Abstract:

Despite the wide range of applications of nanoparticles, the tunability of properties and synthesis of novel materials are limited due to reaction pathways often being poorly understood. Developing an understanding of how precursors transform into active species or monomers is essential to establish targeted synthetic designs but is difficult to predict the participating species with the absence of balance equations. Reported here is a more developed reaction pathway for Cu-P-Se based ternary phases, Cu­­₃PSe₄ and Cu₇PSe₆. By decreasing solvent reactivity to vary active selenium species for the conversion of Cu­₃P to Cu₃PSe₄, a simplified synthetic scheme has been established that has allowed for a balanced, stoichiometric equation. Further analysis of the Cu₃PSe₄ pathway led to the identification of characteristic copper selenium binaries, Cu0.87Se and Cu2-xSe, were identified as quenched intermediates for Cu3PSe4 and Cu7PSe6, respectively. Additionally, extrapolating the synthetic knowledge from the Cu₃PSe₄ system, when altering the Se precursor to molecular diselenide species with large C-Se bond energies, isolates the Cu₇PSe₆ phase (metastable) over Cu₃PSe₄. Thus, implementing this synthetic approach allows for stoichiometric control of colloidal nanoparticle synthesis and promotes opportunities to target desired materials.