Photovoltaics Reaching for the Shockley–Queisser Limit
Since 2016, we have maintained a website(1) that tracks the record efficiency and other performance parameters compared to the thermodynamic Shockley–Queisser (SQ) limit for solar cells made from 14 extensively studied semiconductor materials. In the past four years, solar cells from many of these materials have progressed in efficiency, some very strongly (Figure 1a). This progress is a result of much research effort around the world, recognizing the importance of solar cell efficiency for the future energy supply. Efficiency is a key metric in the development of photovoltaic (PV) systems because the cell cost is only a small fraction of the total cost of a solar power generation system, and hence, increasing efficiency is a near-linear driver for reducing the cost of PV electricity per kilowatt-hour.