White light emission from quantum well structured quantum dots

Four-layer quantum well quantum dots (QWQDs) with structure of CdS/ZnS/CdS/ZnS were synthesized using a reverse micelle process. White light emission can be achieved by this type of QWQD, as the blue and green/orange emission components were originated from CdS core and ZnS inner shell, respectively. The emission spectra of QWQDs can be adjusted by varying the water-to-surfactant ratios in the reverse micelle process which controls the particle size and core/shell nanostructure of QWQDs. Efficient luminescence with PL quantum yield up to 30% can be achieved, due to the effective suppression of non-radiative relaxations from the Auger recombination with the quantum well structure.