NOVELTY - A photovoltaic device comprises an absorber layer comprises a doped or undoped composition of copper, indium, gallium, selenium and sulfur disposed on substrate, and formed by solution-based deposition process involves contacting hydrazine and source of copper, indium, gallium, selenium    USE - As photovoltaic device (claimed) e.g. solar cell.    ADVANTAGE - The solution-based deposition process does not involve oxygen or oxides; and does not require an anneal in a chalcogen-containing atmosphere; uses molecular-based precursors which do not contain carbon, oxygen, or chlorine, thus prevents of film contaminated by carbon, oxygen, or chlorine impurities seen in pyrolytic processes; uses high-throughput solution-based approaches (e.g. spin coating, printing, ink jet printing, spray coating, doctor blading, and dipping) that are faster, cleaner and simpler than electrochemical approaches; and enables facile incorporation of dopants such as aluminum, antimony, sodium, or tellurium, either in uniform or graded manner. The coating and heating are repeated to produce a film having a uniform or a graded composition. The absorber layer has a large grain structure to minimize recombination at the grain boundaries.    DETAILED DESCRIPTION - A photovoltaic device comprises an absorber layer formed on a substrate by a solution-based deposition process; where the absorber layer comprises a doped/undoped composition of formula Cu1-yIn1-xGaxSe2-zSz (where x is 0-1, y is 0.15 and z is 0-2). The absorber layer is formed by a solution-based deposition process involves contacting hydrazine and a source of copper, indium, gallium, selenium, and optionally a source of sulfur and dopant, under conditions 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. The coating step in the solution-based process is spin-coating, stamping, printing, doctor blading, spraying or dipping. The solution-based deposition process employs a soluble molecular precursor in a solution which is free of carbon, oxygen, chlorine, bromine and iodine impurities. The solution-based deposition process employs a hydrazinium-based chalcogenide precursor in a solution which is free of chlorine, bromine and iodine impurities. An INDEPENDENT CLAIM is included for a solution-based deposition process for depositing the absorber layer on the substrate, where the absorber layer comprises a doped or undoped composition.