Bright white-light emission from semiconductor nanocrystals: By chance and by design

The synthesis and characterization of two different kinds of semiconductor NCs, trap-rich CdS and onionlike CdSe/ZnS/CdSe/ZnS NCs that can be used for white-light illumination was reported. Simple mixing of red, green and blue emitting NCs led to possible undesirable changes of the chromaticity coordinators caused by different relative temporal stability of the components. Synthesis of c3s NC system balance the relative strength of the orange and blue components in order to obtain white light. Higher temperatures and long heating times were used for annealing, thereby making it more crystalline. Time resolved fluorescence measurements of the c3s NCs and of core NCs with the same core size were performed on the semiconductors. The experimental result of bright white light emission from semiconductor NCs based on surface state emission of the trap-rich Cds and dual emission from CdSe core, both the system shows high quantam efficiencies.