Ligand Synergy-Driven Room-Temperature Transformation from ZnSe Prenucleation Clusters to Magic-Size Clusters with Optical Absorption at 320 nm.

Selective synthesis of specific magic-size cluster (MSCs) species is crucial for tailoring their properties. Yet the role of surface ligands in directing these pathways remains poorly understood, particularly for ZnSe systems. Here, we show a ligand synergy-driven strategy for the room-temperature transformation of ZnSe prenucleation clusters (PNCs) to MSC-320 (with absorption peaking at 320 nm) via a two-step approach. ZnSe MSC-320 was synthesized by dispersing the prenucleation-stage sample in a dispersion of cyclohexane, octylamine (OTA), and methanol (MeOH). The formation of MSC-320, which followed the first-order kinetics with a rate constant of 0.02 min-1, is consistent with an isomerization mechanism in which precursor compounds transform to their corresponding MSCs. The product selectivity was highly dependent on the synergistic effect of OTA and MeOH, as revealed by optical absorption and nuclear magnetic resonance spectroscopy. By change of the amount of OTA and MeOH, the ligand exchange equilibriums and hydrogen-bonding interactions govern the transformation pathway. This work clarified a PNC-based transformation pathway and establishes the synergistic ligand strategy as a powerful tool for the precise, room-temperature synthesis of targeted semiconductor MSCs.