High-efficient, spherical and thermal-stable carbon dots@silica fluorescent composite as rare earth-free phosphors for white LED

This paper reported a facile synthesis path to realize high-luminescent rare-earth-free composite powder, by embedding blue/green-emitting N-doped carbon dots into silica nano-spheres ([email protected]2). Carbon dots were evenly dispersed in [email protected]2 composites and eventually the aggregation-induced luminescence quenching is eliminated. Compared to the naked CDs, [email protected]2 composites exhibit perfectly spherical morphology with average size of ~200 nm, significantly enhanced emission intensity (>4 times) and better thermal stability (T50 > 150 °C). As-synthesized [email protected]2 own strong blue/green emission with high quantum efficiency (QE) over 60%. White LEDs prototypes with promising properties, i.e. CRI = 89.1, CCT = 4850 K and CIE coordinates = (0.3514, 0.3715), were fabricated by combining blue/green [email protected]2 and red [email protected]3 composites with NUV chip. All results indicate that these rare-earth-free, mono-dispersed spherical, and thermal-stable composite materials with efficient blue/green emission could be an exceptional choice as phosphors for LED application.