Silicon heterojunction solar cell and preparation method thereof

Abstract

The invention provides a silicon heterojunction solar cell and a preparation method thereof. The solar cell is a silicon heterojunction solar cell based on a metal nanoparticle high work function interface. According to the method, the sizes of metal nanoparticles are regulated and controlled, and the metal nanoparticles are introduced to serve as an interface of TCO and a p-type doping layer in the back contact structure. According to the method, the metal nanoparticles with the section diameter of 8-20 nm are adopted as a TCO / p high work function interface, the work function of contact between TCO and a p-type doping layer is improved, effective extraction of holes is promoted, series resistance is reduced, and therefore the open-circuit voltage and the fill factor of the device are improved.

Description

Technical Field

[0001] The present invention relates to a crystalline silicon cell using metal nanoparticles as the interface between TCO and p-type doped layer in a back contact structure and a preparation method thereof, belonging to the technical fields of photovoltaic and semiconductor device manufacturing. Background Art

[0002] Crystalline silicon solar cells are currently the mainstream in the photovoltaic market. To reduce the cost of photovoltaic power generation, improving the photoelectric conversion efficiency of solar cells is the most effective means. Silicon heterojunction cells have advantages such as high open-circuit voltage and simple preparation process, and have received extensive attention. Silicon heterojunction cells use intrinsic hydrogenated amorphous silicon (i-a-Si:H) as the passivation layer and n / p-doped hydrogenated amorphous silicon (n / p-a-Si:H) as the selective contact layer for carriers. Although hydrogenated amorphous silicon provides enough hydrogen to passivate the dangling bonds on the surface of crystalline silicon, since there will be a certain potential barrier when the silicon thin film contacts the TCO, the resulting loss of carrier transport leads to a decrease in the open-circuit voltage and fill factor of the silicon heterojunction solar cell, and the high contact resistance generated due to the contact potential barrier between the silicon thin film and the TCO is the main reason for the relatively high series resistance of the silicon heterojunction solar cell.

[0003] In silicon heterojunction solar cells, since most TCO materials are n-type materials, the hole transport between the p-type doped layer and the TCO mainly relies on trap-assisted tunneling to achieve. Therefore, the matching of the TCO work function and the p-type doped layer work function is the key factor in forming a low-contact potential barrier interface. Most researchers focus on back-junction silicon heterojunction solar cells, that is, silicon heterojunction solar cells with the p-type doped layer and the TCO on the back. For the p-type doped layer and the TCO on the back, the requirements for their optical properties are reduced, while the requirements for their electrical properties are higher, so the TCO / p contact interface is more important. Currently, the p-type doped layer that has been studied more is p-nc-Si:H. The Longi Green Energy Research Institute and the research group of Gaoping Qi from Sun Yat-sen University used p-nc-Si:H thin film and ICO:H as the back field and obtained an efficiency with a certified value of 26.81% and a fill factor of 86.07% (Nat Energy 8 (2023) 789–799). Compared with the traditional p-a-Si:H, p-type nanocrystalline silicon thin films have many advantages, such as a wider bandgap being beneficial to reducing parasitic absorption and a higher conductivity helping to reduce the series resistance of the battery. However, the current highest-efficiency cell is 26.81% from Longi Green Energy, and the fill factor of the cell is 86.07%, still having a certain gap with the theoretical maximum value of 89%. Currently, there is still a problem of poor contact between the doped layer and the TCO.

[0004] Based on this, the main problems existing in the use of p-type silicon thin films and TCO materials in crystalline silicon cells are as follows: (1) Most TCOs are n-type materials, and their work functions are smaller than that of p-type silicon thin films. (2) The work function mismatch between the p-type doped silicon thin film and the TCO forms an interface with a relatively high potential barrier, which affects the collection of carriers. Summary of the Invention

[0005] The object of the present invention is to solve the above problems existing in the prior art. In the crystalline silicon cell, metal nanoparticles are used as the interface between the TCO and the p-type doped layer, which plays a role in improving the interface contact, reducing the depletion layer width, and improving the device performance.

[0006] The technical solution of the present invention:

[0007] The first object of the present invention is to provide a silicon heterojunction solar cell. In the present invention, metal nanoparticles are introduced as the interface between the TCO and the p-type doped layer in the crystalline silicon cell. By regulating the size of the metal nanoparticles, a high work function interface based on the metal nanoparticles is prepared, making the work functions of the TCO and the p-type doped layer more matched, reducing the contact potential barrier, improving the contact of the TCO / p interface, reducing the series resistance, increasing the open circuit voltage of the battery, and improving the battery efficiency.

[0008] The silicon wafer is an n-type or p-type single crystal or polycrystalline silicon wafer. The morphology of the silicon wafer is double-sided polished, single-sided polished, or double-sided textured.

[0009] The p-type doped layer is one of the silicon thin film materials such as p-type doped nanocrystalline silicon p-nc-Si:H, p-type doped nanocrystalline silicon carbide p-nc-SiC:H, p-type doped nanocrystalline silicon oxide p-nc-SiO x :H, p-type doped amorphous silicon p-a-Si:H, p-type doped amorphous silicon carbide p-a-SiC:H, p-type doped amorphous silicon oxide p-a-SiO x :H.

[0010] The metal nanoparticles are one of the nanoparticles such as gold, silver, aluminum, and indium.

[0011] The TCO material includes one of the oxides and their composite multi-oxides of In, Sb, Zn, Sn, or Cd.

[0012] The silicon heterojunction solar cell obtained by the present invention is a double-sided light-receiving cell or a single-sided light-receiving cell. In the double-sided light-receiving cell, metal grid lines are used as electrodes on both sides of the cell; in the single-sided light-receiving cell, metal grid lines are used as electrodes on the light-receiving surface of the cell, and a full metal is used as an electrode on the backlight surface.

[0013] The second object of the present invention also provides a method for manufacturing the above-mentioned silicon heterojunction solar cell. The solar cell includes, from top to bottom in sequence, a metal grid electrode silver, a transparent conductive oxide film, an n-type doped silicon film, an intrinsic passivation layer i-a-Si:H, a crystalline silicon substrate, an intrinsic passivation layer i-a-Si:H, a p-type doped silicon film, metal nanoparticles, a transparent conductive oxide film, a metal grid electrode or a back metal electrode, and is obtained through the following manufacturing method:

[0014] 1) Using an n-type doped crystalline silicon as the initial substrate, perform texturing and cleaning;

[0015] 2) Use plasma enhanced chemical vapor deposition (PECVD) to deposit an i-a-Si:H passivation layer on both sides of the substrate respectively;

[0016] 3) Use plasma enhanced chemical vapor deposition (PECVD) to deposit an n-type doped silicon film and a p-type doped silicon film respectively above the two-sided passivation layers;

[0017] 4) Deposit a metal film on the p-type doped silicon film and form nanoparticles through annealing;

[0018] 5) Magnetron sputter and deposit a TCO film on the n-type doped layer and the p-type doped layer deposited with metal nanoparticles respectively;

[0019] 6) Use evaporation, printing or electroplating methods to deposit metal grid electrodes on both sides; or deposit a metal grid electrode on one side and deposit a full-area back metal electrode on the other side;

[0020] Among them, the metal grid electrode is Ag and the back metal electrode is Al.

[0021] The size of the above-mentioned metal nanoparticles is regulated by preparation methods such as thermal evaporation, magnetron sputtering, laser ablation, electrochemical reduction, etc., so as to obtain an interface that can reduce the TCO / p contact barrier, and the cross-sectional diameter of the nanoparticles is between 8-20 nm.

[0022] Among them, the size of the metal nanoparticles is regulated by thermal evaporation and magnetron sputtering methods through controlling the deposition time, deposition power and subsequent heat treatment methods.

[0023] Among them, the size of the metal nanoparticles is regulated by the laser ablation method through changing the laser power and illumination time.

[0024] Among them, the size of the metal nanoparticles is regulated by the electrochemical reduction method through changing the flow rate of the electrolyte during the electrolytic reduction of metal ions.

[0025] Advantages and positive effects of the present invention:

[0026] By regulating the size of metal nanoparticles, the present invention uses metal nanoparticles as the TCO / p interface material in crystalline silicon cells, which increases the work function of the contact between the TCO and the p-type doping layer, promotes the effective extraction of holes, and reduces the series resistance, thereby increasing the open-circuit voltage and fill factor of the device.

[0027] Mechanism analysis of the present invention:

[0028] Most TCO materials are n-type doped materials, and the carrier transport between the TCO material and the p-type doped silicon thin film relies on trap-assisted tunneling. The formed contact barrier is related to whether the work functions of the TCO and the p-type doping layer match. Since the work function of the p-type doped silicon thin film is higher than that of the TCO material, there is often a relatively high contact barrier between the p-type doping layer and the TCO. Using metal nanoparticles as the interface between the TCO and the p-type doping layer can make up for the deficiency of the TCO work function, thereby reducing the barrier formed by the contact between the TCO and the p-type doping layer, improving the hole transport ability, and thus increasing the open-circuit voltage. At the same time, the improvement of the TCO / p interface contact reduces the series resistance and increases the fill factor of the device. Description of the drawings

[0029] Figure 1 It is a schematic diagram of the structure of the silicon heterojunction solar cell of the present invention (double-sided light-receiving n-type textured structure).

[0030] Figure 2 It is a schematic diagram of the structure of the double-sided light-receiving n-type textured silicon heterojunction cell in Example 1.

[0031] Figure 3 It is a schematic diagram of the structure of the single-sided light-receiving n-type textured silicon heterojunction cell in Example 2.

[0032] Figure 4 It is a schematic diagram of the structure of the single-sided light-receiving n-type planar silicon heterojunction cell in Example 3.

[0033] Figure 5 It is a schematic diagram of the structure of the single-sided light-receiving p-type textured silicon heterojunction cell in Example 4.

[0034] Figure 6 It is a schematic diagram of the structure of the single-sided light-receiving n-type textured silicon heterojunction cell in Comparative Example 1.

[0035] Figure 7 、 Figure 8 、 Figure 9 They are respectively schematic diagrams of the structures of the single-sided light-receiving n-type textured silicon heterojunction cells in Examples 5, 6, and 7. Detailed implementation manners

[0036] Appendix Figure 1The schematic diagram of the silicon heterojunction solar cell structure of the present invention is shown (double-sided light-receiving n-type texture structure). The technical solution of the present invention will be further described in detail below by selecting the materials for each layer and through the preparation examples of specific cells.

[0037] Example 1:

[0038] In this example, the crystalline silicon cell structure is as Figure 2 shown, and from top to bottom, it successively includes: metal grid electrode silver (Ag), transparent conductive oxide thin film - indium tin oxide (ITO), n-type doped nanocrystalline silicon (n-nc-Si:H), intrinsic passivation layer (i-a-Si:H), n-type textured substrate (n-type wafer), intrinsic passivation layer (i-a-Si:H), p-type doped nanocrystalline silicon (p-nc-Si:H), silver nanoparticles (Ag-NPs), transparent conductive oxide thin film - indium tin oxide (ITO), metal grid electrode (Ag).

[0039] The silicon heterojunction solar cell of this example is obtained through the following preparation method:

[0040] 1. Using an n-type monocrystalline silicon wafer as the initial substrate, texturing and cleaning are performed;

[0041] 2. Using plasma-enhanced chemical vapor deposition (PECVD), 5 nm of i-a-Si:H passivation layer is deposited on both sides of the substrate;

[0042] 3. Using plasma-enhanced chemical vapor deposition (PECVD), 10 nm of n-nc-Si:H and 10 nm of p-nc-Si:H are respectively deposited above the two-sided passivation layers;

[0043] 4. Using thermal evaporation, a silver thin film is deposited on the p-type doped silicon thin film, and after annealing, silver nanoparticles with a cross-sectional diameter of 10 nm are formed;

[0044] 5. Magnetron sputtering deposition of ITO thin film is respectively carried out on n-nc-Si:H and p-nc-Si:H deposited with silver nanoparticles;

[0045] 6. Using evaporation method, 1 μm of metal grid electrode Ag is deposited on both sides.

[0046] For the solar cell prepared in this example, the open-circuit voltage on the front side is 0.73 V, the short-circuit current density is 38.79 mA / cm 2 , the fill factor is 84.06%, and the photoelectric conversion efficiency is 23.80%; the open-circuit voltage on the back side is 0.73 V, the short-circuit current density is 34.65 mA / cm 2 , the fill factor is 83.27%, and the photoelectric conversion efficiency is 21.06%.

[0047] Example 2:

[0048] In this embodiment, the crystalline silicon cell structure is as follows Figure 3 shown, from top to bottom, it includes: metal grid electrode silver (Ag), transparent conductive oxide film - indium tin oxide (ITO), n-type doped nanocrystalline silicon (n-nc-Si:H), intrinsic passivation layer (i-a-Si:H), n-type textured substrate (n-type wafer), intrinsic passivation layer (i-a-Si:H), p-type doped nanocrystalline silicon (p-nc-Si:H), silver nanoparticles (Ag-NPs), transparent conductive oxide film - indium tin oxide (ITO), back metal electrode (Al).

[0049] 1. Use an n-type monocrystalline silicon wafer as the initial substrate, texture and clean it;

[0050] 2. Use plasma-enhanced chemical vapor deposition (PECVD) to deposit a 5-nm i-a-Si:H passivation layer on both sides of the substrate;

[0051] 3. Use plasma-enhanced chemical vapor deposition (PECVD) to deposit 10-nm n-nc-Si:H and 10-nm p-nc-Si:H on top of the passivation layers on both sides respectively;

[0052] 4. Use thermal evaporation to deposit a silver film on the p-type doped silicon film and anneal it to form silver nanoparticles with a cross-sectional diameter of 10 nm;

[0053] 5. Magnetron sputter deposit ITO films on n-nc-Si:H and p-nc-Si:H deposited with silver nanoparticles respectively;

[0054] 6. Use evaporation to deposit a 1-μm metal grid electrode Ag on the electron-selective contact side and deposit a full-area back metal electrode Al on the other side.

[0055] The open-circuit voltage of the solar cell prepared in this embodiment is 0.74 V, the short-circuit current density is 40.75 mA / cm 2 , the fill factor is 85.20%, and the photoelectric conversion efficiency is 25.69%.

[0056] Example 3:

[0057] In this embodiment, the crystalline silicon cell structure is as follows Figure 4As shown in the figure, from top to bottom, it successively includes: metal grid electrode silver (Ag), transparent conductive oxide thin film - indium tin oxide (ITO), n-type doped nanocrystalline silicon (n-nc-Si:H), intrinsic passivation layer (i-a-Si:H), n-type double-polished substrate (n-type wafer), intrinsic passivation layer (i-a-Si:H), p-type doped nanocrystalline silicon (p-nc-Si:H), silver nanoparticles (Ag-NPs), transparent conductive oxide thin film - indium tin oxide (ITO), back metal electrode (Al).

[0058] 1. Using an n-type single-crystalline silicon wafer as the initial substrate, perform RCA cleaning;

[0059] 2. Using plasma-enhanced chemical vapor deposition (PECVD), deposit a 5-nm i-a-Si:H passivation layer on both sides of the substrate;

[0060] 3. Using plasma-enhanced chemical vapor deposition (PECVD), deposit 10-nm n-nc-Si:H and 10-nm p-nc-Si:H respectively above the passivation layers on both sides;

[0061] 4. Using thermal evaporation, deposit a silver thin film on the p-type doped silicon thin film and anneal to form silver nanoparticles with a cross-sectional diameter of 10 nm;

[0062] 5. Magnetron sputter deposit ITO thin films on n-nc-Si:H and p-nc-Si:H deposited with silver nanoparticles respectively;

[0063] 6. Using evaporation, deposit a 1-μm metal grid electrode Ag on the side of the electron selective contact and deposit a full-area back metal electrode Al on the other side.

[0064] The open-circuit voltage of the solar cell prepared in this example is 0.74 V, the short-circuit current density is 36.89 mA / cm 2 , the fill factor is 85.52%, and the photoelectric conversion efficiency is 23.35%.

[0065] Example 4:

[0066] In this example, the crystalline silicon cell structure is as Figure 5 shown. From top to bottom, it successively includes: metal grid electrode silver (Ag), transparent conductive oxide thin film - indium tin oxide (ITO), n-type doped nanocrystalline silicon (n-nc-Si:H), intrinsic passivation layer (i-a-Si:H), p-type textured substrate (p-type wafer), intrinsic passivation layer (i-a-Si:H), p-type doped nanocrystalline silicon (p-nc-Si:H), silver nanoparticles (Ag-NPs), transparent conductive oxide thin film - indium tin oxide (ITO), back metal electrode (Al).

[0067] The silicon heterojunction solar cell of this embodiment is obtained through the following preparation method:

[0068] 1. Using a p-type monocrystalline silicon wafer as the initial substrate, perform texturing and cleaning;

[0069] 2. Using plasma-enhanced chemical vapor deposition (PECVD), deposit a 5-nm i-a-Si:H passivation layer on both sides of the substrate;

[0070] 3. Using plasma-enhanced chemical vapor deposition (PECVD), deposit 10-nm n-nc-Si:H and 10-nm p-nc-Si:H on top of the passivation layers on both sides respectively;

[0071] 4. Using thermal evaporation, deposit a silver thin film on the p-type doped silicon thin film and anneal to form silver nanoparticles with a cross-sectional diameter of 10 nm;

[0072] 5. Magnetron sputter deposit ITO thin films on n-nc-Si:H and p-nc-Si:H deposited with silver nanoparticles respectively;

[0073] 6. Using evaporation, deposit a 1-μm metal grid electrode Ag on the side of the electron-selective contact and deposit a full-area back metal electrode Al on the other side.

[0074] The open-circuit voltage of the solar cell prepared in this embodiment is 0.73 V, the short-circuit current density is 40.25 mA / cm 2 , the fill factor is 84.45%, and the photoelectric conversion efficiency is 24.81%.

[0075] Comparative Example 1:

[0076] The structure of the crystalline silicon cell in this comparative example is as Figure 6 shown, and from top to bottom, it includes in sequence: metal grid electrode silver (Ag), transparent conductive oxide thin film - indium tin oxide (ITO), n-type doped nanocrystalline silicon (n-nc-Si:H), intrinsic passivation layer (i-a-Si:H), n-type textured substrate (n-type wafer), intrinsic passivation layer (i-a-Si:H), p-type doped nanocrystalline silicon (p-nc-Si:H), transparent conductive oxide thin film - indium tin oxide (ITO), metal grid electrode (Ag).

[0077] The silicon heterojunction solar cell of this comparative example is obtained through the following preparation method:

[0078] 1. Using an n-type monocrystalline silicon wafer as the initial substrate, perform texturing and cleaning;

[0079] 2. Use plasma enhanced chemical vapor deposition (PECVD) to deposit a 5-nm i-a-Si:H passivation layer on both sides of the substrate;

[0080] 3. Use plasma enhanced chemical vapor deposition (PECVD) to deposit 10-nm n-nc-Si:H and 10-nm p-nc-Si:H on top of the passivation layers on both sides, respectively;

[0081] 4. Magnetron sputter deposit ITO films on n-nc-Si:H and p-nc-Si:H respectively;

[0082] 5. Use evaporation method to deposit a 1-μm metal grid electrode Ag on the side of the electron selective contact, and deposit a full-area back metal electrode Al on the other side.

[0083] The open-circuit voltage of the solar cell prepared in this comparative example is 0.73 V, the short-circuit current density is 39.59 mA / cm 2 , the fill factor is 82.86%, and the photoelectric conversion efficiency is 23.94%.

[0084] Example 5:

[0085] In this example, the crystalline silicon cell structure is as Figure 6 shown, including, from top to bottom in sequence: metal grid electrode silver (Ag), transparent conductive oxide film - indium tin oxide (ITO), n-type doped nanocrystalline silicon (n-nc-Si:H), intrinsic passivation layer (i-a-Si:H), n-type textured substrate (n-type wafer), intrinsic passivation layer (i-a-Si:H), p-type doped nanocrystalline silicon (p-nc-Si:H), silver nanoparticles (Ag-NPs), transparent conductive oxide film - aluminum-doped zinc oxide (AZO), back metal electrode (Al).

[0086] 1. Use an n-type monocrystalline silicon wafer as the initial substrate, texture and clean it;

[0087] 2. Use plasma enhanced chemical vapor deposition (PECVD) to deposit a 5-nm i-a-Si:H passivation layer on both sides of the substrate;

[0088] 3. Use plasma enhanced chemical vapor deposition (PECVD) to deposit 10-nm n-nc-Si:H and 10-nm p-nc-Si:H on top of the passivation layers on both sides, respectively;

[0089] 4. Use thermal evaporation method to deposit a silver film on the p-type doped silicon film and anneal it to form silver nanoparticles with a cross-sectional diameter of 15 nm;

[0090] 5. Magnetron sputter deposit ITO film on n-nc-Si:H;

[0091] 6. Magnetron sputter deposit an AZO thin film on the p-nc-Si:H deposited with silver nanoparticles.

[0092] 7. Use the evaporation method to deposit a 1-μm metal grid electrode Ag on the side of the electron-selective contact, and deposit a full-area back metal electrode Al on the other side.

[0093] The open-circuit voltage of the solar cell prepared in this example is 0.73 V, the short-circuit current density is 39.96 mA / cm 2 , the fill factor is 84.28%, and the photoelectric conversion efficiency is 24.59%.

[0094] Example 6:

[0095] The structure of the crystalline silicon cell in this example is as Figure 7 shown, and successively includes from top to bottom: metal grid electrode silver (Ag), transparent conductive oxide thin film - indium tin oxide (ITO), n-type doped nanocrystalline silicon (n-nc-Si:H), intrinsic passivation layer (i-a-Si:H), n-type textured substrate (n-type wafer), intrinsic passivation layer (i-a-Si:H), p-type doped nanocrystalline silicon (p-nc-Si:H), silver nanoparticles (Ag-NPs), transparent conductive oxide thin film - tin oxide (SnOx), back metal electrode (Al).

[0096] 1. Use an n-type monocrystalline silicon wafer as the initial substrate, texture and clean it;

[0097] 2. Use plasma-enhanced chemical vapor deposition (PECVD) to deposit a 5-nm i-a-Si:H passivation layer on both sides of the substrate respectively;

[0098] 3. Use plasma-enhanced chemical vapor deposition (PECVD) to deposit 10-nm n-nc-Si:H and 10-nm p-nc-Si:H respectively above the two-side passivation layers;

[0099] 4. Use thermal evaporation to deposit a silver thin film on the p-type doped silicon thin film, and anneal it to form silver nanoparticles with a cross-sectional diameter of 15 nm;;

[0100] 5. Magnetron sputter deposit an ITO thin film on the n-nc-Si:H;

[0101] 6. Magnetron sputter deposit a SnOx thin film on the p-nc-Si:H deposited with silver nanoparticles;

[0102] 7. Use the evaporation method to deposit a 1-μm metal grid electrode Ag on the side of the electron-selective contact, and deposit a full-area back metal electrode Al on the other side.

[0103] The open-circuit voltage of the solar cell prepared in this embodiment is 0.72 V, and the short-circuit current density is 39.87 mA / cm 2 , the fill factor is 84.02%, and the photoelectric conversion efficiency is 24.12%.

[0104] Example 7:

[0105] The structure of the crystalline silicon cell in this embodiment is as Figure 8 shown, and it includes, from top to bottom in sequence: metal grid electrode silver (Ag), transparent conductive oxide film - indium tin oxide (ITO), n-type doped nanocrystalline silicon (n-nc-Si:H), intrinsic passivation layer (i-a-Si:H), n-type textured substrate (n-type wafer), intrinsic passivation layer (i-a-Si:H), p-type doped nanocrystalline silicon (p-nc-Si:H), indium nanoparticles (In-NPs), transparent conductive oxide film - indium tin oxide (ITO), back metal electrode (Al).

[0106] 1. Using an n-type single-crystalline silicon wafer as the initial substrate, texturing and cleaning are performed;

[0107] 2. Using plasma-enhanced chemical vapor deposition (PECVD), 5-nm i-a-Si:H passivation layers are deposited on both sides of the substrate respectively;

[0108] 3. Using plasma-enhanced chemical vapor deposition (PECVD), 10-nm n-nc-Si:H and 10-nm p-nc-Si:H are deposited above the passivation layers on both sides respectively;

[0109] 4. Using magnetron sputtering, indium film is deposited on the p-type doped silicon thin film by DC magnetron sputtering, and indium nanoparticles with a cross-sectional diameter of 15 nm are formed after annealing;

[0110] 5. ITO films are deposited on n-nc-Si:H and p-nc-Si:H deposited with indium nanoparticles by magnetron sputtering respectively;

[0111] 6. Using evaporation method, a 1-μm metal grid electrode Ag is deposited on the side of the electron selective contact, and a full-area back metal electrode Al is deposited on the other side.

[0112] The open-circuit voltage of the solar cell prepared in this embodiment is 0.74 V, and the short-circuit current density is 40.20 mA / cm 2 , the fill factor is 83.59%, and the photoelectric conversion efficiency is 24.87%.

[0113] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A silicon heterojunction solar cell, characterized in that: The solar cell uses metal nanoparticles as the interface layer between the transparent conductive oxide TCO and the p-type doping layer, wherein: The p-type doped layer is p-type doped nanocrystalline silicon p-nc-Si:H, p-type doped nanocrystalline silicon carbon p-nc-SiC:H, p-type doped nanocrystalline silicon oxygen p-nc-SiO x :H, p-type doped amorphous silicon pa-Si:H, p-type doped amorphous silicon carbon pa-SiC:H, p-type doped amorphous silicon oxygen pa-SiO x : A silicon thin film material in H; The metal nanoparticles are nanoparticles selected from the group consisting of gold, silver, aluminum and indium; The TCO material is an oxide of In, Sb, Zn, Sn or Cd and a composite oxide thereof.

2. The silicon heterojunction solar cell according to claim 1, characterized in that: The silicon wafer is selected from n-type or p-type single crystal or multi-crystalline silicon wafers, and the morphology of the silicon wafer is double-sided polishing, single-sided polishing or double-sided texturing.

3. The silicon heterojunction solar cell according to claim 1, characterized in that: The solar cell is a double-sided light-receiving cell or a single-sided light-receiving cell.

4. The silicon heterojunction solar cell according to claim 3, characterized in that: In a double-sided photosensitive cell, metal grid lines are used as electrodes on both sides of the cell; in a single-sided photosensitive cell, the light-receiving side of the cell uses metal grid lines as electrodes, and the backlight side uses full metal as electrodes.

5. A method for preparing a silicon heterojunction solar cell according to any one of claims 1 to 4, characterized in that: The solar cell comprises, from top to bottom, a metal grid electrode silver, a transparent conductive oxide film, an n-type doped silicon film, an intrinsic passivation layer ia-Si:H, a crystalline silicon substrate, an intrinsic passivation layer ia-Si:H, a p-type doped silicon film, metal nanoparticles, a transparent conductive oxide film, a metal grid electrode or a back metal electrode, and is obtained by the following preparation method: 1) Using n-type doped crystalline silicon as the initial substrate, texturing and cleaning; 2) using plasma enhanced chemical vapor deposition (PECVD) to deposit ia-Si:H passivation layers on both sides of the substrate; 3) using plasma enhanced chemical vapor deposition (PECVD) to deposit an n-type doped silicon film and a p-type doped silicon film on the passivation layers on both sides; 4) depositing a metal film on the p-type doped silicon film and annealing the film to form nanoparticles; 5) depositing a TCO thin film on the n-type doped layer and the p-type doped layer on which the metal nanoparticles are deposited by magnetron sputtering; 6) Depositing metal gate electrodes on both sides by evaporation, printing or electroplating; or depositing metal gate electrodes on one side and depositing full-area back metal electrodes on the other side; The metal grid electrode is Ag, and the back metal electrode is Al.

6. The method for preparing a silicon heterojunction solar cell according to claim 5, characterized in that: By regulating the size of metal nanoparticles, an interface capable of reducing different TCO / p interface barriers is obtained, and the diameter of the nanoparticle cross section is between 8-20nm.

7. The method for preparing a silicon heterojunction solar cell according to claim 6, characterized in that: The size of metal nanoparticles is regulated by thermal evaporation, magnetron sputtering, laser ablation, and electrochemical reduction.

8. The method for preparing a silicon heterojunction solar cell according to claim 7, characterized in that: The thermal evaporation and magnetron sputtering methods are used to control the size of metal nanoparticles by controlling the deposition time and deposition power, as well as subsequent heat treatment methods.

9. The method for preparing a silicon heterojunction solar cell according to claim 7, characterized in that: The laser ablation method is used to control the size of metal nanoparticles by changing the laser power and illumination time.

10. The method for preparing a silicon heterojunction solar cell according to claim 7, characterized in that: The electrochemical reduction method controls the size of metal nanoparticles by changing the flow rate of the electrolyte during the electrolytic reduction of metal ions.

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