A nano-liter droplet-based microfluidic reactor serves as continuous large-scale production of inorganic perovskite nanocrystals

Abstract

Lead halide perovskite nanocrystals (NCs) exhibit high photoluminescence quantum yield (PLQY), high defect tolerance, narrow half peak width, and wide luminous gamut, making them the ideal optoelectronic materials in numerous fields. Nonetheless, their production still suffers from the limited productivity at the bench level. In this work, we fabricated CsPbX3 (X = Cl, Br, I) NCs within droplet-based micro-reactors, where both the nucleation and growth processes could be precisely controlled inside 130-nL microdroplets. This provides a new paradigm for the large-scale synthesis of perovskite NCs with high PLQY. Compared with other synthetic methods, this method can increase the concentration of reactant precursors by 3–116 times, while lowering the ligand to reactant ratio to 2%–50% of the commonly used hot-injection method. By modulating the reaction temperature and residence time, the structure-function relationship between the morphology of NCs and PL properties was extensively investigated. The microfluidic-based process allows the flexible adjustment in the proportion of PbX2 precursors to achieve the fabrication of perovskite NCs whose luminescence range covers the entire visible spectrum (406–677 nm) within one reaction. Finally, perovskite NCs with different halide ions were encapsulated in polymethyl methacrylate to prepare a colored light-emitting diode strip. [Figure not available: see fulltext.]