Controlling defect state emission in ultra-small sized tellurium doped CdSe nanocrystals via two-phase synthesis method

Abstract

The utilization of semiconductor nanocrystals as white light emission source draws intense attention since semiconductor nanocrystals are promising candidates to fabricate new generation light emitting diodes. However, to synthesize high quality white light emitting semiconductor nanocrystals under mild reaction conditions at single step is a challenge. Here, we synthesized tellurium doped cadmium selenide (Te-doped CdSe) nanocrystals by using two phase synthesis method under mild reaction conditions at single step. Random localization of tellurium atoms in cadmium selenide nanocrystals caused emergence of defect state emission. The defect state emission was controlled by tuning initial Te:Se molar ratio in aqueous phase of the two phase system. Luminescence behaviour of Te-doped CdSe nanocrystals was affected by defect state emission and therefore, dual light emission (composition of blue-green light, whitish color) was observed. The Te-doped CdSe had cubic structure with Te composition at most 10% with size ranging around 1.8 nm. The CRI 1931 coordinates of the Te-doped CdSe nanocrystals revealed that Te-doped CdSe nanocrystals can be a powerful constituent for new generation light emitting diodes.