Controlled Growth of Monocrystalline Organo-Lead Halide Perovskite and Its Application in Photonic Devices

Organo-lead halide perovskites (OHPs) have recently emerged as a new class of exceptional optoelectronic materials, which may find use in many applications, including solar cells, light emitting diodes, and photodetectors. More complex applications, such as lasers and electro-optic modulators, require the use of monocrystalline perovskite materials to reach their ultimate performance levels. Conventional methods for forming single crystals of OHPs like methylammonium lead bromide (MAPbBr₃ ) afford limited control over the product morphology, rendering the assembly of defined microcavity nanostructures difficult. We overcame this by synthesizing for the first time (MA)[PbBr₃ ]⋅DMF (1), and demonstrating its facile transformation into monocrystalline MAPbBr₃ microplatelets. The MAPbBr₃ microplatelets were tailored into waveguide based photonic devices, of which an ultra-low propagation loss of 0.04 dB μm^-1 for a propagation distance of 100 μm was demonstrated. An efficient active electro-optical modulator (AEOM) consisting of a MAPbBr₃ non-linear arc waveguide was demonstrated, exhibiting a 98.4 % PL intensity modulation with an external voltage of 45 V. This novel synthetic approach, as well as the demonstration of effective waveguiding, will pave the way for developing a wide range of photonic devices based on organo-lead halide perovskites.