Designing Yolk–Shell Nanostructures for Reversible Water-Vapor-Responsive Dual-Mode Switching of Fluorescence and Structural Color
Zhi‐Han Zuo, Ziwen Feng, Yingying Peng, Yucong Su, Zhao‐Qing Liu, Guogang Li, Yadong Yin, Yibo Chen
Abstract
Metal halide perovskites offer ample opportunities to develop advanced optoelectronic devices. This work showcases that the integration of metal halide perovskites into metal oxide nanoshells with controllable interior cavities can enable water-vapor-responsive dual-mode switching of fluorescence and structural color. Through a ship-in-a-bottle method to introduce a controlled amount of CsPbBr 3 into MnO 2 nanoshells, we have designed CsPbBr 3 @MnO 2 yolk–shell nanostructures, which can uptake a defined amount of water to exhibit rapid (less than 1 s) and reversible (≥100 cycles) responses in both fluorescence on–off and color change when exposed to dynamic water vapor. These responses originate from the water-triggered phase transformation of CsPbBr 3 to CsPb 2 Br 5 and the structural color change of the MnO 2 shell. The altered electronic and bonding structure at the oxide–halide interface, rapid water accumulation in the yolk–shell cavity, and protective effect of the oxide shell facilitate the reversible transformations. The response characteristics of the yolk–shell nanostructures have been further demonstrated in fabricating patterned films capable of multiple fluorescence/structural color responses, highlighting their potential for applications in advanced anticounterfeiting and encryption.