A yellow carbon dots-based phosphor with high efficiency for white light-emitting devices

The yellow-emitting carbon dots (CDs) were successfully synthesized by a simple one-step hydrothermal route using o-phenylenediamine (o-PD) as the starting material. The emssion peak of CDs shifted from 535 to 563 nm and the corresponding photoluminescence quantum yield (PLQY) enhanced from 10.4% to 23.1% when the reaction solvent of ethanol was replaced by deionized water and reaction temperature was increased by 20 °C. After CDs were effectively and uniformly attached to starch particles by hydrogen bonding and physical adsorption, a new type of environmentally friendly and yellow CDs-based phosphors has been developed. Effective dispersion of small CDs on the surface of large starch particles can lengthen the distance among CDs, as a result, the non-radiative decay process and photoluminescence quenching were steadily hindered. Highly efficient solid-state CDs phosphors with a PLQY of 66.9% were acquired. Combing with the excellent thermal stability and photostability, a daylight white LED based on a single color converter of yellow CDs phosphors was fabricated with a CRI of 83, luminous efficiency of 30.54 lm/W, and CIE coordinates of (0.3429, 0.2817). Suggesting that as-prepared CDs-based phosphors have a great potential in phosphor-based light-emitting devices.