Fluorescence enhancement of perovskite nanocrystals by flexible photonic crystals and its application in optical strain gauge

Flexible photonic crystals (PCs) not only enhance the fluorescence of perovskite nanocrystals (PNCs) that promotes the development of wearable devices but also provide a chance for intelligent electronic skin and a strain gauge, since flexible PCs exhibit sensitive optical response to external stimuli. Herein, a self-assembly approach is developed to construct flexible PCs to enhance the fluorescence of CsPbBr3 PNCs. A stable fluorescence enhancement factor higher than fivefold is achieved under excitation of 3.97 W cm−2. The flexible PNCs/PCs composite membrane exhibits a sensitive, reversible, and reliable optical response to mechanical deformations, laying the foundation for the development of a strain gauge and intelligent skin. Assuming a 1% variation of the photoluminescence intensity can be reliably distinguished by a spectrometer, the sensing resolution on tensile strain is as high as 0.25%.