Perovskite Nanocrystals: An Emerging Nano-Fluorophore for Stimuli-Responsive Photoluminescence

Stimuli-responsive luminescent materials that transduce environmental signals into optical outputs are of great interest for smart sensing and information materials. Metal halide perovskite nanocrystals (PNCs) have recently emerged as an appealing platform for smart luminescent materials, owing to their exceptional sensitivity to a wide range of external stimuli. These stimuli can be broadly classified into physical stimuli (e.g., temperature, mechanical stress, and light), chemical stimuli (including humidity, chemical vapors, and halide ions), and structural or chiral stimuli associated with phase transitions, lattice distortion, or coupling with chiral environments. This mini review summarizes recent advances in stimuli-responsive luminescence systems based on PNCs, with an emphasis on the underlying relationships between structure and property. We first outline the structural features and photophysical fundamentals of PNCs. Representative examples of hydrochromic, thermochromic, mechanochromic, chemical- and halide-responsive luminescence behaviors, as well as stimuli-switchable circularly polarized luminescence (CPL) and smart surface-ligand engineering of PNCs, are discussed. Finally, current challenges and future opportunities for designing robust, programmable, and multifunctional perovskite-based stimuli-responsive luminescent materials are briefly addressed.