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Functional passivation agents have been shown to effectively optimize the crystallization process and passivate defects on the surface and grain boundaries. People have conducted extensive research on the passivation mechanisms of various passivation agents to obtain more effective passivation agents. Researchers are gradually focusing on natural ingredients in the search for suitable passivation agents due to the wide variety, green color, and ease of production. As a result, the natural chlorophyll component chlorin e6 (CE‐6) is first combined with perovskite solar cells (PSCs) to improve their performance. Following the incorporation of CE‐6 into the perovskite layer, various functional groups of CE‐6 are used to effectively reduce traps on the perovskite surface, suppress charge recombination at the interface, improve carrier transfer rate and carrier extraction efficiency, and ultimately improve efficiency. The optimal device achieves a power conversion efficiency (PCE) of 21.14% and maintains its initial PCE of 84% after being stored in a room‐temperature air environment for 500 h. Furthermore, semitransparent PSC (ST‐PSC) is made with 13.33% PCE and 5.53% average visible light transmittance. The findings show that natural material CE‐6 performs well in the perovskite layer and confirms the promising prospects for optimizing ST‐PSC. [ABSTRACT FROM AUTHOR]

Flexible perovskite solar cells (FPSCs) are attracting widespread research and attention for their benefits as the next‐generation wearable electronic products. However, there are still many challenges in the quest to achieve dense, pinhole‐free, high crystal quality, low defect, and stable perovskite films, which limit further improvement in the efficiency and stability of FPSCs. Herein, a novel technique for the incorporation of quaternary ammonium halide (QAH) additives to prepare fluffy porous lead iodide layers by using a two‐step sequential deposition method, is reported. Benefiting from the good diffusion of organic amine salts on porous PbI2 layers, flat and dense perovskite films are produced with large particle sizes, few defects, and high crystal quality. Finally, the champion rigid and flexible p‐i‐n PSCs with the 2‐(acetyloxy)‐N,N,N‐trimethylethanium chloride (AtaCl) additive achieves exciting power conversion efficiencies (PCE) of 23.40% and 21.10%, respectively. The device with the AtaCl additive retains over 90% of its original PCE under ambient conditions (40 ± 5% relative humidity (RH)) over 1000 h of aging without encapsulation. In addition, the flexible device with the AtaCl additive shows excellent stability under mechanical bending conditions, retaining ≈85% of its original PCE after 10 000 cycles (bending radius = 5 mm). [ABSTRACT FROM AUTHOR]

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has been greatly improved recently. However, in organic–inorganic polycrystalline perovskite films many defects inevitably exist, which limits the PCE and stability of PSCs. Herein, a small organic molecule 2‐chlorothiazole‐4‐carboxylic acid (SN) is spin coated on a perovskite film to enhance the performance of PSCs. We find that the multifunctional molecule SN reacts with under‐coordinated Pb2+ ions and I− vacancies because of the presence of the sulfur and nitrogen donor atoms, and the −COOH groups, which are conducive to suppressing charge recombination and passivating defects. Even more, the introduction of the SN layer can effectively adjust the energy level alignment, which is conducive to the separation and extraction of charge carriers in PSCs. Therefore, devices with SN modification show a champion PCE of 22.55 %. Besides, PSCs with SN show impressive stability, retaining 96 % of its initial PCE after storage in ambient air for 500 h. [ABSTRACT FROM AUTHOR]

[Display omitted] Perovskite solar cells (PSCs) have become a promising photovoltaic (PV) technology. Meanwhile, developing an electron transport layer (ETL) has been an effective way to promote the power conversion efficiency (PCE) of PSCs. Here, a 4-morpholine ethane sulfonic acid sodium salt (MES Na+) doped SnO 2 ETL is utilized in planar heterojunction PSCs. The results show that the MES Na+ doped ETL can improve the crystallinity, and absorbance of perovskite films, and passivate interface defects between the perovskite film and SnO 2 ETL. The doping effect accounts for the enhancement of conductivity and the decreasing work function of SnO 2. When 10 mg mL−1 MES Na+ was added to the SnO 2 precursor solution, the device showed the best performance Jsc, Voc, and FF of the PSCs values, which were 23.88 mA cm−2, 1.12 V and 78.69%, respectively, and the PCE was increased from 17.43% to 21.05%. This doping ETL strategy provides an avenue for defect passivation to further increase the efficiency of perovskite solar cells. [ABSTRACT FROM AUTHOR]

After perovskite became a star material, research on perovskite solar cells (PSCs) became a hot topic and developed rapidly. Electron transport layers (ETLs) with high mobility, low‐defect state, and suitable energy level arrangement dominate the development of planar heterojunction PSCs. In this work, the K+ and Cs+ doped composite SnO2 ETL (x mg KC‐SnO2) by a continuous spin‐coating of the x mg Cs+@KOH and SnO2 aqueous solution shows a substantial improvement in carries extraction, transport and collection properties, leading to the increased fill factor (FF) from 72.48% to 81.00% of the planar heterojunction PSCs, and finally the champion device average efficiency is 21.62%. Moreover, this work improves the interface contacts between ETL/Perovskite, as it reduces energy disorder and simultaneously promotes electron transport, charge extraction at the interface, improve energy level alignment and quasi‐Fermi level splitting, and decreased resistance for charge transfer in the device. In conclusion, this simple and effective method of improving the FF value provides a certain shortcut to the performance of plane heterogeneous perovskite devices. [ABSTRACT FROM AUTHOR]

Defect-induced charge carrier recombination between charge transport layers and perovskite layer limits the further improvement of the performance of perovskite solar cells (PSCs). Defect passivation is a promising path for further development improves in the open-circuit voltage (V OC) and the short-circuit current density (J SC) of PSCs. Here, we report a simple method via spin-coating choline halide to passivate buried interface defects of perovskite applied to inverted PSCs. The introduction of choline chloride (CHCl) can remarkably improve the crystalline quality of perovskite films, speed up the transport of carriers and reduce the trap density in perovskite, which universally enhance the performance of PSCs. Finally, the champion CHCl modified device got a high PCE of 22.61% with negligible hysteresis, which is one of the highest efficiencies of inverted PSCs fabricated with a two-step method. This optimization can also improve the stability of PSCs, the CHCl modified device without encapsulation maintained 89% of its initial PCE in air with a relative humidity of 40 ± 5% after near 800 h ageing. This work reveals an effective way of using choline halide for buried interface defects passivation of perovskite film to further improve both the stability and efficiency of solar cells. [Display omitted] • The introduction of choline halide can passivate buried interface defects of perovskite. • Choline halide is demonstrated to improve stability of the inverted perovskite solar cells. • PCE exceeding 22.6% is achieved for inverted perovskite solar cells via a two-step sequential deposition. [ABSTRACT FROM AUTHOR]

[Display omitted] The performance of perovskite solar cells (PSCs) can be improved by optimizing the perovskite film quality and electron transfer layers (ETLs). In this study, high-efficient PSCs with multi-cation hybrid electron transport layer (SnO 2 @Na:Cs ETL) were fabricated using continuous spin-coating. Compared to the pristine SnO 2 , the power conversion efficiency (PCE) of device based on SnO 2 @Na:Cs ETL have reached 22.06% (with an open circuit voltage of 1.13 V), up approximately 21%. The photovoltaic performance of the device is enhanced due to the increase in the transmission rate, electrical conductivity, electron mobility and surface state owing to the multi-cation hybrid. In addition, because SnO 2 @Na:Cs ETL can significantly improve interface contact with the perovskite film and improve its crystallinity, the transport defect state and carrier transport efficiency are significantly improved at the ETL/Perovskite interface. Therefore, the open circuit voltage (V oc) and fill factor (FF) of PSCs was significantly increased. The application of SnO 2 @Na:Cs ETL provides a simple and efficient method to obtain highly-efficient PSCs. [ABSTRACT FROM AUTHOR]

[Display omitted] • The 5PFP-Br is used as a double-interface passivator for PSCs. • The ETL with 5PFP-Br passivation has higher conductivity and electron mobility. • The perovskite with 5PFP-Br passivation has lower interfacial carrier defect state. • The PCE of the treated device increased from 18.09% to 21.15%. • The device based 5PFP-Br double-interface passivator have good stability. In order to obtain high power conversion efficiency and high stability perovskite solar cells, many innovative optimization schemes have been proposed. Thereinto, the interface modification become an effective way to improve the performance of device. Here, A dual-interface passivation by 2, 3, 4, 5, 6-pentafluorophenylammonium bromide-based (5PFP-Br) is used to optimize the performance of device with the structure of ITO/SnO 2 /perovskite/PTAA/Ag. We design the 5PFP-Br layer at SnO 2 /perovskite and perovskite/PTAA interface respectively. The results show that the interface contact between perovskite and charge transport layer is improved obviously. At the same time, the density of carrier transport defect states in the device is reduced, thus reducing the non-radiative recombination of carriers. Meanwhile, the 5PFP-Br layer at perovskite/PTAA interface can effectively passivate Pb defects and reduce the number of grain boundaries in perovskite film, and increase the carrier transfer and collection efficiency. Finally, 5PFP-Br double-interface passivation can further optimize and improve the performance of device. The device based 5PFP-Br double-interface passivation presents an increased efficiency from 18.09% to 21.15%, where FF is raised from 73.30% to 80.04%. At the same time, unpackaged device can still be maintained to more than 90% efficiency after about 1200 h at 25 °C and 25%RH. [ABSTRACT FROM AUTHOR]