A TOPCON crystalline silicon solar cell and a method for preparing the same

Abstract

The present invention belongs to the technical field of solar cells and provides a TOPCON crystalline silicon solar cell and a preparation method thereof. The TOPCON crystalline silicon solar cell of the present invention uses self-assembled molecules as a hole transport layer, and innovatively inserts an anchor layer (the anchor layer is indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), zinc oxide (ZnO), tin dioxide (SnO 2 ) and titanium dioxide (TiO 2 ) at least one of the above; the thickness of the anchoring layer is 1 to 5 nm). The structure of the present invention can make the self-assembled molecules arranged in a high order to form an ultra-thin hole transport layer; at the same time, the ultra-thin self-assembled molecular layer can also have a lower contact resistance with the second passivation layer and the second transparent electrode layer, forming a more efficient match and improving the battery efficiency.

Description

Technical Field

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

[0002] Solar energy is a highly anticipated clean energy source with the advantages of abundant resources and low cost. Photovoltaic cells are one of the most effective ways to convert solar energy into electrical energy. Solar cells such as monocrystalline silicon and polycrystalline silicon have relatively mature industrialization technologies. In recent years, new crystalline silicon solar technology has become a research hotspot in the field of photovoltaic technology and has attracted much attention.

[0003] Solar cells rely on the efficient generation of electrons and holes, and the subsequent collection of these photoexcited charge carriers onto spatially separated electrodes. For solar cells based on crystalline silicon, high-quality wafers are now widely available, which means that the efficiency potential of the cell depends largely on the effectiveness of its selective carrier contacts. Most transport layers currently used in industrial production are based on highly doped silicon, which can have negative effects, including Ogier recombination or parasitic absorption, depending on whether the dopant diffuses into the absorber material or is added to a silicon layer external to the absorber. Given the multi-kilowatt-scale applications of crystalline silicon solar cells, the search for alternative contact schemes that could offer potential advantages in terms of performance, cost, ease of processing or stability is of great relevance. One class of contact schemes that has the potential to avoid the above issues is that which utilizes amorphous silicon materials as “selective carrier” layers.

[0004] At present, new crystalline silicon solar cells often use P-type doped polysilicon or metal oxides such as molybdenum oxide and vanadium oxide as hole selective transport layers. Although the number of examples of successful hole selective transport in these material families is increasing rapidly, the efficiency of their best solar cells is still low, with the highest efficiency being only about 22%. If industrial applications are to be considered, these contact layers still have many challenges. The main problem is that the thickness of these hole transport layers is generally thicker (greater than 10nm) to have good hole selectivity, which will produce large parasitic absorption losses on the light-incoming side of the battery, thereby reducing the photocurrent that the battery can generate. Based on these problems, ultra-thin self-assembled molecular hole transport layers can be a solution. However, self-assembled molecules (such as 2PACz, Meo-2PAC and Meo-4PACz, etc.) lack an anchoring relationship with the traditional crystalline silicon substrate, and the molecular arrangement of the ultra-thin hole transport layer formed on the crystalline silicon substrate is often disordered and chaotic, which makes it difficult for the existing ultra-thin self-assembled hole transport layer to form an efficient match with the crystalline silicon passivation layer and the electrode at the same time, thereby easily generating a large contact resistance between the hole transport layer and the crystalline silicon passivation layer, and between the hole transport layer and the electrode, thereby affecting the photoelectric conversion efficiency of the device. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a TOPCON crystalline silicon solar cell and a preparation method thereof. The TOPCON crystalline silicon solar cell provided by the present invention has high photoelectric conversion efficiency.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a TOPCON crystalline silicon solar cell, comprising an anchoring layer, wherein the anchoring layer is located between a second passivation layer and a self-assembled molecular hole transport layer;

[0008] The second passivation layer is in contact with the surface of the silicon substrate;

[0009] The anchoring layer is at least one of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), zinc oxide (ZnO), tin dioxide (SnO2) and titanium dioxide (TiO2);

[0010] The thickness of the anchoring layer is 1-5 nm.

[0011] Preferably, the self-assembled molecular hole transport layer is a carbazole phosphonic acid small molecule, and the carbazole phosphonic acid small molecule is at least one of 2PACz, Meo-2PACz and Meo-4PACz; the thickness of the self-assembled molecular hole transport layer is 0.1 to 10 nm.

[0012] Preferably, the TOPCON crystalline silicon solar cell further comprises: a first metal electrode layer, a first transparent electrode layer, an N-doped polycrystalline silicon electron transport layer and a first passivation layer which are stacked in sequence; the first passivation layer is in contact with the back side of the silicon substrate.

[0013] Preferably, the TOPCON crystalline silicon solar cell further comprises: a second transparent electrode layer, a second metal electrode layer and an anti-reflection layer stacked in sequence; the second transparent electrode layer is in contact with the self-assembled molecular hole transport layer.

[0014] Preferably, the first transparent electrode layer and the second transparent electrode layer are independently at least one of indium tin oxide (ITO), indium zinc oxide (IZO) and aluminum zinc oxide (AZO); and the thickness of the first transparent electrode layer and the second transparent electrode layer are independently 50 to 500 nm.

[0015] Preferably, the first metal electrode layer and the second metal electrode layer are independently at least one of silver (Ag), gold (Au), copper (Cu) and aluminum (Al); the thickness of the first metal electrode layer and the second metal electrode layer are independently 50 to 500 nm.

[0016] Preferably, the anti-reflection layer is at least one of magnesium fluoride, lithium fluoride (LiF), sodium fluoride (NaF) and silicon oxide (SiO2); and the thickness of the anti-reflection layer is 50 to 500 nm.

[0017] Preferably, the thickness of the N-doped polysilicon electron transport layer is 50-500 nm.

[0018] The present invention also provides a method for preparing the TOPCON crystalline silicon solar cell described in the above technical solution, comprising the following steps:

[0019] providing a silicon substrate;

[0020] A second passivation layer is prepared on the surface of the silicon substrate by plasma enhanced chemical vapor deposition;

[0021] preparing an anchor layer on the surface of the second passivation layer by atomic deposition;

[0022] A self-assembled molecular hole transport layer is prepared on the surface of the anchoring layer by a solution method or an evaporation method.

[0023] Preferably, the method further comprises the following steps:

[0024] Prepare a second transparent electrode layer on the surface of the self-assembled molecular hole transport layer by magnetron sputtering;

[0025] preparing a second metal electrode layer on the surface of the second transparent electrode layer by evaporation;

[0026] preparing an anti-reflection layer on the surface of the second metal electrode layer by evaporation;

[0027] A first passivation layer is prepared on the back side of the silicon substrate by plasma enhanced chemical vapor deposition;

[0028] Preparing an N-doped polycrystalline silicon electron transport layer on the surface of the first passivation layer by plasma enhanced chemical vapor deposition;

[0029] Preparing a first transparent electrode layer on the surface of the N-doped polycrystalline silicon electron transport layer by magnetron sputtering;

[0030] A first metal electrode layer is prepared on the surface of the first transparent electrode layer by using an evaporation method.

[0031] The present invention provides a TOPCON crystalline silicon solar cell, comprising an anchoring layer, wherein the anchoring layer is located between a second passivation layer and a self-assembled molecular hole transport layer; the second passivation layer is in contact with the surface of the silicon substrate; the anchoring layer is at least one of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), zinc oxide (ZnO), tin dioxide (SnO2) and titanium dioxide (TiO2); the thickness of the anchoring layer is 1 to 5 nm.

[0032] The TOPCON crystalline silicon solar cell of the present invention uses self-assembled molecules as a hole transport layer, and innovatively inserts an anchor layer between the self-assembled molecule hole transport layer and the second passivation layer. The structure of the present invention can make the self-assembled molecules arrange in a high order as an ultra-thin hole transport layer; at the same time, the ultra-thin self-assembled molecule layer (1-5nm) can also have a lower contact resistance with the second passivation layer and the second transparent electrode layer, forming a more efficient match and improving the battery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the structure of a TOPCON crystalline silicon solar cell provided by the present invention, wherein, 110-a first metal electrode layer, 111-a first transparent electrode layer, 112-an N-type doped polysilicon electron transport layer, 113-a first passivation layer, 114-a silicon substrate, 115-a second passivation layer, 116-anchoring layer, 117-a self-assembled molecular hole transport layer, 210-a second transparent electrode layer, 211-a second metal electrode layer, 212-an anti-reflection layer;

[0034] Figure 2 A schematic diagram of the structure of a TOPCON crystalline silicon solar cell provided for comparative example 1, wherein, 110-first metal electrode layer, 111-first transparent electrode layer, 112-N-type doped polysilicon electron transport layer, 113-first passivation layer, 114-silicon substrate, 115-second passivation layer, 116-self-assembled molecular hole transport layer, 210-second transparent electrode layer, 211-second metal electrode layer, 212-anti-reflection layer;

[0035] Figure 3 It is a display diagram of the self-assembled molecular hole transport layer provided in Examples 1 to 3 and the comparative example, wherein the left diagram is a display diagram of the self-assembled molecular hole transport layer provided in Examples 1 to 3, and the right diagram is a display diagram of the self-assembled molecular hole transport layer provided in the comparative example. DETAILED DESCRIPTION

[0036] Figure 1The schematic diagram of the structure of the TOPCON crystalline silicon solar cell provided by the present invention, wherein 110-first metal electrode layer, 111-first transparent electrode layer, 112-N-type doped polysilicon electron transport layer, 113-first passivation layer, 114-silicon substrate, 115-second passivation layer, 116-anchor layer, 117-self-assembled molecular hole transport layer, 210-second transparent electrode layer, 211-second metal electrode layer, 212-anti-reflection layer. Figure 1 , the structure of the TOPCON crystalline silicon solar cell provided by the present invention is described in detail.

[0037] The present invention provides a TOPCON crystalline silicon solar cell, comprising an anchoring layer, wherein the anchoring layer is located between a second passivation layer and a self-assembled molecular hole transport layer;

[0038] The second passivation layer is in contact with the surface of the silicon substrate;

[0039] The anchoring layer is at least one of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), zinc oxide (ZnO), tin dioxide (SnO2) and titanium dioxide (TiO2);

[0040] The thickness of the anchoring layer is 1-5 nm.

[0041] In the present invention, unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0042] The TOPCON crystalline silicon solar cell provided by the present invention comprises a silicon substrate, the thickness of the silicon substrate is preferably 100-200 μm; the silicon substrate is preferably single crystal silicon.

[0043] The TOPCON crystalline silicon solar cell provided by the present invention comprises a second passivation layer, and the second passivation layer is stacked on the surface of the silicon substrate. In the present invention, the second passivation layer is preferably silicon oxide (SiO x ), aluminum oxide (AlO x ) and silicon nitride (SiN x ), more preferably silicon nitride. In the present invention, the thickness of the second passivation layer is preferably 1 to 10 nm, more preferably 2 to 5 nm.

[0044] The TOPCON crystalline silicon solar cell provided by the present invention includes an anchoring layer, and the anchoring layer is stacked on the surface of the second passivation layer. In the present invention, the anchoring layer is at least one of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), zinc oxide (ZnO), tin dioxide (SnO2) and titanium dioxide (TiO2). In the present invention, the thickness of the anchoring layer is 1 to 5 nm, preferably 1 to 2 nm, and more preferably 1.5 nm.

[0045] The TOPCON crystalline silicon solar cell provided by the present invention comprises a self-assembled molecular hole transport layer, and the self-assembled molecular hole transport layer is stacked on the surface of the anchor layer. In the present invention, the self-assembled molecular hole transport layer is preferably a carbazole phosphonic acid small molecule, and the carbazole phosphonic acid small molecule is preferably at least one of 2PACz, Meo-2PACz and Meo-4PACz. In the present invention, the thickness of the self-assembled molecular hole transport layer is preferably 0.1 to 10 nm.

[0046] The TOPCON crystalline silicon solar cell provided by the present invention preferably includes a second transparent electrode layer, and the second transparent electrode layer is preferably stacked on the surface of the self-assembled molecular hole transport layer. In the present invention, the second transparent electrode layer is preferably at least one of indium tin oxide (ITO), indium zinc oxide (IZO) and aluminum zinc oxide (AZO). In the present invention, the thickness of the second transparent electrode layer is preferably 50 to 500 nm, and more preferably 100 nm.

[0047] The TOPCON crystalline silicon solar cell provided by the present invention preferably includes a second metal electrode layer, and the second metal electrode layer is stacked on the surface of the second transparent electrode layer. In the present invention, the second metal electrode layer is preferably at least one of silver (Ag), gold (Au), copper (Cu) and aluminum (Al). In the present invention, the thickness of the second metal electrode layer is preferably 50 to 500 nm, and more preferably 200 nm.

[0048] The TOPCON crystalline silicon solar cell provided by the present invention comprises an anti-reflection layer, and the anti-reflection layer is stacked on the surface of the second metal electrode layer. In the present invention, the anti-reflection layer is preferably at least one of magnesium fluoride, lithium fluoride (LiF), sodium fluoride (NaF) and silicon oxide (SiO2). In the present invention, the thickness of the anti-reflection layer is preferably 50 to 500 nm, and more preferably 100 nm.

[0049] The TOPCON crystalline silicon solar cell provided by the present invention preferably includes a first passivation layer, which is stacked on the back of the silicon substrate. In the present invention, the material and thickness of the first passivation layer are preferably consistent with those of the second passivation layer, which will not be repeated here.

[0050] The TOPCON crystalline silicon solar cell provided by the present invention preferably includes an N-doped polycrystalline silicon electron transport layer, and the N-doped polycrystalline silicon electron transport layer is arranged on the surface of the first passivation layer. In the present invention, the thickness of the N-doped polycrystalline silicon electron transport layer is preferably 10 to 200 nm, and more preferably 20 nm.

[0051] The TOPCON crystalline silicon solar cell provided by the present invention preferably includes a first transparent electrode layer, which is arranged on the surface of the N-doped polycrystalline silicon electron transport layer. The material and thickness of the first transparent electrode layer are preferably consistent with those of the second transparent electrode layer, which will not be repeated here.

[0052] The TOPCON crystalline silicon solar cell provided by the present invention preferably includes a first metal electrode layer, which is arranged on the surface of the first transparent electrode layer. The first metal electrode layer is preferably made of the same material and thickness as the second metal electrode layer, which will not be described in detail here.

[0053] The present invention also provides a method for preparing the TOPCON crystalline silicon solar cell described in the above technical solution, comprising the following steps:

[0054] providing a silicon substrate;

[0055] A second passivation layer is prepared on the surface of the silicon substrate by plasma enhanced chemical vapor deposition;

[0056] preparing an anchor layer on the surface of the second passivation layer by atomic deposition;

[0057] A self-assembled molecular hole transport layer is prepared on the surface of the anchoring layer by a solution method or an evaporation method.

[0058] The present invention provides a silicon substrate. In the present invention, before preparing the second passivation layer and the first passivation layer on the surface and back of the silicon substrate, respectively, the present invention preferably performs pretreatment, and the present invention does not specifically limit the operation and parameters of the pretreatment, and the operation familiar to those skilled in the art can be used.

[0059] After providing a silicon substrate, the present invention uses plasma enhanced chemical vapor deposition to prepare a second passivation layer on the surface of the silicon substrate.

[0060] In the present invention, when the second passivation layer is silicon oxide (SiO x ), the parameters of the plasma enhanced chemical vapor deposition include: the working gas is preferably SiH4, the volume flow rate of the working gas is preferably 0.1-100 sccm, the protective atmosphere is preferably argon (Ar), and the current is preferably 1-5A.

[0061] In the present invention, when the second passivation layer is aluminum oxide (AlO x ), the parameters of the plasma enhanced chemical vapor deposition include: the working gas is preferably trimethylaluminum (TMA) and water vapor (H2O), the volume flow rate of the working gas is preferably 0.1-100 sccm, and the volume flow ratio of methylaluminum (TMA) and water vapor (H2O) is preferably 1:1; the protective atmosphere is preferably argon (Ar), and the current is preferably 1-5A.

[0062] In the present invention, when the second passivation layer is silicon nitride (SiN x ), the parameters of the plasma enhanced chemical vapor deposition include: the working gas is preferably silane (SiH4) and ammonia, the volume flow rate of the working gas is preferably 0.1-100 sccm, the volume flow ratio of silane and ammonia is preferably 1:100-100:1, the protective atmosphere is preferably argon (Ar), and the current is preferably 1-5A.

[0063] After obtaining the second passivation layer, the present invention uses atomic deposition to prepare an anchoring layer on the surface of the second passivation layer.

[0064] In the present invention, the parameters of the atomic deposition include: the powder is preferably selected according to the material of the anchor layer, and the deposition vacuum is preferably 0 to 1×10 -4 Pa, the temperature of the deposition pipeline is preferably 50-150° C., the temperature of the deposition chamber is preferably 40-150° C., and the number of deposition cycles is preferably 10-1000.

[0065] After the anchoring layer is prepared, the present invention uses a solution method or an evaporation method to prepare a self-assembled molecular hole transport layer on the surface of the anchoring layer.

[0066] In the present invention, the solution method preferably includes the following steps: preparing a precursor solution containing self-assembly molecules, applying the precursor solution of the self-assembly molecules on the surface of the anchoring layer, and sequentially performing spin coating and annealing. In the present invention, the concentration of the precursor solution containing self-assembly molecules is preferably 0.5 mg / mL. In the present invention, the parameters of the spin coating include: the rotation speed is preferably 1200 to 6000 rpm, the time is preferably 20 to 120 s, and the anti-solvent titration time is preferably 10 to 50 s after the start of the rotation speed. In the present invention, the annealing temperature is preferably 50 to 150 ° C, and the insulation time is preferably 5 to 40 min.

[0067] In the present invention, the evaporation method preferably includes the following steps: evaporating the self-assembled molecular powder onto the surface of the anchoring layer. In the present invention, the purity of the self-assembled molecular powder is preferably 99.999%. In the present invention, the vacuum degree of the evaporation is preferably 1 to 3×10 -4 Pa, the temperature is preferably 200-700°C.

[0068] After preparing the self-assembled molecular hole transport layer, the present invention preferably further comprises preparing a second transparent electrode layer on the surface of the self-assembled molecular hole transport layer by magnetron sputtering.

[0069] In the present invention, the parameters of the magnetron sputtering method include: the target material is selected according to the material of the second transparent electrode layer, the power is preferably 30 to 90 W, and the operating time is preferably 0.5 to 3 hours.

[0070] After preparing the second transparent electrode layer, the present invention preferably further comprises preparing a second metal electrode layer on the surface of the second transparent electrode layer by evaporation.

[0071] In the present invention, the evaporation method preferably comprises: evaporating the second metal electrode powder onto the surface of the anchor layer under a mask; the vacuum degree of the evaporation is preferably 1 to 5×10 -4 Pa, the evaporation rate is The temperature of the evaporation is preferably achieved by adjusting the voltage of the evaporation. In the present invention, the evaporation is preferably performed in an evaporation machine.

[0072] After preparing the second metal electrode layer, the present invention preferably further comprises preparing an anti-reflection layer on the surface of the second metal electrode layer by evaporation.

[0073] In the present invention, the evaporation method preferably comprises: evaporating the anti-reflection powder onto the surface of the second metal electrode layer; the vacuum degree of the evaporation is preferably 1 to 5×10 -4 Pa, the evaporation rate is

[0074] The present invention preferably further comprises preparing a first passivation layer on the back side of the silicon substrate by plasma enhanced chemical vapor deposition.

[0075] In the present invention, the parameters of the plasma enhanced chemical vapor deposition are preferably consistent with the parameters for preparing the second passivation layer, which will not be described in detail herein.

[0076] After preparing the first passivation layer, the present invention preferably further comprises preparing an N-doped polysilicon electron transport layer on the surface of the first passivation layer by plasma enhanced chemical vapor deposition.

[0077] In the present invention, the parameters of the plasma enhanced chemical vapor deposition include: the working gas is preferably silane (SiH4), the volume flow rate of the working gas is preferably 20sccm, the protective atmosphere is argon (Ar), and the current is 1 to 5A.

[0078] After preparing the N-doped polycrystalline silicon electron transport layer, the present invention uses a magnetron sputtering method to prepare a first transparent electrode layer on the surface of the N-doped polycrystalline silicon electron transport layer.

[0079] In the present invention, the parameters of the magnetron sputtering method are preferably consistent with the parameters for preparing the second transparent electrode layer, which will not be described in detail herein.

[0080] After preparing the first transparent electrode layer, the present invention uses an evaporation method to prepare a first metal electrode layer on the surface of the first transparent electrode layer.

[0081] In the present invention, the parameters of the evaporation method are preferably consistent with the parameters for preparing the second metal electrode layer described above, and will not be described in detail herein.

[0082] The TOPCON crystalline silicon solar cell and the preparation method thereof provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0083] Example 1

[0084] according to Figure 1 The structure shown in the figure is used to prepare a TOPCON crystalline silicon solar cell, wherein the thickness of the anchor layer is 1 nm, and the specific preparation method is as follows:

[0085] Step 1: Use plasma enhanced chemical vapor deposition to prepare the first passivation layer (thickness of 5nm, silicon nitride SiN) on the back and surface of the silicon substrate respectively. x ) and the second passivation layer (5nm thick, silicon nitride SiN x ), wherein the parameters of plasma enhanced chemical vapor deposition include: the working gases are silane (SiH4) and ammonia, the volume flow ratio of silane and ammonia is 4:1, the volume flow rate of the working gas is 20sccm, the protective atmosphere is argon (Ar), and the current is 1A.

[0086] An N-type doped polysilicon electron transport layer (with a thickness of 20 nm) was prepared on the surface of the first passivation layer by plasma enhanced chemical vapor deposition. The parameters of the plasma enhanced chemical vapor deposition included: the working gas was silane (SiH4), the volume flow rate of the working gas was 20 sccm, the protective atmosphere was argon (Ar), and the current was 3A.

[0087] Step 2: preparing a first transparent electrode layer on the surface of the N-type doped polysilicon electron transport layer;

[0088] Using the magnetron sputtering method, the sample obtained in step 1 is placed in a magnetron sputtering device, an ITO target is set, the power is controlled to 60 W, the operating time is 1.5 h, and the film thickness is 100 nm.

[0089] Step 3: preparing a first metal electrode layer on the surface of the first transparent electrode layer;

[0090] Using the evaporation method, place the sample obtained in step 2 on the mask and put it into the evaporation chamber until the evaporation vacuum reaches 2×10 -4 Pa, the evaporation voltage is adjusted to the evaporation temperature, and the evaporation rate is controlled to Silver is evaporated onto the first transparent electrode layer to a thickness of 200 nm;

[0091] Step 4: Prepare the anchoring layer

[0092] Using atomic product deposition, ITO was deposited onto the surface of the second passivation layer using an atomic product deposition device, and the deposition vacuum was 1×10 -4 Pa, the deposition channel temperature is 150°C, the deposition chamber temperature is 150°C, the deposition cycle number is 10, and the anchor layer thickness is 1 nm.

[0093] Step 5: preparing a self-assembled molecular hole transport layer;

[0094] The self-assembled molecular hole transport layer was prepared by evaporation. 2PACz powder (purity of 99.999%) was evaporated onto the surface of the anchoring layer. The evaporation vacuum was 1×10 -4 Pa, the evaporation temperature is 200°C, and the thickness of the self-assembled molecular hole transport layer is 0.5 nm.

[0095] Step 6: Prepare a second transparent electrode layer on the surface of the self-assembled molecular hole transport layer:

[0096] Similar to the preparation of the first transparent electrode layer, an IZO target was set, the power was controlled to 50 W, the operating time was 1 h, and the film thickness was 100 nm.

[0097] Step 7: preparing a second metal electrode layer on the surface of the second transparent electrode layer;

[0098] Similar to the preparation of the first metal electrode layer, the mask is not consistent and the thickness is 100nm;

[0099] Step 8: preparing an anti-reflection layer on the surface of the second metal electrode layer;

[0100] Magnesium fluoride is evaporated onto the surface of the second metal electrode layer, and the evaporation rate is controlled at Magnesium fluoride was evaporated onto the film to a thickness of 100 nm.

[0101] Example 2

[0102] Similar to Example 1, the only difference is that in step 4, the number of deposition cycles is 15, the thickness of the anchoring layer formed is 1.5 nm, and the rest is the same as Example 1.

[0103] Example 3

[0104] Similar to Example 1, the only difference is that the number of deposition cycles in step 4 is 20, the thickness of the anchoring layer formed is 2 nm, and the rest is the same as Example 1.

[0105] Comparative Example 1

[0106] Preparation of TOPCON crystalline silicon solar cells based on conventional self-assembled molecules as hole selection layer

[0107] according to Figure 2 The structure shown is used to prepare a TOPCON crystalline silicon solar cell. The structure of the TOPCON crystalline silicon solar cell is, from bottom to top, a first metal electrode layer, a first transparent electrode layer, an N-type doped polycrystalline silicon electron transport layer, a first passivation layer, a silicon substrate, a second passivation layer, a self-assembled molecular layer, a second transparent electrode layer, a second metal electrode layer and an anti-reflection layer.

[0108] Step 1: sequentially prepare a first passivation layer and an N-type doped polysilicon electron transport layer on the back side of a silicon substrate; and prepare a second passivation layer on the surface of the silicon substrate.

[0109] Step 2: preparing a first transparent electrode layer on the surface of the N-type doped polysilicon electron transport layer;

[0110] Using the magnetron sputtering method, the sample obtained in step 1 is placed in a magnetron sputtering device, an ITO target is set, the power is controlled to 60 W, the operating time is 1.5 h, and the film thickness is 100 nm.

[0111] Step 3: preparing a first metal electrode layer on the surface of the first transparent electrode layer;

[0112] Using the evaporation method, place the sample obtained in step 2 on the mask and put it into the evaporation chamber until the evaporation vacuum degree reaches 2×10 -4 Pa, the evaporation voltage is adjusted to the evaporation temperature, and the evaporation rate is controlled to Silver was evaporated onto the film to a thickness of 200 nm.

[0113] Step 4: preparing a self-assembled molecular hole transport layer on the surface of the second passivation layer;

[0114] The self-assembled molecular hole transport layer was prepared by evaporation. 2PACz powder was evaporated onto the surface of the second passivation layer. The evaporation vacuum was 1×10 -4 Pa, the evaporation temperature is 200°C, and the thickness of the self-assembled molecular hole transport layer is 0.5 nm.

[0115] Step 5: preparing a second transparent electrode layer on the surface of the self-assembled molecular hole transport layer;

[0116] Similar to the preparation of the first transparent electrode layer, an IZO target was set, the power was controlled to 50 W, the operating time was 1 h, and the film thickness was 100 nm.

[0117] Step 6: preparing a second metal electrode layer on the surface of the second transparent electrode layer;

[0118] Similar to the preparation of the first metal electrode layer, the mask is not consistent and the thickness is 100nm.

[0119] Step 7: preparing an anti-reflection layer on the surface of the second metal electrode layer;

[0120] Similar to the preparation of the second passivation layer, the evaporation rate is controlled at Magnesium fluoride was evaporated onto the film to a thickness of 100 nm.

[0121] A solar simulator was used to calibrate the intensity of a standard sun and to measure the intensity of a standard sun with an area of ​​1.0 cm. 2 The device of the embodiment is subjected to IV test for a long period of time, the starting voltage is set to 0.8V, the cut-off voltage is set to 0V, the range is set to 100mA, and the result is rounded to two decimal places. The test results are shown in Table 1;

[0122] Table 1 Performance test results of TOPCON crystalline silicon solar cells obtained in the examples and comparative examples

[0123]

[0124] It can be seen from Table 1 that the photoelectric conversion efficiency of Example 1 is the highest.

[0125] Figure 3 The diagrams of the self-assembled molecular hole transport layer provided in Examples 1 to 3 and the comparative example, wherein the left diagram is a diagram of the self-assembled molecular hole transport layer provided in Examples 1 to 3, and the right diagram is a diagram of the self-assembled molecular hole transport layer provided in the comparative example, Figure 3 It can be seen that the anchoring layer can make the self-assembled molecules arrange in a high order as an ultra-thin hole transport layer, making the hole transport of the device more efficient. At the same time, the anchoring layer can also make the ultra-thin self-assembled molecular layer have a lower contact resistance with the second passivation layer of crystalline silicon and the second transparent electrode layer, forming a more efficient match and improving the battery efficiency. This is reflected in the fact that the TOPCON crystalline silicon solar cells provided by Examples 1 to 3 of the present invention have lower device series resistance than the TOPCON crystalline silicon solar cells in Comparative Example 1 using a conventional structure.

[0126] The present invention also optimizes the thickness of the anchoring layer. Compared with Examples 1, 2, and 3, when the thickness of the anchoring layer is 1.5 nm, the anchoring layer can make the device work more efficiently. This is reflected in that the device in Example 2 has a higher fill factor than the devices in Examples 1 and 3. At the same time, the optimized device has a better performance than the traditional structure, which is reflected in that the photoelectric conversion efficiency of the device in Example 2 is higher than that of the device in Comparative Example 1.

[0127] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A TOPCON crystalline silicon solar cell, characterized in that: comprising an anchoring layer, wherein the anchoring layer is located between the second passivation layer and the self-assembled molecular hole transport layer; The second passivation layer is in contact with the surface of the silicon substrate; The anchoring layer is at least one of indium tin oxide, indium zinc oxide, zinc aluminum oxide, zinc oxide, tin dioxide and titanium dioxide; The thickness of the anchoring layer is 1-5 nm.

2. The TOPCON crystalline silicon solar cell according to claim 1, characterized in that: The self-assembled molecular hole transport layer is a carbazole phosphonic acid small molecule, and the carbazole phosphonic acid small molecule is at least one of 2PACz, Meo-2PACz and Meo-4PACz; the thickness of the self-assembled molecular hole transport layer is 0.1-10nm.

3. The TOPCON crystalline silicon solar cell according to claim 1, characterized in that: The TOPCON crystalline silicon solar cell further comprises: a first metal electrode layer, a first transparent electrode layer, an N-doped polycrystalline silicon electron transport layer and a first passivation layer which are stacked in sequence; the first passivation layer is in contact with the back side of the silicon substrate.

4. The TOPCON crystalline silicon solar cell according to claim 3, characterized in that: The TOPCON crystalline silicon solar cell further comprises: a second transparent electrode layer, a second metal electrode layer and an anti-reflection layer which are stacked in sequence; the second transparent electrode layer is in contact with the self-assembled molecular hole transport layer.

5. The TOPCON crystalline silicon solar cell according to claim 4, characterized in that: The first transparent electrode layer and the second transparent electrode layer are independently at least one of indium tin oxide, indium zinc oxide and zinc aluminum oxide; and the thickness of the first transparent electrode layer and the second transparent electrode layer are independently 50 to 500 nm.

6. The TOPCON crystalline silicon solar cell according to claim 4, characterized in that: The first metal electrode layer and the second metal electrode layer are independently at least one of silver, gold, copper and aluminum; and the thickness of the first metal electrode layer and the second metal electrode layer are independently 50 to 500 nm.

7. The TOPCON crystalline silicon solar cell according to claim 4, characterized in that: The anti-reflection layer is at least one of magnesium fluoride, lithium fluoride, sodium fluoride and silicon oxide; the thickness of the anti-reflection layer is 50-500nm.

8. The TOPCON crystalline silicon solar cell according to claim 4, characterized in that: The thickness of the N-doped polysilicon electron transport layer is 50-500 nm.

9. The method for preparing a TOPCON crystalline silicon solar cell according to any one of claims 1 to 8, characterized in that: The following steps are involved: A second passivation layer is prepared on the surface of the silicon substrate by plasma enhanced chemical vapor deposition; preparing an anchor layer on the surface of the second passivation layer by atomic deposition; A self-assembled molecular hole transport layer is prepared on the surface of the anchoring layer by a solution method or an evaporation method.

10. The preparation method according to claim 9, characterized in that: The following steps are also included: Prepare a second transparent electrode layer on the surface of the self-assembled molecular hole transport layer by magnetron sputtering; preparing a second metal electrode layer on the surface of the second transparent electrode layer by evaporation; preparing an anti-reflection layer on the surface of the second metal electrode layer by evaporation; A first passivation layer is prepared on the back side of the silicon substrate by plasma enhanced chemical vapor deposition; Preparing an N-doped polycrystalline silicon electron transport layer on the surface of the first passivation layer by plasma enhanced chemical vapor deposition; Preparing a first transparent electrode layer on the surface of the N-doped polycrystalline silicon electron transport layer by magnetron sputtering; A first metal electrode layer is prepared on the surface of the first transparent electrode layer by using an evaporation method.

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