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2D Dion–Jacobson (DJ) perovskites show structural stability and tunability and are regarded as promising photovoltaic materials. The spacer cations play an important impact on exciton separation and charge transport of 2D perovskites. Herein, a novel spacer with thiazole as core, 2‐thiazolemethanammonium (AMT), owning characters of small molecular size, delocalized π‐electrons, and strong electron‐withdrawing ability, is introduced to construct 2D DJ perovskites. Owing to the strong orbital coupling between AMT spacer and inorganic layers, the AMT‐based perovskite exhibits type II quantum well structure, which is favorable for exciton separation. On contrary, such interaction does not appear in the DJ perovskite when aliphatic propyldiammonium (PDA), with a similar length, is used as spacer. The AMT spacer can also induce better crystallinity, resulting in reduced defect density and improved charge transport ability. The optimized device based on (AMT)MA3Pb4I13 exhibits a power conversion efficiency (PCE) of 19.69%, which is a record for 2D DJ perovskite solar cells (PSCs) (n ≤ 4). This work provides deep understanding of the impact of aromatic spacer on the electronic structure of 2D DJ perovskites and the corresponding photovoltaic performance and provides a new opportunity toward highly efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The surface properties and chemical interactions are critical for perovskite solar cells (PVSCs). In this work, we show that the polypropylene glycol (PPG) can simultaneously passivate the NiOx surface and grain boundaries of perovskite films, allowing more efficient charge transfer at the anode interface and reducing the recombination of PVSCs. As a result, the open‐circuit voltage (Voc) of MAPbI3 based inverted PVSCs increases from 1.087 V to 1.127 V, and the short‐circuit current density (Jsc) is increased from 20.87 mA·cm–2 to 22.32 mA·cm–2, thereby realizing the improvement of the device power conversion efficiency (PCE) from 18.34% to 20.12%. Moreover, the steady‐state output of the PVSCs is remarkably improved by incorporating PPG. Further analysis of surface properties suggests that part of the PPG at the interface can permeate into the precursor solution with the help of DMF solvent and remain in the perovskite layer to form a concentration gradient. The ether bond of PPG and the uncoordinated Pb2+ in the perovskite are coordinated to achieve passivation effects and improve device performance. Our work provides a rational strategy for the preparation of high‐performance PVSCs. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The surface properties and chemical interactions are critical for perovskite solar cells (PVSCs). In this work, we show that the polypropylene glycol (PPG) can simultaneously passivate the NiOx surface and grain boundaries of perovskite films, allowing more efficient charge transfer at the anode interface and reducing the recombination of PVSCs. As a result, the open‐circuit voltage (Voc) of MAPbI3 based inverted PVSCs increases from 1.087 V to 1.127 V, and the short‐circuit current density (Jsc) is increased from 20.87 mA·cm–2 to 22.32 mA·cm–2, thereby realizing the improvement of the device power conversion efficiency (PCE) from 18.34% to 20.12%. Moreover, the steady‐state output of the PVSCs is remarkably improved by incorporating PPG. Further analysis of surface properties suggests that part of the PPG at the interface can permeate into the precursor solution with the help of DMF solvent and remain in the perovskite layer to form a concentration gradient. The ether bond of PPG and the uncoordinated Pb2+ in the perovskite are coordinated to achieve passivation effects and improve device performance. Our work provides a rational strategy for the preparation of high‐performance PVSCs. [ABSTRACT FROM AUTHOR]

High‐performance organic solar cells (OSCs) at the current stage are majorly accomplished from the processing of halogenated solvents, such as chloroform, which will be constrained for upscale fabrication due to the adverse health and environmental impacts. Therefore, exploring the high‐performance OSCs from non‐halogenated solvent processing becomes highly necessary, yet largely lagged behind. Herein, it is demonstrated high‐performance OSCs can be obtained from the hot spin processing of different non‐halogenated solvents, and achieve the highest reported efficiency of OSCs from non‐halogenated solvent processing so far. It is revealed that the phase evolution of ternary blends during solution‐to‐solid transition has a correlation to the substrate temperature. With the elevated substrate temperature of hot spin coating, the optimal blend films can be secured in different kinds of non‐halogenated solvents. As result, high‐performance OSCs are obtained with excellent power conversion efficiencies of 18.25% in o‐xylene, 18.20% in p‐xylene, and 18.12% in toluene, respectively. To the author's best knowledge, these results represent the best‐performed OSCs made from non‐halogenated solvents so far. [ABSTRACT FROM AUTHOR]

In this study, the electronic properties and chemical stability of the Cu/CH3NH3PbI3 interface are investigated in situ by a combination of X‐ray photoelectron spectroscopy and synchrotron radiation photoemission spectroscopy (SRPES). The morphology of Cu deposited perovskite surface is monitored by scanning electron microscopy. The results show that the Cu/CH3NH3PbI3 interface is very stable and no chemical reaction between Cu and the perovskite takes place. Moreover, a 0.45 eV interface dipole and a 0.15 eV upward band bending are obtained at the Cu/CH3NH3PbI3 interface. Based on these fundamental findings, a prototype of Cu/CH3NH3PbI3/NiOx/indium tin oxide solar cell device is constructed to check the power conversion efficiency (PCE) and device stability. Although no electron transport material is used in this device, it still exhibits decent performance. The PCE of the device reaches up to 9.99% and remains almost unchanged over a long‐time (49 d) storage in a N2‐filled glovebox. Through this study it is demonstrated that fundamental understanding of the interfacial structure of a perovskite solar cell is essential in pursuit of rational design of superior perovskite solar cells, and moreover, Cu is a promising electrode candidate for perovskite solar cells. [ABSTRACT FROM AUTHOR]

Lead halide perovskite solar cells (PSCs) have emerged as one of the influential photovoltaic technologies with promising cost-effectiveness. Though with mild processabilities to massive production, inverted PSCs have long suffered from inferior photovoltaic performances due to intractable defective states at boundaries and interfaces. Herein, an in situ passivation (ISP) method is presented to effectively adjust crystal growth kinetics and obtain the well-orientated perovskite films with the passivated boundaries and interfaces, successfully enabled the new access of high-performance inverted PSCs. The study unravels that the strong yet anisotropic ISP additive adsorption between different facets and the accompanied additive engineering yield the high-quality (111)-orientated perovskite crystallites with superior photovoltaic properties. The ISP-derived inverted perovskite solar cells (PSCs) have achieved remarkable power conversion efficiencies (PCEs) of 26.7% (certified as 26.09% at a 5.97 mm 2 active area) and 24.5% (certified as 23.53% at a 1.28 cm 2 active area), along with decent operational stabilities., (© 2024 Wiley‐VCH GmbH.)