Emulsion-LARP method: Optimization of demulsifier for synthesis of methylammonium lead bromide nano-structures

An understanding on the influence of the type of demulsifier used on the degree of crystallization in emulsion process-grown organic-inorganic halide perovskite nanocrystals is presently lacking. We conducted a detailed investigation on the structural and optical properties of methylammonium lead bromide (CH₃NH₃PbBr₃) nano-structures synthesized using the emulsion-ligand-assisted re-precipitation method with three different demulsifiers (acetone, <i>tert</i>-butanol, and butanol). Structural analysis conducted using X-ray diffraction, HRTEM, and Raman studies showed that <i>tert</i>-butanol served as the best demulsifier among the three. A homogenous distribution of spherically shaped nanoparticles with a particle size of ∼16 nm was achieved using the optimized synthesis process. CH₃NH₃PbBr₃ nano-crystals inherent to the cubic <i>Pm</i>3̄<i>m</i> (221) space group with preferential orientation along the (200) and (201) planes were synthesized. The CH₃NH₃PbBr₃ nano-crystals dispersed in toluene exhibited a green photoluminescence at ∼532 nm, which yielded a color purity of 94.6% and carrier lifetime of 1.69 ns.