Recent Advances and Future Opportunities for Thin-Film Solar Cells

The primary objective of worldwide PV solar-cell research and development (R&D) is to reduce the cost of PV modules and systems to a level that will be competitive with conventional ways of generating electric power. To do that, it will be necessary to reduce the cost of PV from ~ $7/Wp in the year 2000 to about $1.50/Wp at the system level. Worldwide PV module production in 2000 is estimated to be about 290 MWp, and is growing at the rate of 20–25% per year. The selling prices of PV modules and systems range from $3–5/Wp and $6–10/Wp, respectively. PV technology in the marketplace today is dominated by crystalline/polycrystalline silicon. Even with greatly increased production volume and significant reduction of cost, it is doubtful that crystalline or polycrystalline silicon will ever meet the long-term cost goal for utility-scale power generation. If one accepts this rationale, it will be useful to see whether thin-film technologies can realistically meet these goals. There is reason to be very optimistic, particularly in view of the remarkable progress that has been made in recent years in terms of high conversion efficiency, long-term stability, and demonstrated large-scale manufacturing capabilities in several thin-film technologies.