Nonstoichiometry Promoted Solventless Recrystallization of a Thick and Compact CsPbBr Film for Real-Time Dynamic X-Ray Imaging.

Inorganic CsPbBr perovskite emerges as a promising material for the development of next-generation X-ray detectors. However, the formation of a high-quality thick film of CsPbBr has been challenging due to the low solubility of its precursor and its high melting point. To address this limitation, a nonstoichiometry approach is taken that allows lower-temperature crystallization of the target perovskite under the solventless condition.

Single-particle optical study on the effect of chloride post-treatment of MAPbI nano/microcrystals.

Surface passivation by post-treatment with methylammonium chloride (MACl) is regarded as a promising strategy to suppress surface defects in organic-inorganic lead halide perovskites and elevate the efficiency of solar cells based on these materials. However, traditional MACl post-treatment methods often impede the performance of the final device, due to the creation of additional unwanted defects. Herein, we report a novel approach for chloride post-treatment by applying a mixed ethanol/toluene solvent and validate its beneficial effect on the structure, composition, and optical properties of methylammonium lead iodide nano/microcrystals and related photosensitive devices.

Photothermal Suzuki Coupling Over a Metal Halide Perovskite/Pd Nanocube Composite Catalyst.

The development of improved catalysts capable of performing the Suzuki coupling reaction has attracted considerable attention. Recent findings have shown that the use of photoactive catalysts improves the performance, while the reaction mechanism and temperature-dependent performance of such systems are still under debate. Herein, we report Pd nanocubes/CsPbBr as an efficient catalyst for the photothermal Suzuki reaction.

Texture Formation in Polycrystalline Thin Films of All-Inorganic Lead Halide Perovskite.

Controlling grain orientations within polycrystalline all-inorganic halide perovskite solar cells can help increase conversion efficiencies toward their thermodynamic limits; however, the forces governing texture formation are ambiguous. Using synchrotron X-ray diffraction, mesostructure formation within polycrystalline CsPbI Br powders as they cool from a high-temperature cubic perovskite (α-phase) is reported. Tetragonal distortions (β-phase) trigger preferential crystallographic alignment within polycrystalline ensembles, a feature that is suggested here to be coordinated across multiple neighboring grains via interfacial forces that select for certain lattice distortions over others.

Incorporation of Cesium Lead Halide Perovskites into g-CN for Photocatalytic CO Reduction.

CsPbBr perovskite-based composites so far have been synthesized by postdeposition of CsPbBr on a parent material. However, construction offers enhanced surface contact, better activity, and improved stability. Instead of applying a typical thermal condensation at highly elevated temperatures, we report for the first time CsPb(Br Cl )/graphitic-CN (CsPbX/g-CN) composites synthesized by a simple and mild solvothermal route, with enhanced efficacy in visible-light-driven photocatalytic CO reduction.

Thermal unequilibrium of strained black CsPbI thin films.

The high-temperature, all-inorganic CsPbI perovskite black phase is metastable relative to its yellow, nonperovskite phase at room temperature. Because only the black phase is optically active, this represents an impediment for the use of CsPbI in optoelectronic devices. We report the use of substrate clamping and biaxial strain to render black-phase CsPbI thin films stable at room temperature.

Purified dispersions of graphene in a nonpolar solvent via solvothermal reduction of graphene oxide.

It is demonstrated that oxidative debris can be separated and largely removed during the surfactant assisted phase transfer of graphene oxide from a water/ethanol mixture to dichlorobenzene. The new procedure described provides a facile method to obtain monolayer dispersed graphene sheets in a nonpolar solvent via solvothermal reduction of graphene oxide accompanied by an effective purification process.