Structure and Reactivity of Atomically-Precise III-V Nanoclusters

Advances in the synthesis of III-V quantum dots, including InP and InAs, have led to their development for current- and next-generation solid-state lighting, wide color gamut displays, and infrared optoelectronics. The most widely adopted synthesis of these III-V quantum dots involves indium carboxylates and E(SiMe₃)₃ (E = P, As) and is understood to proceed through the formation of metastable, atomically-precise intermediates that are often referred to as clusters. In this work, we report that the surface chemistry of In₃₇P₂₀(O₂CR)₅₁ can be leveraged to modify the core structure and control the reactivity of the clusters. Bulkier surface ligands hinder P(SiMe₃)₃ diffusion and allow for the stabilization and isolation of In₂₆P₁₃(O2CR)₃₉, which has been characterized by single-crystal X-ray diffraction. When employing As(SiMe₃)₃ in an identical synthesis, no cluster forms and instead the inclusion of an L-type phosphine ligand is required to isolate an atomically-precise material. The surface and core of the InAs cluster are characterized, revealing important contrasts with InP with implications for understanding the landscape of accessible binary semiconductor clusters.