A hole transport layer, a preparation method thereof, a perovskite solar cell and a perovskite-crystalline silicon tandem cell

Abstract

This invention provides a hole transport layer, its fabrication method, a perovskite solar cell, and a perovskite-silicon tandem solar cell. The hole transport layer comprises layers of modified NiO. x Layers and self-assembled monolayers; the modified NiO x The layer is NiO with a dicarboxylic acid surface modified. x The layer, wherein one end carboxyl group of the dicarboxylic acid is anchored to the NiO x One end of the layer has a carboxyl group anchoring the self-assembled monolayer. This invention utilizes NiO... x A dicarboxylic acid is introduced onto the surface of the layer, allowing the carboxyl group at one end of the dicarboxylic acid to anchor NiO. x The other end of the layer anchors the self-assembled monolayer with carboxyl groups, significantly increasing the NiO content. x The number of carboxyl groups on the surface of the NiO layer increases the yield of NiO. x The bonding force between the perovskite absorber layer and the self-assembled monolayer is beneficial for optimizing the wettability of the perovskite absorber layer. Perovskite solar cells or perovskite-silicon tandem cells fabricated based on this principle exhibit excellent photoelectric performance.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic technology, specifically relating to a hole transport layer, its preparation method, perovskite solar cells, and perovskite-silicon tandem solar cells. Background Technology

[0002] In the field of perovskite solar cell technology, the hole transport layer (HTL) is one of the key components, its role being to collect and transport holes generated in the perovskite layer to the anode. Hole transport layers are mainly classified into three categories: small organic molecules, organic polymers, and inorganic materials. Small organic molecules and polymeric hole transport materials, such as 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), while exhibiting excellent efficiency, suffer from stability issues, especially under humid and continuous light exposure, where their performance is affected. Furthermore, the synthesis process of these materials is complex and costly, and they may require dopants to improve conductivity, further impacting the long-term stability of the device. Inorganic hole transport materials, such as nickel oxide (NiO2),... x Copper thiocyanate (CuSCN) and copper iodide (CuI) have attracted attention due to their high chemical stability, high electrical conductivity, and wide optical band gaps. In particular, NiO... x NiO has attracted much attention due to its simple and diverse preparation methods, high light transmittance, and low cost. x The valence band energy level of NiO matches well with that of perovskite, which facilitates efficient hole transport. Furthermore, its stable crystal structure and non-corrosiveness make it suitable for NiO-based crystals. x Perovskite solar cells exhibit high light and thermal stability.

[0003] Spin-coating has been widely used to prepare nickel oxide on planar substrates, but when transferred to crystalline silicon substrates with textured surfaces, spin-coating can lead to uneven nickel oxide distribution. Therefore, magnetron sputtering is typically used to ensure the uniformity of the nickel oxide layer. However, NiO prepared by magnetron sputtering... x The complex surface chemical composition may lead to Ni 3+ / Ni 2+ The proportion is low, which in turn reduces the number of surface hydroxyl groups. This reduction in surface hydroxyl groups hinders NiO production. x Effective anchoring of self-assembled single molecules (SAM molecules) affects the wettability of the perovskite layer, ultimately leading to a decrease in solar cell performance.

[0004] Therefore, how to improve NiO xImproving the bonding force between the perovskite absorber layer and the self-assembled monolayer, and thus optimizing the wettability of the perovskite absorber layer to enhance the performance of solar cells, is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a hole transport layer, its fabrication method, a perovskite solar cell, and a perovskite-silicon tandem solar cell. The present invention utilizes NiO... x A dicarboxylic acid is introduced onto the surface of the layer, allowing the carboxyl group at one end of the dicarboxylic acid to anchor NiO. x The other end of the layer anchors the self-assembled monolayer with carboxyl groups, significantly increasing the NiO content. x The number of carboxyl groups on the surface of the NiO layer increases the yield of NiO. x The bonding force between the perovskite absorber layer and the self-assembled monolayer is beneficial for optimizing the wettability of the perovskite absorber layer. Perovskite solar cells or perovskite-silicon tandem cells fabricated based on this principle exhibit excellent photoelectric performance.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a hole transport layer, the hole transport layer comprising stacked modified NiO x Layers and self-assembled monolayers.

[0008] The modified NiO x The layer is NiO with a dicarboxylic acid surface modified. x The layer, wherein one end carboxyl group of the dicarboxylic acid is anchored to the NiO x One end of the self-assembled monolayer is anchored by a carboxyl group at the other end.

[0009] In this invention, the main function of the self-assembled monolayer is to improve NiO x The wettability of the layer surface promotes the uniform spreading of the perovskite precursor solution and passivates NiO. x Surface defects reduce interfacial recombination. However, the surface chemical composition of NiOx layers (e.g., those prepared by magnetron sputtering) is complex, with a reduced number of surface hydroxyl groups, which hinders NiO... x Effective anchoring of self-assembled monomolecules affects the wettability of the perovskite layer, leading to reduced solar cell performance. Therefore, this invention addresses this issue by using NiO... x A dicarboxylic acid is introduced onto the surface of the layer, allowing the carboxyl group at one end of the dicarboxylic acid to anchor NiO. x The other end of the layer anchors the self-assembled monolayer with carboxyl groups, significantly increasing the NiO content. x The number of carboxyl groups on the surface of the NiO layer increases the yield of NiO. x The bonding force between the layer and the self-assembled monolayer is beneficial for optimizing the wettability of the perovskite absorber layer.

[0010] Preferably, the chemical structural formula of the dicarboxylic acid is:

[0011]

[0012] Wherein, n is 1-20, for example, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, etc. For example, the dicarboxylic acid can be malonic acid, succinic acid, adipic acid or sebacic acid, etc.

[0013] In this invention, a carbon chain of suitable length helps to improve the modified NiO. x The binding force between the carbon chain and the self-assembled monolayer. If the carbon chain is short, it may lead to different aggregate morphologies during molecular self-assembly, which may hinder the formation of a uniform self-assembled monolayer and affect the bonding with modified NiO. x The bonding of the layer surface reduces the modification of NiO. x The bonding force and stability between the carbon chain and the self-assembled monolayer are considered. Longer carbon chains may increase intermolecular steric hindrance because as the carbon chain length increases, the molecular volume also increases. A larger molecular volume reduces the space for intermolecular interactions, thus increasing steric hindrance and affecting the interaction between the carboxyl groups and NiO. x The surface of the layer and the bonding efficiency of the self-assembled monolayer.

[0014] Preferably, n is 5-15.

[0015] Preferably, the modified NiO x In the layer, the molar ratio of trivalent nickel ions to divalent nickel ions is 1:(1.2-0.6), for example, it can be 1:0.6, 1:0.8, 1:10 or 1:1.2, etc.

[0016] Preferably, the modified NiO x The thickness of the layer is 10-20nm, for example, it can be 10nm, 12nm, 14nm, 16nm, 18nm or 20nm, etc.

[0017] In this invention, modified NiO of suitable thickness x The layer can form stronger chemical bonds with the self-assembled monolayer, improving the interfacial bonding strength. This bonding helps to form a more uniform and dense self-assembled monolayer, thereby optimizing NiO. x Self-assembled monomolecular interfaces enhance charge collection and suppress interfacial reactions and recombination.

[0018] Preferably, the material of the self-assembled monolayer includes MeO-4PACz (4-methoxybenzylmalonium malononitrile) and / or 4PADCB ([4-(7H-dibenzocarbazole-7-yl)butyl]phosphate).

[0019] In a second aspect, the present invention provides a method for preparing a hole transport layer as described in the first aspect, the method comprising the following steps:

[0020] NiO is deposited on the surface of a substrate by magnetron sputtering. x A layer was then applied to the NiO, followed by coating with a dicarboxylic acid solution. x On the top layer, after annealing, modified NiO is obtained. x layer.

[0021] In the modified NiO x A self-assembled monolayer is deposited on the layer to obtain the hole transport layer.

[0022] In this invention, NiO prepared by magnetron sputtering x The complex chemical composition of the layer surface may lead to Ni 3+ / Ni 2+ A lower proportion reduces the number of surface hydroxyl groups, which in turn hinders NiO production. x Effective anchoring of the self-assembled monolayer affects the wettability of the perovskite layer, ultimately leading to a decrease in solar cell performance. Therefore, this invention utilizes NiO... x A dicarboxylic acid is introduced onto the surface of the layer, allowing the carboxyl group at one end of the dicarboxylic acid to anchor NiO. x The other end of the layer anchors the self-assembled monolayer with carboxyl groups, significantly increasing the NiO content. x The number of carboxyl groups on the surface of the NiO layer increases the yield of NiO. x The bonding force between the layer and the self-assembled monolayer optimizes the wettability of the perovskite absorber layer.

[0023] Preferably, the specific parameters of the magnetron sputtering method include:

[0024] The sputtering target is NiO x The sputtering pressure of the target material is 0.5-1 Pa, such as 0.5 Pa, 0.6 Pa, 0.7 Pa, 0.8 Pa, 0.9 Pa or 1 Pa, and the sputtering power is 1-2 KW, such as 1 KW, 1.2 KW, 1.4 KW, 1.6 KW, 1.8 KW or 2 KW.

[0025] Preferably, the concentration of the dicarboxylic acid solution is 0.1-0.5 mg / mL, for example, it can be 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL or 0.5 mg / mL, etc.

[0026] In this invention, a dicarboxylic acid solution of suitable concentration can enhance NiO. x Interfacial bonding forces between the layer and the self-assembled monolayer.

[0027] The present invention does not limit the solvent of the dicarboxylic acid solution, as long as it can fully dissolve the dicarboxylic acid material. For example, it can be ethanol or isopropanol.

[0028] Preferably, the coating method includes spin coating.

[0029] Preferably, in the spin coating method, the spin coating rate of the dicarboxylic acid solution is 4000-6000 rpm, for example, 4000 rpm, 5000 rpm, or 6000 rpm, and the acceleration is 800-1200 rpm. 2 For example, it could be 800 rpm 2 900rpm 2 1000rpm 2 1100rpm 2 Or 1200rpm 2 wait.

[0030] In this invention, a suitable spin-coating rate can form a coating on NiO. x The layer undergoes thorough and uniform surface modification; a suitable spin-coating acceleration facilitates the coating of dicarboxylic acid solution on NiO. x Diffusion on the layer improves the effect of dicarboxylic acid solution on NiO. x Uniformity of surface modification of the layer.

[0031] Preferably, in the spin coating method, the spin coating time of the dicarboxylic acid solution is 20-40s, for example, it can be 20s, 30s or 40s.

[0032] Preferably, the annealing temperature is 80-120℃, for example, 80℃, 90℃, 100℃, 110℃ or 120℃, and the annealing time is 15-25min, for example, 15min, 20min or 25min.

[0033] In this invention, annealing at a suitable temperature helps to promote the reaction of dicarboxylic acids with NiO. x Sufficient surface modification of the layer is crucial for improving the long-term stability of the bond between dicarboxylic acid and nickel oxide.

[0034] Preferably, the deposition method for the self-assembled monolayer includes a solution method. For example, it can be a spin-coating method.

[0035] Thirdly, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a conductive substrate, a first carrier transport layer, a perovskite absorber layer, a second carrier transport layer and an electrode layer stacked together; the first carrier transport layer and the second carrier transport layer transport charges of opposite polarities, and either one of them includes a hole transport layer as described in the first aspect, and the other is an electron transport layer.

[0036] Preferably, the conductive substrate is conductive glass, such as ITO (indium tin oxide) conductive glass or FTO (fluorine-doped tin oxide) conductive glass.

[0037] Preferably, the thickness of the hole transport layer is 1-5 nm, for example, it can be 1 nm, 2 nm, 3 nm, 4 nm or 5 nm.

[0038] Preferably, the electron transport layer includes C 60 Layer and / or SnO2 layer.

[0039] Preferably, the thickness of the electron transport layer is 10-20 nm, for example, it can be 10 nm, 15 nm or 20 nm.

[0040] Preferably, the chemical formula of the perovskite absorber layer is ABX3, wherein A includes CH3NH3. + CH(NH2)2 + or Cs + B includes any one or at least two of the following, where B includes Pb. 2+ and / or Sn 2+ X includes halide ions.

[0041] Preferably, the perovskite absorber layer is a wide bandgap perovskite absorber layer, and the bandgap of the wide bandgap perovskite absorber layer is greater than or equal to 1.6 eV, for example, it can be 1.65 eV, 1.68 eV or 1.7 eV, etc.

[0042] Preferably, the thickness of the perovskite absorber layer is 500-600 nm, for example, it can be 500 nm, 550 nm or 600 nm.

[0043] Preferably, a passivation layer is further disposed between the perovskite absorber layer and the second carrier transport layer.

[0044] Preferably, the material of the passivation layer includes polyimide (PI) and / or phenylethyl ammonium iodide (PEAI).

[0045] In this invention, the use of the above-mentioned passivation layer helps to reduce interface loss, increase surface coverage, and thus improve the stability of the device.

[0046] Preferably, the thickness of the passivation layer is 1-5 nm, for example, it can be 1 nm, 2 nm, 3 nm, 4 nm or 5 nm.

[0047] Preferably, the electrode layer is a metal electrode layer. For example, it may be an Ag electrode layer or an Au electrode layer.

[0048] Fourthly, the present invention provides a perovskite-silicon tandem solar cell, the perovskite-silicon tandem solar cell comprising, in sequence, a crystalline silicon base cell, an intermediate composite layer, a hole transport layer, a perovskite absorption layer, an electron transport layer, a transparent conductive layer, and an electrode layer; the hole transport layer comprises the hole transport layer as described in the first aspect.

[0049] The present invention does not limit the type of crystalline silicon bottom cell. For example, it can be a heterojunction cell, which includes a stacked back electrode, a back transparent conductive layer, a p-type amorphous silicon layer, a first intrinsic amorphous silicon layer, a silicon wafer, a second intrinsic amorphous silicon layer and an n-type amorphous silicon layer.

[0050] The perovskite-silicon tandem solar cell prepared based on the hole transport layer provided by this invention has excellent photoelectric performance.

[0051] It should be noted that when preparing perovskite crystalline silicon tandem solar cells, the crystalline silicon base cell can be prepared on-site or a semi-finished crystalline silicon base cell can be used.

[0052] Preferably, the intermediate composite layer comprises an ITO film.

[0053] Preferably, the thickness of the ITO film is 80-120 nm, for example, it can be 80 nm, 100 nm or 120 nm.

[0054] Preferably, the material of the transparent conductive layer includes ITO.

[0055] Preferably, the thickness of the transparent conductive layer is 30-50 nm, for example, it can be 30 nm, 40 nm or 50 nm.

[0056] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] This invention utilizes NiO x A dicarboxylic acid is introduced onto the surface of the layer, allowing the carboxyl group at one end of the dicarboxylic acid to anchor NiO. x The other end of the layer anchors the self-assembled monolayer with carboxyl groups, significantly increasing the NiO content.x The number of carboxyl groups on the surface of the NiO layer increases the yield of NiO. x The bonding force between the perovskite absorber layer and the self-assembled monolayer is beneficial for optimizing the wettability of the perovskite absorber layer. Perovskite solar cells or perovskite-silicon tandem cells fabricated based on this principle exhibit excellent photoelectric performance. Attached Figure Description

[0059] Figure 1 This is a perovskite film formation based on the hole transport layer provided in Embodiment 1 of the present invention.

[0060] Figure 2 This is a perovskite film formed based on the hole transport layer provided in Comparative Example 1 of the present invention.

[0061] Figure 3 This is a schematic diagram of the structure of the perovskite solar cell provided by the present invention.

[0062] Figure 4 This is a schematic diagram of the structure of the perovskite-silicon tandem solar cell provided by the present invention.

[0063] Among them, 1-FTO conductive glass; 2-hole transport layer; 3-perovskite absorber layer; 4-passivation layer; 5-electron transport layer; 6-metal electrode layer; 7-intermediate composite layer; 8-n-type amorphous silicon layer; 9-second intrinsic amorphous silicon layer; 10-silicon wafer; 11-first intrinsic amorphous silicon layer; 12-p-type amorphous silicon layer; 13-back transparent conductive layer; 14-back electrode; 15-front transparent electrode layer. Detailed Implementation

[0064] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0065] Example 1

[0066] This embodiment provides a hole transport layer, the hole transport layer comprising stacked modified NiO. x Layers and self-assembled monolayers; the modified NiO x The layer is NiO with a dicarboxylic acid surface modified. x The layer, wherein one end carboxyl group of the dicarboxylic acid is anchored to the NiO x One end of the self-assembled monolayer is anchored by a carboxyl group at the other end.

[0067] The chemical formula of the dicarboxylic acid is HOOC-(CH3). 10 -COOH; the modified NiO x In the layer, the molar ratio of trivalent nickel ions to divalent nickel ions is 1:0.8.

[0068] The modified NiO x The thickness of the layer is 15 nm, and the material of the self-assembled monolayer is MeO-4PACz.

[0069] This embodiment also provides a method for preparing the above-mentioned hole transport layer, the method comprising the following steps:

[0070] (1) NiO was prepared using radio frequency magnetron sputtering equipment with high purity (purity > 99.99%). x For sputtering target preparation, a vacuum was drawn until the vacuum level in the reaction chamber dropped to 6 × 10⁻⁶. -4 After Pa, argon gas was introduced, and the sputtering pressure was controlled at 0.7 Pa and the sputtering power at 1.5 kW. A NiO layer with a thickness of 15 nm was sputtered and deposited on the substrate surface. x layer.

[0071] (2) Modification treatment: Take 200 μL of the chemical formula HOOC-(CH3). 10 -COOH, a dicarboxylic acid solution with a concentration of 0.3 mg / mL (HOOC-(CH3) 10 -COOH can be purchased directly from Mairui (model M23716). The dicarboxylic acid solution is added dropwise to the NiO. x On the upper layer, the rotation speed is set to 5000 rpm, and the acceleration of the rotation speed is 1000 rpm. 2 Spin-coating for 30 seconds, then transferring to a heating plate and annealing at 100°C for 20 minutes, yields modified NiO. x layer.

[0072] (3) Dissolve MeO-4PACz in ethanol to obtain a MeO-4PACz solution with a concentration of 0.5 mg / mL. Set the rotation speed to 3000 rpm, spin coat for 30 s, and then transfer it to a heating plate. Anneal at 100 °C for 10 min to form a self-assembled monolayer, thus obtaining the hole transport layer.

[0073] Example 2

[0074] The difference between this embodiment and Example 1 is that the chemical formula of the dicarboxylic acid is HOOC-CH3-COOH.

[0075] The remaining preparation methods and parameters are consistent with those in Example 1.

[0076] Example 3

[0077] The difference between this embodiment and Example 1 is that the chemical formula of the dicarboxylic acid is HOOC-(CH3)5-COOH.

[0078] The remaining preparation methods and parameters are consistent with those in Example 1.

[0079] Example 4

[0080] The difference between this embodiment and Example 1 is that the chemical formula of the dicarboxylic acid is HOOC-(CH3). 15 -COOH.

[0081] The remaining preparation methods and parameters are consistent with those in Example 1.

[0082] Example 5

[0083] The difference between this embodiment and Example 1 is that the chemical formula of the dicarboxylic acid is HOOC-(CH3). 20 -COOH.

[0084] The remaining preparation methods and parameters are consistent with those in Example 1.

[0085] Example 6

[0086] The difference between this embodiment and Example 1 is that the chemical formula of the dicarboxylic acid is HOOC-(CH3). 25 -COOH.

[0087] The remaining preparation methods and parameters are consistent with those in Example 1.

[0088] Example 7

[0089] The difference between this embodiment and Embodiment 1 is that the spin coating speed of the dicarboxylic acid solution in step (2) is adjusted to 3000 rpm.

[0090] The remaining preparation methods and parameters are consistent with those in Example 1.

[0091] Example 8

[0092] The difference between this embodiment and Embodiment 1 is that the spin coating speed of the dicarboxylic acid solution in step (2) is adjusted to 7000 rpm.

[0093] The remaining preparation methods and parameters are consistent with those in Example 1.

[0094] Example 9

[0095] The difference between this embodiment and Embodiment 1 is that the acceleration of the spin coating speed of the dicarboxylic acid solution in step (2) is adjusted to 500 rpm. 2 .

[0096] The remaining preparation methods and parameters are consistent with those in Example 1.

[0097] Example 10

[0098] The difference between this embodiment and Embodiment 1 is that the acceleration of the spin coating speed of the dicarboxylic acid solution in step (2) is adjusted to 1500 rpm. 2 .

[0099] The remaining preparation methods and parameters are consistent with those in Example 1.

[0100] Example 11

[0101] The difference between this embodiment and embodiment 1 is that the annealing temperature in step (2) is 60°C.

[0102] The remaining preparation methods and parameters are consistent with those in Example 1.

[0103] Example 12

[0104] The difference between this embodiment and embodiment 1 is that the annealing temperature in step (2) is 150°C.

[0105] The remaining preparation methods and parameters are consistent with those in Example 1.

[0106] Comparative Example 1

[0107] The difference between this comparative example and Example 1 is that step (2) is omitted, i.e., NiO is not processed. x The layer undergoes modification treatment.

[0108] The remaining preparation methods and parameters are consistent with those in Example 1.

[0109] Figure 1 and Figure 2 Perovskite film formation based on the hole transport layer provided in Embodiment 1 and Comparative Example 1 of the present invention are shown respectively. Figure 1 and Figure 2 The comparison shows that the perovskite film formed without hole transport layer modification has a large number of pores, while the perovskite film formed with hole transport layer modification has good condition.

[0110] Application Example 1-1

[0111] This application example provides a perovskite solar cell, the schematic diagram of which is shown below. Figure 3 As shown, it includes an FTO conductive glass 1, a hole transport layer 2 as described in Example 1, a perovskite absorption layer 3, a passivation layer 4, an electron transport layer 5, and a metal electrode layer 6, which are stacked sequentially.

[0112] The hole transport layer 2 has a thickness of 3 nm; the electron transport layer 5 comprises stacked C 60 Layer and SnO2 layer, C 60 The thickness of the layer is 15 nm, and the thickness of the SnO2 layer is 15 nm; the chemical formula of the perovskite absorber layer 3 is Cs.0.22 FA 0.78 Pb(I 0.85 Br 0.15 )3, with a band gap of 1.68 eV and a thickness of 550 nm; the passivation layer 4 has a thickness of 3 nm and is made of PI; the metal electrode layer 6 is made of Ag and has a thickness of 100 nm.

[0113] This application example also provides a method for fabricating the above-mentioned perovskite solar cell, the method comprising the following steps:

[0114] (a) Modified NiO is sequentially laminated onto the cleaned FTO conductive glass using the hole transport layer preparation method described in Example 1. x Layers and self-assembled monolayers.

[0115] (b) A layer of Cs with the chemical formula was deposited on a self-assembled monolayer using a one-step spin-coating method. 0.22 FA 0.78 Pb(I 0.85 Br 0.15 The perovskite absorber layer of 3 was spin-coated at 5000 rpm for 45 seconds. 300 μL of the anti-solvent chlorobenzene was added dropwise at the 25th second of spin coating. After spin coating, the mixture was annealed at 100℃ for 20 minutes.

[0116] (c) A PI solution (isopropanol, concentration 0.3 mg / mL) was spin-coated onto the perovskite absorber layer at a speed of 5000 rpm for 30 s to obtain a passivation layer.

[0117] (d) A 15 nm thick C layer was deposited on the passivation layer using a high-vacuum thermal evaporation deposition method. 60 The first layer was evaporated at a rate of 0.05 nm / s; then, an electron transport layer of SnO2 with a thickness of 15 nm was deposited using atomic layer deposition.

[0118] (e) A 100 nm thick Ag layer is deposited on the electron transport layer as a metal electrode layer using a high vacuum thermal evaporation coating method.

[0119] Application Examples 1-2 to 1-12

[0120] Application Examples 1-2 to 1-12 each provide a perovskite solar cell, which differs from Application Example 1-1 only in that the hole transport layer is the hole transport layer provided in Examples 2 to 12.

[0121] The remaining preparation methods and parameters are consistent with those in Application Example 1-1.

[0122] Application Comparative Example 1-1

[0123] Comparative Example 1-1 provides a perovskite solar cell, which differs from Comparative Example 1-1 only in that the hole transport layer is the hole transport layer provided in Comparative Example 1.

[0124] The remaining preparation methods and parameters are consistent with those in Application Example 1-1.

[0125] Application Example 2-1

[0126] This application example provides a perovskite-silicon tandem solar cell, the schematic diagram of which is shown below. Figure 4 As shown, the structure includes, in sequence, a back electrode 14, a back transparent conductive layer 13, a p-type amorphous silicon layer 12, a first intrinsic amorphous silicon layer 11, a silicon wafer 10, a second intrinsic amorphous silicon layer 9, an n-type amorphous silicon layer 8, an intermediate composite layer 7, a hole transport layer 2 as described in Example 1, a perovskite absorption layer 3, a passivation layer 4, an electron transport layer 5, a front transparent conductive layer 15, and a metal electrode layer 6.

[0127] The intermediate composite layer 7 is an ITO thin film with a thickness of 400 nm; the back transparent conductive layer 13 and the front transparent conductive layer 15 are both made of ITO with a thickness of 40 nm; the hole transport layer 2 has a thickness of 3 nm; the electron transport layer 5 includes stacked C 60 Layer and SnO2 layer, C 60 The thickness of the layer is 15 nm, and the thickness of the SnO2 layer is 15 nm; the chemical formula of the perovskite absorber layer 3 is Cs. 0.22 FA 0.78 Pb(I 0.85 Br 0.15 )3, with a band gap of 1.68 eV and a thickness of 550 nm; the passivation layer 4 has a thickness of 3 nm and is made of PI; the metal electrode layer 6 is made of Ag and has a thickness of 900 nm.

[0128] This application example also provides a method for fabricating the above-mentioned perovskite-silicon tandem solar cell, the method comprising the following steps:

[0129] (I) A heterojunction cell with a semi-finished product is used as a substrate. The substrate includes a back electrode, a back transparent conductive layer, a p-type amorphous silicon layer, a first intrinsic amorphous silicon layer, a silicon wafer, a second intrinsic amorphous silicon layer and an n-type amorphous silicon layer stacked in sequence.

[0130] A 100 nm thick ITO thin film was sputtered and deposited on the n-type amorphous silicon layer as an intermediate composite layer using magnetron sputtering.

[0131] (II) Using the hole transport layer preparation method described in Example 1, modified NiO is sequentially stacked on the intermediate composite layer. x Layers and self-assembled monolayers.

[0132] (III) A layer of chemical formula Cs was deposited on a self-assembled monolayer using a one-step spin-coating method. 0.22 FA 0.78 Pb(I 0.85 Br 0.15 The perovskite absorber layer of 3 was spin-coated at 5000 rpm for 45 seconds. 300 μL of the anti-solvent chlorobenzene was added dropwise at the 25th second of spin coating. After spin coating, the mixture was annealed at 100℃ for 20 minutes.

[0133] (IV) A PI solution (isopropanol, concentration 0.3 mg / mL) was spin-coated onto the perovskite absorber layer at a speed of 5000 rpm for 30 s to obtain a passivation layer.

[0134] (V) A 15 nm thick C layer was deposited on the passivation layer using a high-vacuum thermal evaporation deposition method. 60 The first layer was evaporated at a rate of 0.05 nm / s; then, an electron transport layer of SnO2 with a thickness of 15 nm was deposited using atomic layer deposition.

[0135] (VI) A 40 nm thick ITO layer was sputtered and deposited on the sub-transport layer as a front transparent conductive layer using magnetron sputtering. Then, a 900 nm thick Ag layer was deposited on the front transparent conductive layer as a metal electrode layer using high vacuum thermal evaporation deposition.

[0136] Application Examples 2-2 to 2-12

[0137] Application Examples 2-2 to 2-12 each provide a perovskite-silicon tandem solar cell, the only difference from Application Example 2-1 being that the hole transport layer is the hole transport layer provided in Examples 2 to 12.

[0138] The remaining preparation methods and parameters are consistent with those in Application Example 2-1.

[0139] Application of Comparative Example 2-1

[0140] Comparative Example 2-1 provides a perovskite-silicon tandem solar cell, which differs from Comparative Example 2-1 only in that the hole transport layer is the hole transport layer provided in Comparative Example 1.

[0141] The remaining preparation methods and parameters are consistent with those in Application Example 2-1.

[0142] Performance testing

[0143] The photoelectric performance of the perovskite solar cells and perovskite-silicon tandem cells provided in the above application examples was tested, including open-circuit voltage (Voc), short-circuit current (Jsc), fill factor (FF), and photoelectric conversion efficiency (PCE).

[0144] Test conditions: AM1.5, 1000W / m 2 , 25±2℃.

[0145] The test results are shown in Tables 1 and 2.

[0146] Table 1

[0147]

[0148] Table 2

[0149]

[0150]

[0151] analyze:

[0152] As shown in Tables 1 and 2, the present invention utilizes NiO x A dicarboxylic acid is introduced onto the surface of the layer, allowing the carboxyl group at one end of the dicarboxylic acid to anchor NiO. x The other end of the layer anchors the self-assembled monolayer with carboxyl groups, significantly increasing the NiO content. x The number of carboxyl groups on the surface of the NiO layer increases the yield of NiO. x The bonding force between the perovskite absorber layer and the self-assembled monolayer is beneficial for optimizing the wettability of the perovskite absorber layer. Perovskite solar cells or perovskite-silicon tandem cells fabricated based on this principle exhibit excellent photoelectric performance.

[0153] As shown in Application Examples 1-1 / 2-1 to 1-6 / 2-6, carbon chain length has a significant impact on the modification effect of dicarboxylic acids. If the carbon chain is short, it may lead to molecular self-assembly forming different aggregate morphologies, which may be detrimental to the formation of a uniform self-assembled monolayer, affecting the modification of NiO. x The bonding of the layer surface reduces the modification of NiO. x The bonding force and stability between the layer and the self-assembled monolayer result in poor battery performance improvement. Longer carbon chains may increase intermolecular steric hindrance because as the carbon chain length increases, the molecular volume also increases. A larger molecular volume reduces the space for intermolecular interactions, thus increasing steric hindrance and affecting the interaction between the carboxyl groups and NiO. x The surface area of ​​the layer and the binding efficiency of the self-assembled monolayer result in poor battery performance improvement.

[0154] As can be seen from Application Examples 1-1, 1-7, and 1-8 (or Application Examples 2-1, 2-7, and 2-8), if the spin-coating speed of the dicarboxylic acid solution is too low, it will result in uneven spreading of the dicarboxylic acid solution on the nickel oxide surface, affecting the coating of NiO. x Surface modification of the layer leads to poor battery performance; if the spin-coating speed of the dicarboxylic acid solution is too high, it will disrupt the surface tension balance of the solution, resulting in poor modified NiO. x The deterioration of the surface morphology of the layer is not conducive to the formation of a uniform self-assembled monolayer, thus affecting the modification of NiO. x The bonding of the layer surface results in poor battery performance improvement.

[0155] As can be seen from Application Examples 1-1, 1-9, and 1-10 (or Application Examples 2-1, 2-9, and 2-10), if the spin-coating speed of the dicarboxylic acid solution is too low, it will lead to NiO... x Uneven surface modification of the layer makes the subsequent self-assembled monolayer not smooth enough, resulting in poor battery performance improvement. If the spin coating speed of the dicarboxylic acid solution is too high, the adhesion between the dicarboxylic acid solution and the nickel oxide surface will be insufficient, resulting in poor modification effect.

[0156] As can be seen from Application Examples 1-1, 1-11, and 1-12 (or Application Examples 2-1, 2-11, and 2-12), if the annealing temperature in step (2) is too low, it will cause the dicarboxylic acid to react with NiO. x The poor modification effect of the layer makes NiO x The reduced bonding strength and stability between the layer and the self-assembled monolayer affects battery performance; if the annealing temperature in step (2) is too high, it will cause the decomposition or structural changes of the dicarboxylic acid, affecting NiO. x The bonding force and stability between the layer and the self-assembled monolayer affect the photoelectric performance of the battery.

[0157] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A hole transport layer, characterized in that, The hole transport layer comprises stacked modified NiO. x Layers and self-assembled monolayers; The modified NiO x The layer is NiO with a dicarboxylic acid surface modified. x The layer, wherein one end carboxyl group of the dicarboxylic acid is anchored to the NiO x One end of the self-assembled monolayer is anchored by a carboxyl group at the other end.

2. The hole transport layer according to claim 1, characterized in that, The chemical structural formula of the dicarboxylic acid is: Where n is 1-20; Preferably, n is 5-15.

3. The hole transport layer according to claim 1 or 2, characterized in that, The modified NiO x In the layer, the molar ratio of trivalent nickel ions to divalent nickel ions is 1:(1.2-0.6).

4. The hole transport layer according to any one of claims 1-3, characterized in that, The modified NiO x The thickness of the layer is 10-20 nm; Preferably, the material of the self-assembled monolayer includes MeO-4PACz and / or 4PADCB.

5. A method for preparing a hole transport layer as described in any one of claims 1-4, characterized in that, The preparation method includes the following steps: NiO is deposited on the surface of a substrate by magnetron sputtering. x A layer was then applied to the NiO, followed by coating with a dicarboxylic acid solution. x On the top layer, after annealing, modified NiO is obtained. x layer; In the modified NiO x A self-assembled monolayer is deposited on the layer to obtain the hole transport layer.

6. The preparation method according to claim 5, characterized in that, The specific parameters of the magnetron sputtering method include: The sputtering target is NiO x The sputtering pressure of the target material is 0.5-1 Pa, and the sputtering power is 1-2 KW. Preferably, the concentration of the dicarboxylic acid solution is 0.1-0.5 mg / mL; Preferably, the coating method includes spin coating; Preferably, in the spin coating method, the spin coating rate of the dicarboxylic acid solution is 4000-6000 rpm, and the acceleration is 800-1200 rpm. 2 ; Preferably, in the spin coating method, the spin coating time of the dicarboxylic acid solution is 20-40 seconds; Preferably, the annealing temperature is 80-120℃ and the annealing time is 15-25 min; Preferably, the deposition method of the self-assembled monolayer includes a solution method.

7. A perovskite solar cell, characterized in that, The perovskite solar cell includes a conductive substrate, a first carrier transport layer, a perovskite absorber layer, a second carrier transport layer, and an electrode layer stacked together. The first carrier transport layer and the second carrier transport layer transport charges of opposite polarities, and either one includes a hole transport layer as described in any one of claims 1-4, and the other is an electron transport layer.

8. The perovskite solar cell according to claim 7, characterized in that, The thickness of the hole transport layer is 1-5 nm; Preferably, the electron transport layer includes C 60 Layer and / or SnO2 layer; Preferably, the thickness of the electron transport layer is 10-20 nm.

9. The perovskite solar cell according to claim 7 or 8, characterized in that, The chemical formula of the perovskite absorber layer is ABX3, where A includes CH3NH3. + CH(NH2)2 + or Cs + B includes any one or at least two of the following, where B includes Pb. 2+ and / or Sn 2+ X includes halide ions; Preferably, the thickness of the perovskite absorber layer is 500-600 nm; Preferably, a passivation layer is further disposed between the perovskite absorber layer and the second carrier transport layer; Preferably, the material of the passivation layer includes polyimide and / or phenylethyl ammonium iodide; Preferably, the thickness of the passivation layer is 1-5 nm; Preferably, the electrode layer is a metal electrode layer.

10. A perovskite-silicon tandem solar cell, characterized in that, The perovskite-silicon tandem solar cell comprises a crystalline silicon base cell, an intermediate composite layer, a hole transport layer, a perovskite absorption layer, an electron transport layer, a transparent conductive layer, and an electrode layer stacked sequentially. The hole transport layer includes the hole transport layer as described in any one of claims 1-4.

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