Flexible and high-color-rendering electroluminescent device via self-adsorptive carbon quantum dots

Abstract

Carbon quantum dots (CQDs) are an emerging type of non-toxic and low-cost novel fluorescent material with significant potential in the field of wearable flexible luminescent devices. Typically, the luminescence and affinity of CQDs are strongly dominated by their surface states. In this study, we innovatively engineered CQDs with cyano and carbonyl functional groups, simultaneously enhancing light absorption and enabling autonomous adsorption onto ZnS/Al₂O₃ particles through a facile mixing process. This produced a ZnS–Al₂O₃–CQDs luminescent composite, which is suitable for alternating current electroluminescence (ACEL). Governed by Förster resonance energy transfer, the CQDs and ZnS exhibit complementary emission spectra, resulting in white light with a high-color-rendering index (R_a = 95.8). Furthermore, the as-fabricated flexible ACEL device demonstrates excellent bending durability and long-term operational stability. This work offers new insights into exploring the application of eco-friendly CQDs through a self-assembly strategy in wearable devices and flexible displays.