Solvent-free synthesis of oxides for CuInSe2 thin films fabrication

A low-cost non-vacuum process for fabrication of CuInSe2 (CIS) films by solvent-free mechanochemical method and spin-coating process is described. First, highly monodisperse Cu, In oxides nanoparticles are synthesized via a facile, solvent-free route, which is the first applied in the CIS solar cells. Second, the oxide particulate precursors are deposited in a thin layer by spin-coating technique. Finally, the dry layers are sintered into CIS thin films with composition control by sequential reduction and selenization. Through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), it is found that near stoichiometric CIS films with a micron-sized dense grains are obtained in our work. Three types of mixed nitrates are used to fabricate oxides, the influence of the degree of mixing on the CIS films have been investigated.