CN113549169B - Phenylfluorenamine polymer hole transport material and preparation method and application thereof - Google Patents

Abstract

A phenylfluorenamine polymer hole transport material, its preparation method and application are disclosed. N-methoxyphenyl-dimethylfluorenamine groups are introduced into a polyvinyl carbazole (PVK) side chain, so that the phenylfluorenamine functionalized PVK polymer hole transport material is designed and synthesized. The polymer hole transport material has low synthesis cost, good solubility, good film forming property, high hole mobility and energy level matched with perovskite, and is applied to trans-form quasi-two-dimensional perovskite solar cells as an undoped polymer hole transport material to obtain high power conversion efficiency.

Description

A kind of phenylfluorenamine polymer hole transport material and its preparation method and application

technical field

The invention belongs to the field of novel hole transport materials for perovskite solar cells, and in particular relates to the structure and synthesis of a phenylfluorenamine-based polymer hole transport material and its application in trans-type perovskite solar cells.

Background technique

Perovskite solar cells (PSCs), which use organic-inorganic hybrid metal halides with a perovskite crystal structure as the light-absorbing layer, have attracted much attention since 2009 due to their simple preparation methods, low production costs, and excellent optoelectronic properties. , the power conversion efficiency (PCE) rapidly increased from 3.8% to 25.5%, becoming the world's most watched and fastest-growing third-generation emerging photovoltaic technology. The main structure of PSCs can be divided into conventional (nip) and trans (pin) types. Conventional nip-type PSCs usually use n-type mesoporous _TiO2 as the electron transport material, which requires high-temperature heat treatment; and by reducing the thickness of the mesoporous layer, the hysteresis of the device is more serious, these shortcomings increase the fabrication cost of conventional structure PSCs and The reliability of its device performance is limited. Compared with conventional PSCs, trans-PSCs have the opposite device structure and charge transport direction, because of their better device stability, smaller hysteresis effect, low-temperature fabrication, suitable for flexible substrates, and compatibility with silicon or copper (In , Ga)Se ₂ photovoltaic technology integration and other advantages will show advantages in the development of commercial large-area PSCs in the future. At present, the efficiency of small-area trans-PSCs reaches the certified value of 22.75%, the efficiency of micro-modules exceeds 18%, and the aperture area is 19.276cm ² .

Hole transport materials (HTMs) as an important interfacial layer between perovskite crystals and electrodes are very important for both conventional and trans-PSCs. The recombination and other aspects of the electrons play a very important role, which can effectively improve the performance of the device. However, for many reported HTMs, a chemical doping process is usually required to enhance the hole mobility/conductivity, which not only increases the overall cost of the device but also compromises the long-term stability of the device. Therefore, in recent years, the development of low-cost HTMs without doping any additives has become one of the major demands for large-area commercial applications of conventional and trans-PSCs. Among them, polymer-free HTMs have the advantages of high heat resistance, strong hydrophobicity, strong film processing ability, compatibility with web printing technology, and good device efficiency and stability in different types of device structures. And received much attention. PEDOT:PSS and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine](PTAA), two polymer classes, are still the most commonly used HTMs in trans-PSCs with the highest efficiency so far The trans-PSCs were also prepared based on PTAA. However, the stability issues caused by the acidity and hygroscopicity of PEDOT:PSS and the high cost of PTAA (1980 USD/g) also greatly hinder the development of large-area trans-PSCs. Compared with traditional conventional devices, the research on the application of polymer undoped HTMs in trans-PSCs is less, and its device performance is still not comparable to that of doped PTAA devices, and the interfacial relationship between polymer HTMs and perovskite layers is also limited. Not systematic enough. Therefore, it is still necessary to further develop new strategies and design novel dopant-free polymer HTMs to achieve low-cost, high-performance, stable, and large-area trans-PSCs applications.

The strategy of combining non-conjugated polyethylene backbone with side chains of hole-transporting groups of different structures has advantages in the construction of new non-conjugated side-chain polymer dopant-free HTMs, and the prepared polymer HTMs have low synthetic cost. , strong film processing ability, good wettability, and transparent windows in the visible region, etc., can achieve better device performance in both conventional and trans-PSCs. Phenylfluorenamine groups have good mobility and can adjust the energy level of molecules, etc., and are used to construct high-performance small-molecule HTMs materials for conventional structure PSCs. At present, polymer HTMs based on phenylfluorenamines have not been reported. In this paper, a N-methoxyphenyl-dimethylfluorenamine group was designed and synthesized by introducing N-methoxyphenyl-dimethylfluorenamine groups into the side chain of polyvinylcarbazole (PVK). Phenylfluorenamine-based non-conjugated side-chain polymer hole-transport materials, and applied to trans-PSCs.

Contents of the invention

The technical problem to be solved by the present invention is: to provide a kind of phenyl fluorene amine polymer hole transport material and its preparation method, which can be applied to novel non-doped polymer HTMs to achieve low cost, high performance, stability, Large-area trans-PSCs applications.

In order to solve the above technical problems, the technical solution provided by the present invention is: the structural formula of the provided phenylfluorene amine polymer hole transport material is as follows:

Where n is any number from 1 to 1000.

The preparation method of the phenylfluorene amine polymer hole transport material, its synthetic route is as follows:

The specific steps are:

(1) Synthesis of intermediate Ⅰ and intermediate Ⅰ': raw material Ⅰ (or raw material Ⅰ'), raw material Ⅱ, sodium tert-butoxide, palladium acetate and tri-tert-butylphosphine solution in toluene solution, 65 ~ 85 ℃ for 3 to 6 hours and then cooled to room temperature. Use saturated sodium chloride solution and dichloromethane to extract, dry over anhydrous magnesium sulfate, filter, vacuum distillation, and obtain intermediate I and intermediate I' of light yellow powder through column chromatography purification;

(2) Synthesis of Intermediate II and Intermediate II': Dissolve Intermediate I (or Intermediate I'), potassium hydroxide and p-diphenol in toluene:isopropanol (1:(6~10)) and mix In the solution, react at 65-85°C until intermediate I (or intermediate I') is completely converted into intermediate II and intermediate II' (6-15 hours). Cool to room temperature, spin dry the mixed solution of isopropanol and toluene under reduced pressure, wash and extract with saturated sodium chloride solution and dichloromethane, dry over anhydrous magnesium sulfate, filter, and distill under reduced pressure to obtain a crude product. Recrystallize with ethanol (methanol)/dichloromethane to obtain intermediate II and intermediate II' of light yellow powder;

(3) Synthesis of PVCz-DFMeNPh and PVCz-FMeNPh: Under anhydrous and anaerobic conditions, intermediate II (or intermediate II') and azobisisobutyronitrile (recrystallized from ethanol) in toluene (or tetrahydrofuran, N -methylpyrrolidone), after 2-3 hours of initiation at 60-65°C, react at 80-85°C for 3-5 days. After the reaction, cool to room temperature, use methanol to crystallize, filter and dry with suction, and use acetone to extract for three days to obtain yellow PVCz-DFMeNPh and PVCz-FMeNPh.

In addition, the present invention also provides the application of the phenylfluorene amine polymer material in the hole transport material, especially the application of preparing it as a hole transport layer to the trans quasi-two-dimensional perovskite solar cell. For example, the device structure of the trans quasi-two-dimensional perovskite solar cell is ITO glass/hole transport layer/quasi-two-dimensional perovskite/electron transport layer (PC61BM)/chromium (Cr)/gold (Au), wherein The hole transport layer is made of the phenylfluorenamine polymer hole transport material provided by the invention.

The preparation method of the trans quasi-two-dimensional perovskite solar cell based on the phenylfluorene amine polymer hole transport material comprises the following steps:

(1) Cleaning: Use acetone, deionized water and ethanol to ultrasonically clean the ITO glass substrate in sequence for 10-20 minutes, then use an _N2 air gun to dry the residual solvent on the ITO surface, and then perform oxygen plasma treatment for 10-15 minutes. The ITO glass substrate is then transferred to a nitrogen glove box;

(2) Preparation of the hole transport layer: Weigh 2 to 15 mg of the phenylfluorene amine polymer hole transport material described in claim 1 and completely dissolve it in 1 mL of chlorobenzene solution, and add an appropriate amount of the solution evenly dropwise On the ITO glass substrate, spin-coat at 3000-5000rpm for 10-20 seconds, then anneal at 90-110°C for 10-15 minutes;

(3) Preparation of perovskite layer: Cool the substrate of the ITO/hole transport layer obtained above to room temperature, preheat it at 120-140°C for 3-5 minutes, and take 50 μl of perovskite solution to cover the ITO/hole transport layer The substrate is spin-coated at 3000-5000 rpm for 10-20 seconds, and then annealed at 90-100° C. for 10-15 minutes to prepare a perovskite layer. Among them, the perovskite solution is prepared as 3-bromo-benzyl ammonium iodide or 3-chlorobenzyl ammonium iodide, methyl ammonium chloride, and lead iodide are mixed in N,N'-dimethyl formazan according to a certain molar ratio. In amides;

(4) Preparation of electron transport layer: Cool the ITO/hole transport layer/perovskite substrate obtained above to room temperature, prepare PC61BM into a 20 mg/mL solution, and then take 30 μl of PC61BM solution to cover the ITO/hole Transport layer/perovskite substrate, spin coating at 800-1200rpm for 30-50 seconds;

(5) Electrode preparation: place the above substrate in a vacuum evaporation box, respectively vapor-deposit Cr (~6nm) and Au (~80nm) on the PC61BM layer to obtain the required trans quasi-two-dimensional Perovskite solar cells.

The phenylfluorene amine polymer hole transport material prepared by the present invention has the following advantages and beneficial effects:

(1) The phenylfluorene amine polymer hole-transporting material prepared by the present invention has a relatively high concentration in solvents such as dimethyl sulfoxide, N,N'-dimethylformamide, toluene, chlorobenzene, and methylene chloride. good solubility;

(2) The raw material cost of the phenylfluorene amine polymer hole transport material prepared by the present invention is low, the preparation process is simple, and it is suitable for industrial production;

(3) The phenylfluorenamine-based polymer hole transport material prepared by the present invention has a high decomposition temperature and good thermal stability. At the same time, the film-forming property is good, and it has good wettability with the perovskite precursor solvent, which is helpful for the crystallization and film-forming of perovskite;

(4) The mobility in the phenylfluorene amine polymer hole transport material prepared by the present invention is better, which is beneficial to the extraction and transmission of holes;

(5) The phenylfluorenamine-based polymer hole transport material prepared by the present invention has a deep HOMO energy level that matches the perovskite;

(6) The phenylfluorene amine polymer hole transport material prepared by the present invention can be used in trans quasi-two-dimensional perovskite solar cells without doping any additives, and the photoelectric conversion efficiency is 18.44%, which is better than the currently commonly used PTAA (the photoelectric conversion efficiency is 16.65% under the same conditions), and has repeatability, shows that the compound of the present invention has a good application prospect.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, explain the present invention together with the examples of the present invention, and do not constitute a limitation to the present invention.

Fig. 1 is the ultraviolet absorption spectrum and the fluorescence emission spectrum under the PVCz-FMeNPh or PVCz-DFMeNPh film state;

Fig. 2 is the thermal weight loss curve of PVCz-FMeNPh or PVCz-DFMeNPh;

Fig. 3 is the differential thermal curve of PVCz-FMeNPh or PVCz-DFMeNPh;

Fig. 4 is the ionization energy measurement curve of PVCz-FMeNPh, PVCz-DFMeNPh and PTAA;

Fig. 5 is the structure of the quasi-two-dimensional perovskite solar cell made of PVCz-FMeNPh, PVCz-DFMeNPh and PTAA;

Figure 6 is a graph showing the relationship between the current and voltage of a quasi-two-dimensional perovskite solar cell made of PVCz-FMeNPh, PVCz-DFMeNPh and PTAA;

Fig. 7 is a distribution diagram of photovoltaic parameters of quasi-two-dimensional perovskite solar cells made of PVCz-FMeNPh, PVCz-DFMeNPh and PTAA.

detailed description

The present invention will be further described below through specific examples, but the specific examples here are only used to explain the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the principles of the present invention shall be included in the present invention.

The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials and reagents used can be obtained from commercial sources unless otherwise specified.

The synthesis of embodiment 1PVCz-FMeNPh

The synthetic route is as follows:

(1) Synthesis of intermediate I': raw material I' (self-made, prepared by recrystallization after reacting 3-bromo-carbazole and 1,2-dichloroethane under the catalysis of potassium carbonate and potassium hydroxide for 6 hours ; 0.924g, 3mmol), raw material II (self-made, obtained by reacting 9,9-dimethyl-2-bromofluorene and 4-methoxyaniline under sodium tert-butoxide and palladium catalyst for 24 hours; 1.041g, 3.3 mmol), sodium tert-butoxide (0.24g, 2.5mmol), palladium acetate (21mg, 0.09mmol) and tri-tert-butylphosphine (18mg, 0.09mmol) were added in a 100ml flask, vacuumed and filled with nitrogen, and 60ml of toluene was added as a solvent , reacted at 85°C for 6 hours and then cooled to room temperature. It was extracted with saturated sodium chloride solution and dichloromethane, dried over anhydrous magnesium sulfate, filtered, distilled under reduced pressure, and purified by column chromatography to obtain intermediate I' (1.36 g, 83.5% yield) as a pale yellow powder. ¹ H NMR (400MHz, DMSO-d ₆ )δ8.05(d, J=7.7Hz, 1H), 7.96(d, J=2.1Hz, 1H), 7.67-7.61(m, 3H), 7.58(d, J＝8.3Hz,1H),7.45-7.42(m,2H),7.26-7.23(m,2H),7.21-7.13(m,2H),7.11(s,1H),7.09(s,1H),7.00 (d,J=2.2Hz,1H),6.92(d,J=9.1Hz,2H),6.75(d,J=8.3,2.2Hz,1H),4.76(t,J=6.0Hz,2H),4.06 (t, J=5.9Hz, 2H), 3.74(s, 3H), 1.30(s, 6H). ¹³ C NMR (101MHz, DMSO-d ₆ ) δ155.90, 155.01, 153.31, 149.35, 141.50, 141.21, 140.21, 139.23,137.69,131.35,127.49,126.77,126.51,126.45,125.55,123.79,123.05,122.47,121.26,121.02,119.62,119.49,119.10,118.38,115.41,114.05,111.27,110.24,55.72,46.77,44.76,43.69, 27.47.

(2) Synthesis of intermediate Ⅱ': Intermediate Ⅰ'(1.08g, 2mmol), potassium hydroxide (0.898g, 16mmol) and p-diphenol (22mg, 0.2mmol) were dissolved in toluene:isopropanol (1 : 8) In the mixed solution, react at 85°C until the intermediate I' is completely converted into intermediate II', and the reaction time is 10 hours. Cool to room temperature, spin dry the mixed solution of isopropanol and toluene under reduced pressure, wash and extract with saturated sodium chloride solution and dichloromethane, dry over anhydrous magnesium sulfate, filter, and distill under reduced pressure to obtain a crude product. Recrystallization from ethanol (methanol)/dichloromethane gave intermediate II' (860 mg, 84.9% yield) as a pale yellow powder. ¹ H NMR (400MHz, DMSO-d ₆ ) δ8.09(d, J=7.7Hz, 1H), 7.97(d, J=2.2Hz, 1H), 7.85(d, J=8.5, 4.4Hz, 2H) ,7.68-7.55(m,3H),7.51-7.43(m,2H),7.30-7.18(m,4H),7.14-7.09(m,2H),7.06(d,J＝2.0Hz,1H),6.96 -6.91(m,2H),6.81(d,J=8.3,2.0Hz,1H),5.60(d,J=15.9Hz,1H),5.11(d,J=9.1Hz,1H),3.76(s, 3H),1.32(s,6H) ^.13C NMR(101MHz,Chloroform-d)δ155.65,155.02,153.44,148.78,141.95,141.79,139.97,139.36,135.93,132.31,129.58,126.99,126.43,0 125.14, 124.81, 123.80, 122.47, 120.66, 120.50, 120.42, 119.18, 117.01, 115.65, 114.76, 111.45, 110.57, 101.58, 55.60, 46.85, 29.82, 27.24.

(3) Synthesis of PVCz-FMeNPh: under anhydrous and anaerobic conditions, intermediate II' (300mg) and azobisisobutyronitrile (recrystallized from ethanol; 3mg) with 1% monomer mass ratio were added to the solution toluene (or In tetrahydrofuran, N-methylpyrrolidone), freeze-dry in liquid nitrogen and vacuumize for 1 minute, then fill with nitrogen, repeat three times, and then seal. After initiation at 65°C for 2 hours, react at 85°C for three days. Cool to room temperature after the reaction, use methanol (ethanol)/dichloromethane to crystallize, filter and dry with suction, use acetone as solvent, extract with Soxhlet extractor for three days to obtain yellow PVCz-FMeNPh (180mg). The number average molecular weight Mn of the polymer PVCz-FMeNPh is 13437, the weight average molecular weight Mw is 17435, and the polydispersity index PDI is 1.30.

The synthesis of embodiment 2PVCz-DFMeNPh

The synthetic route is as follows:

(1) Synthesis of intermediate I: raw material I (self-made, produced by 3,6-dibromo-carbazole and 1,2-dichloroethane under the catalysis of potassium carbonate and potassium hydroxide for 6 hours and then recrystallized) 0.589g, 1.52mmol), starting material II (1.1g, 3.5mmol), sodium tert-butoxide (0.336g, 3.5mmol), palladium acetate (28mg, 0.12mmol) and tri-tert-butylphosphine (24mg, 0.12mmol ) into a 100ml flask, evacuated and filled with nitrogen, added 60ml of toluene as a solvent, reacted at 85°C for 6 hours and then cooled to room temperature. Extraction with saturated sodium chloride solution and dichloromethane, drying over anhydrous magnesium sulfate, filtration, vacuum distillation, and purification by column chromatography gave light yellow powder Intermediate I (1.12 g, 86.2% yield). ¹ H NMR (400MHz, DMSO-d ₆ ) δ7.89(d, J=2.1Hz, 2H), 7.68-7.52(m, 6H), 7.41(d, J=7.3Hz, 2H), 7.27-7.14( m,6H),7.09-7.04(m,4H),6.95(d,J=2.1Hz,2H),6.91-6.85(m,4H),6.70(d,J=8.3,2.1Hz,2H),4.75 (t, J=5.6Hz, 2H), 4.07(t, J=5.9Hz, 2H), 3.71(s, 6H), 1.26(s, 12H). ¹³ C NMR (101MHz, DMSO-d ₆ ) δ155. 89(s), 154.92(s), 153.26(s), 149.30(s), 141.39(s), 140.18(s), 139.23(s), 138.33(s), 131.22(s), 127.45(s), 126.83(s), 126.39(s), 125.82(s), 123.54(s), 122.99(s), 121.20(s), 119.44(s), 118.79(d, J=21.6Hz), 115.36(s), 113.85(s), 111.39(s), 55.67(s), 46.72(s), 31.51(s), 27.44(s), 22.61(s).

(2) Synthesis of intermediate Ⅱ: Dissolve intermediate Ⅰ (0.86g, 1mmol), potassium hydroxide (0.449g, 8mmol) and p-diphenol (11mg, 0.1mmol) in toluene:isopropanol (1:8 ) in the mixed solution, react at 85°C until all of the intermediate I is converted into intermediate II, and the reaction time is 10 hours. Cool to room temperature, spin dry the mixed solution of isopropanol and toluene under reduced pressure, wash and extract with saturated sodium chloride solution and dichloromethane, dry over anhydrous magnesium sulfate, filter, and distill under reduced pressure to obtain a crude product. Recrystallization from ethanol (methanol)/dichloromethane gave intermediate II (640 mg, 78.1% yield) as a pale yellow powder. ¹ H NMR (400MHz, DMSO-d ₆ )δ7.87(d, J=2.2Hz, 2H), 7.82(d, J=8.8Hz, 2H), 7.63-7.52(m, 5H), 7.41(d, J＝7.3Hz, 2H), 7.28-7.15(m, 6H), 7.09-7.04(m, 4H), 6.98(d, J＝2.1Hz, 2H), 6.91-6.86(m, 4H), 6.74(d ,J=8.3,2.1Hz,2H),5.56(d,J=15.9,0.9Hz,1H),5.08(d,J=9.4,0.8Hz,1H),3.70(s,6H),1.26(s, 12H). ¹³ C NMR(101MHz,Chloroform-d)δ155.61,154.96,153.41,141.90,139.33,136.48,132.26,126.95,126.24,126.02,125.14,124.85,122.43,120.46,119.16,117.32,115.55,114.76,111.48 ,55.56,46.81,29.82,27.22.

(3) Synthesis of PVCz-DFMeNPh: under anhydrous and oxygen-free conditions, add intermediate II (300 mg) and azobisisobutyronitrile (recrystallized from ethanol; 3 mg) with 1% monomer mass ratio to the solution toluene (or tetrahydrofuran , N-methylpyrrolidone), freeze-dried in liquid nitrogen and vacuumized for 1 minute, then filled with nitrogen, and sealed after repeating three times. After initiation at 65°C for 2 hours, react at 85°C for three days. After the reaction, cool to room temperature, use methanol (ethanol)/dichloromethane to crystallize, filter and dry with suction, use acetone as solvent, extract with Soxhlet extractor for three days to obtain yellow PVCz-DFMeNPh (160 mg). The number average molecular weight Mn of the polymer PVCz-DFMeNPh is 17787, the weight average molecular weight Mw is 24037, and the polydispersity index PDI is 1.35.

The absorption emission spectrum measurement of embodiment 3PVCz-FMeNPh and PVCz-DFMeNPh

The film samples of PVCz-FMeNPh and PVCz-DFMeNPh were prepared with a chlorobenzene solution with a solubility of 7mg/mL, and were spin-coated on a quartz plate by a spin coater. Using SHIMADZUUV-1750 spectrophotometer and Hitachi F-4600 fluorescence spectrometer to measure the absorption and emission spectra of PVCz-FMeNPh and PVCz-DFMeNPh films, the results are shown in Figure 1. In the film state, the absorption peaks of PVCz-FMeNPh are located at 317nm and 355nm, and the maximum emission peak is at 439nm; the absorption peaks of PVCz-DFMeNPh are at 319nm and 356nm, and the maximum emission peak is at 450nm.

The thermal stability test of embodiment 4PVCz-FMeNPh and PVCz-DFMeNPh

Thermogravimetric analysis (TGA): The decomposition temperatures of PVCz-FMeNPh and PVCz-DFMeNPh were measured using a METTLERTOLEDO TGA2 thermogravimeter. During the test, the nitrogen flow rate was set at 50cm ³ /min, as a purging and protection function, and the heating rate was set at 10°C/min. The sample needs to be dried in advance, and the mass is 3-5 mg. The test results are shown in Figure 2. Differential scanning calorimetry test (DSC): PVCz-FMeNPh and PVCz-DFMeNPh glass transition temperature analysis using Shimadzu DSC-60A differential calorimeter. During the test, nitrogen was used as purging and protection, and the flow rates were set to 40cm ³ /min and 60cm ³ /min respectively. The sample temperature is generally heated from 30°C to 350°C with a heating rate of 10°C/min and a cooling rate of 20°C/min. The sample needs to be dried in advance, and the mass is 3-5 mg. The test results are shown in Figure 3.

Through DSC and TGA tests, PVCz-FMeNPh and PVCz-DFMeNPh have no obvious glass transition peaks, and the 5% thermal weight loss temperatures are 415.53°C and 423.62°C.

The ionization energy measurement of embodiment 5PVCz-FMeNPh, PVCz-DFMeNPh and PTAA

Photoelectron spectroscopy (YPS): The ionization energies of PVCz-FMeNPh, PVCz-DFMeNPh and PTAA were tested using the IPS-4 ionization energy measurement system, and the test results are shown in Figure 4.

Through the YPS spectrum, it can be concluded that the HOMO energy level of PVCz-FMeNPh is -5.56eV, and the LUMO energy level is -2.67eV calculated by combining the absorption band edge; the HOMO energy level of PVCz-DFMeNPh is -5.39eV, calculated by combining the absorption band edge The LUMO energy level is -2.58eV; the HOMO energy level of PTAA is -5.24eV, and the LUMO energy level is calculated to be -2.29eV combined with the absorption band edge.

Example 6 PVCz-FMeNPh, PVCz-DFMeNPh and PTAA are used as hole transport layers in trans quasi-two-dimensional perovskite solar cells.

The PVCz-FMeNPh and PVCz-DFMeNPh polymer monomers prepared by the invention are very easy to dissolve in the perovskite precursor solvent, and are very easy to form a film with more holes during the preparation process of the trans device. The PVCz-FMeNPh and PVCz-DFMeNPh polymers have orthogonal solubility to the perovskite precursor solvent, which can not only have good wettability with the perovskite precursor solvent in the preparation of trans devices, but also maintain uniformity. Dense film morphology. PVCz-FMeNPh and PVCz-DFMeNPh as dopant-free non-conjugated polymer hole transport materials compared with commonly used PTAA in trans quasi-two-dimensional perovskite solar cells (1cm ² ), the device structure is ITO glass /hole transport layer/quasi two-dimensional perovskite layer/electron transport layer (PC61BM)/chromium (Cr)/gold (Au), the structure is shown in Figure 5.

Fabrication steps of trans quasi-two-dimensional perovskite solar cells:

Before this, the perovskite precursor solution needs to be prepared in advance. The specific process is as follows. Add 1mmol of 3-bromo-benzylamine into the reaction flask, add 20ml of absolute ethanol to dissolve it, and add 1mmol of 3-bromo-benzylamine dropwise while stirring. Hydroiodic acid, after reacting at 0°C for 2 hours, raise the temperature to 60°C to evaporate the solvent to obtain a solid, wash the solid with ether three times, and finally place it in a vacuum oven at 30°C for 12 hours. Mix the obtained 3-bromo-benzyl ammonium iodide, MAC1, and _PbI2 in N,N'-dimethylformamide in a molar ratio of 2.5:4.2:5.2, and stir at 60°C for 8 hours to obtain calcium Titanium precursor solution.

(1) Cleaning: First, use acetone, deionized water and ethanol to ultrasonically clean the ITO glass substrate for 15 minutes in sequence, then use an _N2 air gun to dry the residual solvent on the ITO surface, and then perform oxygen plasma treatment for 10 minutes, and then the ITO The glass substrate is transferred to a nitrogen glove box to keep its surface clean for further fabrication steps;

(2) Preparation of hole transport layer: Weigh 5 mg of PVCz-DFMeNPh (or PVCz-FMeNPh) synthesized in this thesis and dissolve it completely in 1 mL of chlorobenzene solution, and take 20 μl of PVCz-DFMeNPh (or PVCz-FMeNPh) solution , evenly dropped onto the ITO glass substrate, spin-coated at 5000rpm for 20 seconds, and then annealed at 100°C for 10 minutes.

(3) Preparation of the perovskite layer: Cool the ITO/hole transport layer substrate obtained above to room temperature, preheat it at 140° C. for 3 minutes, take 50 μl of the perovskite precursor solution and cover the ITO/hole transport layer substrate, Spin coating at 5000 rpm for 20 seconds, and then anneal at 90° C. for 15 minutes to prepare a perovskite layer.

(4) Preparation of electron transport layer: Cool the ITO/hole transport layer/quasi-two-dimensional perovskite layer substrate obtained above to room temperature, configure PC61BM into a 20 mg/mL solution, and then take 30 μl of PC61BM solution to cover the ITO /hole transport layer/substrate of quasi-two-dimensional perovskite layer, spin-coated at 1000rpm for 40 seconds.

(5) Preparation of electrodes: the above-mentioned substrates were installed in a mask plate, placed in a vacuum evaporation box, and chromium (~6nm) and gold (~80nm) were evaporated on the PC61BM layer respectively to obtain the quasi-two-dimensional perovskite solar cells.

Adjust the power of the solar simulator to 100mw/cm ² to simulate the AM1.5G radiation standard, and read the current and voltage values of the device through a computer connected to a Keithley2450 power meter. Before the measurement of the current density-voltage curve, the Newport standard silicon cell 91150 was used to calibrate the light intensity, and the device was in forward and reverse scan mode with a scan rate of 0.02V/s. The current density-voltage curve after the test is shown in FIG. 6 .

At present, the open circuit voltage of the reverse perovskite solar cell corresponding to the PTAA commonly used in the reverse device is 1.2V, the short circuit current is 17.04mA/cm ² , the fill factor is 79%, and the photoelectric conversion efficiency is 16.07% (reverse The scanned open-circuit voltage is 1.2V, the short-circuit current is 16.04mA/cm ² , the fill factor is 83%, and the photoelectric conversion efficiency is 16.65%).

The reverse perovskite solar cell device corresponding to PVCz-FMeNPh has an open circuit voltage of 1.20V in the forward scan, a short circuit current of 17.64mA/cm ² , a fill factor of 70%, and a photoelectric conversion efficiency of 14.79% (the open circuit voltage of the reverse scan is 1.20V, the short-circuit current is 17.29mA/cm ² , the fill factor is 77%, and the photoelectric conversion efficiency is 15.87%).

The reverse perovskite solar cell device corresponding to PVCz-DFMeNPh has an open-circuit voltage of 1.19V in forward scan, a short-circuit current of 18.98mA/cm ² , a fill factor of 81%, and a photoelectric conversion efficiency of 18.24% (open-circuit voltage of reverse scan is 1.17V, short-circuit current of 18.81mA/cm ² , fill factor of 84%, and photoelectric conversion efficiency of 18.44%), which are better than those of PTAA.

Under the same experimental conditions, the present invention collected the statistical data of the photovoltaic parameters of trans-Quasi-2D PSCs based on PVCz-FMeNPh, PVCz-DFMeNPh and PTAA respectively from one hundred devices, as shown in Figure 7, indicating that The trans-Quasi-2D PSCs device of the present invention has good reproducibility. The average PCEs of PVCz-FMeNPh, PVCz-DFMeNPh, and PTAA-based trans-Quasi-2D PSCs were 14.54%, 16.70%, and 15.19%, respectively.

The above is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes and replacements within the technical scope of the present invention. Or simple modifications should be covered within the protection scope of the present invention.

Claims (4)

1. The phenylfluorenamine polymer hole transport material is characterized in that the phenylfluorenamine polymer is a polymer molecule which takes polyvinyl as a main chain and phenylfluorenamine substituted carbazole as a side chain, and has the following chemical structural formula:

wherein n is any number from 26 to 1000.

2. The method for preparing a phenylfluorenamine polymer hole transport material according to claim 1, wherein the synthetic route is as follows:

the method comprises the following specific steps:

(1) Synthesis of intermediate i and intermediate i': reacting the raw material I or the raw material I 'with the raw material II, sodium tert-butoxide, palladium acetate and toluene solution of tri-tert-butylphosphine solution at 65-85 ℃ for 3-6 hours under the protection of nitrogen, cooling to room temperature, extracting with saturated sodium chloride solution and dichloromethane, drying with anhydrous magnesium sulfate, filtering, distilling under reduced pressure, and purifying by column chromatography to obtain an intermediate I or an intermediate I' which is light yellow powder;

(2) Synthesis of intermediate II and intermediate II': dissolving intermediate I or intermediate I', potassium hydroxide and p-diphenol in toluene: isopropanol mixed solution, wherein the ratio of toluene: the isopropanol is 1; reacting at 65-85 ℃ until the intermediate I or the intermediate I ' is completely converted into the intermediate II or the intermediate II ', wherein the reaction time is 6-15 hours, cooling to room temperature, performing rotary drying on the isopropanol and toluene mixed solution under reduced pressure, washing and extracting by using a saturated sodium chloride solution and dichloromethane, drying by using anhydrous magnesium sulfate, filtering, performing reduced pressure distillation to obtain a crude product, and performing recrystallization by using ethanol/dichloromethane or methanol/dichloromethane to obtain the intermediate II or the intermediate II ' which is light yellow powder;

(3) Synthesis of PVCz-DFMeNPh and PVCz-FMeNPh: under anhydrous and anaerobic conditions, placing azodiisobutyronitrile recrystallized from the intermediate II or the intermediate II' and ethanol in toluene or tetrahydrofuran or N-methylpyrrolidone solution, initiating at 60-65 ℃ for 2-3 hours, reacting at 80-85 ℃ for 3-5 days, cooling to room temperature after the reaction is finished, crystallizing by using methanol, carrying out suction filtration and drying, and extracting by using acetone for three days to obtain yellow PVCz-DFMeNPh and PVCz-FMeNPh.

3. The use of the phenylfluorenamine-based polymer hole transport material as claimed in claim 1, wherein the phenylfluorenamine-based polymer is used as an undoped hole transport material in a trans-perovskite solar cell.

4. A method of preparing a trans-perovskite solar cell using the phenylfluorenamine-based polymer material as an undoped hole transport material as claimed in claim 1, characterized by comprising the steps of:

(1) Cleaning: ultrasonically cleaning an ITO glass substrate for 10-20 minutes by adopting acetone, deionized water and ethanol in sequence, and then using N ₂ Blowing the residual solvent on the ITO surface by using an air gun, carrying out oxygen plasma treatment for 10-15 minutes, and then transferring the ITO glass substrate to a nitrogen glove box;

(2) Preparation of hole transport layer: weighing 2-15 mg of the phenylfluorene amine polymer hole transport material of claim 1, completely dissolving the material in 1mL of chlorobenzene solution, uniformly dropwise adding a proper amount of the solution onto an ITO glass substrate, spin-coating at 3000-5000 rpm for 10-20 seconds, and annealing at 90-110 ℃ for 10-15 minutes;

(3) Preparation of perovskite layer: cooling the ITO/hole transport layer substrate obtained in the step (2) to room temperature, preheating for 3-5 minutes at 120-140 ℃, taking 50 mu l of perovskite solution to be paved on the ITO/hole transport layer substrate, spin-coating for 10-20 seconds at 3000-5000 rpm, annealing for 10-15 minutes at 90-100 ℃ to prepare a perovskite layer, wherein the perovskite solution is prepared into one of 3-bromo-benzyl ammonium iodide or 3-chlorobenzyl ammonium iodide, and is mixed with methyl ammonium chloride and lead iodide in N, N' -dimethylformamide according to a certain molar ratio;

(4) Preparation of an electron transport layer: cooling the ITO/hole transport layer/perovskite substrate obtained in the step (3) to room temperature, preparing PC61BM into a solution of 20mg/mL, then taking 30 mu l of PC61BM solution to fully cover the ITO/hole transport layer/perovskite substrate, and spin-coating at 800-1200 rpm for 30-50 seconds;

(5) Preparing an electrode: and (3) placing the substrate obtained in the step (4) in a vacuum evaporation box, and respectively evaporating Cr and Au on the PC61BM layer, wherein the diameter of Cr particles is less than or equal to 6nm, and the diameter of Au particles is less than or equal to 80nm, and finally obtaining the required trans-perovskite solar cell.

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