Colloidal Chemistry in Molten Inorganic Salts: Direct Synthesis of III-V Quantum Dots via Dehalosilylation of (MeSi)Pn (Pn = P, As) with Group III Halides.

Gallium pnictides, such as GaAs and GaP, are among the most widely used semiconductors for electronic, optoelectronic, and photonic applications. However, solution syntheses of gallium pnictide nanomaterials are less developed than those of many other colloidal semiconductors, including indium pnictides, II-VI and IV-VI compounds, and lead halide perovskites. In this work, we demonstrate that the Wells dehalosilylation reaction can be carried out in molten inorganic salt solvents to synthesize colloidal GaAs, GaP, and GaPAs nanocrystals. We demonstrate that discrete colloidal nanocrystals can be nucleated and grown in a molten salt with control over their size and composition. Additionally, we found that reaction temperatures above 400 °C are crucial for annealing structural defects in GaAs nanocrystals. We also highlight the utility of the as-synthesized GaP nanocrystals by showing that GaP can be solution-processed into high-refractive-index coatings and patterned by direct optical lithography with micron resolution. Finally, we demonstrate that dehalosilylation reactions in molten salts can be generalized to synthesize indium pnictide (Pn = As, P) and ternary (InGaAs and InGaP) quantum dots.