NOVELTY - Photovoltaic device comprises substrate; and absorber layer disposed on substrate; the absorber layer comprises doped or undoped composition; where the absorber layer is formed by solution-based deposition process involving contacting hydrazine and source of copper, indium, gallium, selenium or optionally a source of sulfur, and further optionally a source of dopant, under conditions sufficient to produce homogeneous solution; coating the solution on substrate to produce a coated substrate; and heating coated substrate to produce photovoltaic device.    USE - As photovoltaic device such as solar cell, with solution-processed chalcogenide absorber layer.    ADVANTAGE - The present solution-based technique does not involve oxygen or oxides and does not require anneal in chalcogen-containing atmosphere. The present molecular-based precursors do not contain carbon, oxygen or chlorine, thus it does not produce films having contamination by carbon, oxygen or chlorine impurities that are commonly seen in pyrolytic processes. The present technique involves high-throughput solution-based approaches, such as spin coating, printing, ink jet printing, spray coating, doctor blading, and dipping; which are faster, cleaner and simpler than electrochemical approaches. The present solution-based technique enables the facile incorporation of dopants such as aluminum, antimony, sodium or tellurium, either in uniform or in a graded manner. The present technique employs molecular precursors rather than nanoparticle precursors. This enables the formation of a true solution before solution-based thin-film deposition, thus allows better mixing of the elements on molecular scale and provides better grain growth at lower temperatures. The present technique is simple to implement and it permits one to tailor the chemical composition of the absorber layer by simply changing the ratio of elements in the solution or dissolving other elements, such as gallium, sodium and antimony, into the deposition solution. Such incorporation facilitates grain growth and optimization of the absorber layer and can improve the electrical characteristics of the device. The precursor and solution employ only metal chalcogenide, chalcogen, and hydrazine or hydrazine-like compound, thus eliminating many sources for potential film impurities, including carbon, oxygen and halides. The present process is very simple and does not require vacuum-based treatments, thus is potentially very low cost.    DETAILED DESCRIPTION - Photovoltaic device comprises substrate; and absorber layer disposed on substrate; where absorber layer comprises doped or undoped composition of formula Cu1-yIn1-xGaxSe2-zSz (where x is 0-1; y is 0-0.15; and z is 0-2); and where absorber layer is formed by solution-based deposition process involving contacting hydrazine and source of copper, indium, gallium, selenium or optionally a source of sulfur, and further optionally a source of dopant, under conditions sufficient to produce homogeneous solution; coating the solution on substrate to produce a coated substrate; and heating a coated substrate to produce photovoltaic device.