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Low‐dimensional (LD) perovskite has provided an exciting avenue for exploring stable perovskite solar cells (PSCs). However, PSCs based on LD perovskites still suffer from poor efficiency owing to unfavorable charge carrier dynamics. Here, cystamine (CYS) is employed as a ligand to construct LD Dion‐Jacobson (LDDJ) perovskite (CYS)MAn‐1PbnI3n+1 (n = 1, 2, 3..., MA: methylamine) for improving carrier properties. The disulfide bond not only changes the polarization characteristic but also increases the coupling between inorganic slabs due to the low barrier of rotation around the S‐S axis, thus reducing the exciton binding energy of CYS‐based LDDJ perovskite. Disulfide bonds provide a scene for charge localization in the interlayer region, which is conducive to reducing the anisotropy of charge transfer. Thanks to these merits, the (CYS)MA4Pb5I16 film delivers improved carrier diffusion length (electron for 1345 nm and hole for 950 nm) and mobility (9.23 cm2 V−1 S−1). As a result, the (CYS)(MA)4Pb5I16 PSC achieves a champion power conversion efficiency (PCE) of 16.52%, which is much higher than that of HDA and BA cations‐based PSCs (HDA: 1,6‐Hexanediamine, BA: Butylamine). Furthermore, the state‐of‐the‐art device only lost 8% of its initial PCE after 1600 h in the atmosphere. [ABSTRACT FROM AUTHOR]

The two‐step sequentially deposition strategy has been widely used to produce high‐performance FAPbI3‐based solar cells. However, due to the rapid reaction between PbI2 and FAI, a dense perovskite film forms on top of the PbI2 layer immediately and blocks the FAI diffusion into the bottom of the PbI2 film for a complete reaction, which results in a low‐efficiency and limited reproducibility of perovskite solar cells (PSCs). Here, high‐quality α‐FAPbI3 perovskite films by crystal growth regulation with 4‐fluorobenzamide additives is fabricated. The additives can interact with FAI to suppress the fast reaction between the FAI and PbI2 and effectively passivate the under‐coordinated Pb2+ or I‐ defects. As a result, α‐FAPbI3 perovskite films with low trap density and large grain size are prepared. The modified PSCs present a high‐power conversion efficiency of 24.08%, maintaining 90% of their initial efficiency after 1400 h in high humidity. This study provides an efficient strategy of synergistic crystallization and passivation to form high‐quality α‐FAPbI3 films for high‐performance PSCs. [ABSTRACT FROM AUTHOR]

Intercalation regulation is a special way to tune the photophysical properties of perovskite without changing the organic cations. Here, it is found that dimethyl sulfoxide can be effectively intercalated into synthesized (OHC6H5CH2CH2NH3)2PbBr4 perovskite through hydrogen bonds between organic spacer layers and solvent molecules. The new intercalated perovskite can be stored for more than two months under a relative humidity of about 60% at room temperature without encapsulation. The single crystal microwire array device based on this special structure presents photoelectric response of a light on/off ratio of 400 under 365 nm irradiation at 3 V. The device has a low dark current of 10−13 A. Moreover, the inserted solvent molecules can be removed from the perovskite or reinserted into the perovskite under different processing conditions. The results show the potential to regulate the optoelectronic properties of perovskites by reversibly binding intercalated molecules with perovskites. [ABSTRACT FROM AUTHOR]

Perovskites as promising photovoltaic materials have been widely investigated due to their excellent photoelectric properties. Perovskite optoelectronic devices have been applied in fields of portable energy, light monitors, image sensors, etc. In recent years, wearable perovskite optoelectronic devices have been developed for their advantages of flexibility, stretchability, and light weight. In this review, the latest development of flexible and wearable perovskite optoelectronic devices is summarized. First, the preparation methods of optoelectronic devices are introduced, especially focusing on the large‐scale fabrication. Then the latest advances of various flexible devices are presented. In particular, the stability and safety of wearable devices, as well as the impact factors and corresponding solutions are discussed. Finally, the challenges for practical applications are put forward and discussed. [ABSTRACT FROM AUTHOR]

BiFeO3 (BFO) is a potentially important Pb‐free ferroelectric with a narrow bandgap and is expected to become a novel photodetector. The photocurrent in BFO3 strongly depends on the temperature but only a few studies have investigated in detail the relationships between photocurrent and temperature. Here, the temperature‐dependent photocurrent and the corresponding photosensing properties of a Ag/BFO/indiumtin oxide (ITO) photodetector based on an optimized planar‐structured electrode configuration are investigated. The photocurrent and responsivity of the BFO3‐based photodetector can first be increased and then be decreased with increasing temperature. The largest photocurrent and responsivity can reach 51.5 µA and 6.56 × 10−4 A W−1 at 66.1 °C, which is enhanced 126.3% as compared with that at room temperature. This may be caused by the temperature‐modulated bandgap and barrier height in Ag/BFO/ITO device. This study clarifies the relationship between photosensing performance and the operating temperature of BFO‐based photodetector and will push forward the application of ferroelectric materials in photoelectric field. [ABSTRACT FROM AUTHOR]

Ferroelectric materials hold great promise toward next generation of optoelectronic devices because of their unique characteristics such as above‐bandgap photovoltage and polarization‐dependent photocurrent. But the relative low photocurrent value limits their potential applications in real devices. In order to improve the photovoltaic performance and detailed and systematic investigations about the role of temperature gradient on the photocurrent in indium tin oxide (ITO)/BiFeO3 (BFO)/ITO device under various temperature gradients across both sides are carried out. The observed results reveal an enhancement in photocurrent under applying different temperature gradients, which is mainly associated with light intensity. The applied temperature gradients induce interesting mechanisms under weak and strong lights. Due to the temperature gradient controlled photocurrent, the photosensing performance of ITO/BFO/ITO photodetector device with respect to 365 nm light can be strongly modulated. This presented strategy offers a feasible route for enhancing the photovoltaic performances of the BFO material based device, which offers the capability to push forward the practical applications of ferroelectric photovoltaic devices. The output current modulation in BiFeO3 (BFO) device with temperature gradients exhibits reversed trends under weak and strong light illuminations, which offers a feasible route for enhancing the photovoltaic performances of the BFO materials. [ABSTRACT FROM AUTHOR]

Low-dimensional Ruddlesden-Popper (LDRP) perovskites still suffer from inferior carrier transport properties. Here, we demonstrate that efficient exciton dissociation and charge transfer can be achieved in LDRP perovskite by introducing γ-aminobutyric acid (GABA) as a spacer. The hydrogen bonding links adjacent spacing sheets in (GABA) 2 MA 3 Pb 4 I 13 (MA=CH 3 NH 3 + ), leading to the charges localized in the van der Waals gap, thereby constructing "charged-bridge" for charge transfer through the spacing region. Additionally, the polarized GABA weakens dielectric confinement, decreasing the (GABA) 2 MA 3 Pb 4 I 13 exciton binding energy as low as ≈73 meV. Benefiting from these merits, the resultant GABA-based solar cell yields a champion power conversion efficiency (PCE) of 18.73 % with enhanced carrier transport properties. Furthermore, the unencapsulated device maintains 92.8 % of its initial PCE under continuous illumination after 1000 h and only lost 3 % of its initial PCE under 65 °C for 500 h., (© 2023 Wiley-VCH GmbH.)