Figure 9.

Conversion of lead halide nanoplatelets to perovskites by gas–solid heterophase reaction with methyl ammonium halide. a) Schematic of the synthesis setup using a home‐built vapor‐transport system. Crystal structure of b) lead halide and c) lead halide perovskite CH₃NH₃PbX₃. d) Thickness of PbI₂ platelets before (images above data line) and after being converted to CH₃NH₃PbI₃ (images below data line). Note that the color of the PbI₂ platelets changed corresponding to the change in thickness (as measured by AFM). a–d) Reproduced with permission.139 Copyright 2014, Wiley‐VCH.