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 degrees 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.