Optically Switchable Full-Color Quantum Dots via Diarylethene Photoswitches for Smart Display and Security

Optically switchable functions are highly interesting for AI applications in smart displays, memory encryption, and neuromorphic computing. The use of molecular photoswitches to precisely modulate functionalities at the nanoscale, such as photoluminescence (PL), is essential for developing photoswitchable nanomaterials. However, it is challenging to achieve the universal regulation of full-color PL, particularly for the efficient optical modulation while maintaining both high PL quantum yield (PLQY) and effective photoswitchable states. Herein, we report a simple and efficient photoswitchable system achieved through the hybridization of quantum dots (QDs) and diarylethene (DAE) photoswitches. The PL intensity of the three primary colors (RGB) can be reversibly switched on and off using the same DAE upon exposure to specific light. Our design exhibits a maximum PLQY exceeding 90% in the on state while maintaining a PL on/off ratio approaching 100, which represents one of the current highest values. The excellent performance relies on the synergistic energy transfer mechanism of the Förster resonance energy transfer and triplet energy transfer. Our photoswitchable materials enable the straightforward preparation of RGB QDs@DAE films for applications in reversible patterned display and information encryption. The patterns and information can be erased and rewritten multiple times, offering flexible and reusable smart materials toward data storage, advanced display, and anti-counterfeiting technologies.