Synthesis of Highly Emissive Mn-Doped ZnSe Nanocrystals without Pyrophoric Reagents

Manganese-doped zinc selenide quantum dots (Mn:ZnSe d-dots) with high optical quality, pure dopant emission with 40-60% photoluminescence quantum yield, were synthhesized with air-stable and generic starting materials, namely zinc (manganese) fatty acids salts with corresponding free fatty acids, Se powder, fatty amine, and octadecene. The prophoric, highly toxic, and expensive organo-phospines were eliminated from the existing synthetic protocols for high quality Mn:SnSe d-dots, which changed the reaction profile substantially mainly because of the enhanced reacitivity of elemental Se with presence of fatty amines. The reaction temperatures for two key processes involved in nucleation-doping, namely, formation of MnSe nanoclusters and their overcoating by the host, were both reduced. Multiple injection techniques were employed to realize balanced diffusion of the Mn ions in the d-dots. The resulting d-dots were found to be in zinc--blende crystals structure, with optimal spherical shape, nearly monodispersed, and controlled in their Mn-Zn ratio,