A Directed Route to Colloidal Nanoparticle Synthesis of the Copper Selenophosphate Cu PSe.

The first colloidal nanoparticle synthesis of the copper selenophosphate Cu PSe , a promising new material for photovoltaics, is reported. Because the formation of binary copper selenide impurities seemed to form more readily, two approaches were developed to install phosphorus bonds directly: 1) the synthesis of molecular P Se and subsequent reaction with a copper precursor, (P-Se)+Cu, and 2) the synthesis of copper phosphide, Cu P, nanoparticles and subsequent reaction with a selenium precursor, (Cu-P)+Se. The isolation and purification of Cu P nanoparticles and subsequent selenization yielded phase-pure Cu PSe .