Orientation-Dependent Conversion of VLS-Grown Lead Iodide Nanowires into Organic-Inorganic Hybrid Perovskites.

ABSTRACT: In this study, we demonstrate Sn-assisted vapor-liquid-solid (VLS) growth of lead iodide (PbI₂) nanowires with van der Waals layered crystal structure and subsequent vapor-phase conversion into methylammonium lead iodide (CH₃NH₃PbI₃) perovskites. Our systematic microscopic investigations confirmed that the VLS-grown PbI₂ nanowires display two major growth orientations of [0001] and [1¯21¯0], corresponding to the stacking configurations of PbI₂ layers to the nanowire axis (transverse for [0001] vs. parallel for [1¯21¯0]). The resulting difference in the sidewall morphologies was correlated with the perovskite conversion, where [0001] nanowires showed strong localized conversion at top and bottom, as opposed to [1¯21¯0] nanowires with an evenly distributed degree of conversion. An ab initio energy calculation suggests that CH₃NH₃I preferentially diffuses and intercalates into (112¯0) sidewall facets parallel to the [1¯21¯0] nanowire axis. Our results underscore the ability to control the crystal structures of van der Waals type PbI₂ in nanowire via the VLS technique, which is critical for the subsequent conversion process into perovskite nanostructures and corresponding properties.

SUBMITTER: Shim H 

PROVIDER: S-EPMC7830942 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature