Large-Scale Synthesis of Highly Luminescent InP@ZnS Quantum Dots Using Elemental Phosphorus Precursor

InP quantum dots (QDs) are nontoxic emitters, which are considered an alternative to CdSe-based QDs. However, the limited choice and high cost of P precursors have a negative impact on their practical applicability. In this work, we report the large-scale synthesis of highly luminescent InP@ZnS QDs from an elemental P precursor (P-4), which was simply synthesized via the sublimation of red P powder. The size of the InP QDs was controlled by varying the reaction parameters such as the reaction time and temperature, and the type of In precursors. This way, the photoluminescence properties of the synthesized InP@ZnS QDs could be easily tuned across the entire visible range, while their quantum yield could be increased up to 60% via the optimization of reaction conditions. Furthermore, possible reaction pathways for the formation of InP QDs using the P-4 precursor have been investigated with nuclear magnetic resonance spectroscopy and it was demonstrated that the direct reaction of P-4 precursor with In precursor produces InP structures without the formation of intermediate species. The large-scale production of InP@ZnS QDs was demonstrated by yielding more than 6 g of QDs per one-batch reaction. We strongly believe that the newly developed approach bears the potential to be widely used for manufacturing inexpensive high-quality QD emitters.