Hole Transport Material Research Articles

Dibenzo[b,d]thiophene 5,5-dioxide-based dopant-free hole-transporting material with passivation effect in inverted perovskite solar cells

For the rocket development of organic-inorganic hybrid perovskite solar cells (OIH–PSCs), the research of low-cost, dopant-free hole-transporting materials (HTMs) with high performance and stability is still an urgent problem. In this work, we synthesize organic small molecule HTM with sulfone-containing benzodithiophene (BDTOxide) as the central unit, termed BDTOxide-MTP. The synthetic cost of DBTOxide-MTP in the lab is 238 CNY/g, which is just one-fifth of the cost of the PTAA (1200 CNY/g). BDTOxide-MTP exhibits the deep highest occupied molecular orbital energy level, high hole transport mobility, and excellent passivation effect. BDTOxide-MTP is introduced into inverted OIH-PSCs as a dopant-free hole transport layer, the champion efficiency of MAPbI3-xClx-based devices reaches 18.72 % with an excellent VOC of 1.13 V, while the efficiency of the control device based on PTAA is about 18.49 %. The device based on BDTOxide-MTP exhibits comparable stability to the one based on PTAA, which can maintain over 90 % of the original efficiency after 46 days in a nitrogen environment.

Machine Learning Approach for Predicting the Hole Mobility of the Perovskite Solar Cells

AbstractTraditional computational approaches such as Monte Carlo simulation, molecular dynamics, and density functional theory (DFT) have contributed to understanding the role of hole mobility in the development of suitable hole transporting materials (HTMs) for perovskite solar cell efficiency. However, these methods often involve significant computational expenses, thereby limiting the number of feasible studies and hindering the extraction of valuable structure−property guidelines for a rational design of novel HTMs. To address these challenges, this study proposes an ultrafast predictive model that balances prediction accuracy and time efficiency, a critical aspect for predicting the hole mobility of HTMs for perovskite optimization. The model, which leverages the Random Forest learning algorithm, enables comprehensive and rapid analysis of photovoltaic features taken from previous experiments/literature and processed with the RDKit Python library. Notably, recognizing the challenges associated with high correlation in the dataset, a method to improve the calculation of feature importance in random forests is applied. The results highlight bertz_ct, chi1, and logP as key predictive features of HTM performance. However, the model underscores the need to uncover additional predictive features based on structure–property relationships to predict the optimized hole mobility. This approach significantly accelerates the discovery process, outperforming prevalent statistical methods in the prediction of hole mobility and HTM performance. This research signifies a pivotal step toward cost‐effective, accelerated stability and efficiency of HTMs, with implications for the advancement of optoelectronic devices.

Spiro-Bifluorene-Cored Dopant-Free Conjugated Polymeric Hole-Transporting Materials Containing Passivation Parts for Inverted Perovskite Solar Cells.

Two spiro-bifluorene-based dopant-free HTMs (X22 and X23) have been synthesized by facilely condensing spiro-bifluorene diamine with 3,4-ethylenedioxythiophene (EDOT)-5,7-dicarbonyl dichloride and 2,3,5,6-tetrafluoro-terephthaloyl dichloride, respectively. In the X22 molecule, lone pairs of electrons on the sulfur (S) and oxygen (O) functional groups interact with the perovskite materials. The hole mobility (μh) of X22 (3.9 × 10-4 cm2 V-1 S1-) is more than twice that of X23 (1.4 × 10-4 cm2 V-1 S1-). The conductivity (σ0) of X22 is 2.73 × 10-4 S cm-1, which is also higher than that of X23 (2.39 × 10-4 S cm-1). The EDOT moiety benefits the contact angle of CH3NH3PbI3 precursor solutions on HTMs as low as 24°. The X22-based device with an indium-doped tin oxide/hole transport material (HTM)/CH3NH3PbI3/phenyl-C61-butyric acid methyl ester (PC61BM)/bathocuproine/Ag structure achieves a power conversion efficiency (PCE) of 19.18%. The PCE of the device based on X23 containing fluorine is 18.70%, and the contact angle between HTM and the perovskite precursor solution is 32°. The X22- and X23-based devices at ambient temperature (≈25 °C) in N2 retain 86% and 79% of the initial PCE after 150 days. The effect of S, O, and F heteroatoms plays an important role in the side chain modification of HTMs, improving defect passivation in HTM/CH3NH3PbI3 interfaces by multiple functional groups.

Buried interface modification toward efficient perovskite solar cell based on PVK hole transport layer

Poly (9-vinylcarbazole) (PVK) is an attractive hole transport material for organometallic-halide perovskite solar cell (PSC) because of its excellent hole transport ability and great film-forming property. Nowadays, the PVK hole-transport-layer (HTL) based PSC suffered from low power conversion efficiency (PCE), which mainly caused by bad interface contact between PVK and perovskite film, including the energy level mismatch. Doing PVK is an effective and facial method to modify the buried interface of perovskite film. In this work, 1,1-bis [(di-4-tolylamino)phenyl]cyclohexane (TAPC) was added into PVK HTL. Experimental results show that a highest occupied molecular orbital (HOMO) level elevation was achieved after doping TAPC. Meanwhile perovskite films with increased crystallinity, reduced defect density and enhanced light absorbance were obtained. Finally, the PCE of PSCs were enhanced from 10.81% of the control device to 15.65% of PVK + 40% TAPC device. The reason that responsible for the energy level lifting, morphology improvement and performance enhancement were thoroughly investigated and analyzed. This work provides an alternative option for the dopant in PVK to improve the buried interface of perovskite film, and therefore, the performance of PSCs.

Fluorination effects on bithiophene bridged hole transporting materials for perovskite solar cells

ABSTRACT The use of hole transporting material (HTM) remains indispensable for efficient charge extraction in perovskite solar cells. In this work, a series of small-molecule HTMs are designed by introducing fluorine atoms into the central part of 2,2′-bithiophene core. The effect of fluorination on the photophysical, electrochemical, and hole transport properties is systematically explored using Quantum chemistry calculation. The Calculated results reveal that all the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) of the studied molecules are well matched with the energy band structure of perovskite. Three fluorine substituted hole-transporting materials possess lower reorganisation energy than the reference molecule BT-MTP. The higher mobility and matched energy levels of predicted HTMs are beneficial for improving the performance of PSCs. All the designed HTMs display higher hole mobility than those of the BT-MTP. Especially, molecule DFBT-p-MTP exhibits better optical properties and stability, indicating that fluorination is an effective strategy to improve the performance of the device in real application. This work provides an avenue for designing low-cost small molecule HTMs for high-performance perovskite solar cells.

Graphene oxide-titanium oxide-polyaniline hybrid materials for high-performance dye-sensitized solar cells

A new solar cell that comprises a graphene oxide and titanium oxide nanoparticle (NP) composite with graphitized polyaniline (PANI) has been tested in polymer solar cells (PSCs). In this study, a series of conjugated polymers were synthesized and evaluated as the absorber and hole-transport layer materials in organic solar cells, demonstrating the significant impact of the chemical structure of the polymers on solar cell performance. The incorporation of graphene oxide (GOX) and titanium oxide TiO2 NP in conjugated polymers, particularly when graphitized within the PANI layer, led to improved open-circuit voltages compared to structurally similar polymers without NP. The morphology of the composite films was analyzed and related to the photovoltaic performance of polymers synthesized with polyaniline PANI-base and PANI-salt. Optimal NP addition in PANI-salt, PANI-base, PANI-base-TiO2, and PANI-base-GOX resulted in open-circuit voltages and efficiencies of 433 mV and 3.67%, 250 mV and 0.595%, 310 mV and 1.358%, and 520 mV and 2.366%, respectively. This study underscores the importance of polymer film uniformity in the performance of PSCs, with the highest efficiency obtained using a conjugated polymer with the best PANI-salt and PANI-base-GOX films. The research sheds light on the relationship between polymer structure and device photovoltaic performance, which is crucial for the design of new polymeric materials for efficient use and stable OSCs and PSCs.

Self-Assembled Molecules with Asymmetric Backbone for Highly Stable Binary Organic Solar Cells with 19.7 % Efficiency.

The hole-transporting material (HTM), poly (3,4-ethylene dioxythiophene) poly(styrene sulfonate) (PEDOT : PSS), is the most widely used material in the realization of high-efficiency organic solar cells (OSCs). However, the stability of PEDOT : PSS-based OSCs is quite poor, arising from its strong acidity and hygroscopicity. In addition, PEDOT : PSS has an absorption in the infrared region and high highest occupied molecular orbital (HOMO) energy level, thus limiting the enhancement of short-circuit current density (Jsc) and open-circuit voltage (Voc), respectively. Herein, two asymmetric self-assembled molecules (SAMs), namely BrCz and BrBACz, were designed and synthesized as HTM in binary OSCs based on the well-known system of PM6 : Y6, PM6 : eC9, PM6 : L8-BO, and D18 : eC9. Compared with BrCz, BrBACz shows larger dipole moment, deeper work function and lower surface energy. Moreover, BrBACz not only enhances photon harvesting in the active layer, but also minimizes voltage losses as well as improves interface charge extraction/ transport. Consequently, the PM6 : eC9-based binary OSC using BrBACz as HTM exhibits a champion efficiency of 19.70 % with a remarkable Jsc of 29.20 mA cm-2 and a Voc of 0.856 V, which is a record efficiency for binary OSCs so far. In addition, the unencapsulated device maintains 95.0 % of its original efficiency after 1,000 hours of storage at air ambient, indicating excellent long-term stability.

The dopant-free hole transport material based on benzo[1,2-b:4,5-b']dithiophene with high efficiency in inverted perovskite solar cells

In the commercialization process of organic-inorganic hybrid perovskite solar cells (OIH–PSCs), the research of dopant-free hole transport materials (HTMs) with high efficiency is still an urgent problem. In this work, we synthesize two organic small molecule HTMs with well-known benzodithiophene (BDT) as the central unit, abbreviated as BDTO-MTP and BDTT-PMTP. Compared with BDTO-MTP (with oxygen-substituted alkyl chain and diphenylamine derivatives as the terminal group), BDTT-PMTP introduces thiophene to replace oxygen beside the central group, triphenylamine to replace diphenylamine derivatives as the terminal group. Both BDTO-MTP and BDTT-PMTP exhibit high hole mobility without doping. It is worth noting that two new materials are introduced into inverted OIH-PSCs as a doped-free hole transport layer, the champion efficiency of MAPbI3-based devices based on BDTT-PMTP reaches 21.08%, and the highest efficiency of BDTO-MTP-based devices can also reach 19.54%. The results show that the planar building blocks with the similarity of BDT will be an excellent and universal choice for the future design of dopant-free small molecule HTMs with high efficiency.

Dopant-Free Pyrene-Based Hole Transporting Material Enables Efficient and Stable Perovskite Solar Cells.

Dopant-free hole transporting materials (HTMs) is significant to the stability of perovskite solar cells (PSCs). Here, we developed a novel star-shape arylamine HTM, termed Py-DB, with a pyrene core and carbon-carbon double bonds as the bridge units. Compared to the reference HTM (termed Py-C), the extension of the planar conjugation backbone endows Py-DB with typical intermolecular π-π stacking interactions and excellent solubility, resulting in improved hole mobility and film morphology. In addition, the lower HOMO energy level of the Py-DB HTM provides efficient hole extraction with reduced energy loss at the perovskite/HTM interface. Consequently, an impressive power conversion efficiency (PCE) of 24.33 % was achieved for dopant-free Py-DB-based PSCs, which is the highest PCE for dopant-free small molecular HTMs in n-i-p configured PSCs. The dopant-free Py-DB-based device also exhibits improved long-term stability, retaining over 90 % of its initial efficiency after 1000 h exposure to 25 % humidity at 60 °C. These findings provide valuable insights and approaches for the further development of dopant-free HTMs for efficient and reliable PSCs.

Dopant‐Free Pyrene‐Based Hole Transporting Material Enables Efficient and Stable Perovskite Solar Cells

AbstractDopant‐free hole transporting materials (HTMs) is significant to the stability of perovskite solar cells (PSCs). Here, we developed a novel star‐shape arylamine HTM, termed Py‐DB, with a pyrene core and carbon‐carbon double bonds as the bridge units. Compared to the reference HTM (termed Py‐C), the extension of the planar conjugation backbone endows Py‐DB with typical intermolecular π–π stacking interactions and excellent solubility, resulting in improved hole mobility and film morphology. In addition, the lower HOMO energy level of the Py‐DB HTM provides efficient hole extraction with reduced energy loss at the perovskite/HTM interface. Consequently, an impressive power conversion efficiency (PCE) of 24.33 % was achieved for dopant‐free Py‐DB‐based PSCs, which is the highest PCE for dopant‐free small molecular HTMs in n‐i‐p configured PSCs. The dopant‐free Py‐DB‐based device also exhibits improved long‐term stability, retaining over 90 % of its initial efficiency after 1000 h exposure to 25 % humidity at 60 °C. These findings provide valuable insights and approaches for the further development of dopant‐free HTMs for efficient and reliable PSCs.

Low-cost dopant-free fluoranthene-based branched hole transporting materials for efficient and stable n-i-p perovskite solar cells

It has been widely recognized that hole transporting materials (HTMs) play a key role in the rapid progress of perovskite solar cells (PVSCs). However, common organic HTMs such as spiro-OMeTAD not only suffer from high synthetic costs, but also usually require the additional chemical doping process to improve their hole transport ability, which unfortunately induces the terrible stability issue. Therefore, it is urgent to develop low-cost dopant-free HTMs for efficient and stable PVSCs. In this work, we have successfully developed a new class of efficient dopant-free fluoranthene-based HTMs (TPF1–5) with quite low lab synthetic costs by combining donor-acceptor and branched structure designs. The detailed structure-property study revealed that tuning the twisted arms at different substitution sites would regulate the intermolecular interactions and film-forming ability, thereby significantly affecting the performance of the HTMs. By applying these HTMs in conventional PVSCs, the dopant-free TPF1-based devices not only achieved the best efficiency of 21.76%, which is comparable to that of the doped spiro-OMeTAD control devices, but also showed much better operational stability, which maintained over 87% of the initial efficiency under maximum power point tracking after 1038 h.

Thiophene-based compounds containing naphthalene groups as Hole Transport Materials for efficient Perovskite Solar Cells or light absorbers in Organic Solar Cells

This study mainly focuses on modelling and analysis of the reference molecule (M104) as well as four engineered molecules (MMS1-MMS4) as Hole Transport Materials or as light absorbers in Organic Solar Cells. These new molecules are based on thiophene derivatives as acceptor groups, naphthalene as π-bridged groups, and OMeTPA as donor groups. Extensive research was carried out at the molecular level for the studied molecules using DFT and TD-DFT computer simulations to explore their photovoltaic characteristics. All the compounds under investigation were preferred candidate for HTMs in perovskite solar cells because of their superior HOMO delocalization, lower hole reorganization energies, lower chemical reactivity, higher radiative lifetime, higher light-harvesting efficiency, higher dipole moment and spontaneous solvation process inside dichloromethane. The examined molecules' bonded electron-hole pairs can readily split into positive and negative charges to escape coulomb attraction. This increases the short-circuit current density and facilitates hole transport. MMS4, with its larger maximum absorbance (538.76 nm in dichloromethane), suitable structural features and lower bandgap (2.82 eV), was the most optimal chemical with remarkable photovoltaic capabilities. In conclusion, this work makes a strong case for the synthesis of these high-performing materials by researchers for use in subsequent investigations.

Rational designing of phenothiazine dioxide based hole transporting materials for efficient perovskite solar cells

In this study, we design five novel non-fullerene end capped acceptor based efficient hole transporting materials (HTMs) from phenothiazine dioxide-based core. MPW1PW91 functional with a 6-31G basis set was employed for all DFT calculations and simulation analysis. By substituting acceptor groups in PDO2, numbers of parameters like band gaps, the frontier molecular orbitals (FMOs), higher absorption parameters, and electronic properties like ionization potential, electron affinity, binding energy, and light harvesting efficiency (LHE) were well tuned. In addition, significant variations in other geometrical parameters such as dipole moment, and reorganizational energy parameters were also noticed for the derived molecules compared to the reference molecule (R). Device performance was analyzed by performing calculations of open circuit voltage (VOC) and fill factor (FF). Consequently, all the designed derivatives demonstrated an improved VOC of 0.84 V for an optimized designed structure. In comparison, it was limited to a VOC of 0.57 V for the reference (R) PDO2, displaying an increment in efficiency which is essential to use these molecules as highly efficient HTMs for perovskite solar cell devices in the future.

Collaborative Management of Light‐Absorbing Supplementation and Defect Passivation Based on Green‐Emitting ((CH3)4N)2(C2H5)4N·MnBr4 Single Crystals for Efficient and Stable Inverted Perovskite Solar Cells

In conventional p–i–n inverted perovskite solar cells (PSCs), there exists considerable energy loss due to both unsatisfactory light path design and trap‐induced interfacial defects. The sunlight is absorbed competitively by conductive oxide substrates and hole transport material in front of the perovskite layer, while the opaque metal back electrode also prevents light penetration. Worse yet, there is severe nonradiative charge recombination caused by defects between the perovskite layer and the electron transport material. To tackle the above two issues, a new green‐emitting material ((CH3)4 N)2(C2H5)4N·MnBr4 is synthesized and introduced in/on the perovskite layer to achieve both defect passivation and light complementation. The green luminescence of this single crystal at the interface is found to provide secondary light absorption, as evidenced by a remarkable promotion of short‐circuit current density. It is also found that the excess PbI2 on the surface of perovskite can be effectively removed, and as the interfacial additive, ((CH3)4 N)2(C2H5)4 N·MnBr4 inhibits trap‐assisted recombination losses, which provides favorable energy‐level alignment and extends charge carrier lifetime. As a result, the champion PCE (21.23%) of the target‐treated ((CH3)4 N)2(C2H5)4 N·MnBr4 device exceeds that 19.5% of the pristine‐without ((CH3)4 N)2(C2H5)4 N·MnBr4 device. This work provides an effective interfacial strategy for high‐performance and stable inverted PSCs.

Poly[Bis(4‐Phenyl)(2,4,6‐Trimethylphenyl)Amine] in Perovskite Solar Cells: Advances via Molecular Engineering

To improve the performance of perovskite solar cells (PSCs), studying the materials that constitute each layer of the device is important. Among the commonly used materials in the hole‐transport layer (HTL), poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine] (PTAA) stands out as one of the most employed. This hole‐transport material (HTM) offers many advantages, including thin‐film fabricating feasibility, ease of synthesis, and sufficient energy levels. Further, PSCs employing PTAA as the HTL exhibit a high‐power conversion efficiency. However, it has some drawbacks, including low crystallinity and poor device stability. To overcome these limitations, extensive studies focusing on improving its properties by molecular engineering have been conducted. In this review, the strategies for engineering the molecular structures of triaryl amine polymers are introduced. The strategies are classified into three groups: backbone engineering, side‐chain substitution, and a combination of both. Furthermore, future directions for achieving HTMs with various properties for high‐performance PSCs are suggested.

Enhanced fill factor and stability of perovskite solar cells with a multifunctional additive of starch-iodine complex

The efficiency and stability of perovskite solar cells (PSCs) can be greatly affected by various factors such as passivating the perovskite film, oxidizing the hole-transport material of 2,2′,7,7′-tetras(N,N-p-methoxyaniline)-9,9′-spirodifluorene (Spiro-OMeTAD), and inhibiting the iodide migration. Here we introduce a multifunctional starch-iodine complex in the perovskite film to enhance the fill factor and stability of PSCs. Results demonstrate that the starch-iodine complex from the perovskite film can release iodine molecules to gently oxidize the Spiro-OMeTAD, which can significantly increase the PSC's fill factor. Moreover, the remaining starch can effectively passivate the perovskite film to obviously improve the PSC's long-term stability. Furthermore, the starch-iodine complex can absorb and store the iodide ions to generate a starch-triiodide complex, which can release iodide ions to promote iodide defect self-healing and suppress iodide migration in the perovskite films, resulting in a further enhancement of the PSC's long-term stability. As a result, the PSC based on the starch-iodine complex obtains a superior cell efficiency of 22.60% with a high fill factor of 79.54%, and keeps 91.12% of its original efficiency after 1500 h.

Enhancing the photovoltaic responses of MAPbI3 poly-crystalline perovskite films via adjusting the properties of PEDOT:PSS hole transport material with a low-polarity solvent treatment process

The surface and electrical characteristics of the poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) materials are manipulated using a low-polarity solvent treatment process, which influences the formation and nucleation/crystal growth process of the CH3NH3PbI3 (MAPbI3) perovskite films and thereby determining the crystal orientation and grain size. The hydrophilicity of the PEDOT:PSS composite material fabricated on the ITO/glass sample is reduced with the xylenes solvent treatment or a hexamethyldisilazane:xylenes solvent mixture treatment, which can be used to form the photo-active perovskite crystals and thereby reducing the photocurrent hysteresis of the fabricated perovskite based photovoltaic devices. It is worthwhile to mention that the non-perfectness of closed-loop in the photocurrent density-voltage curves under the forward and backward scans can be used as an indicator to assess the properties of the MAPbI3 films. Our findings can facilitate the development of perovskite based optoelectronic devices.

Spiro[fluorene-9,9′-xanthene]-based hole transporting materials modulated by mono- and bis- benzodioxino[2,3-b]pyrazine pendant groups for perovskite QLEDs

In this work, we designed and synthesized two new hole-transporting materials with a nonplanar three-dimensional (3D) conformation. They were achieved by incorporating spiro[fluorene-9,9′-xanthene] as a cross-shaped configuration scaffold and adding either mono- (H1) or bis- benzodioxino[2,3-b]pyrazine (H2) pyrazine as pendant groups. Both compounds exhibit remarkable thermal stability, with thermal decomposition temperature (Td) of 462 (H1) and 504 °C (H2), respectively. Moreover, the structural substitution with benzodioxino[2,3-b]pyrazine units successfully aligned the energy levels of both materials with the perovskite quantum dot luminescence layer. Hereby, the fabricated perovskite QLEDs using H1 as hole-transporting materials (HTMs) featured an excellent average external quantum efficiency (EQE) of up to 9.5% with a maximum luminance of 22368 cd m−2, which is much higher than that of the H2-based devices with an EQE of 6.6% under the same conditions. The excellent device performance from H1 can be attributed to its asymmetric structure by the introduction of monosubstituted benzodioxino[2,3-b]pyrazine groups, as evidenced by its high hole mobility of 1.90 × 10−4 cm2 V−1 s−1 and improved interface interaction with adjunct layers. Thus, this design approach may bring a fresh perspective to the utilization of solution-processable small-molecule HTMs in high-performance Pe-QLEDs and other optoelectronics in the future.

Simple hole transporting material based 2,7- carbazole for perovskite solar cells: Structural, photophysical, and theoretical studies

A simple carbazole-based hole transport material, termed HTM1, has been deposited as thin films. The samples were elaborated via a Physical Vapor Deposition to ensure the production of high-quality thin films. The study of the morphological and photophysical properties of the investigated compound was revealed through Scanning Electron Microscopy, Atomic Force Microscopy, Ultraviolet–Visible, and Photoluminescence spectroscopy. A flat surface with low roughness values was observed in the SEM and AFM images. Moreover, the obtained films revealed a higher absorption in the UV region. Optical parameters such as the energy gap (2.9 eV) and refractive index were determined using transmittance measurements. The temperature-dependent photoluminescence over a range of 77–300 K has also been investigated. It is found that, as the temperature decreases, a new emission band appears, which may be due to the formation of excimers. Added to that, theoretical investigation of the highest occupied molecular orbital, the lowest unoccupied molecular orbital, the density of states, and the optical energy gap were studied using density functional theory (DFT) with the hybrid B3LYP exchange-correlation function and the 6-311G (d,p) basis set. Absorption spectra was generated using the TD-DFT method. The absorption maximum obtained (398 nm) for HTM1 closely matched with the experimental value (393 nm). Following these characterizations, simulation studies on the photovoltaic performances of the HTM1 for perovskite solar cells have been done. This cell provided a maximum PCE of 21.31%.

Improvement in Dibenzofuran-Based Hole Transport Materials for Flexible Perovskite Solar Cells.

The π-conjugated system and the steric configuration of hole transport materials (HTMs) could greatly affect their various properties and the corresponding perovskite solar cells' efficiencies. Here, a molecular engineering strategy of incorporating different amounts of p-methoxyaniline-substituted dibenzofurans as π bridge into HTMs was proposed to develop oligomer HTMs, named mDBF, bDBF, and tDBF. Upon extending the π-conjugation of HTMs, their HOMO energy levels were slightly deepened, significantly increasing the thermal stability and hole mobility. The incorporation of p-methoxyaniline bridges built one or two additional triphenylamine propeller structures, resulting in a denser film. Here, the tDBF-based n-i-p flexible perovskite solar cells createdchampion efficiency, giving a power conversion efficiency of 19.46%. And the simple synthesis and purification process of tDBF contributed to its low manufacturing cost in the laboratory. This work provided a reference for the development of low-cost and efficient HTMs.