Photovoltaics (PV) is the process of converting sunlight directly into electricity. Recently PV energy conversion has become one of the major alternative energy sources for the production of electricity. The aim of PV community is to decrease the PV module price below 1$ per watt peak.
Three major thin film technologies (Cadmium telluride, copper indium selenide, and silicon thin films) are competing to be the ultimate winner for mass production. The advances made in amorphous silicon photovoltaic technology have lead to large-scale commercial deployment. Amorphous silicon devices made on lightweight flexible substrates are getting more attention due to the flexibility to deposit by roll to roll processes, which in turn reduces the cost per watt-peak and also the cost of ownership. The eminent role of the roll-to-roll continuous deposition technique in propelling the technology to global market is elucidated. The logical emergence of this technology as a lightweight solar-power generator is expected to hit the market in coming years. Silicon thin films are having many advantages with respect to their environmental friendliness and low cost, but still needs to cut short their cost per watt peak to compete with other technologies. Application of nanotechnology and novel light trapping concepts will lead the silicon PV to be the major market share holder. This is going to be the challenge and mission for the silicon research community for the next couple of years.