VLS Homoepitaxy of Lead Iodide Nanowires for Hybrid Perovskite Conversion

초록

Controlled fabrication of lead halide-based perovskite (LHP) nanostructures provides a new methodology for exploiting the excellent optoelectronic properties of the material. Here, we report the vapor-liquid-solid (VLS) growth of a highly uniform and dense array of [0001]-oriented PbI2 nanowires using PbI2 thin film as the epitaxial substrate layer. We show that reducing the lattice mismatch of the van der Waals epitaxial PbI2 substrate layer is necessary to accommodate the aligned nanowire growth. Our proposed layer growth model suggests that the nanowire growth is stabilized by maintaining the {0001} liquid-solid interface, which stems from the nucleation on the PbI2 substrate layer. We also demonstrate that the strain-induced nanowire deflection after conversion into CH3NH3PbI3 depends on the transfer sequence and conversion time. These findings provide a general opportunity to design and fabricate nanostructures, such as heterojunctions or superstructures for future device applications, rationally based on lead halide or LHP nanowires.

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