Perovskite laminated cell and preparation method thereof
By using a hydrogen-containing first TCO layer and a second TCO layer with hydroxyl groups on its surface in perovskite tandem solar cells, the problem of the charge transport layer being dissolved by polar solvents was solved, achieving efficient tunneling recombination and improving the stability and efficiency of the cells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINT NEW ENERGY TECH CO LTD
- Filing Date
- 2024-10-30
- Publication Date
- 2026-05-01
AI Technical Summary
In existing perovskite tandem solar cells, the charge transport layer is easily dissolved by the polar solvents used in the preparation of the perovskite light-absorbing layer, which affects the cell performance.
By employing the synergistic effect of the first TCO layer and the second TCO layer, the first TCO layer contains hydrogen elements for passivating the bottom cell, and the surface of the second TCO layer has hydroxyl groups that form covalent bonds with the passivation groups of the charge transport layer, thus avoiding dissolution by polar solvents and achieving efficient tunneling recombination.
It improves the stability and efficiency of battery devices, enhances carrier mobility, and maintains the stability of the top cell structure.
Smart Images
Figure CN121968875A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery technology and relates to a perovskite tandem battery and its preparation method. Background Technology
[0002] Perovskite solar cells are a novel solar cell technology that uses perovskite material as the light-absorbing layer. This material possesses excellent photoelectric properties, including high absorption coefficient, good performance in low-light conditions, and low material cost. Furthermore, due to its tunable bandgap, it can be used as the top cell in combination with crystalline silicon, copper indium gallium selenide, or gallium arsenide bottom cells to form perovskite tandem solar cells, increasing the utilization rate of sunlight at different wavelengths and thus reducing costs while increasing efficiency.
[0003] In perovskite tandem solar cells, the intermediate tunneling composite layer serves to connect the upper and lower cells and facilitate recombination of charge carriers, making its importance self-evident. Currently, commonly used tunneling composite layer materials are single-layer transparent conductive oxide (TCO) materials or double-layer pn-type crystalline silicon materials, such as ITO (indium tin oxide), IZO (indium zinc oxide), poly-Si(p+) & poly-Si(n+), or uc-Si(p+) & uc-Si(n+), etc. Among these, the tunneling composite layer process for crystalline silicon materials is complex and has low transmittance. Therefore, most tunneling composite layers currently use TCO materials, which have the characteristics of high transmittance and good conductivity.
[0004] Currently, in high-efficiency perovskite tandem devices, the perovskite top cell typically involves first fabricating a charge transport layer, followed by the perovskite light-absorbing layer. However, the charge transport layer is easily dissolved by the polar solvents used in fabricating the perovskite light-absorbing layer, affecting cell performance. Therefore, there is an urgent need to provide a solution to address these issues. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a perovskite tandem solar cell and its fabrication method. Through the synergistic effect of the first and second TCO layers, the present invention achieves efficient tunneling recombination while avoiding the dissolution of the first charge transport layer by the polar solvent used in the fabrication of the perovskite light-absorbing layer, thereby significantly improving the stability and efficiency of the solar cell device.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] In a first aspect, the present invention provides a perovskite tandem solar cell, the perovskite tandem solar cell comprising a bottom cell, a tunneling composite layer and a perovskite top cell arranged in sequence.
[0008] Along the direction from the bottom cell to the perovskite top cell, the tunneling composite layer includes a first TCO layer and a second TCO layer stacked sequentially; the first TCO layer contains hydrogen; and the surface of the second TCO layer has hydroxyl groups.
[0009] The perovskite top solar cell includes a first charge transport layer, a perovskite light-absorbing layer, a second charge transport layer, and an electrode stacked together; the first charge transport layer is in contact with the second TCO layer, and the first charge transport layer has passivation groups, which form covalent bonds with hydroxyl groups on the surface of the second TCO layer.
[0010] This invention provides a perovskite tandem solar cell, wherein the tunneling recombination layer comprises a first TCO layer and a second TCO layer. The first TCO layer can undertake tunneling recombination, and the first TCO layer can improve its own charge carrier mobility and charge carrier concentration by hydrogen doping. At the same time, the hydrogen contained in the first TCO layer can passivate the bottom cell (e.g., a crystalline silicon bottom cell), and passivation can improve the dangling bonds of the crystalline silicon bottom cell. The second TCO layer can undertake tunneling recombination, and the hydroxyl groups on the surface of the second TCO layer can be tightly anchored to the passivation groups of the first charge transport layer through covalent bonds, thereby avoiding the dissolution of the first charge transport layer by the polar solvent used to prepare the perovskite light-absorbing layer, and thus improving the stability and efficiency of the solar cell device.
[0011] In summary, the present invention, through the synergistic effect of the first TCO layer and the second TCO layer, can achieve efficient tunnel recombination, improve the carrier mobility between the bottom cell and the top cell, and keep the top cell structure stable, thereby greatly improving the stability and efficiency of the battery device.
[0012] It should be noted that the perovskite tandem battery structure provided by this invention is applicable to both nip and pin perovskite tandem structures.
[0013] The present invention does not limit the type of polar solvent used to prepare the perovskite light-absorbing layer, including but not limited to dimethylformamide or dimethyl sulfoxide.
[0014] Preferably, the bottom cell includes any one of crystalline silicon bottom cell, CIGS (copper indium gallium selenide) bottom cell, or perovskite bottom cell.
[0015] In this invention, the crystalline silicon bottom cell includes, but is not limited to, heterojunction cells, TOPCon cells, or PERC cells.
[0016] Preferably, the material of the first TCO layer includes at least one of ITO (indium tin oxide), IZO (indium zinc oxide), IWO (indium tungsten oxide), and ICO (indium cerium oxide).
[0017] Preferably, based on the total amount of matter in the first TCO layer, the amount of matter in the hydrogen element is 0.5-2%, for example, it can be 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8% or 2%, etc., but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0018] Preferably, the thickness of the first TCO layer is 5-30nm, for example, it can be 5nm, 6nm, 8nm, 10nm, 12nm, 15nm, 18nm, 20nm, 22nm, 25nm, 28nm or 30nm, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0019] Preferably, the material of the second TCO layer includes at least one of ITO having hydroxyl groups, IZO having hydroxyl groups, IWO having hydroxyl groups, and ICO having hydroxyl groups.
[0020] Preferably, the thickness of the second TCO layer is 5-20nm, for example, it can be 5nm, 6nm, 8nm, 10nm, 12nm, 15nm, 18nm or 20nm, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0021] Preferably, the thickness ratio of the first TCO layer to the second TCO layer is (0.5-3):1, for example, it can be 0.5:1, 0.6:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1 or 3:1, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0022] In this invention, when the thickness ratio of the first TCO layer to the second TCO layer is too large, it will affect the bonding between the second TCO layer and the first charge transport layer with passivating groups, thereby making the first charge transport layer easily dissolve by the polar solvent used in the perovskite light-absorbing layer; when the thickness ratio of the first TCO layer to the second TCO layer is too small, it will affect the hydrogenation passivation effect of the first TCO layer on the bottom cell.
[0023] Preferably, the total thickness of the tunneling composite layer is 15-40nm, for example, it can be 15nm, 18nm, 20nm, 20nm, 25nm, 30nm, 35nm, 38nm or 40nm, etc., but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0024] In this invention, when the total thickness of the tunneling composite layer is too thick, it will increase its parasitic absorption; when the total thickness of the tunneling composite layer is too thin, it will affect the contact between the upper and lower interfaces and the composite effect.
[0025] Preferably, the charges transported by the first charge transport layer and the second charge transport layer are of opposite polarity.
[0026] In this invention, when the first charge transport layer is a hole transport layer, the second charge transport layer is an electron transport layer; when the first charge transport layer is an electron transport layer, the second charge transport layer is a hole transport layer.
[0027] Preferably, the passivation groups of the first charge transport layer include acidic groups.
[0028] Preferably, the acidic group includes at least one of a phosphate group, a carboxylic acid group, and a sulfonic acid group.
[0029] Preferably, the material of the first charge transport layer includes at least one of ME-4PACz, MeO-2PACz, 2PACz, p-aminobenzoic acid, p-bromobenzoic acid, 4-hydroxyethylpiperazine ethanesulfonic acid, and 2-aminoethanesulfonic acid.
[0030] In this invention, ME-4PACz, MeO-2PACz, and 2PACz are all self-assembled molecular materials that also function as hole transporters, and all three contain phosphate groups. Self-assembled molecular materials are easily dissolved by the polar solvents used to prepare the perovskite light-absorbing layer, but by forming covalent bonds between the phosphate groups and the hydroxyl groups on the surface of the second TCO layer, tight anchoring is achieved, thus preventing dissolution.
[0031] p-Aminobenzoic acid and p-bromobenzoic acid can play a role in hole transport. Both contain carboxylic acid groups, which can form covalent bonds with hydroxyl groups to achieve tight anchoring.
[0032] 4-Hydroxyethylpiperazine ethanesulfonic acid and 2-aminoethanesulfonic acid can play a role in hole transport. Both contain sulfonic acid groups, which can form covalent bonds with hydroxyl groups to achieve tight anchoring.
[0033] Preferably, a third TCO layer is further disposed between the electron transport layer and the electrode, and the material of the third TCO layer includes at least one of ITO, IZO, IWO and ICO.
[0034] In this invention, a third TCO layer is provided between the electron transport layer and the electrode to collect lateral current.
[0035] Preferably, the second charge transport layer comprises a first electron transport layer and a second electron transport layer stacked together, with the first electron transport layer located close to the perovskite light-absorbing layer. The second electron transport layer serves as a buffer.
[0036] In a second aspect, the present invention provides a method for preparing the perovskite tandem solar cell described in the first aspect, the method comprising:
[0037] A first TCO layer, a second TCO layer, a first charge transport layer, a perovskite light-absorbing layer, a second charge transport layer, and an electrode are sequentially fabricated on the surface of the bottom cell to obtain the perovskite tandem cell.
[0038] The first TCO layer contains hydrogen; the surface of the second TCO layer has hydroxyl groups; the first charge transport layer has passivation groups, and the passivation groups form covalent bonds with the hydroxyl groups on the surface of the second TCO layer.
[0039] Preferably, the method for preparing the first TCO layer includes the following steps:
[0040] A hydrogen-containing TCO layer is magnetron sputtered onto the surface of the bottom battery, and then annealed to obtain the first TCO layer.
[0041] In this invention, after magnetron sputtering a TCO layer containing hydrogen, the hydrogen in the TCO layer can enter the crystalline silicon bottom cell through an annealing step to passivate the dangling bonds on the crystalline silicon surface. Passivation can improve the dangling bonds of the crystalline silicon bottom cell.
[0042] Preferably, during the magnetron sputtering process, the flow rate ratio of the introduced argon, oxygen, and hydrogen is 100:4:(0.5-5), for example, it can be 100:4:0.5, 100:4:1, 100:4:2, 100:4:3, 100:4:4, or 100:4:5, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0043] Preferably, in the method for preparing the first TCO layer, the annealing temperature is 250-450℃, for example, it can be 250℃, 280℃, 300℃, 320℃, 350℃, 380℃, 400℃, 420℃ or 450℃, etc., but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0044] Preferably, in the method for preparing the first TCO layer, the annealing time is 15-30 min, for example, it can be 15 min, 18 min, 20 min, 25 min, 28 min or 30 min, etc., but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0045] In this invention, the first TCO layer needs to be annealed at a high temperature to allow the hydrogen element to passivate.
[0046] Preferably, in the method for preparing the first TCO layer, the annealing is performed under vacuum.
[0047] Preferably, the method for preparing the second TCO layer includes the following steps:
[0048] Atomic deposition is performed on the surface of the first TCO layer to obtain a TCO precursor layer with hydroxyl groups on the surface, and then annealing is performed to obtain the second TCO layer.
[0049] In this invention, the TCO precursor layer prepared by atomic deposition has hydroxyl groups on its surface, and naturally, the second TCO layer also has hydroxyl groups on its surface. Annealing is performed during the preparation of the second TCO layer to improve the quality of the TCO film.
[0050] Preferably, the temperature of the atomic deposition is 120-170°C, for example, it can be 120°C, 130°C, 140°C, 150°C, 160°C or 170°C, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0051] Preferably, the material of the TCO precursor layer includes SnO2 and In2O3.
[0052] In this invention, when the material of the TCO precursor layer is SnO2 and In2O3, the corresponding second TCO layer is an ITO layer with hydroxyl groups on its surface.
[0053] Preferably, in the method for preparing the second TCO layer, the annealing temperature is 100-150℃, for example, it can be 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0054] In this invention, because there are a large number of hydroxyl groups in the TCO precursor layer, high-temperature annealing is not possible, and annealing is required at a lower temperature.
[0055] Preferably, in the method for preparing the second TCO layer, the annealing time is 15-30 min, for example, it can be 15 min, 18 min, 20 min, 22 min, 25 min, 28 min or 30 min, etc., but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0056] Preferably, in the method for preparing the second TCO layer, the annealing is performed under a nitrogen atmosphere.
[0057] As a preferred technical solution of the present invention, the preparation method specifically includes the following steps:
[0058] (1) Using indium tin oxide as the target material, argon, oxygen and hydrogen gas with a flow rate ratio of 100:4:(0.5-5) are introduced to magnetron sputter a layer containing hydrogen on the surface of the bottom cell. Then, the layer is annealed in vacuum at 250-450℃ for 15-30 min to obtain the first TCO layer, which contains hydrogen.
[0059] (2) Atomic deposition is performed on the surface of the first TCO layer to obtain a TCO precursor layer with hydroxyl groups on the surface, and then annealed at 100-150℃ for 15-30 min in an inert atmosphere to obtain the second TCO layer.
[0060] The TCO precursor layer is made of SnO2 and In2O3; the surface of the second TCO layer has hydroxyl groups.
[0061] (3) A first charge transport layer and a perovskite light-absorbing layer are sequentially spin-coated on the surface of the second TCO layer. Then, a second charge transport layer is prepared on the surface of the perovskite light-absorbing layer. A third TCO layer is magnetron sputtered on the surface of the second charge transport layer. An electrode is deposited on the surface of the third TCO layer to obtain the perovskite tandem battery.
[0062] The material of the first charge transport layer is any one of ME-4PACz, MeO-2PACz, or 2PACz; the phosphate groups of the first charge transport layer form covalent bonds with the hydroxyl groups on the surface of the second TCO layer; the material of the second charge transport layer is an electron transport material; and the material of the third TCO layer is ITO.
[0063] 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.
[0064] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0065] This invention provides a perovskite tandem solar cell, wherein the tunneling recombination layer comprises a first TCO layer and a second TCO layer. The first TCO layer can undertake tunneling recombination, and the first TCO layer can improve its own charge carrier mobility and charge carrier concentration by hydrogen doping. At the same time, the hydrogen contained in the first TCO layer can passivate the bottom cell (e.g., a crystalline silicon bottom cell), and passivation can improve the dangling bonds of the crystalline silicon bottom cell. The second TCO layer can undertake tunneling recombination, and the hydroxyl groups on the surface of the second TCO layer can be tightly anchored to the passivation groups of the first charge transport layer through covalent bonds, thereby avoiding the dissolution of the first charge transport layer by the polar solvent used to prepare the perovskite light-absorbing layer, and thus improving the stability and efficiency of the solar cell device.
[0066] In summary, the present invention, through the synergistic effect of the first TCO layer and the second TCO layer, can achieve efficient tunnel recombination, improve the carrier mobility between the bottom cell and the top cell, and keep the top cell structure stable, thereby greatly improving the stability and efficiency of the battery device. Attached Figure Description
[0067] Figure 1 This is a schematic diagram of the structure of the perovskite tandem solar cell provided in Embodiment 1 of the present invention;
[0068] Wherein, 111-silicon substrate; 211-first intrinsic amorphous silicon layer; 212-p-type microcrystalline silicon layer; 213-bottom cell ITO layer; 214-first electrode; 311-second intrinsic amorphous silicon layer; 312-n-type microcrystalline silicon layer; 313-first TCO layer; 314-second TCO layer; 315-hole transport layer; 556-perovskite light-absorbing layer; 557-first electron transport layer; 558-second electron transport layer; 559-third TCO layer; 560-second electrode. Detailed Implementation
[0069] The technical solution of the present invention will be further illustrated below through specific embodiments.
[0070] Example 1
[0071] This embodiment provides a perovskite tandem solar cell, such as Figure 1 As shown, the perovskite tandem solar cell includes a bottom cell, a tunneling composite layer, and a perovskite top cell stacked sequentially from bottom to top;
[0072] The bottom cell is a heterogeneous crystalline silicon bottom cell, which includes a bottom cell ITO layer 213, a p-type microcrystalline silicon layer 212, a first intrinsic amorphous silicon layer 211, a silicon substrate 111, a second intrinsic amorphous silicon layer 311, and an n-type microcrystalline silicon layer 312 stacked sequentially from bottom to top; a first electrode 214 is disposed on the surface of the bottom cell ITO layer 213 away from the silicon substrate 111, and the first electrode 214 is a silver electrode;
[0073] The tunneling composite layer includes a first TCO layer 313 and a second TCO layer 314 stacked sequentially from bottom to top. The first TCO layer 313 is in contact with the n-type microcrystalline silicon layer 312. The first TCO layer 313 is an ITO layer containing hydrogen and has a thickness of 15 nm. The mass content of the hydrogen is 1%. The second TCO layer 314 is an ITO layer with hydroxyl groups on its surface and has a thickness of 10 nm.
[0074] The perovskite top solar cell comprises, from bottom to top, a hole transport layer 315, a perovskite light-absorbing layer 556, a first electron transport layer 557, a second electron transport layer 558, a third TCO layer 559, and a second electrode 560, stacked sequentially. The hole transport layer 315 is connected to the second TCO layer 314. The hole transport layer 315 is made of a self-assembled molecular material, specifically ME-4PACz. The phosphate groups in ME-4PACz form covalent bonds with the hydroxyl groups on the surface of the second TCO layer 314. The thickness of the hole transport layer 315 is 3 nm. The perovskite light-absorbing layer 556 is Cs. 0.05 FA 0.73 MA 0.22 Pb(I 0.77 Br 0.23 )3, with a thickness of 500nm; the first electron transport layer 557 is C 60 The first layer has a thickness of 18 nm; the second electron transport layer 558 is a tin dioxide layer with a thickness of 13 nm; the third TCO layer 559 is an ITO layer with a thickness of 100 nm; and the second electrode 560 is a silver electrode with a thickness of 800 nm.
[0075] This embodiment also provides a method for preparing the above-mentioned perovskite tandem solar cell, the method comprising the following steps:
[0076] (1) Using indium tin oxide as the target material, argon, oxygen and hydrogen gas with a flow rate ratio of 100:4:1 are introduced to magnetron sputter a layer containing hydrogen on the surface of the n-type microcrystalline silicon layer 312 of the heterocrystalline silicon bottom cell. Then, the layer is annealed at 300°C for 20 min under vacuum to obtain the first TCO layer 313 with a thickness of 15 nm.
[0077] (2) At 150°C, atomic deposition was performed on the surface of the first TCO layer 313 to obtain a precursor layer composed of SnO2 and In2O3 with hydroxyl groups on the surface. Then, it was annealed at 150°C for 2 hours under a nitrogen atmosphere to obtain the second TCO layer 314 with a thickness of 10 nm.
[0078] (3) A Me-4PACz solution with a concentration of 1 mmol / L was dropped onto the surface of the second TCO layer 314, wherein the solvent was ethanol. The solution was spin-coated at 3000 rpm for 30 s and annealed at 100°C for 10 min to obtain the ME-4PACz layer, namely the hole transport layer 315, with a thickness of 3 nm.
[0079] (4) The perovskite precursor solution was dropped onto the surface of the ME-4PACz layer and rotated at 1000 rpm for 10 s, followed by 5000 rpm for 30 s. At the initial moment of rotating at 5000 rpm, 140 μL of ethyl acetate was dropped onto the sample surface. After the rotation was completed, a perovskite liquid film was obtained. The perovskite liquid film was annealed at 110 °C for 10 min to obtain a perovskite light-absorbing layer 556 with a thickness of about 500 nm. The perovskite precursor solution included 1.05 mol / L PbI2, 0.35 mol / L PbBr2, 0.03 mol / L CsI, 1.05 mol / L FAI and 0.35 mol / L MABr, and the solvent was a mixed solution of DMF and DMSO with a volume ratio of 4:1.
[0080] (5) with The evaporation rate was such that a layer of C was deposited on the perovskite light-absorbing layer 556. 60 The first electron transport layer 557, with a thickness of 18 nm, is obtained.
[0081] (6) At 90℃, in C 60 A tin dioxide layer is atomically deposited on the surface of the layer to obtain the second electron transport layer 558, which has a thickness of 13 nm.
[0082] (8) A layer of ITO is magnetron sputtered on the surface of the tin dioxide layer to obtain the third TCO layer 559 with a film thickness of 100 nm.
[0083] (9) Finally The evaporation rate is such that a silver electrode is deposited on the surface of the ITO layer obtained in step (8), thus obtaining the second electrode 560 with a thickness of 800 nm.
[0084] Example 2
[0085] The difference between this embodiment and Embodiment 1 is that the thickness of the first TCO layer is changed to 30nm.
[0086] The remaining parameters are the same as in Example 1.
[0087] Example 3
[0088] The difference between this embodiment and Embodiment 1 is that the thickness of the first TCO layer is changed to 5nm.
[0089] The remaining parameters are the same as in Example 1.
[0090] Example 4
[0091] The difference between this embodiment and Embodiment 1 is that the thickness of the second TCO layer is changed to 20nm.
[0092] The remaining parameters are the same as in Example 1.
[0093] Example 5
[0094] The difference between this embodiment and Embodiment 1 is that the thickness of the second TCO layer is changed to 5nm.
[0095] The remaining parameters are the same as in Example 1.
[0096] Example 6
[0097] The difference between this embodiment and Embodiment 1 is that the ME-4PACz material is replaced with MeO-2PACz.
[0098] The remaining parameters are the same as in Example 1.
[0099] Example 7
[0100] The difference between this embodiment and Embodiment 1 is that the ME-4PACz material is replaced with 2PACz.
[0101] The remaining parameters are the same as in Example 1.
[0102] Example 8
[0103] The difference between this embodiment and Embodiment 1 is that the thickness of the first TCO layer is changed to 30nm and the thickness of the second TCO layer is changed to 20nm, so that the total thickness of the tunneling composite layer is 50nm.
[0104] The remaining parameters are the same as in Example 1.
[0105] Example 9
[0106] The difference between this embodiment and Embodiment 1 is that the thickness of the first TCO layer is changed to 5nm and the thickness of the second TCO layer is changed to 5nm, so that the total thickness of the tunneling composite layer is 10nm.
[0107] The remaining parameters are the same as in Example 1.
[0108] Example 10
[0109] The difference between this embodiment and Embodiment 1 is that the thickness of the first TCO layer is changed to 20nm and the thickness of the second TCO layer is changed to 5nm, so that the thickness ratio of the first TCO layer to the second TCO layer is 4:1.
[0110] The remaining parameters are the same as in Example 1.
[0111] Example 11
[0112] The difference between this embodiment and Embodiment 1 is that the thickness of the first TCO layer is changed to 6nm and the thickness of the second TCO layer is changed to 20nm, so that the thickness ratio of the first TCO layer to the second TCO layer is 0.3:1.
[0113] The remaining parameters are the same as in Example 1.
[0114] Comparative Example 1
[0115] The difference between this comparative example and Example 1 is that the second TCO layer is omitted, so that the tunneling composite layer only contains the first TCO layer, and the thickness of the first TCO layer is adjusted to 25nm.
[0116] The remaining parameters are the same as in Example 1.
[0117] Comparative Example 2
[0118] The difference between this comparative example and Example 1 is that the first TCO layer is omitted, so that the tunneling composite layer only contains the second TCO layer, and the thickness of the second TCO layer is adjusted to 25nm.
[0119] The remaining parameters are the same as in Example 1.
[0120] Performance testing
[0121] The photoelectric performance of the perovskite tandem solar cells provided in the above embodiments and comparative examples was tested under the following conditions: AM1.5g standard solar spectrum, 25°C.
[0122] The test results are shown in Table 1.
[0123] Table 1
[0124]
[0125] analyze:
[0126] As can be seen from Examples 1-5, the introduction of the first TCO layer and the second TCO layer, namely the H:ITO and OH:ITO double transparent conductive layer, in this invention to act as the tunneling recombination junction in the tandem solar cell is very effective. The photoelectric conversion efficiency (PCE) of the perovskite tandem solar cell remains above 27%, and the highest photoelectric conversion efficiency of the tandem solar cell device is as high as 28.88%.
[0127] As can be seen from Examples 1 and 6-7, when the molecular self-assembly material in the perovskite top cell is replaced, the photoelectric conversion efficiency of the device remains above 28%, which indicates that the H:ITO and OH:ITO double transparent conductive layers have a certain degree of universality as tunneling composite layers in tandem solar cells.
[0128] As can be seen from Examples 1 and 8-9, adjusting the thickness of the first TCO layer and the second TCO layer has a significant impact on the performance of the device. When the total thickness is too thick, it will increase parasitic absorption, resulting in a decrease in the photoelectric conversion efficiency of the battery. When the total thickness is too thin, it will affect the contact between the upper and lower interfaces and the recombination effect, resulting in a decrease in the photoelectric conversion efficiency of the battery.
[0129] As can be seen from Examples 1 and 10-11, when the thickness ratio of the first TCO layer to the second TCO layer is too large, it will affect the bonding between the second TCO layer and the hole transport layer with phosphate groups (i.e., the molecular self-assembly layer). The molecular self-assembly layer is easily dissolved by the polar solvent used in the perovskite light-absorbing layer, thereby reducing the photoelectric conversion efficiency of the battery. When the thickness ratio of the first TCO layer to the second TCO layer is too small, it will affect the hydrogenation passivation effect of the first TCO layer on the bottom cell, thereby affecting the photoelectric conversion efficiency of the battery.
[0130] As can be seen from Example 1 and Comparative Examples 1-2, compared with a single H:ITO layer or OH:ITO layer as a tunneling composite layer, the combination of H:ITO and OH:ITO in this invention is obviously more effective. The H:ITO layer can provide hydrogen passivation while undertaking tunneling composite, and the OH:ITO layer can anchor to the molecular self-assembled layer through covalent bonds while undertaking tunneling composite. This can prevent the polar solvent in the subsequent perovskite precursor from dissolving the molecular self-assembled layer, thereby greatly improving the photoelectric conversion efficiency of the device.
[0131] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.
Claims
1. A perovskite tandem solar cell, characterized in that, The perovskite tandem solar cell includes a bottom cell, a tunneling composite layer, and a perovskite top cell stacked sequentially. Along the direction from the bottom cell to the perovskite top cell, the tunneling composite layer includes a first TCO layer and a second TCO layer stacked sequentially; the first TCO layer contains hydrogen; and the surface of the second TCO layer has hydroxyl groups. The perovskite top solar cell includes a first charge transport layer, a perovskite light-absorbing layer, a second charge transport layer, and an electrode stacked together; the first charge transport layer is in contact with the second TCO layer, and the first charge transport layer has passivation groups, which form covalent bonds with hydroxyl groups on the surface of the second TCO layer.
2. The perovskite tandem solar cell according to claim 1, characterized in that, The bottom cell includes any one of crystalline silicon bottom cell, CIGS bottom cell, gallium arsenide bottom cell, or perovskite bottom cell.
3. The perovskite tandem solar cell according to claim 1 or 2, characterized in that, The material of the first TCO layer includes at least one of ITO containing hydrogen, IZO containing hydrogen, IWO containing hydrogen, and ICO containing hydrogen. Preferably, based on the total amount of matter in the first TCO layer, the amount of matter in the hydrogen element is 0.5-2%; Preferably, the thickness of the first TCO layer is 5-30 nm.
4. The perovskite tandem solar cell according to any one of claims 1-3, characterized in that, The material of the second TCO layer includes at least one of ITO having hydroxyl groups, IZO having hydroxyl groups, IWO having hydroxyl groups, and ICO having hydroxyl groups; Preferably, the thickness of the second TCO layer is 5-20 nm.
5. The perovskite tandem solar cell according to any one of claims 1-4, characterized in that, The thickness ratio of the first TCO layer to the second TCO layer is (0.5-3):1; Preferably, the total thickness of the tunneling composite layer is 15-40 nm.
6. The perovskite tandem solar cell according to any one of claims 1-5, characterized in that, The charges transported by the first charge transport layer and the second charge transport layer are of opposite electrical nature; Preferably, the passivation groups of the first charge transport layer include acidic groups; Preferably, the acidic group includes at least one selected from phosphate groups, carboxylic acid groups, and sulfonic acid groups; Preferably, the material of the first charge transport layer includes at least one of ME-4PACz, MeO-2PACz, 2PACz, p-aminobenzoic acid, p-bromobenzoic acid, 4-hydroxyethylpiperazine ethanesulfonic acid, and 2-aminoethanesulfonic acid; Preferably, a third TCO layer is further disposed between the second charge transport layer and the electrode, wherein the material of the third TCO layer includes at least one of ITO, IZO, IWO and ICO.
7. A method for preparing a perovskite tandem solar cell according to any one of claims 1-6, characterized in that, The preparation method includes: A first TCO layer, a second TCO layer, a first charge transport layer, a perovskite light-absorbing layer, a second charge transport layer, and an electrode are sequentially fabricated on the surface of the bottom cell to obtain the perovskite tandem cell. The first TCO layer contains hydrogen; the surface of the second TCO layer has hydroxyl groups; the first charge transport layer has passivation groups, and the passivation groups form covalent bonds with the hydroxyl groups on the surface of the second TCO layer.
8. The method for preparing a perovskite tandem solar cell according to claim 7, characterized in that, The method for preparing the first TCO layer includes the following steps: A hydrogen-containing TCO layer is magnetron sputtered onto the surface of the bottom battery, and then annealed to obtain the first TCO layer. Preferably, during the magnetron sputtering process, the flow rate ratio of the introduced argon, oxygen and hydrogen is 100:4:(0.5-5); Preferably, in the method for preparing the first TCO layer, the annealing temperature is 250-450°C; Preferably, in the method for preparing the first TCO layer, the annealing time is 15-30 min.
9. The method for preparing a perovskite tandem solar cell according to claim 7 or 8, characterized in that, The method for preparing the second TCO layer includes the following steps: Atomic deposition is performed on the surface of the first TCO layer to obtain a TCO precursor layer with hydroxyl groups on the surface, and then annealing is performed to obtain the second TCO layer. Preferably, the temperature of the atomic deposition is 120-170°C; Preferably, the material of the TCO precursor layer includes SnO2 and In2O3; Preferably, in the method for preparing the second TCO layer, the annealing temperature is 100-150°C; Preferably, in the method for preparing the second TCO layer, the annealing time is 15-30 min.
10. The method for preparing a perovskite tandem solar cell according to any one of claims 7-9, characterized in that, The preparation method specifically includes the following steps: (1) Using indium tin oxide as the target material, argon, oxygen and hydrogen gas with a flow rate ratio of 100:4:(0.5-5) are introduced to magnetron sputter a layer containing hydrogen on the surface of the bottom cell. Then, the layer is annealed in vacuum at 250-450℃ for 15-30 min to obtain the first TCO layer, which contains hydrogen. (2) Atomic deposition is performed on the surface of the first TCO layer to obtain a TCO precursor layer with hydroxyl groups on the surface, and then annealed at 100-150℃ for 15-30 min in an inert atmosphere to obtain the second TCO layer. The TCO precursor layer is made of SnO2 and In2O3; the surface of the second TCO layer has hydroxyl groups. (3) A first charge transport layer and a perovskite light-absorbing layer are sequentially spin-coated on the surface of the second TCO layer. Then, a second charge transport layer is prepared on the surface of the perovskite light-absorbing layer. A third TCO layer is magnetron sputtered on the surface of the second charge transport layer. An electrode is deposited on the surface of the third TCO layer to obtain the perovskite tandem battery. The material of the first charge transport layer is any one of ME-4PACz, MeO-2PACz, or 2PACz; the phosphate groups of the first charge transport layer form covalent bonds with the hydroxyl groups on the surface of the second TCO layer; the material of the second charge transport layer is an electron transport material; and the material of the third TCO layer is ITO.