Initial Power Conversion Efficiency Research Articles

Mechanical Compression‐Enabled Carbon‐Based Perovskite Solar Cells with Enhanced Efficiency and Stability

Carbon electrode‐based perovskite solar cells (C‐PSCs) without hole transport layer (HTL) have been emerging as a promising low‐cost photovoltaic technology with excellent stability for commercialization. However, the loose physical contact between the carbon electrode and perovskite layer, as well as the relatively poor conductivity of the carbon film, contributes mainly to the large gap in the power conversion efficiency (PCE) between C‐PSCs and the metal (Ag, Au, etc.,) electrode‐based counterparts. To this end, a simple but effective mechanical compression strategy for efficient C‐PSCs is developed. The mechanical compression densifies the porous carbon electrode for high film conductivity and also provides intimate contact between carbon and perovskite layers for fast charge extraction. Consequently, the resulting HTL‐free C‐PSCs using MAPbI3 (MA = methylammonium) absorber yield a PCE of 15.29%, corresponding to a 27.6% improvement compared to the counterpart without mechanical pressing treatment. Moreover, the compacted carbon film also serves as an enhanced barrier against the intrusion of water and oxygen, and the unencapsulated device retains 88.9% of its initial PCE after 1000 h of aging in ambient conditions with 35 ± 2% humidity. This work paves a simple and effective way toward efficient and stable C‐PSC.

Glutathione-Coated Gold Nanoparticles Enabling Bifunctional Therapy at the Buried Interface for Efficient and UV-Resistant Perovskite Solar Cells.

Very recently, the poor contact between the perovskite and carrier selective layer has been regarded as a critical issue for improving the performance and stability of perovskite solar cells (PSCs). In this study, the buried interface of regularly structured PSCs has been targeted. Glutathione-coated gold nanoparticles (GSH-AuNPs) are used as double-sided passivating agents to improve the quality of the perovskite films. It has been demonstrated that the GSH-AuNPs interact strongly with the SnO2 underlayer and the upper perovskite layer, significantly reducing the defect densities of this interface. Thus, the power conversion efficiency (PCE) of the PSCs can be increased from 20.46% (control, 19.38%, IPCE corrected) to 22.22% (GSH-AuNPs modified, 21.10%, IPCE corrected) with notable enhancement in Voc and FF. Moreover, the strong interaction between the C═O groups of GSH-AuNPs and the undercoordinated Pb2+ species of the perovskite films inhibits the formation of metallic Pb0. As a result, the unencapsulated GSH-AuNPs-modified devices retained 80% of their initial PCEs after 1000 h at ambient conditions, with a relative humidity (RH) of 60 ± 5%. UV-resistant PSCs have also been demonstrated after introducing GSH-AuNPs. Therefore, our findings demonstrate the bidirectional therapy strategy as a feasible approach for achieving efficient and UV-resistant PSCs.

Enhanced efficiency and stability of dye-sensitized solar cells utilizing FeCo2S4 nanowires as Pt-free counter electrodes

Replacing traditional Pt-based counter electrodes with low-cost and highly stable materials is crucial for the development of commercially viable dye-sensitized solar cells (DSSCs). In this study, we synthesized a ternary Pt-free FeCo2S4 nanowire (NW)-based sulfide electrocatalyst by a three-step solvothermal method. This material was then used as a counter electrode in DSSCs to facilitate the reduction of triiodide species. The formation of FeCo2S4 NW was confirmed by various characterization techniques such as X-ray diffraction, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Scanning electron microscopy analysis revealed the structure of the nanowires. Electrochemical studies, which included cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization methods, revealed the excellent stability, superior electrocatalytic activity and remarkable kinetics of FeCo2S4 NW in the reduction of triiodide to iodide. Photovoltaic measurements of the fabricated DSSCs yielded a power conversion efficiency (PCE) of 7.88 % for the FeCo2S4-based devices, outperforming the control device made of Pt (PCE=7.45 %). This improvement was primarily due to the increase in short-circuit current density (JSC), thanks to the lower charge transfer resistance (RCT) of FeCo2S4 NW (JSC=15.23 mA/cm2; RCT=5.54 Ω cm2) compared to Pt (JSC=14.12 mA/cm2; RCT=7.07 Ω cm2). In addition, the FeCo2S4 NW-based solar cells exhibited excellent stability and maintained their high PCE value even after 10 days of aging under ambient conditions, while Pt-based DSSCs showed a 3 % decrease from their initial PCE value. This FeCo2S4 NW counter electrode proves to be an excellent alternative to Pt, and the presented results provide valuable insights for the development of cost-effective and highly stable DSSCs.

Tri-Step Water-Assisted Strategy for Suppressing Cs4PbBr6 Phase in Printable Carbon-Based CsPbBr3 Solar Cells to Achieve High Stability.

Often deemed the "natural nemesis" of perovskites, water molecules have been largely circumvented by the majority of researchers in the field of perovskite solar cells. This has resulted in significant hurdles in investigating the beneficial impacts of water molecules on perovskite crystallization. Herein, it is found that by utilizing ethanol with minimal water content and subjecting all-inorganic perovskite to three distinct annealing temperatures within the same solvent, the residual CsBr can be effectively removed, and the formation of the Cs4PbBr6 phase can be curtailed. By selecting an optimal water content, substantial improvements are observed in the crystalline quality of CsPbBr3, the perovskite/carbon interface, and the mesoporous filling effect. The Urbach energy (Eu) is reduced from 38.96 to 35.59meV, and the defect density decreased from 4.16×1014 to 3.39×1014cm-3. As a result, the power conversion efficiency (PCE) improved from 7.55% in the control group to 9.37%. Under severe environmental conditions with a temperature (T) of 85°C and a relative humidity (RH) of 40%, tracking tests over 1200h retained 89.3% of the initial PCE. This research signifies a breakthrough in the fabrication of highly stable and efficient all-inorganic printable mesoscopic perovskite solar cells.

The Conjugated/Non-Conjugated Linked Dimer Acceptors Enable Efficient and Stable Flexible Organic Solar Cells.

The fabrication of the flexible devices with excellent photovoltaic performance and stability is critical for the commercialization of organic solar cells (OSCs). Herein, the conjugated dimer acceptor DY-TVCl and the non-conjugated dimer acceptor DY-3T based on the monomer MY-BO are synthesized to regulate the molecular glass transition temperatures (Tg) for improving the morphology stability of active layer films. And the crack onset strain values for the blend films based on dimer acceptors are superior than that of small molecule, which are beneficial for the preparation of flexible devices. Accordingly, the binary device based on PM6:DY-TVCl achieves a maximum power conversion efficiency (PCE) of 18.01%. Meanwhile, the extrapolated T80(time to reach 80% of initial PCE) lifetimes of the PM6:DY-TVCl-based device and PM6:DY-3T-based device are 3091 and 2227h under 1-sun illumination, respectively, which are better than that of the PM6:MY-BO-based device (809h). Furthermore, the flexible devices based on DY-TVCl and DY-3T exhibit the efficiencies of 15.23% and 14.34%, respectively. This work affords a valid approach to improve the stability and mechanical robustness of OSCs, as well as ensuring the reproducibility of organic semiconductors during mass production.

Wide-bandgap MAPbBr3 perovskite solar cells using bifunctional-molecule additives achieving a high open-circuit voltage of 1.63 V

Wide-bandgap methyl ammonium lead bromide (MAPbBr3) perovskite solar cells (PSCs) attracts considerable attention due to their large open-circuit voltage (VOC), high phase stability and great potential for multi-junction tandem PSCs. However, the low film quality and high defect density of perovskite films limit the development of MAPbBr3 PSCs. Here, we employ a bifunctional-molecule of 3-chlorbenzylamine additive (3-CBA) to fabricate high quality MAPbBr3 films in ambient air and facilitate the crystallization of MAPbBr3 film, leading to higher orientated perovskite film. Additionally, 3-CBA associating with uncoordinated Pb ions effectively passivates the bulk defects, which suppresses the carrier recombination in perovskite films and obtains a high VOC of 1.63 V. To further suppress the carrier recombination at MAPbBr3/carbon interface, the 3-CBA is also used to modify the surface of the MAPbBr3 films. As a result, the 3-CBA modified MAPbBr3 film exhibits decreased roughness and increased coverage on substrates, which raises the power conversion efficiency (PCE) to 9.55 %. More importantly, the chlorphenyl in 3-CBA for both bulk and surface treatment makes the MAPbBr3 surface more hydrophobic, which enhances the stability of unencapsulated PCSs allowing it to maintain over 98 % of the initial PCE under 80 °C thermal stress and 40–70 % relative humidity. This work provides a reliable approach to enhance both the VOC and stability for MAPbBr3 wide-bandgap PSCs.

Facet orientation control of tin-lead perovskite for efficient all-perovskite tandem solar cells

Developing high-performance narrow-bandgap (NBG) perovskite solar cells based on tin-lead (Sn-Pb) perovskite is critical for the advancement of all-perovskite tandem solar cells. However, the limitations of the device current density and efficiency are magnified by the issues concerning poor carrier transport caused by a substantial number of defects in thick NBG films. This problem is further exacerbated by the quality of film crystallization, which is associated with the rapid and uncontrolled crystallization of Sn-rich perovskite chemistry using the antisolvent approach. We regulate the crystallization of Sn-contained perovskite with a mild gas-quench approach to fabricate a highly crystal-oriented and well-arranged NBG perovskite absorber. This strategy effectively boosts electron transport and light absorption of the NBG perovskite. Consequently, the average power conversion efficiency (PCE) of the NBG perovskite solar cells increases from 19.50 % to 21.18 %, with the best device achieving an excellent PCE of 21.84 %. Furthermore, when combined with a wide-bandgap perovskite subcell to form an all-perovskite tandem solar cell, a PCE of 25.23 % is achieved. After being stored in the glovebox for 1000 h, the unencapsulated device maintains over 90 % of its initial PCE, demonstrating long-term stability and durability. This work presents a promising approach for developing high-efficiency NBG perovskite solar cells.

Tungsten-Doped ZnO as an Electron Transport Layer for Perovskite Solar Cells: Enhancing Efficiency and Stability.

This study delves into enhancing the efficiency and stability of perovskite solar cells (PSCs) by optimizing the surface morphologies and optoelectronic properties of the electron transport layer (ETL) using tungsten (W) doping in zinc oxide (ZnO). Through a unique green synthesis process and spin-coating technique, W-doped ZnO films were prepared, exhibiting improved electrical conductivity and reduced interface defects between the ETL and perovskite layers, thus facilitating efficient electron transfer at the interface. High-quality PSCs with superior ETL demonstrated a substantial 30% increase in power conversion efficiency (PCE) compared to those employing pristine ZnO ETL. These solar cells retained over 70% of their initial PCE after 4000 h of moisture exposure, surpassing reference PSCs by 50% PCE over this period. Advanced numerical multiphysics solvers, employing finite-difference time-domain (FDTD) and finite element method (FEM) techniques, were utilized to elucidate the underlying optoelectrical characteristics of the PSCs, with simulated results corroborating experimental findings. The study concludes with a thorough discussion on charge transport and recombination mechanisms, providing insights into the enhanced performance and stability achieved through W-doped ZnO ETL optimization.

Solid additive enables efficient and stable organic solar cells by stabilizing morphology of active layer

Additive strategy is an effective method for optimizing the morphology of active layer in organic solar cells (OSCs). However, common high boiling points solvent additives may compromise device stability. In this work, 1‑bromo-8-chloronaphthalene (BCN) was used as a solid additive to improve device performance. The introduction of BCN promotes the crystallinity, H-aggregation and fibrillation of L8-BO. The active layer film with additive BCN exhibits optimized phase separation and refined fiber network, thus enhancing the exciton dissociation and charge transport in the corresponding devices. Compared with control devices (without additives), the power conversion efficiency (PCE) of optimized devices (with 20 wt % BCN) based on D18:L8-BO was increased from 17.49 % to 18.20 %. The detailed process of device fabrication is in experimental section. Furthermore, devices processed by BCN preserved 96.6 % and 96.3 % of the initial PCE after aging for 60 min with maximum power point (MPP) tracking and aging of storage for 960 h, respectively. The universality of BCN was verified in different systems, which offers promising opportunities to regulate BHJ morphology toward highly efficient OSCs.

Enhanced Thermal and Photostability of Perovskite Solar Cells by a Multifunctional Eu (III) Trifluoromethanesulfonate Additive

AbstractPerovskite solar cells (PSCs) have witnessed a meteoric rise in device performance. However, maintaining photostability, particularly under thermal stress, remains a challenge due to defect formation in the perovskite layer. This study introduces europium (III) trifluoromethanesulfonate [Eu(OTF)3] as a multifunctional additive in two‐step processed perovskite films, significantly improving the performance and high‐temperature photostability of n‐i‐p PSCs. Density function theory (DFT) calculations reveal that the OTF− anion strongly coordinates with Pb2+, effectively inhibiting iodine vacancy defect formation. The addition of Eu(OTF)3 promotes perovskite grain growth to ≈2 µm and enhances film crystallinity. PSCs with a structure of ITO/SnO2/perovskite/PDCBT/NiOx/Au achieve a champion power conversion efficiency (PCE) of 23.8%. Under 85 ± 5 °C and 1 sun illumination at an open circuit in ambient air, the PSCs with Eu(OTF)3 retain 82% of their initial PCE after aging for 1500 h.

Enhancing efficiency and stability of inverted perovskite solar cells through synergistic suppression of multiple defects via poly(ionic liquid)-buried interface modification

The stability of perovskite solar cells (PSCs) is adversely affected by nonradiative recombination resulting from buried interface defects. Herein, we synthesize a polyionic liquid, poly(p-vinylbenzyl trimethylammonium hexafluorophosphate) (PTA), and introduce it into the buried interface of PSCs. The quaternary ammonium cation (N(–CH3)3+) in PTA can fill the vacancies of organic cations within the perovskite structure and reduce shallow energy level defects. Additionally, the hexafluorophosphate (PF6−) in PTA forms a Lewis acid-base interaction with Pb2+ in the perovskite layer, effectively passivating deep energy level defects. Furthermore, hydrogen bonding can be established between organic cations and the PF6− anion, preventing the formation of shallow energy level defects. Through this synergistic mechanism, the deep and shallow energy level defects are effectively mitigated, resulting in improved device performance. As a result, the resulting treated inverted PSC exhibits an impressive power conversion efficiency (PCE) of 24.72 %. Notably, the PTA-treated PSCs exhibit remarkable stability, with 88.5 % of the original PCE retained after undergoing heat aging at 85 °C for 1078 h, and 89.1 % of the initial PCE maintained following continuous exposure to light for 1100 h at the maximum power point. Synergistically suppressing multiple defects at the buried interface through the use of polyionic liquids is a promising way to improve the commercial viability of PSCs.

Buried interface molecular hybrid for inverted perovskite solar cells.

Perovskite solar cells with an inverted architecture provide a key pathway for commercializing this emerging photovoltaic technology because of the better power conversion efficiency and operational stability compared with the normal device structure. Specifically, power conversion efficiencies of the inverted perovskite solar cells have exceeded 25% owing to the development of improved self-assembled molecules1-5 and passivation strategies6-8. However, poor wettability and agglomeration of self-assembled molecules9-12 cause interfacial losses, impeding further improvement in thepower conversion efficiency and stability. Here we report a molecular hybrid at the buried interface in inverted perovskite solar cells that co-assembled the popular self-assembled molecule [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) with the multiple aromatic carboxylic acid 4,4',4″-nitrilotribenzoic acid (NA) to improve the heterojunction interface. The molecular hybrid of Me-4PACz with NA could substantially improve the interfacial characteristics. The resulting inverted perovskite solar cells demonstrated a record certified steady-state efficiency of 26.54%. Crucially, this strategy aligns seamlessly with large-scale manufacturing, achieving one of the highest certified power conversion efficiencies for inverted mini-modules at 22.74% (aperture area 11.1 cm2). Our device also maintained 96.1% of its initial power conversion efficiency after more than 2,400 h of 1-sun operation in ambient air.

Modulating perovskite crystallization and band alignment using coplanar molecules for high-performance indoor photovoltaics

The proper bandgap and exceptional photostability enable CsPbI3 as a potential candidate for indoor photovoltaics (IPVs), but indoor power conversion efficiency (PCE) is impeded by serious nonradiative recombination stemming from challenges in incomplete DMAPbI3 conversion and lattice structure distortion. Here, the coplanar symmetric structure of hexyl sulfide (HS) is employed to functionalize the CsPbI3 layer for fabricating highly efficient IPVs. The hydrogen bond between HS and DMAI promotes the conversion of DMAPbI3 to CsPbI3, while the coplanar symmetric structure enhances crystalline order. Simultaneously, surface sulfidation during HS-induced growth results in the in situ formation of PbS, spontaneously creating a CsPbI3 N-P homojunction to enhance band alignment and carrier mobility. As a result, the CsPbI3&HS devices achieve an impressive indoor PCE of 39.90% (Pin: 334.6 μW cm−2, Pout: 133.5 μW cm−2) under LED@2968 K, 1062 lux, and maintain over 90% initial PCE for 800 h at ∼30% air ambient humidity.

Water- and heat-activated dynamic passivation for perovskite photovoltaics

Further improvements in perovskite solar cells require better control of ionic defects in the perovskite photoactive layer during the manufacturing stage and their usage1–5. Here we report a living passivation strategy using a hindered urea/thiocarbamate bond6–8 Lewis acid–base material (HUBLA), where dynamic covalent bonds with water and heat-activated characteristics can dynamically heal the perovskite to ensure device performance and stability. Upon exposure to moisture or heat, HUBLA generates new agents and further passivates defects in the perovskite. This passivation strategy achieved high-performance devices with a power conversion efficiency (PCE) of 25.1 per cent. HUBLA devices retained 94 per cent of their initial PCE for approximately 1,500 hours of ageing at 85 degrees Celsius in nitrogen and maintained 88 per cent of their initial PCE after 1,000 hours of ageing at 85 degrees Celsius and 30 per cent relative humidity in air.

Bimolecular Crystallization Modulation Boosts the Efficiency and Stability of Methylammonium‐Free Tin–Lead Perovskite and All‐Perovskite Tandem Solar Cells

AbstractThe elimination of methylammonium (MA) cation from mixed tin–lead (Sn–Pb) narrow‐bandgap (NBG) perovskites is an effective approach to enhance the operational stability of all‐perovskite tandem solar cells (TSCs). Unfortunately, the uncontrolled nucleation and crystallization processes of MA‐free Sn–Pb perovskites usually lead to inferior film quality and device performance. Herein, a bimolecular crystallization modulation strategy is reported by using guanidine thiocyanate (GuaSCN) and aminoacetamide hydrochloride (AHC) together as additives to improve the film quality of MA‐free Sn–Pb perovskites. It is demonstrated that the use of bimolecular additives can effectively improve the crystallinity, increase the grain size, and induce a preferred (100) orientation for the corresponding films, leading to high‐quality absorber with considerably reduced defect density and suppressed non‐radiative recombination. In addition, the bimolecular additives can reduce the self‐p‐doping hole concentration within the perovskite films and enhance the charge extraction at the perovskite/electron transport layer interface. The modified NBG perovskite solar cells deliver a power conversion efficiency (PCE) of 22.14%. Coupled with the wide‐bandgap (WBG) subcell, the all‐perovskite TSCs give a champion certified PCE of 27.15%, which is the highest certified PCE for MA‐free all‐perovskite TSCs. Encapsulated tandem devices maintain 90% of the initial PCE after 473 h operation.

One‐Step Synthesis of Lead‐Free and Hole Transport Layer‐Free Methylammonium Bismuth Chloride ((CH3NH3)3Bi2IxCl9−x)‐Based Perovskite Solar Cells

The scientific community is moving toward a green environment using several nontoxic photon‐absorbing materials like tin, germanium, antimony, and bismuth. Bismuth halides have essential advantages like low toxicity, Earth abundance, good chemical stability, and optoelectronic behavior which make them suitable for lead‐free perovskite solar cells. Herein, a streamlined one‐step spin‐coating technique is employed using DMF to enhance the morphology of thin films based on BiCl3 perovskite. The resulting thin films of methylammonium bismuth halide ((CH3NH3)3Bi2IxCl9−x) display a remarkably uniform, pinhole‐free, and finely nanostructured morphology, ensuring consistent surface coverage. For the development of hole conductor‐free Bi‐perovskite solar cells (PSCs), carbon is utilized as both counter electrode and hole extraction layer. The device configuration entails FTO/Compact TiO2/meso‐TiO2/((CH3NH3)3Bi2IxCl9−x)/Carbon/FTO, a novel arrangement for Bi‐PSCs. Notably, the fabricated devices demonstrate commendable photovoltaic properties, including Voc of 280 mV, Jsc of 0.25 mA, fill factor of 0.60, and a notably elevated power conversion efficiency (PCE) of 0.042% which has proven significantly advantageous in achieving higher PCE. Furthermore, the fabricated devices exhibit robust chemical stability over 40 d when exposed to an ambient atmosphere without encapsulation. The solar cells retain 25% of their initial PCE after 168 h, further highlighting their durability and suitability for practical applications.

Minimization of Energy Level Mismatch of PCBM and Surface Passivation for Highly Stable Sn-Based Perovskite Solar Cells by Doping n-Type Polymer.

Developing high-performance and stable Sn-based perovskite solar cells (PSCs) is difficult due to the inherent tendency of Sn2+ oxidation and, the huge energy mismatch between perovskite and Phenyl-C61-butyric acid methyl ester (PCBM), a frequently employed electron transport layer (ETL). This study demonstrates that perovskite surface defects can be passivated and PCBM's electrical properties improved by doping n-type polymer N2200 into PCBM. The doping of PCBM with N2200 results in enhanced band alignment and improved electrical properties of PCBM. The presence of electron-donating atoms such as S, and O in N2200, effectively coordinates with free Sn2+ to prevent further oxidation. The doping of PCBM with N2200 offers a reduced conduction band offset (from 0.38 to 0.21eV) at the interface between the ETL and perovskite. As a result, the N2200 doped PCBM-based PSCs show an enhanced open circuit voltage of 0.79V with impressive power conversion efficiency (PCE) of 12.98% (certified PCE 11.95%). Significantly, the N2200 doped PCBM-based PSCs exhibited exceptional stability and retained above 90% of their initial PCE when subjected to continuous illumination at maximum power point tracking for 1000h under one sun.

Designed Additive to Regulated Crystallization for High Performance Perovskite Solar Cell

AbstractIt is a crucial role for enhancing the power conversion efficiency (PCE) of perovskite solar cells (PSCs) to prepare high‐quality perovskite films, which can be achieved by delaying the crystallization of perovskite film. Hence, we designed difluoroacetic anhydride (DFA) as an additive to regulating crystallization process thus reducing defect formation during perovskite film formation. It was found DFA reacts with DMSO by forming two molecules, difluoroacetate thioether ester (DTE) and difluoroacetic acid (DA). The strong bonding DTE⋅PbI2 and DA⋅PbI2 retard perovskite crystallization process for high‐quality film formation, which was monitored through in situ UV/Vis and PL tests. By using DFA additives, we prepared perovskite films with high‐quality and low defects. Finally, a champion PCE of 25.28 % was achieved with excellent environmental stability, which retained 95.75 % of the initial PCE after 1152 h at 25 °C under 25 % RH.

Application of biodegradable poly(lactide-co-glycolide) (PLGA) for efficient & stable perovskite solar cells

Since numerous defects can deteriorate the efficiency as well as long-term stability of perovskite solar cells (PSCs), it is important to control the defects for the industrialization of PSCs. Among various defects, interest is mainly focused on treating the uncoordinated Pb2+, which not only causes the lower performance of PSCs, but also is considered as a risk to the environment and human. Herein, we investigate a FDA (Food and Drug Administration) approved biodegradable poly(lactide-co-glycolide) (PLGA) as a polymer additive to passivate uncoordinated Pb2+. PLGA contains carbonyl groups (CO), which can strongly form a coordination bonding with Pb2+, resulting in the reduction of non-radiative charge recombination and improvement of charge carrier movement. Therefore, the power conversion efficiency (PCE) of air-processed PSCs enhances from 15.87 % to 17.09 %, especially the fill factor enhances from 77.19 % to 81.33 %. The PLGA passivated devices exhibit superior thermal stability maintaining 70 % of the initial PCE for ∼100 h in the air conditions without any encapsulation, moreover, in the test of Pb leakage from perovskite, restricted dissolving of Pb in water was confirmed as a result of immobilization of uncoordinated Pb2+ ion by PLGA.

Designed Additive to Regulated Crystallization for High Performance Perovskite Solar Cell.

It is a crucial role for enhancing the power conversion efficiency (PCE) of perovskite solar cells (PSCs) to prepare high-quality perovskite films, which can be achieved by delaying the crystallization of perovskite film. Hence, we designed difluoroacetic anhydride (DFA) as an additive to regulating crystallization process thus reducing defect formation during perovskite film formation. It was found DFA reacts with DMSO by forming two molecules, difluoroacetate thioether ester (DTE) and difluoroacetic acid (DA). The strong bonding DTE⋅PbI2 and DA⋅PbI2 retard perovskite crystallization process for high-quality film formation, which was monitored through in situ UV/Vis and PL tests. By using DFA additives, we prepared perovskite films with high-quality and low defects. Finally, a champion PCE of 25.28 % was achieved with excellent environmental stability, which retained 95.75 % of the initial PCE after 1152 h at 25 °C under 25 % RH.