Third generation photovoltaics: comparative evaluation of advanced solar conversion options

Although "second generation" thin-film technologies offer substantial potential material cost advantages compared to "first generation" silicon wafers, the former eventually will run into their own material cost limits, for example, encapsulants to ensure 30-year life. Improved efficiency is the key to cost reduction past this stage. This leads to the conclusion that efficiency will differentiate between viable and non-viable thin-film technologies in the longer term. Efficiency limitations upon the performance of candidates for a "third generation" of high performance thin-film technology are discussed.