Surface chemistry engineering enables polar solvent resistant and highly emissive perovskite nanocrystals for multifunctional applications

The extremely poor stability of perovskite nanocrystals (NCs) in polar solvent is a critical unsolved problem and seriously hinder their practical application scenarios. Herein, a surface chemistry engineering strategy is proposed for synthesizing robust CsPbX 3 (X = Cl, Br, I) NCs in non-toxic ethanol-based solvent by building an extensive inter-ligand H-bond network on perovskite lattice. The obtained unsealed CsPbX 3 NCs show unprecedented year-long stability in ethanol. Notably, a water (∼6–50%, v/v) post-treatment can obviously decrease surface defects of NCs, thus yielding a significant enhancement in their emission efficiency (increased from 9.6% to 83.4% for CsPbBr 3 NCs in ethanol). We further translated the obtained CsPbBr 3 NCs to fluorescent sensor and visible-light-driven photocatalysts, achieving ultra-high sensitivity (limit of detection is 11 nM) and high photocatalytic efficiency (>99% removal within 10 min). Overall, the low-cost, easy-to-process, highly efficient and ethanol/water tolerant perovskites NCs indicate their promising application prospect in multifunctional photoelectric devices.