Amine-derived synthetic approach to color-tunable InP/ZnS quantum dots with high fluorescent qualities

Abstract

High-quality, Cd-free InP quantum dots (QDs) have been conventionally synthesized by exclusively selecting tris(trimethylsilyl) phosphine (P(TMS)(3)) as a phosphorus (P) precursor, which is problematic from the standpoint of green and economic chemistry. Thus, other synthetic chemistries adopting alternative P sources to P(TMS)(3) have been introduced, however, they could not guarantee the production of satisfactorily fluorescence-efficient, color-pure InP QDs. In this study, the unprecedented controlled synthesis of a series of band-gap-tuned InP QDs is demonstrated through a hot-injection of a far safer and cheaper tris(dimethylamino) phosphine in the presence of a key coordinating solvent of oleylamine that enables successful QD nucleation/growth. Effects of the co-existence of Zn additive, the core growth temperature, and the amount of P source injected on the growth behaviors of InP QD are investigated. After ZnS overcoating by a successive injection of 1-dodecanethiol only, high-fluorescence-quality, green-to-red color emission-tunable core/shell QDs of InP/ZnS are obtained. The fluorescent characteristics of different color-emitting QDs desirably exhibit little fluctuations in quantum yield and emission bandwidth, specifically ranging 51-53 % and 60-64 nm, respectively. Lastly, the utility of the introduction of a secondary shelling process in rendering the QDs are more bright, photostable is also proved.