Aqueous synthesis of multilayer Mn:ZnSe/Cu:ZnS quantum dots with white light emission

In this work, we prepared white-emitting multilayer Mn:ZnSe/Cu:ZnS quantum dots (QDs) in an aqueous solution. The core-shell multilayer structure provides a unique opportunity to dope different types of impurities into each host layer. White-emitting Mn: ZnSe/Cu: ZnS QDs have two emission bands at around 477 nm and 585 nm. The latter emission band around 585 nm is assigned to Mn-induced emission. The first emission band around 477 nm is caused by both the trap emission in the ZnSe core and Cu-doping emission from the trap state in the ZnS shell to the Cu+ energy level. Due to doping of Cu and Mn in QDs, internally doped Mn:ZnSe/Cu:ZnS QDs have good stability against UV irradiation or alteration due to surroundings during blending with polymers, making as-prepared QDs available for white light-emitting diodes.