Organic-inorganic Hybrid Perovskite Solar Cells Research Articles

Fluorinated hole transport material resistant to high annealing temperature applied in inverted perovskites solar cells

A dopant-free and low-cost hole transport material (HTM) with dibenzo[b,d]thiophene as the center unit, bis(4-methoxyphenyl)amine as the terminal unit, and fluorine substitution adjacent to the methoxyl (named DBT-4F-MOP) is designed and applied in inverted organic-inorganic hybrid perovskite solar cells (OIH-PSCs). The synthetic cost of DBT-4F-MOP in the lab is just as low as 115 CNY/g, which is much lower than the benchmark HTM poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA, 2500 CNY/g). Due to the introduction of the fluorine atoms, the annealing temperature of the HTM can be increased by over 150 ℃. The highest efficiency of the inverted device based on it can reach 16.8 %, with an open circuit voltage of 1.04 V, a short circuit current of 21.57 mA cm−2, and a fill factor of 74.69 %, while the reference device based on PTAA can reach a PCE of 17.54 %. This work provides an avenue for the design of low-cost, dopant-free, and high-annealing temperature HTMs for inverted OIH-PSCs.

Anion Binding Interaction Enhances the Robustness of Iodide for High-Performance Perovskite Solar Cells.

Owing to the ionic bond nature of the Pb-I bond, the iodide at the interface of perovskite polycrystalline films was easily lost during the preparation process, resulting in the formation of a large number of iodine vacancy defects. The presence of iodine vacancy defects can cause nonradiative recombination, provide a pathway for iodide migration, and be harmful to the power conversion efficiency (PCE) and stability of organic-inorganic hybrid perovskite solar cells (HPSCs). Here, in order to increase the robustness of iodides at the interface, a strategy to introduce anion binding effects was developed to stabilize the perovskite films. It was demonstrated that the N,N'-diphenylurea (DPU), characterized by high anionic binding constants and a Y-shaped structure, provides a relatively strong hydrogen bond donor site to effectively reduce the iodine loss during film preparation and inhibits iodide migration in the device working condition. As expected, the reduced iodine loss considerably improves the quality of the perovskite films and suppresses nonradiative recombination. The performance of the device after DPU modification was significantly increased, with the PCE rising from 23.65 to 25.01% with huge stability enhancement as well.

Maximizing photovoltaic performance of all-inorganic perovskite CsSnI3-xBrx solar cells through bandgap grading and material design

In the modern era of technology, worldwide paradigms have been shifted toward the utilization of green energy. Sun energy is the most astonishing eco-friendly resource of energy and can be harnessed with the help of photovoltaic cells. Hybrid (Organic-Inorganic) perovskite solar cells (PSCs) are emerged with incredible photovoltaic (PV) performance. Nevertheless, a significant challenge lies in their lower stability under diverse environmental conditions. To deal with this challenge, all inorganic cesium-based PSC has been studied and analyzed, results improved stability in comparison to hybrid PSC. However, the noxious nature of lead is deleterious to the environment. So, this work primarily aimed, to study lead-free all inorganic tin-based perovskite compound CsSnI3-xBrx, as the main light absorber layer. Further, to elevate the PV performance of PSC, bandgap grading is performed on CsSnI3-xBrx by varying bromide concentration x from 0 to 3. Bandgap grading encourages the absorption of a wide range of the light spectrum, by modulating bandgap (Eg) / affinity(χ) through the distance of the CsSnI3-xBrx layer. Additionally, it enhances light-generated charge carrier separation and collection by end electrodes. In this work, two different strategies have been adopted, linear and parabolic. During linear grading, the impact of variation in x (0 to 3) has been analyzed over the thickness 50–––500 nm in 10 linear steps for CsSnI3-xBrx. The highest PCE fetched from linearly graded layered FTO / CeO2 / CsSnI3-xBrx / CFTS / Gold PSC is 21.68 %. Similarly, in the parabolic graded absorber layer, the influence of change in the bowing factor (0 to 1), has been analyzed relative to different values of x (0 to 3). With improvement in PV performance, the maximum PCE delivered by parabolic-graded PSC is 23.61 %. Additionally, this work extends to check the compatibility of distinct electron transport layers (ETLs) and hole transport layers (HTLs). Upon analysis, it has been found that the best PV performance was obtained while selecting SnO2 / PEDOT as ETL / HTL respectively.

Elucidating Interfacial Hole Extraction and Recombination Kinetics in Perovskite Thin Films

Hybrid organic–inorganic perovskite solar cells (PSCs) are receiving huge attention owing to their marvelous advantages, such as low cost, high efficiency, and superior optoelectronics characteristics. Despite their promising potential, charge-carrier dynamics at the interfaces are still ambiguous, causing carrier recombination and hindering carrier transport, thus lowering the open-circuit voltages (Voc) of PSCs. To unveil this ambiguous phenomenon, we intensively performed various optoelectronic measurements to investigate the impact of interfacial charge-carrier dynamics of PSCs under various light intensities. This is because the charge density can exhibit different mobility and charge transport properties depending on the characteristics of the charge transport layers. We explored the influence of the hole transport layer (HTL) by investigating charge transport properties using photoluminescence (PL) and time-resolved (TRPL) to unveil interfacial recombination phenomena and optoelectronic characteristics. We specifically investigated the impact of various thicknesses of HTLs, such as 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD), and poly(triaryl)amine (PTAA), on FA0.83MA0.17Pb(Br0.05I0.95)3 perovskite films. The HTLs are coated on perovskite film by altering the HTL’s concentration and using F4-TCNQ and 4-tert-butylpyridine (tBP) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSi) as dopants both for spiro-OMeTAD and PTAA. These HTLs diversified the charge concentration gradients in the absorption layer, thus leading to different recombination rates based on the employed laser intensities. At the same time, the generated charge carriers are rapidly transferred to the interface of the HTL/absorption layer and accumulate holes at the interface because of inefficient capacitance and mobility differences caused by differently doped HTL thicknesses. Notably, the charge concentration gradient is low at lower light intensities and did not accumulate holes at the HTL/absorption layer interface, even though they have high charge mobility. Therefore, this study highlights the importance of interfacial charge recombination and charge transport phenomena to achieve highly efficient and stable PSCs.

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.

Bulk and interface passivation through potassium iodide additives engineering enables high-performance and humidity-stable CsPbBr3 perovskite solar cells

Organic-inorganic hybrid perovskite solar cells (PSCs) have gained significant attention in the past decade due to their exceptional photovoltaic performance and unique advantages. However, the organic cation component of the hybrid perovskites results in poor humidity resistibility and thermal stability. Replacing organic cations with inorganic cations, such as Cs+, to fabricate all-inorganic CsPbX3 PSCs, is an effective way to improve their stability. Among the CsPbX3 PSCs, full-brominated CsPbBr3 PSCs have excellent moisture and thermal tolerance, with great potential for commercialization. However, these PSCs suffer from energy loss during operation, and their photoelectric conversion efficiency is lower than that of mainstream hybrid PSCs. Additive engineering is an effective method to improve the quality of perovskite films, which introduces functional additives into the perovskite precursor to induce perovskite crystallization, achieve the passivation of uncoordinated ions defects, and finely tune the energy level structures. In this study, Potassium iodide (KI) was added to the CsBr precursor solution to participate in the formation of the CsPbBr3 perovskite thin film. The partial substitution of A-site cation in the ABX3 perovskite occurred during the film formation, leading to beneficial variation of the crystal structure and photoelectronic performance in the CsPbBr3 system. The planar-architecture device based on the modified CsPbBr3 layer could reach a best efficiency of 10.06 %, together with a high open-circuit voltage (Voc) of 1.60 V. The KI-doped CsPbBr3 based PSC can retain over 90 % of the original PCE even after 30 days of aging, thanks to the diminished defect density by the KI passivation.

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.

BMP]+[BF4]--Modified CsPbI1.2Br1.8 Solar Cells with Improved Efficiency and Suppressed Photoinduced Phase Segregation.

With the rapid progress in a power conversion efficiency reaching up to 26.1%, which is among the highest efficiency for single-junction solar cells, organic-inorganic hybrid perovskite solar cells have become a research focus in photovoltaic technology all over the world, while the instability of these perovskite solar cells, due to the decomposition of its unstable organic components, has restricted the development of all-inorganic perovskite solar cells. In recent years, Br-mixed halogen all-inorganic perovskites (CsPbI3-xBrx) have aroused great interests due to their ability to balance the band gap and phase stability of pure CsPbX3. However, the photoinduced phase segregation in lead mixed halide perovskites is still a big burden on their practical industrial production and commercialization. Here, we demonstrate inhibited photoinduced phase segregation all-inorganic CsPbI1.2Br1.8 films and their corresponding perovskite solar cells by incorporating a 1-butyl-1-methylpiperidinium tetrafluoroborate ([BMP]+[BF4]-) compound into the CsPbI1.2Br1.8 films. Then, its effect on the perovskite films and the corresponding hole transport layer-free CsPbI1.2Br1.8 solar cells with carbon electrodes under light is investigated. With a prolonged time added to the reduced phase segregation terminal, this additive shows an inhibitory effect on the photoinduced phase segregation phenomenon for perovskite films and devices with enhanced cell efficiency. Our study reveals an efficient and simple route that suppresses photoinduced phase segregation in cesium lead mixed halide perovskite solar cells with enhanced efficiency.

Temperature- and illumination-dependent recombination of the photoinduced charge carriers in organic–inorganic hybrid perovskite solar cells

Temperature- and illumination-dependent recombination of the photoinduced charge carriers in organic–inorganic hybrid perovskite solar cells

Enhancing the efficiency of the organic-inorganic hybrid perovskite cells using Al-doped ZnO as an Electron Transport Layer and CNTs as a Hole Transport Layer: An experimental and numerical study

Perovskite solar cells (PSCs) have become the subject of much discussion in the photovoltaic field due to their excellent performance over the past few years. This study presents the production, characterization, and simulation of Al-doped ZnO (AZO) as an electron transport layer (ETL) at a concentration of 1% in organic-inorganic hybrid perovskite solar cells (PSC). We experimentally elaborate the AZO thin films using the sol-gel dip-coating method. We further examined the resulting film for structural, morphological, and optical properties for use in solar cells (SCs), using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and UV–visible spectroscopy. Furthermore, this work presents an optimization process led by simulation that generates high performance using CNTs, CH3NH3PbI3, and AZO as a hole transport layer (HTL), absorber layer, and ETL respectively in solar cells using SCAPS 1D software. We have carefully examined the impact of several parameters, including the layer thicknesses, temperature, defect density of the absorber layer, defect density at interfaces between AZO and perovskite and perovskite and CNTs, and series and shunt resistances (Rs and Rsh). An optimized PSC of ITO/AZO/MAPbI3/CNTs/Au is designed here with an efficiency of 25.62%, open-circuit voltage (Voc) of 1.3955 V, fill factor (FF) of 72.32%, and current density (Jsc) of 25.382 mA/cm2. Our findings provide a remarkable efficiency using the proposed model; nevertheless, as researchers, we still need to simulate and conduct experiments to increase the cell's efficiency to potentially use it in solar cells(SCs).

The first demonstration of entirely roll-to-roll fabricated perovskite solar cell modules under ambient room conditions

The rapid development of organic-inorganic hybrid perovskite solar cells has resulted in laboratory-scale devices having power conversion efficiencies that are competitive with commercialised technologies. However, hybrid perovskite solar cells are yet to make an impact beyond the research community, with translation to large-area devices fabricated by industry-relevant manufacturing methods remaining a critical challenge. Here we report the first demonstration of hybrid perovskite solar cell modules, comprising serially-interconnected cells, produced entirely using industrial roll-to-roll printing tools under ambient room conditions. As part of this development, costly vacuum-deposited metal electrodes are replaced with printed carbon electrodes. A high-throughput experiment involving the analysis of batches of 1600 cells produced using 20 parameter combinations enabled rapid optimisation over a large parameter space. The optimised roll-to-roll fabricated hybrid perovskite solar cells show power conversion efficiencies of up to 15.5% for individual small-area cells and 11.0% for serially-interconnected cells in large-area modules. Based on the devices produced in this work, a cost of ~0.7 USD W−1 is predicted for a production rate of 1,000,000 m² per year in Australia, with potential for further significant cost reductions.

The Role of Grain Boundaries in Organic–Inorganic Hybrid Perovskite Solar Cells and its Current Enhancement Strategies: A Review

Grain boundaries (GBs) in perovskite polycrystalline films are the most sensitive place for the formation of the defect states and the accumulation of impurities. Thus, abundant works have been carried out to explore their properties and then try to solve the induced problems. Currently, two important issues remain. First, the role of GBs in charge carrier dynamics is unclear due to their component complexity/defect tolerance nature and the insufficiency in testing accuracy. Some works conclude that GBs are benign, while others consider GBs as carrier recombination centers. Things for sure are the deterioration in ion transport and perovskite decomposition. Second, to solve the known hazards of GBs, a lot of additives have been added to anchoring ions and passivate defects. But in most of those works, GBs and perovskite surfaces are treated in the same manner ignoring the fact that GB is essentially a homogeneous junction in a narrow and slender space, while surface is a heterogeneous junction with a stratified structure. In this review, we focus on works insight into GBs and additives for them. Additionally, we also discuss the prospects of the maturity of GB exploration toward upscaling the manufacture of perovskite photovoltaic and related optoelectronic devices.

A Different, Nondestructive Method of Investigating In Situ Degradation in Hybrid Perovskite Solar Cells

One of the most significant impediments to the upscaling of hybrid organic-inorganic perovskite (HOIP) solar cells is poor stability. So, to effectively establish precautionary strategies, it is necessary to have a comprehensive grasp of the mechanisms that contribute to their degradation. Conventional characterization techniques used for in situ degradation assessment of perovskite solar cells either track just universal parameters, which yields poor insights about localized degradation processes, or the technique itself induces degradation, which may confound results. Developed in this study is a nondestructive technique of analyzing in situ active layer degradation in HOIP solar cells’ active layer utilizing a combination of optical modelling and ageing device’s reflectance tracking. The optical dielectric functions of the solar cell’s functional layers were modelled using the layers’ transmitted and reflected light spectra. The transfer matrix approach was used to fit the reflectance spectrum of entire solar cell layer stacks utilizing the computed dielectric functions for individual materials and accounting for the possibility of lead iodide gradient layer formation in the model. Leveraging no other characterization method, the presence of a lead iodide gradient layer was identified within the solar cell layer stack, an unmistakable indicator of methyl ammonium lead iodide perovskite (MAPI) degradation, probing with only photons.

Inducing 2D Structure at Grain‐Boundary via Triazinane Molecular Modification to Improve Stability of Inverted Perovskite Solar Cells

Active layers of p–i–n organic–inorganic hybrid perovskite solar cells (PSCs) are passivated by star‐shape, multifunctional triazinane molecules, cyanuric acid (CA), and Tris(dibutylhydroxy‐ benzyl)isocyanuric acid (TPCA). The most interesting is that CA is used as a bulk additive is able to induce a two‐dimensional (2D) structure at grain boundaries (GBs) of the perovskite when excess PbI2 is present. TPCA is also important to use as a perovskite surface modifier and to reduce the defects in perovskite layer further. The reduced ideality factors, enhanced photoluminescence, and prolonged lifetimes all indicate suppression of non‐radiative recombination. The combination of the two substantially improves fill‐factors and open‐circuit voltages of the devices. This leads to markedly enhanced stabilities of the devices.

Rapid Evaporation of a Metal Electrode for a High-Efficiency Perovskite Solar Cell.

Organic-inorganic hybrid perovskite solar cells (PSCs) have attracted considerable attention due to the excellent optoelectronic properties of perovskite materials. The energy consumption and high cost issues of metal electrode evaporation should be addressed before large-scale manufacturing and application. We developed an effective metal electrode evaporation procedure for the fabrication of high-efficiency planar heterojunction (PHJ) PSCs, with an inverted device structure of glass/indium tin oxide (ITO)/poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA)/perovskite/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/(E)-β-caryophyllene (BCP)/Ag. The effect of the evaporation rate for an evaporator with a small-volume metal cavity on the performance of PHJ-PSC devices was investigated systematically. Through controlling the processes of Ag electrode evaporation, the charge dynamics of the devices were studied by analyzing their charge recombination resistance and lifetime, as well as their defect state density. Our findings reveal that the evaporation rate of an evaporator with a small cavity is favorable for the performance of PHJ-PSCs. As a result, PHJ-PSCs fabricated using a very thin, non-doped PTAA film exhibit photoelectric conversion efficiency (PCE) of 19.21%, with an open-circuit voltage (Voc) of 1.132 V. This work showcases the great potential of rapidly evaporating metal electrodes to reduce fabrication costs, which can help to improve the competitiveness in the process of industrialization.

Enhancement of Interfacial Properties by Indoloquinoxaline‐Based Small Molecules for Highly Efficient Wide‐Bandgap Perovskite Solar Cells

AbstractInterfacial engineering in organic–inorganic hybrid perovskite solar cells (PSCs) has attracted significant attention, aiming to achieve high‐performing and highly stable devices. Here, newly designed organic small molecules based on quinoxaline and triphenylamine for inverted type wide‐bandgap PSCs are introduced, with the objective of enhancing the interfacial properties between perovskite and NiOx hole transport layer (HTL). The incorporation of an organic interlayer effectively reduces the energy level offset between the HTL and wide‐bandgap perovskite, while passivating defects within the perovskite layer. It leads to improved charge extraction and minimized non‐radiative recombination at the interface. Furthermore, the enhanced interfacial characteristics and hydrophobicity contribute to the improvement of perovskite film quality, resulting in larger grain size and higher crystallinity. As a result, the power conversion efficiency (PCE) of the PSC is enhanced from 18.9% to 20.1% with the incorporation of the IQTPAFlu interlayer, accompanied by an increase in Voc to ≈1.3 V, achieving a significantly low Voc deficit of 0.46 V. And the IQTPAFlu‐based devices demonstrate stable and consistent performance over 500 h, with ≈91% of their initial PCE retained. The highly stable wide‐bandgap PSCs, characterized by high Voc and PCEs, hold great promise as potential candidates for tandem solar cells.

Open-Circuit-Voltage Improvement Mechanism of Perovskite Solar Cells Revealed by Operando Spin Observation.

Organic-inorganic hybrid perovskite solar cells have attracted much attention as important next-generation solar cells. Their solar cell performance is known to change during operation, but the root cause of the instability remains unclear. This report describes an investigation using electron spin resonance (ESR) to evaluate an improvement mechanism for the open-circuit voltage, VOC, of inverted perovskite solar cells at the initial stage of device operation. The ESR study revealed electron transfer at the interface from the perovskite layer to the hole-transport layer not only under dark conditions but also under light irradiation, where electrons are subsequently trapped in the hole-transport layer. An electron barrier is enhanced at the perovskite/hole-transport-layer interface, improving field-effect passivation at the interface. Thereby, the interface recombination velocity is reduced, and thus the VOC improves. These findings are crucially important for elucidating the mechanisms of device performance changes under operation. They reveal a relation between charge transfer and performance improvement, which is valuable for the further development of efficient perovskite solar cells.

Optimized Doping of Diffusion Blocking Layers and Their Impact on the Performance of Perovskite Photovoltaics.

The roll-to-roll printing production process for hybrid organic-inorganic perovskite solar cells (PSCs) demands thick and high-performance solution-based diffusion blocking layers. Inverted (p-i-n) PSCs usually incorporate solution-processed PC70BM as the electron-transporting layer (ETL), which offers good electron charge extraction and passivation of the perovskite active layer grain boundaries. Thick fullerene diffusion blocking layers could benefit the long-term lifetime performance of inverted PSCs. However, the low conductivity of PC70BM significantly limits the thickness of the PC70BM buffer layer for optimized PSC performance. In this work, we show that by applying just enough N-DMBI doping principle, we can maintain the power conversion efficiency (PCE) of inverted PSCs with a thick (200 nm) PC70BM diffusion blocking layer. To better understand the origin of an optimal doping level, we combined the experimental results with simulations adapted to the PSCs reported here. Importantly, just enough 0.3% wt N-DMBI-doped 200 nm PC70BM diffusion blocking layer-based inverted PCSs retain a high thermal stability at 60 °C of up to 1000 h without sacrificing their PCE photovoltaic parameters.

Efficient all lead-free perovskite solar cell simulation of FASnI3/FAGeCl3 with 30% efficiency: SCAPS-1D investigation

Hybrid organic–inorganic perovskite solar cells (PSCs) currently receives extensive amounts of focus as one of e main study areas in photovoltaic technology, despite its significant progress and high efficiency; the PSCs face numerous issues, such as stability over time and toxic effects of lead. Recently, to address the problem of toxicity, FASnI3 is commonly used to be an absorber in perovskite solar device due to its promising performance. During this article, we formed and modeled a lead-free n-i-p perovskite solar device made of FASnI3 on i-layer and FAGeCl3 for a p-layer, FASnI3 in the n-layer using the simulator SCAPS-1D. To gain better understanding of this solar cell, various parameters impacting the device performance including thickness and doping level of i-layer, n-layer and p-layer thickness, the total i-layer density of defect and the impact of the temperature on the efficiency of device, are investigated and discussed. This new study is interesting since we added a thin layer of FASnI3 that was strongly n-doped to achieve great performance. The importance and effect of n+-FASnI3 on the device performance were showed and discussed. The efficiency of the device has been demonstrated to be affected by both the thickness and doping level of the extra layer n+-FASnI3. The Voc of the concerned device was increased to 1.1 V after adding n+-FASnI3 layer, the current density Jsc increased to 31.42 mA/cm2, the Fill Factor up to 87.33%, after including n+-FASnI3 into the PSC, a high efficiency of 30.19% can be obtained. These simulation results will allow it achievable to develop and manufacture, high-efficiency, with no-lead PSCs.

Synergistic Surface Defect Passivation of Ionic Liquids for Efficient and Stable MAPbI3-Based Inverted Perovskite Solar Cells.

Organic-inorganic hybrid perovskite solar cells are fabricated using polycrystalline perovskite thin films, which possess high densities of point and surface defects. The surface defects of perovskite thin films are the key factors that affect the device performance. Therefore, the reduction of harmful defects is the primary task for improving device performance. Therefore, in this study, high-quality perovskite thin films are prepared using an ionic liquid, dithiocarbamate diethylamine (DADA), to passivate the interface. The electron-rich sulfur atom in the DADA molecule chelates with the uncoordinated lead ion in the perovskite films, and the diethylammonium cation forms a hydrogen bond with the free iodine ion, which further improves the passivation. The synergistic passivation and improved morphology of the perovskite thin films substantially reduce the number of charged defects on the film surface and prolong the carrier lifetime. In addition, the DADA surface treatment increases the work function of the perovskite film, which is beneficial for carrier transport. Under standard solar-lighting conditions, the power conversion efficiency (PCE) of the device increases from 19.13 to 21.36%, and the fill factor is as high as 83.17%. Owing to both the hydrophobicity of DADA molecules and the passivation of ion defects, the PCE of the device remains above 80%, even for the device stored for 500 h in air at a relative humidity of 65%, and the device stability is substantially improved.