Tuning the Reactivity of Indium Alkanoates by Tertiary Organophosphines for the Synthesis of Indium-Based Quantum Dots

Indium-based quantum dots (QDs), such as InP, InAs, and CuInS2, are considered as the most promising candidates as cadmium/lead-free QDs. At present, the synthesis of these QDs is limited by the unbalanced reactivity of various precursors, specifically the sluggish reactivity of indium alkanoates. Here, we demonstrate that, with a phosphine-to-indium molar ratio beyond 3:1, decarboxylation reactions of indium alkanoates by aliphatic tertiary organophosphines become apparent, forming a series of new indium complexes, instead of purely enhancing the solubility of indium alkanoates at a low molar ratio. These new indium complexes are proven to be highly reactive indium precursors. By varying the organophosphine and indium alkanoate molar ratios, the resulting indium-complexes offer the needed tunability of reactivity for the synthesis of high-quality In-based QDs.