One-step synthesized single component white emitting carbon microspheres for lighting

Abstract

Single component white emitting materials are highly desired for lighting due to the negligible reabsorption, low energy transfer loss, and stable emission spectra. Carbon-based materials attracted much attention for their tunable luminescent properties and low toxicity nature. In this work, single-component white light emission solid-state carbon microspheres (CMSs) with photoluminescence quantum yield (PLQY) of 22.5% are synthesized by a simple one-step hydrothermal process. Beneficial from the large size of CMSs and Si and N related functional groups onto CMSs, the PL spectrum of the CMSs shows a broad and nearly Gaussian spectrum covering almost the entire visible spectrum. The cold white light-emitting diode (WLED), fabricated by putting the CMSs over a 365 nm ultraviolet (UV) LED chip, shows a color coordinate of (0.28, 0.34), correlated color temperature (CCT) of 8250 K and high color rendering index (CRI) of 82. Meanwhile, only little changes in CCT and CRI of the WLEDs were found at different operation voltages and times, attesting to the good color stability of the WLEDs based on single-component white phosphor of CMSs. These results reveal the potential of carbon-based white phosphor to be used in the field of white lighting.