Thin-film CIS alloy PV materials fabricated using non-vacuum, particles-based techniques

CuInSe2 (CIS) and its alloys with gallium and sulfur are excellent thin-film photovoltaic materials, but the vacuum deposition processes typically used to fabricate thin-film CIS alloy photovoltaic (PV) devices are complex and expensive. A new class of thin-film deposition processes based on non-vacuum processing of particulate materials offers a simple, inexpensive alternative to fabricating high-efficiency CIS alloy PV. Suitable particulate materials can be prepared by a variety of techniques, including precipitation, pulverization, aerosol pyrolysis, vapor condensation, etc. Particulate precursors can be deposited in thin layers by simple techniques such as printing, spraying or dip coating. Porous precursor layers can be densified into dense, polycrystalline films by atmospheric-pressure sintering. By taking advantage of the unique materials science of CIS alloy films, one can mitigate the inherent disadvantages of particle-based processing, e.g. layer porosity. Using non-vacuum particles-based processes, efficiencies of 11.7% and 5% have been confirmed by NREL for CIS alloy cells and modules, respectively.