Trans-perovskite solar cell and preparation method thereof

Abstract

The invention relates to the technical field of solar cells, in particular to a trans-perovskite solar cell and a preparation method thereof, an interface modification layer is prepared between a hole transport layer and a perovskite light absorption layer, and the material of the interface modification layer is prepared from a betahistine mesylate solution with the concentration of 1-2.5 mg / ml. According to the invention, the multi-point crystal boundary defect of the perovskite solar cell can be effectively passivated, and the performance of the perovskite solar cell device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and specifically to a perovskite solar cell and a preparation method thereof. Background Art

[0002] The rapid development of modern society requires more energy to support. Therefore, finding new types of energy, especially green, clean and renewable energy, has become a major focus of scientific research. Among them, solar energy has the advantages of being inexhaustible, green and pollution-free, and has attracted much attention from scientists. As a typical representative of the third-generation solar cells, perovskite solar cells are one of the most promising solar cells after polycrystalline silicon solar cells, single-crystalline silicon solar cells, and thin-film solar cells.

[0003] In recent years, with the continuous development of material science and process technology, perovskite photovoltaic devices (PSCs) based on PVK materials have shown excellent photovoltaic performance. Nevertheless, the power conversion efficiency (PCE) is still far lower than the Shockley-Queisser theoretical (S-Q) limit efficiency (33%). To obtain a high PCE, it is necessary to ensure as little carrier recombination as possible. During the carrier recombination process, radiative recombination is inevitable and has little impact on device performance. In contrast, non-radiative recombination will cause energy loss and thus reduce the PCE. During the non-radiative recombination process, the energy generated by the recombination of electron-hole pairs will be transferred to the surrounding lattice in the form of heat, resulting in a low open-circuit voltage (V OC )、fill factor (FF), and short-circuit current density (J SC ) of the PSC. As a semiconductor device, the defects located at the grain boundaries of the PVK layer will greatly reduce its electrical performance. Researchers used Kelvin force microscopy and conductive atomic force microscopy to characterize the PVK thin film and found that carriers need to cross the potential barrier at the grain boundary during the transmission process. Therefore, the existence of grain boundaries is not conducive to the long-distance transmission of carriers. Relevant experimental results also show that the existence of grain boundaries will lead to non-radiative recombination and ultimately reduce the electrical performance of the PVK active layer. Therefore, passivating grain boundary defects is also one of the important ways to inhibit non-radiative recombination in PSCs.

[0004] Currently, the performance of perovskite devices is usually improved by passivating the defects at the upper interface of the inverted PSCs. However, simply passivating the defects at the upper interface has problems such as a single passivation site and a low coordination strength with perovskite, and it cannot deeply passivate the large number and complex defects at the perovskite interface, nor can it ensure the aging effect of the passivation effect. Summary of the Invention

[0005] The present invention aims to solve the defects existing in the prior art, and provides a reverse perovskite solar cell and a preparation method thereof, which can effectively passivate the multi-site grain boundary defects of the perovskite solar cell and improve the device performance of the perovskite solar cell.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a preparation method of a reverse perovskite solar cell, including preparing an interfacial modification layer between a hole transport layer and a perovskite light absorption layer, and the material of the interfacial modification layer is prepared from a betahistine mesylate solution with a concentration of 1-2.5 mg / ml.

[0008] Preferably, the preparation of the interfacial modification layer includes spin-coating a solution containing betahistine mesylate on the hole transport layer and then annealing.

[0009] Preferably, the material of the hole transport layer is selected from any one or more of Meo-2PACz, Meo-4PACz, and NiO.

[0010] Preferably, the material of the perovskite light absorption layer adopts a material with an ABX3 structure, wherein A is a monovalent cation, including but not limited to rubidium (Rb) + , cesium (Cs) + , formamidine (HN=CHNH3) + (FA), methylamine (CH3NH3) + (MA) or a combination thereof; B is a divalent cation, including but not limited to tin (Sn) 2+ , lead (Pb) 2+ or a combination thereof; X is a monovalent anion, including but not limited to chlorine (Cl) - , bromine (Br) - , iodine (I) - or a combination thereof.

[0011] Preferably, the preparation method further includes preparing an electron transport layer and a metal electrode.

[0012] Preferably, the material of the electron transport layer is selected from any one or more of PCBM, BCP, and SnO2.

[0013] Preferably, the material of the metal electrode is selected from any one or more of gold, silver, and copper.

[0014] Preferably, the preparation method further includes preparing a wetting layer between the interfacial modification layer and the perovskite light absorption layer.

[0015] Preferably, the material of the wetting layer is alumina.

[0016] Second aspect, the present invention provides a perovskite solar cell prepared by the above preparation method.

[0017] The beneficial effects of the present invention are as follows:

[0018] In the process of preparing the perovskite solar cell of the present invention, by using betahistine mesylate molecules as the interface modification material in the buried interface of the perovskite, due to the amphiphilicity of the sulfonic acid group in the molecule, a uniform molecular layer can be formed at the interface, and it can also coordinate with Pb 2 + or I- ions on the perovskite surface to improve interface contact, reduce the energy barrier at the interface, promote charge extraction and transport, reduce interface recombination, and stabilize the surface structure; the betahistine mesylate molecules form a dipole layer at the interface, and the positive and negative charge separation characteristics in its molecular structure can adjust the energy level arrangement at the interface; in addition, the hydrophobic groups in the molecule can form a protective film at the interface to block the penetration of moisture and oxygen. The above effects cooperate with each other, which can effectively passivate the multi-site grain boundary defects of the perovskite solar cell and improve the performance and stability of the perovskite device.

[0019] After introducing betahistine mesylate molecules as the interface modification layer in the perovskite solar cell of the present invention, a perovskite film with more uniform grains, fewer defects, and stronger light absorption ability can be obtained, thereby improving the open-circuit voltage and short-circuit current density of the perovskite solar cell, and further improving the photoelectric conversion efficiency of the battery. Description of the Drawings

[0020] Figure 1 It is the efficiency diagram of the perovskite solar cell devices prepared in Examples 1-4 and Comparative Example 1;

[0021] Figure 2 It is the J-V curve diagram of the perovskite solar cells prepared in Example 2 and Comparative Example 1;

[0022] Figure 3 It is the dark current diagram of the perovskite solar cell devices prepared in Example 2 and Comparative Example 1;

[0023] Figure 4 It is the steady-state power output diagram of the perovskite solar cell devices prepared in Example 2 and Comparative Example 1;

[0024] Figure 5 It is the XRD diagram of the perovskite light absorption layer prepared in Example 2 and Comparative Example 1;

[0025] Figure 6 It is the field emission scanning electron microscope diagram of the perovskite light absorption layer prepared in Example 2 and Comparative Example 1 (right figure: Example 2, left figure: Comparative Example 1). Detailed Embodiments

[0026] To enable those skilled in the art to better understand the technical solution of the invention, the present invention will be further described in detail below in conjunction with specific embodiments.

[0027] In order to effectively passivate the multi-site grain boundary defects of perovskite solar cells and improve the performance of perovskite devices, the present invention first provides a method for preparing a reverse perovskite solar cell, including preparing an interface modification layer between a hole transport layer and a perovskite light-absorbing layer, and the material of the interface modification layer is prepared from a betahistine mesylate solution with a concentration of 1-2.5 mg / ml.

[0028] Betahistine mesylate, alias, N-methyl-2-pyridineethylamine dimethanesulfonate, the molecular formula is C8H 12 N2·2(CH4O3S).

[0029] Betahistine mesylate as the interface modification layer has the following four functions in the present invention:

[0030] 1. Interface modification and contact improvement

[0031] The sulfonic acid group (-SO3H) in the betahistine mesylate molecule has amphiphilicity and can form a uniform molecular layer at the interface. The sulfonic acid group coordinates with Pb 2 + or I- ions on the perovskite surface, and the nitrogen atom on the pyridine ring of the molecule has a lone pair of electrons, which can form a coordination bond with the perovskite, thereby further stabilizing the perovskite crystal structure, improving the overall performance of the device, and can also interact with the surface of the charge transport layer, thereby improving the interface contact, reducing the energy barrier at the interface, promoting the extraction and transport of charges, and reducing the interface recombination.

[0032] 2. Defect passivation

[0033] Common defects on the perovskite surface include uncoordinated Pb 2+ and halogen vacancies, and the sulfonic acid group (-SO3H) in betahistine mesylate can form a coordination bond with uncoordinated Pb 2+ to passivate these defect states, achieving the effect of reducing non-radiative recombination centers, increasing the open-circuit voltage and the photoelectric conversion efficiency.

[0034] 3. Energy level regulation

[0035] The betahistine mesylate molecules form a dipole layer at the interface, and the positive and negative charge separation characteristics in its molecular structure can adjust the energy level arrangement at the interface, optimize the energy level matching between the charge transport layer and the perovskite layer. This not only reduces the energy loss caused by energy level mismatch, but also improves the charge extraction efficiency and the fill factor.

[0036] 4. Enhanced Stability

[0037] The hydrophobic groups (such as alkyl chains) in betahistine mesylate molecules can form a protective film at the interface to block the penetration of moisture and oxygen. At the same time, its coordination with the perovskite surface can stabilize the surface structure, inhibit ion migration and phase separation, improve the environmental stability and thermal stability of perovskite solar cells, and extend the device life.

[0038] In some embodiments of the present invention, the concentration of the betahistine mesylate solution is any one of 1 mg / ml, 2 mg / ml, 2.5 mg / ml or a value between the two. If the concentration is lower than this, it will lead to insufficient modification, and if it is higher than this, it will lead to interface deterioration and produce negative effects.

[0039] The preparation of the interfacial modification layer in the present invention includes spin-coating a solution containing betahistine mesylate on the hole transport layer and then annealing. In some embodiments of the present invention, the spin-coating parameters are a rotation speed of 3000 r, a spin-coating time of 30 s, and an acceleration of 3000 r / s. In some embodiments of the present invention, the annealing parameters are annealing at 100 °C for 5 min.

[0040] The material of the hole transport layer in the present invention is selected from any one or more of Meo-2PACz, Meo-4PACz, NiO (nickel oxide).

[0041] The material of the perovskite light-absorbing layer in the present invention uses a material with the ABX3 structure, where A is a monovalent cation, including but not limited to rubidium (Rb) + , cesium (Cs) + , formamidine (HN=CHNH3) + (FA), methylamine (CH3NH3) + (MA) or a combination thereof; B is a divalent cation, including but not limited to tin (Sn) 2+ , lead (Pb) 2+ or a combination thereof; X is a monovalent anion, including but not limited to chlorine (Cl) - , bromine (Br) - , iodine (I) - or a combination thereof.

[0042] The preparation method in the present invention further includes preparing an electron transport layer and a metal electrode.

[0043] The material of the electron transport layer in the present invention is selected from any one or more of PCBM, BCP, SnO2.

[0044] The material of the metal electrode in the present invention is selected from any one or several of gold, silver, and copper.

[0045] The preparation method of the present invention further includes preparing a wetting layer between the interface modification layer and the perovskite light-absorbing layer. In some embodiments of the present invention, the material of the wetting layer is alumina. Alumina can play a role in increasing the wettability of perovskite. The polar surface energy of alumina can regulate the spreading property of the perovskite precursor solution, enabling the perovskite solution to adhere more uniformly, improving filling, and reducing holes or defects.

[0046] The present invention also provides a reverse perovskite solar cell prepared by the above preparation method.

[0047] After introducing betahistine mesylate molecules as the interface modification layer into the reverse perovskite solar cell of the present invention, a perovskite thin film with more uniform grains, fewer defects, and stronger light absorption ability can be obtained, thereby improving the open-circuit voltage and short-circuit current density of the perovskite solar cell, and further improving the photoelectric conversion efficiency of the cell.

[0048] The above is a detailed description of the technical solution of the present invention, and the following are specific embodiments.

[0049] Example 1

[0050] This example provides a reverse perovskite solar cell. The device structure from bottom to top is: conductive glass (the oxide layer material is ITO), hole transport layer (the material is Meo-2PACz), interface modification layer (the material is betahistine mesylate), wetting layer (the material is alumina), perovskite light-absorbing layer, electron transport layer (the material is PCBM+BCP), and metal electrode (the material is Ag).

[0051] This example also provides a preparation method for the above reverse perovskite solar cell, including the following steps:

[0052] (1) Cleaning the conductive glass: Rub the conductive glass (ITO) with dishwashing liquid, ultrasonically clean it with deionized water, acetone, and isopropanol for 20 minutes each, then place it in an oven at 70°C for drying, treat it with ultraviolet ozone for 20 minutes, and spin-coat the hole transport layer within 30 minutes in a glove box.

[0053] (2) Preparing the hole transport layer: Weigh 70 μl of a 0.5 mg / ml Meo-2PACz ethanol solution, spread it evenly on the conductive glass and let it stand for 10 s, then spin-coat it. The spin-coating parameters are 3000 r - 30 s - 3000 r / s. After spin-coating, anneal it at 100°C for 10 minutes.

[0054] (3) Preparing the interface modification layer: Weigh 70 μl of a 1 mg / ml betahistine mesylate solution (the solvent is isopropanol), spin-coat it on the hole transport layer. The spin-coating parameters are 3000 r - 30 s - 3000 r / s. After spin-coating, anneal it at 100°C for 5 minutes.

[0055] (4) Wetting layer: Dissolve 50 μL of alumina dispersion in 2 mL of IPA, shake it on an oscillator for more than 2 h, take 70 μL and spin-coat it on the interface modification layer. The spin-coating parameters are 5000 r - 30 s - 3000 r / s. After spin-coating, anneal it at 100 °C for 10 min.

[0056] (5) Perovskite light-absorbing layer: Prepare the precursor solution: Weigh 0.0084 g of methylammonium bromide, 0.0195 g of cesium iodide, 0.0159 g of rubidium iodide, 0.6569 g of lead iodide, 0.0275 g of lead bromide, and 0.2195 g of formamidinium hydroiodide. Add 1 mL of a mixed solution of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) to this ratio, with a volume ratio of DMF:DMSO of 4:1. Place it on a stirrer and wait for it to completely dissolve to complete the preparation of the perovskite precursor solution;

[0057] Spin-coat the perovskite precursor solution on the wetting layer. The spin-coating is carried out in two steps. The first step is static spin-coating, with the spin-coating parameters set to 1000 r - 10 s - 1000 r / s. The second step is dynamic spin-coating, with the spin-coating parameters set to 3000 r - 40 s - 3000 r / s. And 100 μL of anisole is added at the last 15 s (the glove box temperature is 20 - 22 °C, and the dropping rate of anisole should not be too fast or too slow, and it should form a column and be dropped within about 1 s). After spin-coating, anneal it at 100 °C for 10 min (the annealing time should not exceed 1 min above or below, and anneal immediately after spin-coating).

[0058] (6) Electron transport layer: Spin-coat 70 μL of 20 mg / ml PCBM (the solvent is chlorobenzene CB) on the perovskite light-absorbing layer, with the spin-coating parameters of 1500 r - 30 s - 1500 r / s, without annealing; then spin-coat 70 μL of 0.5 mg / ml BCP solution (the solvent is IPA), with the spin-coating parameters of 5000 r - 30 s - 2500 r / s, without annealing.

[0059] (7) Metal electrode: Evaporate a silver metal electrode with a thickness of 120 nm.

[0060] Example 2

[0061] Same as Example 1, the only difference is that when preparing the interface modification layer, the concentration of betahistine mesylate solution is 2 mg / ml.

[0062] Example 3

[0063] Same as Example 1, the only difference is that when preparing the interface modification layer, the concentration of betahistine mesylate solution is 2.5 mg / ml.

[0064] Example 4

[0065] Same as Example 1, with the only difference being that when preparing the interface modification layer, the concentration of betahistine mesylate solution is 3 mg / ml.

[0066] Comparative Example 1

[0067] Same as Example 1, with the only difference being that there is no interface modification layer.

[0068] Effect Example 1 Electrochemical Performance Test of the Device

[0069] Table 1 shows the electrochemical performance parameters of the perovskite solar cell devices prepared in Examples 1 to 4 and Comparative Example 1. Figure 1 is the efficiency diagram of the perovskite solar cell devices prepared in Examples 1 to 4 and Comparative Example 1. Figure 2 is the J-V curve diagram of the perovskite solar cells prepared in Example 2 and Comparative Example 1.

[0070] Table 1

[0071]

[0072] From Table 1 and Figures 1 to 2 it can be seen that under the condition that the concentration of betahistine mesylate solution is 1 - 2.5 mg / ml, the PCE, V OC , J SC of the perovskite solar cells prepared are all significantly better than those of Comparative Example 1, indicating that the betahistine mesylate molecules under the defined dosage of the present invention can interact with the surface of the charge transport layer, thereby improving the interface contact, reducing the energy barrier at the interface, promoting the extraction and transport of charges, reducing the interface recombination, passivating the surface defects of the perovskite, achieving the effect of reducing the non-radiative recombination centers, increasing the open-circuit voltage and the photoelectric conversion efficiency, and can also adjust the energy level arrangement at the interface, optimize the energy level matching between the charge transport layer and the perovskite layer, improve the charge extraction efficiency, and improve the fill factor (FF). However, if the concentration of the betahistine mesylate molecules exceeds the range defined by the present invention, as shown in Example 4, it will lead to interface deterioration, produce negative effects, and affect the battery performance.

[0073] Figure 3 is the dark current of the perovskite solar cell devices prepared in Example 2 and Comparative Example 1. It can be seen that the lowest value of Example 2 is lower, indicating that the leakage current is lower and the device performance is better.

[0074] Figure 4 is the steady-state power output diagram of the perovskite solar cell devices prepared in Example 2 and Comparative Example 1 in a glove box under a normal-temperature pure nitrogen atmosphere. It can be seen that at 600 s of testing, the device of Example 2 can still maintain high stability, while the device prepared in Comparative Example 1 has poor stability.

[0075] Effect Example 2: Characterization of Film Surface Properties

[0076] Figure 5 XRD patterns of the perovskite light-absorbing layers prepared in Example 2 and Comparative Example 1. It can be seen that the peak intensity of 001 of the perovskite light-absorbing layer in Example 2 is significantly enhanced, indicating that betahistine mesylate molecules enhance the film crystallinity. This molecule delays the crystallization rate and improves the overall crystallinity of the film.

[0077] Figure 6 Field emission scanning electron microscope images of the perovskite light-absorbing layers prepared in Example 2 (right figure) and Comparative Example 1 (left figure). It can be seen that the addition of betahistine mesylate molecules in Example 2 inhibits the precipitation of lead iodide and makes the grains more uniform. This result is also the same as that of the XRD test.

[0078] The above are only the preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention. The protection scope of the present invention should be subject to the scope defined by the claims. For those of ordinary skill in the art, without departing from the spirit and scope of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a perovskite solar cell, characterized in that, It includes preparing an interfacial modification layer between a hole transport layer and a perovskite light-absorbing layer, and the material of the interfacial modification layer is prepared from a betahistine mesylate solution with a concentration of 1 to 2.5 mg / ml.

2. The preparation method according to claim 1, wherein The preparation of the interfacial modification layer includes spin-coating a solution containing betahistine mesylate on the hole transport layer and then annealing.

3. The preparation method according to claim 1 or 2, characterized in that, The material of the hole transport layer is selected from any one or more of Meo-2PACz, Meo-4PACz, and NiO.

4. The preparation method according to claim 1 or 2, characterized in that, The material of the perovskite light-absorbing layer adopts a material with a structure of ABX3, where A is a monovalent cation, including but not limited to rubidium (Rb). + , cesium (Cs). + , formamidinium (HN=CHNH3) + (FA), methylammonium (CH3NH3) + (MA), or a combination thereof; B is a divalent cation, including but not limited to tin (Sn). 2+ , lead (Pb). 2+ , or a combination thereof; X is a monovalent anion, including but not limited to chlorine (Cl). - , bromine (Br). - , iodine (I). - , or a combination thereof.

5. The preparation method according to claim 1 or 2, characterized in that, The preparation method further includes preparing an electron transport layer and a metal electrode.

6. The preparation method according to claim 1 or 2, characterized in that, The material of the electron transport layer is selected from any one or more of PCBM, BCP, and SnO2.

7. The preparation method according to claim 1 or 2, characterized in that, The material of the metal electrode is selected from any one or several of gold, silver, and copper.

8. The preparation method according to claim 1 or 2, characterized in that, The preparation method further includes preparing a wetting layer between the interfacial modification layer and the perovskite light-absorbing layer.

9. The preparation method according to claim 8, characterized in that, The material of the wetting layer is alumina.

10. A reverse perovskite solar cell prepared by the preparation method according to any one of claims 1 to 9.

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