Rapid Route to Polar Solvent-Directed Growth of Perovskite Nanowires

Abstract

Despite recent impressive advances in the synthesis of all-inorganic perovskite CsPbX3 (X = Cl, Br, and I) via facile solution-based approaches, it remains challenging to achieve well-defined morphologies of interest, particularly one-dimensional (1D) nanowires. Herein, we report a robust polar-solvent-assisted route to 1D CsPbBr3 nanowires via room temperature supersaturated recrystallization. Notably, compared to CsPbBr3 nanocubes synthesized in the absence of polar solvent acetonitrile (ACN), upon the introduction of a suitable amount of ACN into antisolvent toluene, CsPbBr3 nanowires are rapidly yielded, experiencing a cubic-to-orthorhombic phase transformation and a blue-shifted emission. The formation mechanism of CsPbBr3 nanowires can be qualitatively understood on the basis of the role of ACN as a structure-directing agent. Intriguingly, the addition of ACN renders an accelerated anion-exchange reaction between CsPbBr3 and halide salts (i.e., Br-to-Cl and Br-to-I exchanges) due to improved dissolution of the halide ions in ACN. The polar solvent-directed growth strategy may represent an effective means of expanding the diversity of morphologies accessible to perovskite nanocrystals. As such, it facilitates an investigation into the dimension-dependent optical and optoelectronic properties of perovskite-based nanomaterials and devices. These CsPbBr3 nanowires can be potentially used for nanoscale photonic, electronic, and optoelectronic devices, including photodetectors, light-emitting diodes, lasers, and solar cells.