Facile Microwave Synthesis of Efficient Green Emissive Carbon Dots Powder and Their Application in Visible Light Communication and White Light Emitting Devices

Abstract

Highly green emissive solid‐state carbon dots (CDs) with photoluminescence quantum efficiency of 58% are prepared through a rapid microwave assisted heating method. Due to the spatial confinement from the biuret crystal matrix, aggregation among CDs is effectively suppressed, thus allowing the CDs to give efficient emission in the solid‐state. The CDs show excitation independent emission and mono‐exponential decay characteristics with a nearly constant lifetime of ≈13 ns upon varying the detected emissions, indicating the presence of a single type of emissive state in the CDs. Due to their high quantum efficiency and short lifetime, the obtained CDs are applied as the color conversion layer of a near‐ultraviolet micro light‐emitting diode (µLED) chip (405 nm) for visible light communication, achieving a modulation bandwidth of 165 MHz, which is much higher than the bandwidth of the conventional combination of Ce3+‐doped yttrium aluminum garnet phosphor with GaN LED. Moreover, the green emitting solid‐state CDs are applied to fabricate a prototype white LED device, which exhibits good lighting suitability with a color rendering index of 90.6 and a Commission Internationale de L'Eclairage chromaticity coordinates of (0.327, 0.332).

Leveraging Intermolecular Charge Transfer for High-Speed Optical Wireless Communication

“…However, conventional color-converting materials utilized for OWCs have primarily revolved around intricate organic, ceramic, and perovskite compositions. The widespread adoption and commercial viability of these materials face substantial obstacles stemming from their convoluted synthesis procedures, increased manufacturing expenses, and considerable toxicity. − As a result, the incorporation of innovative materials and strategies into affordable optical communication, aimed at improving modulation bandwidth and increasing data transmission rates, has become an exciting area of research for materials scientists, physicists, and engineers.…”