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.