Cu-Doped ZnInGaSe Nanocrystals with Controlled Stoichiometry for Green Emission

As one of Cd-free semiconductor nanocrystals, Zn-based nanocrystals are widely studied due to their wide band gap to be a candidate for blue- and green-emitting materials. Herein, ZnInGaSe nanocrystals were synthesized with the controlled stoichiometry from the intermediate of ZnInGaSe magic size clusters. The approach via the magic size clusters greatly increases the amount of Ga in ZnInGaSe NCs. After the growth of the ZnS shell, ZnInGaSe/ZnS core/shell nanocrystals exhibited improved green emission. Furthermore, Cu as the impurity was introduced into ZnInGaSe NCs to reduce the vacancy defects to promote the photoluminescence. Finally, a photoluminescence quantum yield of 35.7% was obtained in Cu:ZnInGaSe/ZnS core/shell nanocrystals. The donor–acceptor recombination mechanism was proposed to explain the optical properties in ZnInGaSe NCs. Cu:ZnInGaSe nanocrystals were utilized in light-emitting diodes, showing the potential of ZnInGaSe nanocrystals for optoelectronic devices.