White light emission from semiconductor nanocrystals by in situ colour tuning in an alternating thermodynamic-kinetic fashion

Abstract

White light emission from semiconductor nanocrystals was directly obtained by the in situ control of the size and size distribution of nanocrystals in a one-pot hot-injection synthesis. By directing the crystal growth from a thermodynamics-based regime into a kinetics-based one, nanocrystals with a multimodal size distribution showing two or three primary emission colours were simply obtained without any post-mixing processes. The colour axis and colour rendering index of the nanocrystals were flexibly adjusted by changing the experimental parameters of the synthetic process. The as-prepared nanocrystals showed a pure white light and a high colour rendering index so they could be directly used as phosphors for near-UV white light emitting diodes (WLEDs). With the capability of direct tuning the colour composition, the manufacturing process has been significantly simplified and is expected to be a general approach for nanocrystals-based WLEDs. © 2011 The Royal Society of Chemistry.