Self‐Tracking Solar Concentrator with Absorption of Diffuse Sunlight

The highest solar cell efficiencies are obtained with concentrating systems. However, these systems have two major drawbacks: tracking is needed and diffuse sunlight poorly absorbed. Here, a system that overcomes both limitations presented, by exploiting light-induced halide segregation in mixed perovskite films. A monolayer of silica microspheres focuses direct film below. Through phase low bandgap region forms the focal point. Together funneling excited states toward regions, this results voltage increase characteristic for Diffuse still absorbed high material, avoiding loss conventional concentrators. formation regions dynamic, can follow position focus as sun moves throughout day, making unnecessary. With detailed optical electrical simulations, it shown concept lead to an current. This leads 6.6% absolute power conversion efficiency compared without microspheres. Absorption emission measurements confirm concentration effect, showing promising potential self-optimizing system.