The present invention provides a photovoltaic device, such as, a solar cell, having a substrate and an absorber layer disposed on the substrate. The absorber layer includes a doped or undoped composition represented by the formula: Cu1-yIn1-xGaxSe2-zSz wherein 0≦x≦1; 0≦y≦0.15 and 0≦z≦2; wherein the absorber layer is formed by a solution-based deposition process which includes the steps of contacting hydrazine and a source of Cu, a source of In, a source of Ga, a source of Se, and optionally a source of S, and further optionally a source of a dopant, under conditions sufficient to produce a homogeneous solution; coating the solution on the substrate to produce a coated substrate; and heating the coated substrate to produce the photovoltaic device. A photovoltaic device and a process for making same based on a hydrazinium-based chalcogenide precursor are also provided.