Carbazole derivative, preparation method and application

Abstract

The invention discloses a carbazole derivative as well as a preparation method and application thereof, a pi conjugated system of carbazole is expanded by introducing a thiophene unit, and (4-(3, 6-di (thiophene-3-yl)-9H-carbazole-9-yl) butyl) phosphonic acid (4PAThCz) is designed. Compared with classical 2PACz, the 4PAThCz shows long-range orderliness and compact pi-pi accumulation, and the molecular dipole moment is enhanced. In addition, the distorted molecular structure of 4PAThCz is helpful to improve solubility and inhibit excessive self-aggregation. The characteristics facilitate hole extraction and transmission, inhibit carrier recombination in a photovoltaic device, and facilitate preparation of an efficient and stable solar cell.

Description

Technical Field

[0001] The present invention relates to the technical field of hole transport materials, and in particular to carbazole derivatives, preparation methods and applications. Background Art

[0002] Since their first application in 2018, self-assembled monolayers (SAMs) have attracted widespread attention due to their great potential as hole transport layers (HTLs) in perovskite and organic photovoltaic devices. SAMs are composed of anchoring groups, linking groups, and functional groups, and can be regarded as two-dimensional arrays composed of organic molecules with a thickness of a single molecule or a few molecules. Among them, the anchoring group has a strong affinity for metal oxides and can form a stable connection with the substrate through covalent bonds. The functional group determines the required electronic properties, while the spacer group acts as a bridge between the anchoring group and the functional group. Compared with traditional polymer and metal oxide HTLs, SAM HTLs have significant advantages, including lower parasitic absorption and extremely small electrical losses. In recent years, SAM HTLs have made important breakthroughs in the photovoltaic field, which has improved the photoelectric conversion efficiency (PCE) of organic solar cells (OSCs) and perovskite solar cells.

[0003] To optimize the target functionality of SAM HTLs, extensive research has been conducted on the design of functional group structures. Triphenylamine, thiophenazine, and carbazole are commonly used P-type functional groups in SAM HTLs, with carbazole-derived materials performing the best. The carbazole unit offers advantages such as excellent charge injection capability, superior thermal and photochemical stability, and low cost. Despite this, several drawbacks still limit the performance of SAMs, such as poor surface wettability, mismatched energy level alignment, and insufficient interfacial dipoles for hole extraction.

[0004] This work designs a novel SAM material, (4-(3,6-di(thiophen-3-yl)-9H-carbazol-9-yl)butyl)phosphonic acid (4PAThCz). Compared to the classic 2PACz, 4PAThCz exhibits long-range order and tight π-π stacking, enhancing the molecular dipole moment. Furthermore, the twisted molecular structure of 4PAThCz improves solubility and inhibits excessive self-aggregation. These properties facilitate hole extraction and transport, suppressing carrier recombination in photovoltaic devices, and ultimately enabling efficient and stable OSCs.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide carbazole derivatives, preparation methods and applications. The present application expands the π conjugated system of carbazole by introducing thiophene units, while maintaining long-range order and tight π-π stacking, enhancing the molecular dipole moment, improving solubility and inhibiting excessive self-aggregation, thereby facilitating hole extraction and transport, inhibiting carrier recombination in photovoltaic devices, and thus facilitating the realization of efficient and stable solar cells.

[0007] The present invention is achieved in that:

[0008] In a first aspect, the present invention provides a carbazole derivative named (4-(3,6-di(thiophen-3-yl)-9H-carbazole-9-yl)butyl)phosphonic acid, having a structure as shown in Formula I:

[0009]

[0010] In a second aspect, the present invention provides a method for preparing the carbazole derivatives described in the aforementioned embodiment, and the synthesis route is as follows:

[0011]

[0012] In a third aspect, the present invention provides a use of a carbazole derivative in a photoelectric functional device.

[0013] In a fourth aspect, the present invention provides an organic solar cell comprising a SAMs layer between an ITO layer and an active layer, wherein the SAMs layer comprises the carbazole derivative described in the aforementioned embodiment.

[0014] In a fifth aspect, the present invention provides a perovskite solar cell comprising a hole transport layer, wherein the hole transport layer comprises the carbazole derivative described in the aforementioned embodiment.

[0015] The present invention has the following beneficial effects:

[0016] This application introduces a thiophene unit to expand the π-conjugated system of carbazole and designs (4-(3,6-di(thiophene-3-yl)-9H-carbazole-9-yl)butyl)phosphonic acid (4PAThCz). Compared with the classic 2PACz, 4PAThCz exhibits long-range order and tight π-π stacking, which enhances the molecular dipole moment. In addition, the twisted molecular structure of 4PAThCz helps improve solubility and inhibit excessive self-aggregation. These properties are beneficial for hole extraction and transport, inhibit carrier recombination in photovoltaic devices, and are conducive to the preparation of efficient and stable solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 (a) 3,6-di(thiophen-3-yl)-9H-carbazole 1 H NMR and (b) 13 C NMR;

[0019] Figure 2 (a) 9-(4-bromobutyl)-3,6-di(thiophen-3-yl)-9H-carbazole 1 H NMR and (b) 13 C NMR;

[0020] Figure 3 (a) diethyl (4-(3,6-di(thien-3-yl)-9H-carbazol-9-yl)butyl)phosphonate 1 H NMR and (b) 13 C NMR;

[0021] Figure 4 (a) (4-(3,6-di(thiophen-3-yl)-9H-carbazol-9-yl)butyl)phosphonic acid (4PAThCz) 1 H NMR and (b) 13 C NMR;

[0022] Figure 5 (a) FT-IR spectra and (b) TGA curves of 2PACz and 4PAThCz;

[0023] Figure 6 Molecular structures, calculated ESP, dipole moments, HOMO, and LUMO orbital distributions of (a) 2PACz and (b) 4PAThCz;

[0024] Figure 7 (a) UPS spectra of ITO / 2PACz and ITO / 4PAThCz; (b) molar absorption coefficients of 2PACz and 4PAThCz; (c) In 3d XPS spectra of ITO, ITO / 2PAThCz and ITO / 4PAThCz; (d) C1s fitting XPS spectra of ITO / 2PAThCz and ITO / 4PAThCz; (e) S2p fitting XPS spectrum of ITO / 4PAThCz;

[0025] Figure 8The XPS full spectra and O1s fitting spectra of (a, d) ITO, (b, e) ITO / 2PACz, and (c, f) ITO / 4PAThCz are shown;

[0026] Figure 9 EDS images of (a) ITO, (b) ITO / 2PACz, and (c) ITO / 4PAThCz; distribution diagrams of C, N, and P elements of (d) ITO / 2PACz and (e) ITO / 4PAThCz;

[0027] Figure 10 (a) Water and (b) diiodomethane contact angles of ITO, ITO / 2PACz, and ITO / 4PAThCz;

[0028] Figure 11 (a) Energy level diagram of SAMs, active layer materials, electron transport materials, and electrodes; (b) current density-voltage (JV) curves of the best binary and ternary devices with 2PACz and 4PAThCz; (c) summary of reported high-performance OSCs using SAMs as HTL; (d) corresponding EQE spectra; (e) hole devices with SAMs as HTL; (f) TPV and (g) TPC curves of OSCs based on 2PACz and 4PAThCz; (h) photostability and (i) long-term storage stability of encapsulated devices with different SAMs;

[0029] Figure 12 Schematic diagram of the connection between (a) 2PACz, (c) 4PAThCz and ITO, simulated IRI isosurfaces of (b) 2PACz and (d) 4PAThCz; (e) molecular stacking patterns in 2PACz and (f) 4PAThCz single crystals;

[0030] Figure 13 (a) JV curves of the PM6:L8-BO binary device based on 2PACz and 4PAThCz; (b) JV curves of the large-area D18:L8-BO:BTP-eC9 ternary device based on 4PAThCz. The inset is a photograph of the large-area device.

[0031] Figure 14 AFM image of the active layer deposited on the SAM. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. Where specific conditions are not specified in the embodiments, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially. The amounts and ratios of the reagents involved, if not clearly stated, are all calculated by mass or mass ratio.

[0033] An embodiment of the present invention provides a carbazole derivative named (4-(3,6-di(thiophen-3-yl)-9H-carbazole-9-yl)butyl)phosphonic acid, and having a structure as shown in Formula I:

[0034]

[0035] The present invention also provides a method for preparing the carbazole derivatives described in the above embodiments. The synthesis path is as follows:

[0036]

[0037] An embodiment of the present invention further provides a use of a carbazole derivative in a photoelectric functional device.

[0038] In an optional embodiment, the optoelectronic functional device includes a solar cell.

[0039] In an optional embodiment, the solar cell is an organic solar cell.

[0040] In an optional embodiment, the solar cell is a perovskite solar cell.

[0041] An embodiment of the present invention further provides an organic solar cell, comprising a SAMs layer located between an ITO layer and an active layer, wherein the SAMs layer comprises the carbazole derivative described in the above embodiment.

[0042] In an optional embodiment, the method for preparing the SAMs layer includes: attaching a slurry containing the carbazole derivative on an ITO layer, and annealing the slurry to obtain the SAMs layer.

[0043] In an optional embodiment, the annealing temperature is 110-130° C., and the annealing time is 6-8 minutes.

[0044] An embodiment of the present invention further provides a perovskite solar cell, comprising a hole transport layer, wherein the hole transport layer comprises the carbazole derivative described in the above embodiment.

[0045] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0046] Description of main reagent parameters

[0047] The main drugs and reagents required for this application are shown in Table 1. All drugs were used directly after purchase without further purification.

[0048] Table 1 Main pharmaceutical reagents

[0049]

[0050]

[0051] Description of main characterization test methods

[0052] (1) Nuclear magnetic resonance (NMR): Chloroform-d or DMSO-d6 was used as solvent and TMS was used as internal standard. The data were collected on a JNM-ECZ-400S / L1 NMR spectrometer (JEOL, Japan). 1 HNMR and 13 CNMR spectra, scanned 32 times and 1024 times, respectively.

[0053] (2) Fourier transform infrared spectroscopy (FT-IR): The measurements were performed using a Nicolet iS50 FT-IR spectrometer (America) in the wavenumber range of 550–4000 cm-1.

[0054] (3) Ultraviolet-visible absorption spectrum (UV-vis): The UV-visible absorption spectrum of the solution was measured by UV-3600i Plus spectrophotometer, and the sample was dissolved in methanol.

[0055] (4) Energy dispersive X-ray spectroscopy (EDS) spectra: collected on a ZEISS Gemini SEM 300 scanning electron microscope.

[0056] (5) Ultraviolet photoelectron spectroscopy (UPS): A Thermo Fisher Scientific Nexsa instrument was used to analyze the energy level changes of different samples through HeI (21.22 eV) emission line excitation.

[0057] (6) X-ray photoelectron spectroscopy (XPS): measured on a Thermo Scientific K-Alpha instrument using an AlKα (hν = 1486.6 eV) X-ray source.

[0058] (7) Atomic force microscopy (AFM): acquired by Bruker Dimension ICON scanning probe microscope.

[0059] (8) Single crystal structure data: measured on a Bruker D8 VENTURE X-ray diffractometer using graphite monochromatized Mo Kα radiation

[0060] (9) Light stability test: LED solar simulator (Guang Zhou Crysco Equipment) was used with a light intensity of 100 mW cm -2 .

[0061] (10) Contact angle: The contact angle was measured using deionized water and diiodomethane droplets on an inverted fluorescence microscope (IX73+DP80, Japan).

[0062] (11) Thermogravimetric analysis (TGA): Thermogravimetric analysis (TG) was performed using a thermogravimetric analyzer (209F1 TG, Netzsch, Germany) under a nitrogen atmosphere from room temperature to 800 °C at a temperature increase rate of 10 °C min -1 .

[0063] (12) Current density-voltage curve (JV): The JV characteristic curve of OSCs was measured using Keithley 2400 in a glove box under nitrogen atmosphere. -2 Measured under standard sunlight (AM 1.5G).

[0064] (13) External quantum efficiency (EQE) curve: The EQE spectrum was measured using a solar cell spectral response measurement system (QE-R3011, Enlitech). The device area is 3.2 mm 2 .

[0065] Description of material simulation calculation method

[0066] The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were obtained using density functional theory (DFT) Gaussian functions, B3LYP exchange-correlation (xc) functionals, and the 6-31G* orbital basis set. All results for ITO were obtained using the DFT CP2K functional, with the spin-polarized PBE exchange-correlation functional using the DZVP basis set for valence electrons. Electrostatic terms were calculated using an auxiliary plane wave basis set with a cutoff of 350 Ry. Four molecules were placed on a 4-layer ITO substrate and the system was relaxed with an energy convergence criterion of 1 × 10 -6 eV. Considering the van der Waals interaction between the substrate and the molecules, a DFT-D3BJ treatment was used. For all calculations, the vacuum thickness is always greater than A Gamma Point k-point grid was used. Interaction Region Indicator (IRI) isosurfaces were calculated using Multiwfn. Structure rendering was performed using VMD.

[0067] Example 1

[0068] This embodiment provides a method for preparing a carbazole derivative, and the synthetic route is as follows:

[0069]

[0070] The detailed synthesis process includes:

[0071] (1) Synthesis of 3,6-di(thiophen-3-yl)-9H-carbazole

[0072] 3,6-Dibromo-9H-carbazole (1.0 g, 3.0 mmol), 3-thiopheneboronic acid (0.85 g, 6.6 mmol) and tetrakis(triphenylphosphine)palladium(0) (0.2 g, 0.18 mmol, 3 mol%) were dissolved in 15 mL of toluene and 10 mL of tetrahydrofuran, and then 3 mL of 2M NaCO aqueous solution was added. The mixture was heated to 90 ° C under nitrogen protection and stirred for 48 h. After the reaction was completed, the reaction mixture was poured into 50 mL of deionized water and extracted with dichloromethane. The organic phase was dried over anhydrous NaSO, and the organic solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: ethyl acetate = 10:1, volume ratio) to obtain 0.54 g of a white solid. 1 H NMR and 13 C NMR Figure 1 As shown, the yield was 53%. 1 H NMR(400MHz,Chloroform-d)δ,ppm:8.32(d,J=1.7Hz,2H),8.08(s,1H),7.69(dd,J=8.4,1.8Hz,2H) ,7.52(dd,J=4.9,1.4Hz,2H),7.49(dd,J=3.0,1.4Hz,2H),7.45(d,J=5.3Hz,2H),7.44-7.42(m,2H). 13 C NMR (100MHz, DMSO-D6) δ, ppm: 143.18, 140.01, 127.34, 126.94, 124.97, 123.64, 119.36, 118.52, 111.91.

[0073] (2) Synthesis of 9-(4-bromobutyl)-3,6-di(thiophen-3-yl)-9H-carbazole

[0074] 3,6-di(thiophen-3-yl)-9H-carbazole (0.5 g, 1.5 mmol) was dissolved in 10 mL of 1,4-dibromobutane, followed by the addition of tetrabutylammonium bromide (0.1 g, 0.3 mmol) and 3 mL of 50% KOH aqueous solution. The mixture was stirred at 70 ° C for 24 h. After the reaction was completed, the product was extracted with dichloromethane, the organic layer was dried over anhydrous Na SO, and the solvent was removed under reduced pressure. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 5:1, volume ratio) to obtain 0.6 g of a white solid. 1 H NMR and 13 CNMR Figure 2 As shown, the yield was 85%. 1 H NMR(400MHz,Chloroform-d)δ,ppm:8.34(s,2H),7.74(d,J=8.5Hz,2H),7.53(d,J=5.1Hz,2H),7.49(d,J=2.9Hz,2H),7.46-7.4 3(m,2H),7.42(d,J=8.7Hz,2H),4.36(d,J=7.0Hz,2H),3.40(t,J=6.4Hz,2H),2.09(h,J=8.8,7.8Hz,2H),1.93(p,J=6.8Hz,2H). 13 C NMR (100MHz, DMSO-d6) δ, ppm: 142.97, 140.22, 127.36, 127.16, 126.94, 125.08, 123.29, 119.53, 118.65, 110.29, 42.11, 35.24, 30.36, 27.89.

[0075] (3) Synthesis of diethyl (4-(3,6-di(thiophen-3-yl)-9H-carbazol-9-yl)butyl)phosphonate

[0076] 9-(4-bromobutyl)-3,6-di(thiophen-3-yl)-9H-carbazole (0.6 g, 1.1 mmol) was dissolved in 10 mL of triethyl phosphite, and the reaction mixture was heated to 160 ° C and refluxed for 24 h. After the reaction was completed, the solvent was distilled off under reduced pressure. The crude product was purified by column chromatography (petroleum ether: ethyl acetate = 1:1, volume ratio) to obtain 0.5 g of a brown oil. 1 H NMR and 13 C NMR Figure 3 As shown, the yield was 74%. 1H NMR(400MHz,DMSO-d6)δ,ppm:8.60(d,J=1.8Hz,2H),7.88-7.79(m,4H),7.70-7.60(m,6H),4.42(t,J=6.9Hz ,2H),3.93-3.78(m,4H),1.85(h,J=7.3Hz,2H),1.81-1.67(m,2H),1.58-1.42(m,2H),1.11(t,J=7.1Hz,6H). 13 C NMR(100MHz,DMSO-d6)δ,ppm:142.97,140.23,127.32,127.06,126.91,124.97,123.22,119.46 ,118.57,110.34,61.29,61.23,42.47,29.90,29.75,25.42,24.05,20.27,20.22,16.75,16.70.

[0077] (4) Synthesis of (4-(3,6-di(thiophen-3-yl)-9H-carbazol-9-yl)butyl)phosphonic acid (4PAThCz)

[0078] Diethyl (4- (3,6-di (thiophene-3-yl) -9H-carbazole-9-yl) butyl) phosphonate (0.5g, 0.96mmol) was dissolved in 10mL of anhydrous tetrahydrofuran under nitrogen atmosphere, and 1.47g (1.27mL, 9.6mmol) of trimethylsilyl bromide was added dropwise. The reaction was stirred at room temperature for 24h. After the reaction was completed, 20mL of methanol was added and stirred for 3h to quench the reaction. After rotary evaporation to remove the solvent, the residue was dissolved in 10mL of methanol, and 30mL of deionized water was added dropwise until the solution became turbid and stirred overnight. Filter, wash with water, and dry to obtain 0.34g of a white powdery product. 1 H NMR and 13 C NMR Figure 4 As shown. Yield 75%. 1 H NMR(400MHz,DMSO-d6)δ,ppm:8.62(d,J=1.8Hz,2H),7.86-7.78(m,4H),7.71-7 .59(m,6H),4.41(t,J=7.0Hz,2H),1.88(t,J=7.2Hz,2H),1.56(t,J=5.9Hz,4H). 13C NMR(100MHz,DMSO-d6)δ,ppm:143.00,140.26,127.35,127.07,126.95,125.05,1 23.24,119.50,118.61,110.36,42.77,30.31,30.16,28.58,27.22,21.01,20.97.

[0079] Example 2

[0080] This embodiment provides a method for preparing an organic solar cell device. The solar cell is manufactured using a conventional device structure of ITO / SAMs / active layer / PNDIT-F3N / Ag, wherein the SAMs are 2PACz and 4PAThCz, and the active layer is PM6:L8-BO, D18:L8-BO, or D18:L8-BO:BTP-eC9. The method specifically includes the following steps:

[0081] The ITO glass was ultrasonically pre-cleaned with detergent, deionized water, acetone, and 2-propanol for 30 min each. The ITO glass was plasma treated for 2 min before use. -1 The SAMs were spin-coated onto the ITO substrate and annealed at 120 °C for 7 min. Then, the active layer materials PM6:L8-BO (1:1.2, total concentration 16.5 mg ml -1 )、D18:L8-BO(1:1.2,total concentration 10mg ml -1 ) or D18:L8-BO:BTP-eC9 (1:0.6:0.6, total concentration 10 mg ml -1 ) and annealed at 100°C for 5 min. Subsequently, an electron transport layer, PNDIT-F3N (1.2 mg / ml, 4200 rpm), was spin-coated on the active layer. Finally, 110 nm of Ag was deposited on the PNDIT-F3N layer by evaporation.

[0082] Example 3

[0083] This embodiment provides a method for preparing an organic solar cell device. The specific steps are different from those of Example 2 only in that PNDIT-F3N is not spin-coated on the active layer, but Ag is directly evaporated.

[0084] Results and Discussion

[0085] 1. Basic properties of SAMs

[0086] In Example 1 of the present application, a synthesis method of 4PAThCz was prepared and the chemical structure of the material was confirmed by nuclear magnetic resonance (NMR). In addition, the Fourier transform infrared (FT-IR) spectrum of 4PAThCz was 778 cm -1 The appearance of the characteristic peak of CS at the Figure 5 a). Thermogravimetric tests characterized the thermal stability of 2PACz and 4PAThCz, such as Figure 5 b, The initial thermal decomposition temperatures of 2PACz and 4PAThCz are greater than 300 °C, and both of them have sufficiently high thermal stability for practical optoelectronic applications.

[0087] Density functional theory (DFT) calculations were used to investigate the intrinsic properties of 2PACz and 4PAThCz. Figure 6 The electrostatic surface potential (ESP) of 2PACz and 4PAThCz was calculated, among which 4PAThCz showed a higher electron density on the thiophene ring. The calculated dipole moments of 2PACz and 4PAThCz were 1.9 and 3.2D, respectively, verifying that the introduction of thiophene effectively enhanced the charge transport capability. The simulated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of 2PACz and 4PAThCz were -5.45, -5.17, -0.76 and -0.9 eV, respectively. Ultraviolet photoelectron spectroscopy (UPS) was further used to evaluate the energy level of the SAMs modified indium tin oxide (ITO) substrate ( Figure 7 a). The HOMO level of 4PAThCz is estimated to be -5.36 eV, which is upshifted compared to 2PACz (-5.47 eV). The appropriate energy level facilitates the efficient extraction and transport of holes at the interface and hinders electrons from reaching the anode. Figure 7 b shows the UV-visible absorption of SAM dilute solution. 2PACz and 4PAThCz have strong absorption in the UV region, with maximum molar absorption coefficients of 4.5×10 4 and 3.6×10 4 Lmol -1 cm -1 .

[0088] In order to study the anchoring adsorption of SAMs on ITO substrates, we used X-ray photoelectron spectroscopy (XPS) to characterize the surface atomic composition of ITO / SAMs. Figure 8 As shown in Figures ac, C1s, N 1s and P 2p signals appear in the full XPS spectrum of ITO / SAMs, confirming the presence of a SAM layer on the ITO surface. 3 / 2 and In 3d 5 / 2The characteristic peaks of ITO shifted from 451.05 and 443.47 eV of ITO to 451.53 and 443.98 eV of ITO / 2PACz, 451.77 and 444.22 eV of ITO / 4PAThCz, respectively. Figure 8 c). A similar trend is also observed for the O 1s peak ( Figure 8 df). The larger shift indicates a stronger interaction between 4PAThCz and ITO. Compared with ITO / 2PACz, the XPS fitting spectrum of ITO / 4PAThCz shows the newly emerged CS and S2p signals related to the thiophene units ( Figure 7 Energy dispersive X-ray spectroscopy (EDS) mapping was further tested to monitor the surface element distribution such as Figure 9 . ITO is mainly composed of indium (In, 80.2%, by weight), oxygen (O, 12.1%) and tin (Sn, 5.7%). For SAMs-modified ITO, the In content dropped to ~50%, and the O and Sn contents rose rapidly to 33% and 12%, respectively. The uniform distribution of carbon, nitrogen and phosphorus indicates that 2PACz and 4PAThCz are effectively and uniformly anchored to the ITO surface. The excellent coverage of SAM helps to passivate surface defects, reduce exciton recombination, and thus improve the FF of the device.

[0089] The surface quality of the interfacial layer is a key indicator related to interfacial contact, device efficiency and stability. Given that the thickness of SAMHTL is only one molecule, the impact of surface quality becomes more significant. Therefore, the surface wettability of bare ITO, 2PACz and 4PAThCz modified ITO was compared using contact angle measurements of deionized water and diiodomethane droplets, respectively. Figure 10 As shown in a, the water contact angle of ITO / 4PAThCz is 80.2°, which is much higher than 45.4° of bare ITO and 40.0° of ITO / 2PACz. This indicates that the hydrophobicity of 4PAThCz modification is significantly improved. Figure 10 As shown in Figure 2b, contact angle measurements using diiodomethane show that the ITO / 4PAThCz sample has a smaller contact angle of 16.9°, compared to 23.1° for bare ITO and 22.8° for ITO / 2PACz. These characteristics facilitate the uniform deposition of organic semiconductor materials dissolved in solutions such as chloroform, chlorobenzene, and toluene.

[0090] 4.3.2 Molecular Packing of SAMs

[0091] In order to further discuss the arrangement and stacking of SAMs on ITO substrate, the intermolecular interactions of SAMs were calculated. Figure 11 The interaction between SAMs and ITO was simulated, and SAMs were adsorbed on the ITO surface through the tridentate anchoring mode of phosphonic acid groups with excellent stability. Figure 12 a, c simulate the π-π stacking distance of SAMs molecules on the ITO surface, 2PACz is 4PAThCz is In addition, the interaction region indicator (IRI) isosurface of SAM was simulated, e.g. Figure 12 As shown in b and d, the blue area represents the significant attraction of chemical bonds, hydrogen bonds, and halogen bonds; the red area represents the significant repulsion (steric hindrance effect in the ring and cage); and the green area represents the van der Waals (vdW) interaction. 2PACz has significant vdW interactions with adjacent molecules, and there is no obvious significant attraction and repulsion between molecules. In contrast, for 4PAThCz, these vdW interaction forces are significantly enhanced due to the presence of extended planar conjugated functional groups, which elucidates its more compact π-π stacking arrangement. In order to study the thiophene modification and its effect on intermolecular stacking, the single crystal structure of the SAM was tested. As Figure 12 As shown in e, 2PACz exhibits a high degree of planar symmetry, with the C and N atoms of the functional groups in the same plane. More importantly, 2PACz molecules exhibit misaligned parallel aggregation with a vertical π-π stacking distance of The longitudinal slip distance is In contrast, the 4PAThCz molecule displays a distorted structure with a dihedral angle of 17.4° between the central pyrrole ring and the thiophene ( Figure 12 f), which means that the thiophene unit reduces the planarity and symmetry of the SAM. Compared with 2PACz, 4PAThCz exhibits a compact stacking pattern with a smaller π-π stacking distance of The longitudinal slip distance is The results agree well with the simulations. These results indicate that the thiophene unit completely alters the molecular stacking behavior of 4PAThCz, resulting in stronger π-π stacking, which facilitates the formation of a dense and ordered SAM HTL on ITO. These advantages can increase the interfacial dipole moment, reduce interfacial defects, and enhance hole transfer, thereby improving device efficiency.

[0092] 4.3.3 Photovoltaic Performance of Organic Solar Cells

[0093] Thanks to the enhanced dipole moment, perfect π-π interaction, suitable energy level and excellent wettability of the 4PAThCz monolayer, the conventional device structure of ITO / SAMs / active layer / PNDIT-F3N / Ag was used to prepare OSC in Example 2, where the SAMs were 2PACz and 4PAThCz, and the active layers were PM6:L8-BO (1:1.2, wt.%), D18:L8-BO (1:1.2, wt.%) and D18:L8-BO:BTP-eC9 (1:0.6:0.6, wt.%). The energy level diagram of the device components is shown in Figure 2. Figure 11As shown in a, the HOMO energy level of SAM is close to that of donor PM6 and D18, which is beneficial to hole transport and reduces interface energy loss. The device using 4PAThCz as HTL and D18:L8-BO as binary active layer obtained a PCE of 19.79% ( Figure 11 b), open circuit voltage (V OC ) is 0.900V, J SC 26.85 mA cm -2 , FF is 82.0%, which is better than the device based on 2PACz (PCE=19.34%, V OC =0.900V, J SC =26.40 mA cm -2 When the D18:L8-BO:BTP-eC9 ternary blend was used as the active layer, the 4PAThCz- and 2PACz-based OSCs achieved maximum PCEs of 20.78% and 20.2%, respectively, which are the highest efficiencies of OSCs reported in the literature to date ( Figure 11 c). External quantum efficiency (EQE) curve is as follows Figure 11 d. The maximum EQE value of the OSC based on 4PAThCz at 540 nm is ∼92.0%, which is slightly higher than that of 2PACz, which may be due to the larger dipole moment of 4PAThCz. For OSCs based on 2PACz / D18:L8-BO, 4PAThCz / D18:L8-BO, 2PACz / D18:L8-BO:BTP-eC9, and 4PAThCz / D18:L8-BO:BTP-eC9, the integrated J SC 25.97, 26.20, 27.33, and 27.61 mA cm, respectively. -2 , which is consistent with the results obtained from the JV results.

[0094] In order to verify the performance of solar cells with 4PAThCz as HTL SC The hole mobility and defect density were tested by space charge limited current (SCLC) to enhance the FF. The device structure was ITO / SAMs / D18:L8-BO / Ag, and the preparation method was as in Example 3. The double logarithmic JV curve can be divided into three different parts, including the ohmic region, the trap-filled region, and the trap-free region ( Figure 11 e). The hole mobility can be obtained from the trap-free region and is estimated to be 4.85×10 for 2PACz and 4PAThCz, respectively. -4 and 5.90×10 -4 cm 2 V -1 s -1It is worth noting that the intersection of the ohmic region and the trap filling region represents the trap filling limit voltage (VTFL), which determines the trap density (n trap ). 2PACz based devices, VTFL and n trap 0.544V and 1.84×10 22 m -3 , the corresponding values of 4PAThCz dropped to 0.473 V and 1.57×10 22 m -3 In addition, transient photovoltage (TPV) and transient photocurrent (TPC) tests were also performed ( Figure 11 fg) to evaluate carrier lifetime and charge extraction time. The carrier lifetime of the 4PAThCz-based device was 19.2μs, which is longer than that of 2PACz (11.4μs), indicating that surface traps in 4PAThCz are suppressed. The charge extraction time was reduced from 0.265μs in 2PACz to 0.208μs in 4PAThCz, indicating that 4PAThCz can promote hole extraction within the device.

[0095] Finally, the photostability test (11 h) was conducted using 2PACz and 4PAThCz as HTL packaged binary devices. -2 After continuous irradiation for 130 h under the light intensity of 80 ). In contrast, the T 80 In addition, the long-term storage stability of the packaged binary devices was tested ( Figure 11 i). The 4PAThCz-based OSC retained 90.5% of its initial efficiency after 1200 hours of storage in a glove box, slightly higher than the 2PACz-based device (89.6%). This result indicates that 4PAThCz as a HTL significantly enhances device stability, likely due to its more rigid and conjugated molecular structure.

[0096] In order to verify the universality of 4PAThCz, we further applied SAMs to the PM6:L8-BO active layer system. The preparation method was as in Example 2. The device based on 2PACz obtained the best PCE of 19.25%, and the PCE of 4PAThCz was 19.6% ( Figure 13 a). The morphology of the active layer deposited on the SAM was investigated by AFM ( Figure 14 ), the uniform and flat fiber network structure is one of the reasons for its high efficiency. In addition, in order to evaluate the scalability of 4PAThCz as HTL, a 1.01cm effective area was further fabricated. 2 OSC( Figure 13The large-area ternary device based on 4PAThCz achieved an excellent PCE of 18.72%, V OC 0.875V, J SC 27.49 mA cm -2 , FF is 77.8%.

[0097] summary

[0098] This application proposes (4-(3,6-di(thiophen-3-yl)-9H-carbazol-9-yl)butyl)phosphonic acid as an efficient hole transport material for high-performance OSCs. 4PAThCz, which has non-condensed ring thiophene units at the 3 and 6 positions of carbazole, exhibits better molecular stacking behavior, which helps to form a smaller intermolecular distance and a twisted structure, achieving a larger dipole moment, fast hole extraction ability, and reduced charge recombination. The results show that 4PAThCz has a large dipole moment of 3.2D and a high hole mobility of 5.90×10 - 4 cm 2 V -1 s -1 , these features can simultaneously promote the FF and J of OSCs SC As a result, the D18:L8-BO binary device achieved a high efficiency of 19.79% and an excellent FF of 82%. Furthermore, the PCE of the D18:L8-BO:BTP-eC9-based ternary device reached a high PCE of 20.78%. This chapter provides a highly effective strategy for the design of high-performance SAMs, aiming to optimize the molecular dipole moment and minimize charge recombination.

[0099] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A carbazole derivative, characterized in that It is named (4-(3,6-di(thiophen-3-yl)-9H-carbazol-9-yl)butyl)phosphonic acid and has the structure shown in Formula I:

2. A method for preparing the carbazole derivative according to claim 1, characterized in that: The synthesis path is as follows:

3. Application of a carbazole derivative in optoelectronic functional devices.

4. The use of the carbazole derivative in a photoelectric functional device according to claim 3, characterized in that: The optoelectronic functional device includes a solar cell.

5. The use of the carbazole derivative in a photoelectric functional device according to claim 4, characterized in that: The solar cell is an organic solar cell.

6. The use of the carbazole derivative in a photoelectric functional device according to claim 4, characterized in that: The solar cell is a perovskite solar cell.

7. An organic solar cell, characterized in that: The invention comprises a SAMs layer located between the ITO layer and the active layer, wherein the SAMs layer comprises the carbazole derivative according to claim 1.

8. The organic solar cell according to claim 7, characterized in that The preparation method of the SAMs layer comprises: adhering a slurry containing the carbazole derivative on an ITO layer, and performing annealing to obtain the SAMs layer.

9. The organic solar cell according to claim 7, characterized in that The annealing temperature is 110-130°C, and the annealing time is 6-8 minutes.

10. A perovskite solar cell, characterized in that: The invention comprises a hole transport layer, wherein the hole transport layer comprises the carbazole derivative according to claim 1.

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