Emerging High-Efficiency Low-Cost Solar Cell Technologies

The dramatic decrease in price of silicon solar cells over the last 5 years has allowed the solar industry to grow at an impressive rate, but has also led to the demise of many solar cell startup companies that were developing next-generation technologies. Many believe that photovoltaic modules will need to cost less than $0.50 per watt and have power conversion efficiency > 25% to compete with fossil fuel power plants on a large scale. While it is likely that conventional silicon solar cells will reach this cost target, it will be challenging for them to reach the efficiency target. Some of the promising approaches that will be discussed involve lifting off thin single crystal solar cells from a wafer that can be reused. Others involve better understanding what causes recombination and polycrystalline thin films so that substantially better thin-film solar cells can be made. One of the most promising, yet not heavily researched, approaches is to make tandem solar cells using materials that function well even when they are polycrystalline and defective. Recent advances with hybrid perovskite semiconductors and their potential use in tandems will be emphasized.

Speaker: Mike McGehee, Stanford