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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]

Organic solar cells (OSCs) show the potential to harness solar energy at a lower cost and in a greener way with the merits of mechanical flexibility and potential low‐cost upscaling production with solution processing. Meanwhile, the common use of toxic halogenated solvents causes pollution to the natural environment, and thus, needs to be avoided. Following the authors' previous work on the design of top‐illuminated ultrathin Ag‐based device structure highlighting most merits of OSC, herein non‐halogen solvent and additive processing OSCs are presented, which exhibit high power conversion efficiency (PCE) of 17.64%, close to the best PCE with the commonly used halogen solvent. Interestingly, it is observed that the additive and the multicomponent strategy (blending third component BTP‐S2 into PM6:L8‐BO binary blend) synergistically affect the optimal morphology and device performance. Finally, OSC devices featuring green solvent processing, indium tin oxide‐free, flexibility, and upscaling merits are fabricated and exhibit the best PCE of 13.76% with high mechanical robustness and good stability against heat or light illumination. This work provides a prospective potential for manufacturing the OSC toward practical applications. [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]

PEDOT:PSS is one of the most frequently used hole transporting layer (HTL) for solution-processed optoelectronic devices, but seems unsuccessful in high-performance lead based perovskite solar cells (PVSCs) due to the high open-circuit voltage (VOC) loss as induced by the improper interfacial chemical interactions, i.e. the coordination between sulfonic group and Pb2+. To address this issue, we change this chemical interaction by incorporating potassium citrate (PC) into the PEDOT:PSS film. The PC modification significantly improves the PL intensity by nearly one order of magnitude, verifying the strong passivation effect. Accordingly, the VOC loss of MAPbI3 based inverted PVSCs is dramatically reduced by 0.23 eV, and the device performance is improved from 16.31% to 19.66%, which is among the highest PVSCs with PEDOT:PSS as HTL. Interestingly, we find the energy level alignment plays a negligible role in determining the device performance of PVSCs, while the change of interfacial chemical interaction induced passivation effect contributes to the improved device performance of PVSCs. We further unveil that the passivation effect of PC is attributed to the synergistic effect of K+ and citrate group. Our work stresses the importance of tuning the interfacial interactions, and should have implication for developing high-performance PVSCs. [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]

Abstract Most of present 2D perovskites are based on the insulated butylamine or phenylethylamine as the spacing ammonium cation, which require good orientation to improve charge transport. Here, we report a novel 2D perovskite (PyEA) 2 MA n-1 PbnI 3n+1 (n = 1–9) based on methylammonium (MA) and a new spacing ammonium of 4-Pyridine-ethyl ammonium (PyEA) cations. Considering the absorption of perovskite films, we choose a high n value of 9 to establish a 2D perovskite system of (PyEA) 2 MA 8 Pb 9 I 28 with a bandgap of 1.65 eV as the active layer. The morphology of (PyEA) 2 MA 8 Pb 9 I 28 film is improved by using an additive of methylammonium thiocyanate (MASCN), which leads to a highly efficient inverted solar cells with a planar structure of ITO/PEDOT: PSS/(PyEA) 2 MA 8 Pb 9 I 28 /PC 61 BM/BCP/Ag. An optimized efficiency of 9.05% is achieved. By virtue of the stable 2D perovskites, the unencapsulated device retains 50% efficiency after 7 days restored in air with a humidity of 55 ± 5%, indicating excellent stability against moisture and oxygen. The high efficiency and good stability are attributed to the improved intermolecular interaction among PyEA molecules via hydrogen bond, which enables the charge transport between inorganic slabs in 2D perovskite. This work provides a new strategy to construct 2D perovskite for highly efficient and stable perovskite solar cells via hydrogen bond. Graphical abstract A new spacing ammonium cation of 4-pyridine-ethyl ammonium (PyEA) was designed to construct 2D perovskite (PyEA) 2 MAn-1Pb n I 3n+1. The solar cell devices based on this 2D perovskite delivered the optimized efficiency of 9.05% with excellent ambient stability due to the improved charge transport caused by the intermolecular interaction among PyEA molecules via hydrogen bond. Image 1 Highlights • 4-Pyridine-ethyl ammonium (PyEA) is designed as a new second space cation for 2D perovskite synthesis. • The charge transport in PVSCs is improved due to the conjugated interaction among PyEA molecules via hydrogen bond. • Solar cell devices based on (PyEA) 2 MA 8 Pb 9 I 28 films achieve a best efficiency of 9.05% with good ambient stability. • This work provides a new strategy to construct 2D perovskites for high efficiency and stability via hydrogen bond. [ABSTRACT FROM AUTHOR]

Two Bingel fullerenes, PCP and MCM, as electron transporting materials (ETMs) have been developed for achieving thick-film perovskite solar cells (PVSCs) with efficiencies beyond 19% with a planar absorber layer over 1 micrometer. Almost no PVSCs have exhibited PCEs above 18% with a 1 micrometer planar layer before, owing to the excess perovskite defects deteriorating charge extraction and the performance of thick-film based devices. Benefiting from the nearly identical optoelectronic properties of two ETMs stemming from tailored chemical structures, the studies on them allow us to unveil the fact that subtle molecular interaction (anion–π and Lewis acid–base) between ETMs and perovskites strongly affects the charge extraction at the heterointerface, which in turn influences the device hysteresis and performance. Particularly, weak Lewis base–acid O–Pb2+ interaction between MCM and the perovskite helps passivate the trap-states at the interface, resulting in a smooth electron extraction and reduced device hysteresis (the average hysteresis index (HI) of 0.03 ± 0.01). However, the strong N–Pb2+ coordination induces misalignment of the energy levels at the perovskite/PCP heterojunction, causing electron accumulation at the junction, and hence the large HI (0.17 ± 0.05) in devices. This work provides new insights into the charge extraction at the perovskite/organic interface and the possible molecular interaction from organics to cure perovskite defects. [ABSTRACT FROM AUTHOR]

Abstract: Herein three polymeric hole extraction materials (HEMs), poly(benzene‐dithiophene) (PB2T)‐O, PB2T‐S, and PB2T‐SO are presented for p–i–n perovskite solar cells (PVSCs). This study reveals that the perovskite device hysteresis and performance heavily rely on the perovskite grain boundary conditions. More specifically, they are predetermined through the molecular interaction between Lewis base atoms of HEMs and perovskites. It is revealed that only changing the side chain terminals (OCH3, SCH3, and SOCH3) of HEMs results in effective modulating PVSC performance and hysteresis, due to the effective tune of interaction strength between HEM and perovskite. With an in situ grown perovskite‐HEM bulk heterojunction structure, PB2T‐O with weak binding group (OCH3, −78.9 kcal mol−1 bonding energy) to lead ions allows delivering hysteresis‐free and efficient devices, which is sharp contrast to the strong binding PB2T‐SO (−119.3 kcal mol−1 bonding energy). Overall, this work provides new insights on PVSC hysteresis and the related curing methods via multifunctional HEM design in PVSCs. [ABSTRACT FROM AUTHOR]

The essential challenge for accessing high‐performance organic optoelectronics strongly relies on how to enable organic materials with high charge transport capabilities. This short review gives an elucidation of the mild n‐doping that occurs between Lewis base anions and n‐semiconductors, as well as their extension to develop solution‐processable conductive interlayers for organic and 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.)

We find that conjugated polymers can undergo reversible structural phase transitions during electrochemical oxidation and ion injection. We study poly[2,5-bis(thiophenyl)-1,4-bis(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)benzene] (PB2T-TEG), a conjugated polymer with glycolated side chains. Using grazing incidence wide-angle X-ray scattering (GIWAXS), we show that, in contrast to previously known polymers, this polymer switches between two structurally distinct crystalline phases associated with electrochemical oxidation/reduction in an aqueous electrolyte. Importantly, we show that this unique phase change behavior has important physical consequences for ion-polaron pair transport. Notably, using moving front experiments visualized by both optical microscopy and super-resolution photoinduced force microscopy (PiFM), we show that a laterally propagating ion-polaron pair front in PB2T-TEG exhibits non-Fickian transport, retaining a sharp step-edge profile, in stark contrast to the Fickian diffusion more commonly observed in polymers like P3MEEMT. This structural phase transition is reminiscent of those accompanying ion uptake in inorganic materials like LiFePO 4 . We propose that the engineering of similar properties in future conjugated polymers may enable the realization of new materials with superior performance in electrochemical energy storage or neuromorphic memory applications.