Unity Quantum Yield of High-Entropy Quantum Dots Composited With Photonic Crystals for Information Encryption

The escalating demand for advanced anti-counterfeiting and information encryption technologies has driven the exploration of luminescent materials with high quantum yield, multi-level encoding capability, and long-term stability. This study extends the high-entropy paradigm to I-III-VI quantum dots (QDs) for the first time, successfully synthesizing CuZnCrGaSe/ZnSe/ZnS (CZCrGSe/ZnSe/ZnS) core/shell/shell high-entropy QDs via a one-pot nucleation strategy combined with stepwise hot-injection shell coating. By optimizing reaction parameters and composition ratios, combined with a precisely designed ZnSe/ZnS double shell for efficient defect passivation, the QDs achieve an emission wavelength of 540 nm and a record-breaking photoluminescence quantum yield (PLQY) of 100%, which stands as the highest PLQY reported for alloy QDs to date. Integrating these high-performance QDs into stimulus-responsive photonic crystals (PCs) yields dual-mode nanocomposite films capable of exhibiting two reversible optical states: structural color and fluorescent color. The luminescent properties of high-entropy QDs synergistically modulate with the photonic bandgap of the PCs, enabling multidimensional information encryption. This functionality was validated through a visual encoding/decoding system capable of secure binary code conversion. This work achieves a significant breakthrough in the luminescent performance of alloy QDs and provides a novel strategy for developing eco-friendly, high-performance optical encryption materials.