Stability of Perovskite Thin Films under Working Condition: Bias-Dependent Degradation and Grain Boundary Effects

Witnessed by the rapid increase of power conversion efficiency to 25.5%, organic–inorganic hybrid perovskite solar cells (PSCs) are becoming promising candidates of next-generation photovoltaics. However, PSCs can be unstable under the influence of light and bias. Especially, grain boundaries (GBs) are vulnerable to attack by light and bias in perovskite films, leading to degradation of photovoltaic properties of PSCs. Herein, photocurrent atomic force microscopy and Kelvin probe force microscopy are employed to systematically investigate the bias-dependent charge transport behaviors and stability of (FAPbI₃)_0.85(MAPbBr₃)_0.15 perovskite under working condition. Bias-dependent morphology and photocurrent images show irreversible decomposition of the perovskite at a bias of 0.1 V or below, which is accelerated by light illumination, leading to formation of an interfacial layer that restricts carrier transport. Meanwhile, GBs appear to enhance carrier transport at larger bias, but serve as breakthrough sites for perovskite decomposition at smaller bias. Introducing excess methylammonium iodide promotes decomposition, while potassium iodide passivation greatly relieves the decomposition. These results support the ion migration mechanism of decomposition through interfaces and GBs. This work provides a deeper understanding of bias-induced degradation of PSCs as well as bias-dependent double-edged roles of GBs, and forms valuable guidance for appropriate operation of PSCs.     

Self-Organized Co3O4-SrCO3 Percolative Composites Enabling Nanosized Hole Transport Pathways for Perovskite Solar Cells

Perovskite solar cells (PSCs) are expected to profoundly impact the photovoltaic society on account of its high-efficiency and cost-saving manufacture. As a key component in efficient PSCs, the hole transport layer (HTL) can selectively collect photogenerated carriers from perovskite absorbers and prevent the charge recombination at interfaces. However, the mainstream organic HTLs generally require multi-step synthesis and hygroscopic dopants that significantly limit the practical application of PSCs. Here, a self-organized percolative architecture composed of narrow bandgap oxides (e.g., Co₃O₄, NiO, CuO, Fe₂O₃, and MnO₂) and wide bandgap SrCO₃ oxysalt as efficient HTLs for PSCs is presented. The percolation of dual phases offers nanosized hole transport pathways and optimized interfacial band alignments, enabling significantly improved charge collection compared with the single phase HTLs. As a consequence, the power conversion efficiency boosted from 8.08% of SrCO₃ based device and 15.47% of Co₃O₄ based device to 21.84% of Co₃O₄-SrCO₃ based one without notable hysteresis. The work offers a new direction by employing percolative materials for efficient charge transport and collection in PSCs, and would be applicable to a wide range of opto-electronic thin film devices.     

Interface Dipole Induced Field-Effect Passivation for Achieving 21.7% Efficiency and Stable Perovskite Solar Cells

Organolead halide hybrid perovskite solar cells (PSCs) have become a shining star in the renewable devices field due to the sharp growth of power conversion efficiency; however, interfacial recombination and carrier-extraction losses at heterointerfaces between the perovskite active layer and the carrier transport layers remain the two main obstacles to further improve the power conversion efficiency. Here, novel field-effect passivation has been successfully induced to effectively suppress the interfacial recombination and improve interfacial charge transfer by incorporating interfacial polarization via inserting a high work function interlayer between perovskite and holes transport layer. The charge dynamics within the device and the mechanism of the field-effect passivation are elucidated in detail. The unique interfacial dipoles reinforce the built-in field and prevent the photogenerated charges from recombining, resulting in power conversion efficiency up to 21.7% with negligible hysteresis. Furthermore, the hydrophobic interlayer also suppresses the perovskite decomposition by preventing the moisture penetration, thereby improving the humidity stability of the PSCs (>91% of the initial power conversion efficiency (PCE) after 30 d in 65 ± 5% humidity). Finally, several promising research perspectives based on field-effect passivation are also suggested for further conversion efficiency improvements and photovoltaic applications.     

Fully High‐Temperature‐Processed SnO2 as Blocking Layer and Scaffold for Efficient,Stable, and Hysteresis‐Free Mesoporous Perovskite Solar Cells

Planar perovskite solar cells (PSCs) based on low‐temperature‐processed (LTP) SnO₂ have demonstrated excellent photovoltaic properties duo to the high electron mobility, wide bandgap, and suitable band energy alignment of LTP SnO₂. However, planar PSCs or mesoporous (mp) PSCs based on high‐temperature‐processed (HTP) SnO₂ show much degraded performance. Here, a new strategy with fully HTP Mg‐doped quantum dot SnO₂ as blocking layer (bl) and a quite thin SnO₂ nanoparticle as mp layer are developed. The performances of both planar and mp PSCs has been greatly improved. The use of Mg‐SnO₂ in planar PSCs yields a high‐stabilized power conversion efficiency (PCE) of close to 17%. The champion of mp cells exhibits hysteresis free and stable performance with a high‐stabilized PCE of 19.12%. The inclusion of thin mp SnO₂ in PSCs not only plays a role of an energy bridge, facilitating electrons transfer from perovskite to SnO₂ bl, but also enhances the contact area of SnO₂ with perovskite absorber. Impedance analysis suggests that the thin mp layer is an “active scaffold” selectively collecting electrons from perovskite and can eliminate hysteresis and effectively suppress recombination. This is an inspiring advance toward high‐performance PSCs with HTP mp SnO₂.     

Enhanced Stability of Perovskite Solar Cells with Low‐Temperature Hydrothermally Grown SnO2 Electron Transport Layers

Perovskite solar cells (PSCs) may offer huge potential in photovoltaic conversion, yet their practical applications face one major obstacle: their low stability, or quick degradation of their initial efficiencies. Here, a new design scheme is presented to enhance the PSC stability by using low‐temperature hydrothermally grown hierarchical nano‐SnO₂ electron transport layers (ETLs). The ETL contains a thin compact SnO₂ layer underneath a mesoporous layer of SnO₂ nanosheets. The mesoporous layer plays multiple roles of enhancing photon collection, preventing moisture penetration and improving the long‐term stability. Through such simple approaches, PSCs with power conversion efficiencies of ≈13% can be readily obtained, with the highest efficiency to be 16.17%. A prototypical PSC preserves 90% of its initial efficiency even after storage in air at room temperature for 130 d without encapsulation. This study demonstrates that hierarchical SnO₂ is a potential ETL for fabricating low‐cost and efficient PSCs with long‐term stability.     

Multiple Function Synchronous Optimization by PbS Quantum Dots for Highly Stable Planar Perovskite Solar Cells with Efficiency Exceeding 23%

Colloidal lead sulfide (PbS) quantum dots (QDs), which possess quantum confinement effect and processing compatibility with perovskite, are regarded as an excellent material for optimizing perovskite solar cells (PSCs). However, the existing PSCs optimized by PbS QDs are still facing the challenges of poor performance of the charge transport layers, low utilization in the near-infrared (NIR) region, and unsuitable energy level alignment, which limit the improvement of power conversion efficiency (PCE). Herein, a synchronous optimization strategy is realized via simultaneously introducing PbS QDs into SnO₂ electron transport layer and employing rare-earth-doped PbS QDs (Eu:PbS QDs) film with hydrophobic chain ligands as the NIR light-absorping layer and hole transport layer (HTL) of devices. PbS QDs effectively decrease the density of trap states by passivating defects. Eu:PbS QDs film with adjustable bandgap is employed as an absorption layer to broaden the NIR spectral absorption. The well-matched energy level between Eu:PbS QDs layer and perovskite layer implies efficient hole transfer at the interface. The successful synchronous optimization greatly elevates all photovoltaic parameters, reaching a maximum PCE of 23.27%. This PCE is the highest for PSCs utilizing PbS QDs material in recent years. The optimized PSCs retain long-term moisture and light stability.     

TBP precursor agent passivated ZnO electron transport layer for highly efficient polymer solar cells

Defects passivation in electron transport layer (ETL) is a key issue to optimize the performance of polymer solar cells (PSCs). In this work, a novel strategy is developed to form defects passivated ZnO ETL by introducing 4-tert-butylpyridine (TBP) agent into precursor. While the power conversion efficiency (PCE) of the inverted PSCs based poly{4,8-bis [(2-ethylhexyl)oxy]benzo [1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno [3,4-b]thiophene-4,6-diyl}:[6,6]-phenyl C71-butyric acid methyl ester (PTB7:PC₇₁BM) with the pure ZnO ETL is 8.02%, that of the device with modified ZnO ETL is dramatically improved to 10.26%, with TBP accounting for ~28% efficiency improvement. Our study demonstrates that the precursor agent significantly affect the surface morphology and size of ZnO in ETL. Furthermore, it proves that the ZnO ETL with TBP (T-ZnO) is beneficial to polish interfacial contact between ETL and active layer and depress exciton quenching loss, resulting in enhanced exciton dissociation, efficient carrier collection and reduced charge recombination, thus improving the device performance. To verify the universality of T-ZnO ETL, the champion photovoltaic performance with a PCE of 11.74% (10% improvement) is obtained in the PBDB-T-2F:IT-4F based nonfullerene PSCs using T-ZnO as ETL. Our work developed a new, universal and facile strategy for designing highly efficient PSCs based on fullerene and nonfullerene blend systems.     

Pyrite‐Based Bi‐Functional Layer for Long‐Term Stability and High‐Performance of Organo‐Lead Halide Perovskite Solar Cells

Organo‐lead halide perovskite solar cells (PSCs) have received great attention because of their optimized optical and electrical properties for solar cell applications. Recently, a dramatic increase in the photovoltaic performance of PSCs with organic hole transport materials (HTMs) has been reported. However, as of now, future commercialization can be hampered because the stability of PSCs with organic HTM has not been guaranteed for long periods under conventional working conditions, including moist conditions. Furthermore, conventional organic HTMs are normally expensive because material synthesis and purification are complicated. It is herein reported, for the first time, octadecylamine‐capped pyrite nanoparticles (ODA‐FeS₂ NPs) as a bi‐functional layer (charge extraction layer and moisture‐proof layer) for organo‐lead halide PSCs. FeS₂ is a promising candidate for the HTM of PSCs because of its high conductivity and suitable energy levels for hole extraction. A bi‐functional layer based on ODA‐FeS₂ NPs shows excellent hole transport ability and moisture‐proof performance. Through this approach, the best‐performing device with ODA‐FeS₂ NPs‐based bi‐functional layer shows a power conversion efficiency of 12.6% and maintains stable photovoltaic performance in 50% relative humidity for 1000 h. As a result, this study has the potential to break through the barriers for the commercialization of PSCs.     

Tuning Hole Transport Layer Using Urea for High‐Performance Perovskite Solar Cells

Interface engineering is critical to the development of highly efficient perovskite solar cells. Here, urea treatment of hole transport layer (e.g., poly(3,4‐ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS)) is reported to effectively tune its morphology, conductivity, and work function for improving the efficiency and stability of inverted MAPbI₃ perovskite solar cells (PSCs). This treatment has significantly increased MAPbI₃ photovoltaic performance to 18.8% for the urea treated PEDOT:PSS PSCs from 14.4% for pristine PEDOT:PSS devices. The use of urea controls phase separation between PEDOT and PSS segments, leading to the formation of a unique fiber‐shaped PEDOT:PSS film morphology with well‐organized charge transport pathways for improved conductivity from 0.2 S cm^?1 for pristine PEDOT:PSS to 12.75 S cm^?1 for 5 wt% urea treated PEDOT:PSS. The urea‐treatment also addresses a general challenge associated with the acidic nature of PEDOT:PSS, leading to a much improved ambient stability of PSCs. In addition, the device hysteresis is significantly minimized by optimizing the urea content in the treatment.     

Dopant‐Free,Amorphous–Crystalline Heterophase SnO2 Electron Transport Bilayer Enables >20% Efficiency in Triple‐Cation Perovskite Solar Cells

Improving the ohmic contact and interfacial morphology between an electron transport layer (ETL) and perovskite film is the key to boost the efficiency of planar perovskite solar cells (PSCs). In the current work, an amorphous–crystalline heterophase tin oxide bilayer (Bi‐SnO₂) ETL is prepared via a low‐temperature solution process. Compared with the amorphous SnO₂ sol–gel film (SG‐SnO₂) or the crystalline SnO₂ nanoparticle (NP‐SnO₂) counterparts, the heterophase Bi‐SnO₂ ETL exhibits improved surface morphology, considerably fewer oxygen defects, and better energy band alignment with the perovskite without sacrificing the optical transmittance. The best PSC device (active area ≈ 0.09 cm²) based on a Bi‐SnO₂ ETL is hysteresis‐less and achieves an outstanding power conversion efficiency of ≈20.39%, which is one of the highest efficiencies reported for SnO₂‐triple cation perovskite system based on green antisolvent. More fascinatingly, large‐area PSCs (active areas of ≈3.55 cm²) based on the Bi‐SnO₂ ETL also achieves an extraordinarily high efficiency of ≈14.93% with negligible hysteresis. The improved device performance of the Bi‐SnO₂‐based PSC arises predominantly from the improved ohmic contact and suppressed bimolecular recombination at the ETL/perovskite interface. The tailored morphology and energy band structure of the Bi‐SnO₂ has enabled the scalable fabrication of highly efficient, hysteresis‐less PSCs.     

Inorganic Electron Transport Materials in Perovskite Solar Cells

In the past decade, the perovskite solar cell (PSC) has attracted tremendous attention thanks to the substantial efforts in improving the power conversion efficiency from 3.8% to 25.5% for single-junction devices and even perovskite-silicon tandems have reached 29.15%. This is a result of improvement in composition, solvent, interface, and dimensionality engineering. Furthermore, the long-term stability of PSCs has also been significantly improved. Such rapid developments have made PSCs a competitive candidate for next-generation photovoltaics. The electron transport layer (ETL) is one of the most important functional layers in PSCs, due to its crucial role in contributing to the overall performance of devices. This review provides an up-to-date summary of the developments in inorganic electron transport materials (ETMs) for PSCs. The three most prevalent inorganic ETMs (TiO₂, SnO_2, and ZnO) are examined with a focus on the effects of synthesis and preparation methods, as well as an introduction to their application in tandem devices. The emerging trends in inorganic ETMs used for PSC research are also reviewed. Finally, strategies to optimize the performance of ETL in PSCs, effects the ETL has on J–V hysteresis phenomenon and long-term stability with an outlook on current challenges and further development are discussed.     

Origin of high fill factor in polymer solar cells from semiconducting polymer with moderate charge carrier mobility

The fill factor of polymer bulk heterojunction solar cells (PSCs), which is mainly governed by the processes of charge carrier generation, recombination, transport and extraction, and the competition between them in the device, is one of the most important parameters that determine the power conversion efficiency of the device. We show that the fill factor of PSCs based on thieno[3,4-b]-thiophene/benzodithiophene (PTB7):[6,6]-phenyl C₇₁-butyric acid methylester (PC₇₁BM) blend that only have moderate carrier mobilities for hole and electron transport, can be enhanced to 76% by reducing the thickness of the photoactive layer. A drift–diffusion simulation study showed that reduced charge recombination loss is mainly responsible for the improvement of FF, as a result of manipulating spatial distribution of charge carrier in the photoactive layer. Furthermore, the reduction of the active layer thickness also leads to enhanced built-in electric field across the active layer, therefore can facilitate efficient charge carrier transport and extraction. Finally, the dependence of FF on charge carrier mobility and transport balance is also investigated theoretically, revealing that an ultrahigh FF of 80–82% is feasible if the charge mobility is high enough (∼10⁻³–10⁻¹ cm²/V s).     

Towards Simplifying the Device Structure of High‐Performance Perovskite Solar Cells

Perovskite solar cells (PSCs) are considered one of the most promising next‐generation examples of high‐tech photovoltaic energy converters, as they possess an unprecedented power conversion efficiency with low cost. A typical high‐performance PSC generally contains a perovskite active layer sandwiched between an electron‐transport layer (ETL) and a hole‐transport layer (HTL). The ETL and HTL contribute to the charge extraction in the PSC. However, these additional two layers complicate the manufacturing process and raise the cost. To extend this technology for commercialization, it is highly desired that the structure of PSCs is further simplified without sacrificing their photovoltaic performances. Thus, ETL‐free or/and HTL‐free PSCs are developed and attract more and more interest. Herein, the commonly used methods in reducing the defect density and optimizing the energy levels in conventional PSCs in order to simplify their structures are summarized. Then, the development of diverse ETL‐free or/and HTL‐free PSCs is discussed, with the PSCs classified, including their working principles, implemented technologies, remaining challenges, and future perspectives. The aim is to redirect the way toward low‐cost and high‐performance PSCs with the simplest possible architecture.     

Synergetic Excess PbI2 and Reduced Pb Leakage Management Strategy for 24.28% Efficient,Stable and Eco-Friendly Perovskite Solar Cells

Introducing excess PbI₂ has proven to be an effective in situ passivation strategy for enhancing efficiency of perovskite solar cells (PSCs). Nevertheless, the photoinstability and hysteresis are still tough issues owing to the photolysis nature of PbI₂. Moreover, the humidity-related degradation of perovskite films is also a difficult territory to cover in such an in situ passivation strategy. Herein, a synergistic strategy is reported via initiatively inducing vertical graded PbI₂ distribution (GPD) in the whole perovskite film and capping a cis-Ru(H₂dcbpy)(dnbpy)(NCS)₂ (Z907) internal encapsulation (IE) layer on the surface to ameliorate the above issues. The GPD design can enhance luminescence, prolong carrier lifetimes, ascertaining the improvement of efficiency and elimination of photoinstability in the PSCs. Besides, the introduced IE layer not only can promote the moisture and thermal resistance, but also inhibit Pb leakage and ion migration in the PSCs. Through the synergetic regulations, the resultant PSCs exhibit an impressive open circuit voltage (V_OC) of 1.253 V, fill factor of 81.25%, and power conversion efficiency (PCE) of 24.28%. Moreover, the PSCs maintain 91% of its initial PCE at relative humidity of 85% after 500 h aging and 94% under continuous heating at 85 °C after 750 h aging.     

Tailoring the Interface in FAPbI3 Planar Perovskite Solar Cells by Imidazole-Graphene-Quantum-Dots

Organic–inorganic hybrid perovskites have reached an unprecedented high efficiency in photovoltaic applications, which makes the commercialization of perovskite solar cells (PSCs) possible. In the past several years, particular attention has been paid to the stability of PSC devices, which is a critical issue for becoming a practical photovoltaic technology. In particular, the interface-induced degradation of perovskites should be the dominant factor causing poor stability. Here, imidazole bromide functionalized graphene quantum dots (I-GQDs) are demonstrated to regulate the interface between the electron transport layer (ETL) and formamidinium lead iodide (FAPbI₃) perovskite layer. The incorporation of I-GQDs not only reduces the interface defects for achieving a better energy level alignment between ETL and perovskite, but also improves the film quality of FAPbI₃ perovskite including enlarged grain size, lower trap density, and a longer carrier lifetime. Consequently, the planar FAPbI₃ PSCs with I-GQDs regulation achieve a high efficiency of 22.37% with enhanced long-term stability.     

Stabilization of α-phase FAPbI3 via Buffering Interfacial Region for Efficient p–i–n Perovskite Solar Cells

Formamidinium lead triiodide (FAPbI₃) with an ideal bandgap and good thermal stability has received wide attention and achieved a record efficiency of 26% in n–i–p (regular) perovskite solar cells (PSCs). However, imperfect FAPbI₃ formation on the typical hole transport layer (HTL), high interfacial trap-state density, and unfavorable energy alignment between the HTL and FAPbI₃ result in the inferior photovoltaic performance of p–i–n (inverted) PSCs with FAPbI₃ absorber. Herein, the α-phase FAPbI₃ is stabilized by constructing a buffer interface region between the NiO_x HTL and FAPbI₃, which not only diminishes NiO_x/FAPbI₃ interfacial reactions and defects but also facilitates carrier transport. Upon the construction of a buffer interface region, FAPbI₃ inverted PSC exhibits a high-power conversion efficiency of 23.56% (certified 22.58%) and excellent stability, retaining 90.7% of its initial efficiency after heating at 80 °C for 1000 h and 84.6% of the initial efficiency after operating at the maximum power point under continuous illumination for 1100 h. Besides, as a light-emitting diode device, the FAPbI₃ inverted PSC can be directly lit with an external quantum efficiency of 1.36%. This study provides a unique and efficient strategy to advance the application of α-phase FAPbI₃ in inverted PSCs.     

High-performance inverted polymer solar cells with lead monoxide-modified indium tin oxides as the cathode

The photovoltaic stability of polymer solar cells (PSCs) can be greatly improved by adopting an inverted device structure. This paper reports high-performance inverted PSCs with lead monoxide (PbO)-modified indium tin oxide (ITO) as the cathodes. A thin PbO layer can effectively lower the work function of ITO from 4.5 to 3.8 eV. The optimal inverted PSCs with poly(3-hexylthiophene) (P3HT) as the donor and [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) as the acceptor exhibited high photovoltaic performance: open-circuit voltage of 0.59 V, short-circuit current density of 10.8 mA cm⁻², fill factor of 0.632, and power conversion efficiency of 4.00% under simulated AM1.5G illumination (100 mW cm⁻²). The photovoltaic efficiency is significantly higher than that of the control inverted PSCs with unmodified ITO as the cathode. It is even better than that of the control PSCs with normal architecture, which have an optimal efficiency of 3.5%. The lowering in the work function by the PbO modification is attributed to the charge transfer between PbO and ITO, as evidenced by the X-ray photoelectron spectra.     

Efficient Polymer Solar Cells Based on Poly(3‐hexylthiophene):Indene‐C70 Bisadduct with a MoO3 Buffer Layer

Polymer solar cells (PSCs) with poly(3‐hexylthiophene) (P3HT) as a donor, an indene‐C₇₀ bisadduct (IC₇₀BA) as an acceptor, a layer of indium tin oxide modified by MoO₃ as a positive electrode, and Ca/Al as a negative electrode are presented. The photovoltaic performance of the PSCs was optimized by controlling spin‐coating time (solvent annealing time) and thermal annealing, and the effect of the spin‐coating times on absorption spectra, X‐ray diffraction patterns, and transmission electron microscopy images of P3HT/IC₇₀BA blend films were systematically investigated. Optimized PSCs were obtained from P3HT/IC₇₀BA (1:1, w/w), which exhibited a high power conversion efficiency of 6.68%. The excellent performance of the PSCs is attributed to the higher crystallinity of P3HT and better a donor–acceptor interpenetrating network of the active layer prepared under the optimized conditions. In addition, PSCs with a poly(3,4‐ethylenedioxy‐thiophene):poly(styrenesulfonate) (PEDOT:PSS) buffer layer under the same optimized conditions showed a PCE of 6.20%. The results indicate that the MoO₃ buffer layer in the PSCs based on P3HT/IC₇₀BA is superior to that of the PEDOT:PSS buffer layer, not only showing a higher device stability but also resulting in a better photovoltaic performance of the PSCs.     

An Ultrathin Ferroelectric Perovskite Oxide Layer for High‐Performance Hole Transport Material Free Carbon Based Halide Perovskite Solar Cells

The hole transport material (HTM) free carbon based perovskite solar cells (C‐PSCs) are promising for its manufactural simplicity, but they currently suffer from low power conversion efficiencies (PCE) largely because of the voltage loss. Here, a new strategy to increase the PCE by incorporating an ultrathin ferroelectric oxide PbTiO₃ layer between the electron transport material and the halide perovskite is reported. The resulting C‐PSCs have achieved PCEs up to 16.37%, which is the highest record for HTM‐free C‐PSCs to date, mainly ascribable to the ferroelectric layer enhanced open circuit voltage. Detail measurements and analysis show an enhanced built‐in potential in the C‐PSCs as well as suppression of the non‐radiative recombination due to the ferroelectric PbTiO₃ layer incorporation, accounting for the boosted V_OC and photovoltaic performance.     

Fused-ring electron acceptor as an efficient interfacial material for planar and flexible perovskite solar cells

Perovskite solar cell (PSC) has attracted great attention due to its high power conversion efficiency (PCE), low cost and solution processability. The well-designed interface and the modification of electron transport layer (ETL) are critical to the PCE and long-term stability of PSCs. In this article, a fused-ring electron acceptor is employed as the interfacial material between TiO₂ and the perovskite in rigid and flexible PSCs. The modification improves the surface of TiO₂, which decreases the defects of ETL surface. Moreover, the modified surface has lower hydrophilicity, and thus is beneficial to the growth of perovskite with large grain size and high quality. As a result, the interfacial charge transfer is promoted and the interfacial charge recombination can be suppressed. The highest PCE of 19.61% is achieved for the rigid PSCs after the introduction of ITIC, and the hysteresis effect is significantly reduced. Flexible PSC with ITIC obtains a PCE of 14.87%, and the device stability is greatly improved. This study provides an efficient candidate as the interfacial modifier for PSCs, which is compatible with low-temperature solution process and has a great practical potential for the commercialization of PSCs.