Lyotropic Liquid Crystalline Phases of Anisotropic Nanoparticles of Organic-Inorganic Metal Halide Perovskites: Photoluminescence from Self-Assembled Ordered Microstructures of Semiconductors

A simple method (which could be completed within 60 minutes at 298 K) was developed to transform layered organic–inorganic metal halide perovskites into colloidal lyotropic liquid crystalline dispersions with microscopic structural orderliness as well as semiconducting properties and photoluminescence. Experimentally, hexagonal-shaped mesogenic nanoplatelets of two-dimensional lead iodide perovskites (R-NH3)2PbI4 were synthesized by antisolvent-induced rapid microcrystallization and stabilized by surfactants, and self-assembled into discotic–nematic phases with optical anisotropy and greenish-blue fluorescence. Combining the stimuli-responsive, light-interactive, and reconfigurable ordered structures of liquid crystals with the adjustable semiconductivity of hybrid perovskites, these photoluminescent soft anisotropic materials may be used for polarized light emission or detection.