Carbon nanodot-based flexible and self-powered white displays

Carbon nanodots (CDs) have emerged as a promising luminescent material, showing significant potential in biological imaging, information security, and illumination displays within the internet of things (IoT). However, CDs-based electroluminescent devices, especially flexible and self-powered white displays, remain scarcely reported, which limit their applications in human-machine interactions and wearable optoelectronics in the IoT. Herein, we present a pioneering CDs-based flexible and self-powered white display system with a Commission Internationale de L’Eclairage (CIE) coordinate of (0.31, 0.39) by integrating CDs-based alternating current electroluminescent (ACEL) devices with triboelectric nanogenerators. The CDs-based white ACEL devices can be dynamically modulated from light green to white under various supplied frequencies ranging from 50 to 500 Hz. The devices also render from cold white to warm white with correlated color temperature from 9705 to 4538 K, as the concentration ratios of ZnS:Cu phosphors to CDs change from 22:2 to 22:8. Furthermore, these devices exhibit excellent flexibility and stability, maintaining over 95% of their electroluminescent intensities after 4500 cycles even under a large bending angle of 180° with a bending radius of 4.9 mm. Finally, this CDs-based flexible and self-powered white display system is worn on the human body to realize real-time illumination display powered by biomechanical energy, such as hand slapping and walking. This work provides a novel design strategy toward high-performance CD-based flexible and self-powered white displays and expands their potential applications in wearable optoelectronics for the IoT.