Efficiency Potential of Photovoltaic Materials and Devices Unveiled by Detailed-Balance Analysis

Efficiencies of many solar-cell technologies steadily approach their thermodynamic limits, and consistent, thermodynamically correct methods are needed to address the remaining fundamental loss mechanisms. Unfortunately, the communities working on different technologies use different standards to determine the band gap of a solar cell, which in turn is used to quantify voltage losses. Motivated by the idealized efficiency limit of Shockley and Queisser, the authors offer an analytic perspective on the band gap that applies to $a\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}l$ photovoltaic technologies, allowing meaningful comparison of losses.