Intragrain 3D perovskite heterostructure for high-performance pure-red perovskite LEDs.

Metal-halide perovskites are promising light-emitter candidates for next-generation light-emitting diodes (LEDs). Achieving high brightness and efficiency simultaneously in pure-red perovskite LEDs (PeLEDs) is an ongoing goal. Three-dimensional (3D) CsPbIBr emitters have excellent carrier transport capability and high colour purity, which could allow efficient and ultrabright pure-red PeLEDs.

Highly Tension-Strained Copper Concentrates Diluted Cations for Selective Proton-Exchange Membrane CO Electrolysis.

Electrolysis of carbon dioxide (CO) in acid offers a promising route to overcome CO loss in alkaline and neutral electrolytes, but requires concentrated alkali cations (typical ≥3 M) to mitigate the trade-off between low pH and high hydrogen evolution reaction (HER) rate, causing salt precipitation. Here we report a strategy to resolve this problem by introducing tensile strain in a copper (Cu) catalyst, which can selectively reduce CO to valuable multicarbon products, particularly ethylene, in a pH 1 electrolyte with 1 M potassium ions. We find that the tension-strained Cu creates an electron-rich surface that concentrates diluted potassium ions, contributing to CO activation and HER suppression.

Hetero-Nucleation Induced [111]-Oriented Mixed Halide Perovskite for Stable Pure Red Light-Emitting Diodes.

Mixed halide 3D perovskites are promising for bright, efficient, and wide-color gamut light-emitting diodes (LEDs) due to their excellent carrier transport, high luminescence, and easily tunable bandgaps. However, serious halide ion migration inside mixed halide 3D perovskite results in poor operational and spectral stability of the as-fabricated LEDs. Here, a hetero-nucleation crystallization strategy is reported to grow [111]-orientation preferred mixed halide 3D perovskite CsPbIBr thin films for stable pure red LEDs.

Planar defect-free pure red perovskite light-emitting diodes via metastable phase crystallization.

Solution-processable all-inorganic CsPbIBr perovskite holds great potential for pure red light-emitting diodes. However, the widely existing defects in this mixed halide perovskite markedly limit the efficiency and stability of present light-emitting diode devices. We here identify that intragrain Ruddlesden-Popper planar defects are primary forms of such defects in the CsPbIBr thin film owing to the lattice strain caused by inhomogeneous halogen ion distribution.