α-Chalcocite Nanoparticle Synthesis and Stability

While intensively investigated as a solar light absorber in photovoltaic applications, the use of alpha-chalcocite (alpha-Cu2S) as such has been hindered by its conversion to a copper-deficient, nonstoichiometric phase, djurleite. Here we study this transformation in copper sulfide nanoparticles. We discuss the relative stabilities of alpha-chalcocite and djurleite as synthesized here, how this influences the conditions for obtaining these phases, and the affect of the reaction conditions on the phase transformation rate. Nanoparticle phases are characterized by powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC). Size and morphology was characterized by transmission electron microscopy (TEM). Additionally, the a-chalcocite particles were characterized by UV/visible/NIR absorption spectroscopy (UV/vis/NIR) and energy dispersive X-ray spectroscopy (EDS).