High-performance wide-band-gap perovskite solar cell and preparation method thereof

Abstract

The invention discloses a high-performance wide-band-gap perovskite solar cell and a preparation method thereof, and the perovskite solar cell sequentially comprises an ITO conductive glass layer, a 2-(3, 6-dimethoxy-9H-carbazole-9-yl) ethyl] phosphonic acid hole transport layer, a perovskite layer formed by doping 3, 3 '-diethyl oxacarbonyl cyanine iodine and Cs0.05 (FA 0.77 MA0.23) 0.95 Pb (I0.77 Br0.23) 3, and a [6, 6-dimethoxy-9H-carbazole-9-yl) ethyl] phosphonic acid hole transport layer from top to bottom. The thin film solar cell is characterized by comprising an electron transport layer, a 2, 9-dimethyl-4, 7-biphenyl-1, 10-phenanthrene hole barrier layer and a metal Ag electrode layer, and the metal Ag electrode layer is arranged between the electron transport layer and the 2, 9-dimethyl-4, 7-biphenyl-1, 10-phenanthrene hole barrier layer. According to the scheme, a component regulation and control strategy is adopted, 3, 3 '-diethyloxacarbonyl cyanine iodine (DiOC2 (3)) is used as an additive to be doped with a perovskite precursor in an equal proportion, polyfunctional groups (C = N, C = C, C-O-C and C-N) are introduced to act synergistically with perovskite at symmetric sites and coordinate with free Pb < 2 + >, Pb vacancy defects are passivated, non-radiative recombination is effectively inhibited, open-circuit voltage loss is reduced, and the performance of the perovskite solar cell is improved. The high-efficiency and high-stability wide-band-gap perovskite solar cell is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a high-performance wide-bandgap perovskite solar cell and a preparation method thereof. Background Art

[0002] In recent years, due to the development of secondary energy, there is currently a shortage of energy, so people have turned their attention to the development of new energy. As one of the new energy sources, solar energy has attracted much attention. Among them, photovoltaic power generation technology has attracted research from academia and industry. Silicon-based solar cells have been industrialized and the technology is very mature, but their production process will cause environmental pollution, which limits their widespread application. Therefore, studying new types of solar cells is an effective way to solve this problem. However, among the many new types of solar cells, a solar cell based on a perovskite structure (ABX3) has attracted worldwide attention.

[0003] As a new type of photovoltaic cell, perovskite cells have the characteristics of high conversion efficiency, low cost, adjustable optical properties, compatibility, etc. In just over a decade, their conversion efficiency has gradually reached the same level as crystalline silicon solar cells. Compared with other solar cells, the preparation process of perovskite solar cells is simple and the pollution is the lowest, so it is very likely to replace the position of crystalline silicon solar cells and achieve industrialization; however, perovskite has not reached the required standards for industrialization, which is related to the high-density defects generated in its film, which greatly affects its stability. Compared with the 25-year life of crystalline silicon solar cells, it seems a bit small. Based on this, it is urgent to develop a high-performance and high-stability perovskite solar cell. There is a density of trap states inside and on the surface of perovskite, and the density is particularly high inside. This is mainly because the perovskite film is a polycrystalline film with a large number of grain boundaries. The existence of these grain boundaries will hinder the transmission of carriers, thereby generating recombination centers and increasing the density of defect states. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a high-performance wide bandgap perovskite solar cell and a preparation method thereof, wherein a 3,3′-diethyloxacarbocyanine iodoacetonitrile solution having multiple functional groups is doped into Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 perovskite layer in perovskite solar cells, which has the advantages of passivating defects, inhibiting non-radiative recombination, reducing open circuit voltage loss, and improving performance and stability.

[0005] In order to achieve the above technical effects, the present invention is implemented by the following technical solutions: a high-performance wide bandgap perovskite solar cell, characterized in that the high-performance single-junction perovskite solar cell used comprises, from bottom to top, an ITO conductive glass layer, a 2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid hole transport layer (MeO-2PACz), a 3,3′-diethyloxacarbocyanine iodide and Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 doped perovskite layer, [6,6]-phenyl-C61-butyric acid isomethyl ester electron transport layer (PCBM), 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline hole blocking layer (BCP) and metal Ag electrode layer.

[0006] Furthermore, the 3,3′-diethyloxacarbocyanine iodide and Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 The preparation process of the perovskite layer formed by doping is as follows:

[0007] (1) Weigh CsI, FAI, MABr, PbI2 and PbBr2 in a mass ratio of 18.88-19.96:187.69-189.11:35.70-37.45:531.47-533.54:128.15-129.89 = CsI:FAI:MABr:PbI2:PbBr2;

[0008] (2) Add the weighed CsI, FAI, MABr, PbI2 and PbBr2 to the sample bottle in sequence, then add 800 μl of N,N-dimethylformamide solution and 200 μl of dimethyl sulfoxide solution to the sample bottle in sequence, place it on a magnetic stirrer at 60°C and 500 rpm for one hour to form a 1.5 M mixed solution;

[0009] (3) Filter the mixed solution through a 0.22 μm organic filter membrane into a sample bottle, and then add 3,3′-diethyloxacarbocyanine iodine acetonitrile solution to the mixed solution at a volume ratio of mixed solution: 3,3′-diethyloxacarbocyanine iodine acetonitrile solution = 60 to 120:1 to obtain 3,3′-diethyloxacarbocyanine iodine and Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I0.77 Br 0.23 )3 doped perovskite layer.

[0010] Furthermore, the concentration of the 3,3′-diethyloxacarbocyanine iodoacetonitrile solution is 1 mg / ml.

[0011] Another object of the present invention is to provide a method for preparing a high-performance wide bandgap perovskite solar cell, comprising the following steps:

[0012] S1. Cleaning the glass sheet: during the cleaning process, detergent, isopropyl alcohol, anhydrous ethanol and deionized water are added in sequence and ultrasonically cleaned for 15 to 20 minutes each, and then placed in a drying oven for drying;

[0013] S2, respectively, take 1.0 mg / ml of 2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACZ), 20 mg / ml of [6,6]-phenyl-C61-butyric acid isomethyl ester (PCBM), and 1 mg / ml of 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP), and take 1 mg / ml of 3,3′-diethyloxacarbocyanine iodide and Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 doped perovskite layer (Perovskite: DiOC2(3)) solution is ready for use;

[0014] S3, placing the dried glass slide into a UV ozone analyzer for 20 minutes;

[0015] S4, statically spin-coat 40-50 μl MeO-2PACz (1.0 mg / ml) solution on ITO at 5000-6000 rpm for 30 s, and anneal on a heating table at 100°C for 10 min after spin coating;

[0016] S5, dynamically suspend 50-60 μl of 3,3′-diethyloxacarbocyanine iodoacetonitrile solution doped perovskite precursor solution on the upper layer of MeO-2PACz, using a two-step anti-solvent method, the first step is to statically spin-coat the perovskite precursor solution at a speed of 1100-2000 rpm, a spin-coating time of 2s, and an acceleration of 2000-3000 rpm / s; the second step is to dynamically drop 150-200 μl of chlorobenzene at a speed of 6000-7000 rpm, a spin-coating time of 35s, an acceleration of 3000-4000 rpm / s when the countdown is 10s, and after the spin coating is completed, place it on a heating table and anneal at 100°C for 30 minutes;

[0017] S6, dynamically apply 40-50 μl PCBM and 7-9 μl BCP solution in sequence, with the two being rotated at 1500-2000 rpm for 50 s and 6000-7000 rpm for 25 s respectively, and then let it stand after the suspension application;

[0018] S7, scrape off part of the active layer with tweezers to expose the electrode, and then coat it in the vacuum coating machine of silver (Ag) electrode.

[0019] The beneficial effects of the present invention are:

[0020] In the present invention, a component control strategy is adopted, 3,3′-diethyloxacarbocyanine iodoacetonitrile solution is introduced into the perovskite precursor, and the energy level arrangement of the perovskite is changed by using multiple functional groups to act at symmetric sites, which is beneficial to the extraction and transmission of carriers.

[0021] In the present invention, under the action of 3,3′-diethyloxacarbocyanine iodine organic matter, the crystal growth of perovskite is delayed, the grain size of perovskite is increased, and the perovskite grows uniformly downward in the vertical direction, thereby reducing the open circuit voltage loss and the defect density;

[0022] In the present invention, the ether bond group in the 3,3′-diethyloxacarbocyanine iodine organic compound is extremely hydrophobic. Due to the difference in electronegativity between the carbon atom and the oxygen atom in the ether bond, the presence of the carbon chain makes the ether molecule as a whole extremely hydrophobic, thereby improving the stability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0024] Figure 1 It is the forward scanning and reverse scanning JV curve diagram of Example 2;

[0025] Figure 2 The JV curves of different volume ratios of Example 1 and Example 2 of the present invention;

[0026] Figure 3 The EIS electrochemical impedance spectra of Example 1 and Example 2 of the present invention are shown;

[0027] Figure 4 FTIR images of Example 1 and Example 2 of the present invention;

[0028] Figure 5 The SEM surface images of Example 1 and Example 2 of the present invention;

[0029] Figure 6 The SEM cross-sectional views of Example 1 and Example 2 of the present invention;

[0030] Figure 7 UPS diagrams of Embodiment 1 and Embodiment 2 of the present invention;

[0031] Figure 8 SCLC diagrams (defect state density diagrams) of Examples 1 and 2 of the present invention;

[0032] Fig. 9 It is the humidity stability curve diagram of Example 1 and Example 2 of the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] A high-performance wide-bandgap perovskite solar cell structure from bottom to top: ITO / MeO-2PACz / Perovskite / PCBM / BCP / Ag

[0036] The preparation method is as follows:

[0037] S1. Clean the glass sheet. During the cleaning process, detergent, isopropanol, anhydrous ethanol and deionized water are added in sequence and ultrasonically cleaned for 15 minutes each, and then placed in a drying oven for drying;

[0038] S2, respectively, take 1.0 mg / ml of 2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACZ), 20 mg / ml of [6,6]-phenyl-C61-butyric acid isomethyl ester (PCBM), and 1 mg / ml of 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP), and the prepared Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 Perovskite solution is ready for use;

[0039] The above-mentioned method of stirring evenly and then standing still is specifically configured as follows:

[0040] Take a certain amount of MeO-2PACz powder, put it into a sample bottle, add ethanol solution, and prepare it to a concentration of 1.0 mg / ml; take a certain amount of PCBM powder, put it into a sample bottle, add chlorobenzene solution, and prepare it to a concentration of 20 mg / ml; take a certain amount of BCP powder, put it into a sample bottle, add ethanol solution, and prepare it to a concentration of 1.0 mg / ml; heat and stir at 60°C until completely dissolved.

[0041] S3, placing the dried glass slide in a UV ozone apparatus for 20 minutes;

[0042] S4: 40-50 μl MeO-2PACz (1.0 mg / ml) solution was statically spin-coated on ITO at 5000-6000 rpm for 30 s. After the spin coating was completed, the surface was placed on a heating table for annealing at 100°C for 10 min.

[0043] S5. Dynamically suspend 50-60μ of perovskite precursor solution on the upper layer of MeO-2PACz, using a two-step anti-solvent method. In the first step, the perovskite precursor solution is statically spin-coated at a speed of 1100-2000rpm, a spin-coating time of 2s, and an acceleration of 2000-3000rpm / s; in the second step, 150-200μl of chlorobenzene is dynamically added at a speed of 6000-7000rpm, a spin-coating time of 35s, an acceleration of 3000-4000rpm / s, and a countdown of 10s. After the spin coating is completed, anneal on a heating table at 100℃ for 30min;

[0044] S6, dynamically apply 40-50 μl PCBM and 7-9 μl BCP solution in sequence, with the two being rotated at 1500-2000 rpm for 50 s and 6000-7000 rpm for 25 s respectively, and then let it stand after the suspension application;

[0045] S7, scrape off part of the active layer with tweezers to expose the electrode, and then coat it in the vacuum coating machine of silver (Ag) electrode.

[0046] Example 2

[0047] A high-performance single-junction perovskite solar cell structure from bottom to top: ITO / MeO-2PACz / Perovskite:DiOC2(3) / PCBM / BCP / Ag

[0048] The preparation method is as follows:

[0049] S1. Clean the glass sheet. During the cleaning process, detergent, isopropanol, anhydrous ethanol and deionized water are added in sequence and ultrasonically cleaned for 15 minutes each, and then placed in a drying oven for drying;

[0050] Take 1.0 mg / ml of 2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACZ), 20 mg / ml of [6,6]-phenyl-C61-butyric acid isomethyl ester (PCBM) and 1 mg / ml of 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP), and take 1 mg / ml of 3,3′-diethyloxacarbocyanine iodide and Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 doped perovskite layer (Perovskite: DiOC2(3)) solution is ready for use;

[0051] S3, placing the dried glass slide in a UV ozone analyzer for 20 minutes;

[0052] S4, statically spin-coat 40-50 μl MeO-2PACz (1.0 mg / ml) solution on ITO at 5000-6000 rpm for 30 s, and anneal on a heating table at 100°C for 10 min after spin coating;

[0053] S5, dynamically suspend 50-60 μl of 3,3′-diethyloxacarbocyanine iodoacetonitrile solution doped perovskite precursor solution on the upper layer of MeO-2PACz, using a two-step anti-solvent method, the first step is to statically spin-coat the perovskite precursor solution at a speed of 1100-2000 rpm, a spin-coating time of 2s, and an acceleration of 2000-3000 rpm / s; the second step is to dynamically drop 150-200 μl of chlorobenzene at a speed of 6000-7000 rpm, a spin-coating time of 35s, an acceleration of 3000-4000 rpm / s when the countdown is 10s, and after the spin coating is completed, place it on a heating table and anneal at 100°C for 30 minutes;

[0054] S7, dynamically apply 40-50 μl PCBM and 7-9 μl BCP solution in sequence, with the two being rotated at 1500-2000 rpm for 50 s and 6000-7000 rpm for 25 s respectively, and then let it stand after the suspension application;

[0055] S8, scrape off part of the active layer with tweezers to expose the electrode, and then coat it in the vacuum coating machine of silver (Ag) electrode.

[0056] Example 3

[0057] The high-efficiency ternary perovskite solar cells with different structures prepared in combination with Examples 1-2 were tested for their respective performances, as follows:

[0058] By attaching Figure 1 It can be seen that after the 3,3′-diethyloxacarbocyanine iodine component regulation strategy, the photoelectric conversion efficiency of the device is the highest when the volume ratio of the precursor solution to the perovskite is 60:1.

[0059] By attaching Figure 2 It can be seen that the photoelectric conversion efficiency of the perovskite device has been greatly improved by introducing 3,3′-diethyloxacarbocyanine iodide, from 18.31% to 21.9%, with significant effects. In addition, under the condition of forward and reverse scanning, the hysteresis factor It can be ignored. The smaller the HI factor is, the less affected by the hysteresis phenomenon is, which means that the number of defects is effectively reduced.

[0060] By attaching Figure 3 It can be seen that after the 3,3′-diethyloxacarbocyanine iodine component regulation strategy, R s Reduce, R rec The increase further indicates that non-radiative recombination is suppressed, which is beneficial to the transport of carriers.

[0061] By attaching Figure 4 It can be seen that the perovskite film after the 3,3′-diethyloxacarbocyanine iodine component regulation strategy is in the range of 2500-1600 cm -1 and 1250~1000cm -1 The stretching vibration peaks of C=N and CN groups appear at the positions of the 200 nm and 200 nm, respectively, which proves that DiOC2(3) can bind well to Pb 2+ It acts as a Lewis acid and Lewis base to effectively passivate Pb vacancies. -1 and 1100~1000cm -1 The C=C and COC stretching vibration peaks appear at , indicating that the C=C bond as the central site group and the COC bond as the symmetric site group effectively stabilize the perovskite lattice to form a low-defect, high-crystallinity perovskite film, which is beneficial to the transport of carriers.

[0062] By attaching Figure 5 and attached Figure 6 It can be seen that after the 3,3′-diethyloxacarbocyanine iodine component regulation strategy, the perovskite grain size becomes larger, the defects between the grain boundaries are reduced, the film quality is denser, and there is only one grain in the vertical direction. The resistance between the grain boundaries is reduced, which is conducive to improving the carrier extraction and transmission capabilities, thereby bringing less open circuit voltage loss and higher carrier mobility.

[0063] By attaching Figure 7 It can be seen that after the 3,3′-diethyloxacarbocyanine iodine component regulation strategy, WF It decreases from 4.22eV to 4.12eV, and the VBM is located at 1.30eV and 1.55e respectively. The energy level position moves up and is more closely matched with the energy levels of ETL and HTL. During the electron and hole transmission process, the potential barrier is lowered, thereby increasing the transmission rate, reducing non-radiative recombination, and reducing the defect state density.

[0064] By attaching Figure 8 It can be seen that after the 3,3′-diethyloxacarbocyanine iodine component regulation strategy, the electron and hole defect state densities have decreased, which can be obtained by the trap filling limit voltage. Less defect state density is conducive to carrier migration.

[0065] By attaching Fig. 9 It can be seen that after the 3,3′-diethyloxacarbocyanine iodine component regulation strategy, the hydrophobicity of the perovskite film is improved, and the unpackaged device can still maintain 95% of its initial PCE after storage in a N2 environment (25°C, 35% RH) for 500 hours. While inhibiting ion migration through multi-site synergistic effects, it can also interact strongly with the lattice and passivate grain boundary defects, thereby preventing water and oxygen from destroying the perovskite structure.

Claims

1. A high-performance wide-bandgap perovskite solar cell, characterized in that: The high-performance single-junction perovskite solar cell used includes, from bottom to top, an ITO conductive glass layer, a 2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid hole transport layer (MeO-2PACz), a 3,3′-diethyloxacarbocyanine iodide and Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 doped perovskite layer (Perovskite:DiOC2(3)), [6,6]-phenyl-C61-butyric acid isomethyl ester electron transport layer (PCBM), 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline hole blocking layer (BCP) and metal Ag electrode layer.

2. A high performance wide bandgap perovskite solar cell according to claim 1, characterized in that: The 3,3′-diethyloxacarbocyanine iodide and Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 The preparation process of the perovskite layer formed by doping is as follows: (1) Weigh CsI, FAI, MABr, PbI2 and PbBr2 in a mass ratio of 18.88-19.96:187.69-189.11:35.70-37.45:531.47-533.54:128.15-129.89 = CsI:FAI:MABr:PbI2:PbBr2; (2) Add the weighed CsI, FAI, MABr, PbI2 and PbBr2 into a sample bottle, then add 800 μl of N,N-dimethylformamide solution and 200 μl of dimethyl sulfoxide solution into the sample bottle in sequence, place it on a magnetic stirrer at 60°C and 500 rpm for one hour to form a 1.5 M mixed solution; (3) Filter the mixed solution through a 0.22 μm organic filter membrane into a sample bottle, and then add 3,3′-diethyloxacarbocyanine iodine acetonitrile solution to the mixed solution in a volume ratio of perovskite precursor solution: 3,3′-diethyloxacarbocyanine iodine acetonitrile solution = 60 to 120:1 to obtain 3,3′-diethyloxacarbocyanine iodine and Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 doping formed perovskite layer.

3. A high performance wide bandgap perovskite solar cell according to claim 2, characterized in that: The concentration of the 3,3′-diethyloxacarbocyanine iodoacetonitrile solution is 1 mg / ml.

4. A method for preparing a high-performance wide-bandgap perovskite solar cell, comprising the following steps: S1. Cleaning the glass sheet: during the cleaning process, detergent, isopropyl alcohol, anhydrous ethanol and deionized water are added in sequence and ultrasonically cleaned for 15 to 20 minutes each, and then placed in a drying oven for drying; S2, respectively, take 1.0 mg / ml of 2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACZ), 20 mg / ml of [6,6]-phenyl-C61-butyric acid isomethyl ester (PCBM), and 1 mg / ml of 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP), and take 1 mg / ml of 3,3′-diethyloxacarbocyanine iodide and Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 doped perovskite layer (Perovskite: DiOC2(3)) solution is ready for use; S3, placing the dried glass slide into a UV ozone analyzer for 20 minutes; S4, statically spin-coat 40-50 μl MeO-2PACz (1.0 mg / ml) solution on ITO at 5000-6000 rpm for 30 s, and anneal on a heating table at 100°C for 10 min after spin coating; S5, dynamically suspend 50-60 μl of 3,3′-diethyloxacarbocyanine iodoacetonitrile solution doped perovskite precursor solution on the upper layer of MeO-2PACz, using a two-step anti-solvent method, the first step is to statically spin-coat the perovskite precursor solution at a speed of 1100-2000 rpm, a spin-coating time of 2s, and an acceleration of 2000-3000 rpm / s; the second step is to dynamically drop 150-200 μl of chlorobenzene at a speed of 6000-7000 rpm, a spin-coating time of 35s, an acceleration of 3000-4000 rpm / s when the countdown is 10s, and after the spin coating is completed, place it on a heating table and anneal at 100°C for 30 minutes; S6, dynamically apply 40-50 μl PCBM and 7-9 μl BCP solution in sequence, with the two being rotated at 1500-2000 rpm for 50 s and 6000-7000 rpm for 25 s respectively, and then let it stand after the suspension application; S7, scrape off part of the active layer with tweezers to expose the electrode, and then coat it in the vacuum coating machine of silver (Ag) electrode.

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