar cell is a heterojunction cell, and the photoelectric conversion unit comprises: A substrate, comprising a first surface and a second surface arranged opposite to each other, wherein the substrate is N-type doped or P-type doped; A first intrinsic layer, located on a first surface of the substrate, wherein the first intrinsic layer is an intrinsic amorphous silicon layer and / or an intrinsic microcrystalline silicon layer; A first doped layer, located on the first intrinsic layer, wherein the first doped layer is an amorphous silicon layer and / or a microcrystalline silicon layer, and the doping type is the same as the doping type of the substrate; A second intrinsic layer, located on the second surface of the substrate, wherein the second intrinsic layer is an intrinsic amorphous silicon layer and / or an intrinsic microcrystalline silicon layer; The second doped layer is located on the second intrinsic layer. The second doped layer is an amorphous silicon layer and / or a microcrystalline silicon layer. The doping type of the second doped layer is opposite to that of the substrate.

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