초록 |
Lead iodide (PbI2) is widely used as a precursor for the conversion into organic-inorganic hybrid perovskite (OIHP) materials such as CH3NH3PbI3, promising candidates for optoelectronic and energy harvesting applications. Once fabricated in nanostructures, particularly in 1D nanowires, PbI2 is expected to boost the current properties of OIHP materials (e.g., absorption coefficient and carrier mobility). Here, we show that the orientation of PbI2 van der Waals nanowires grown by vapor-liquid-solid (VLS) method can be controlled via PbBr2 introduction. [0001]-oriented, homoepitaxially-grown PbI2 nanowires are observed to kink in [-12-10] direction upon the addition of trace amount of PbBr2 during the VLS growth. A kinetic model based on the observation suggests that the kinking is governed by the surface energetics of the triple phase line of Pb catalyst. This study suggests a potential of precursor structure engineering to realize enhanced device performance of OIHP materials. |