Kinetically Regulated Growth of CsPbBr 3 /CdSe Core/Shell Quantum Dots for Stable Light-Emitting Diodes

Abstract

Perovskite quantum dots (Pe-QDs) have attracted considerable attention for optoelectronic applications owing to their excellent optical properties; however, their practical use is limited by intrinsic instability. Constructing an inorganic shell is an effective strategy to improve stability, yet conventional layer-by-layer shell growth often induces severe ripening and structural degradation of perovskite cores. Here we present a one-step synthesis strategy to directly construct CsPbBr3/CdSe core/shell Pe-QDs by simultaneously introducing perovskite and shell precursors into the reaction system. Owing to their higher intrinsic reactivity, perovskite nuclei form preferentially at the initial stage. Subsequently, CdSe shell growth is triggered over the surface of perovskite cores. The CdSe shell effectively passivates surface defects and acts as an inorganic barrier that suppresses environmental degradation and halide ion exchange. As a result, the core-shell Pe-QDs exhibit significantly enhanced stability and improved optoelectronic performance. The resulting light-emitting diodes (LEDs) show a 3.5-fold increase in maximum external quantum efficiency (EQE) and a 13-fold extension in operational lifetime compared with devices based on pristine CsPbBr3 Pe-QDs. This work provides a feasible approach for constructing stable perovskite core/shell nanostructures and advances the development of durable perovskite optoelectronic devices.