Miniaturization requests and progress in nanofabrication are prompting worldwide interest in nanophosphors as white-emission 30x24x24 wall cabinet mercury-free lighting sources.By comparison with their bulk counterparts, nanophosphors exhibit reduced concentration quenching effects and a great potential to enhance luminescence efficiency and tunability.In this paper, the physics of the nanophoshors is overviewed with a focus on the impact of spatial confinement and surface-to-volume ratio on the luminescence issue, as well as rare earth-activated multicolor emission for white light (WL) output.
In this respect, the prominently practiced strategies to achieve WL emission are single nanophosphors directly yielding WL by means of co-doping and superposition of the individual red, green, and blue emissions from different nanophosphors.Recently, a new class of efficient broadband WL emitting nanophosphors has been proposed, i.e.
, nominally un-doped rare earth free oxide (yttrium oxide, Y2O3) nanopowders and vegas golden knights background Cr transition metal-doped garnet nanocrystals.In regard to this unconventional WL emission, the main points are: it is strictly a nanoscale phenomenon, the presence of an emitting center may favor WL emission without being necessary for observing it, and, its inherent origin is still unknown.A comparison between such an unconventional WL emission and the existing literature is presented to point out its novelty and superior lighting performances.