Building Perovskite Solar Cells That Last

At the heart of a solar cell sits an absorber layer that converts sunlight into electricity. Metal-halide perovskites (MHPs) are a new class of such absorber materials, which have exceptional optoelectronic properties and can be manufactured by using low-cost, scalable solution-processing or vapor-based deposition methods. Consequently, perovskite photovoltaics (PV) have progressed at an unprecedented pace and have gone from experimental breakthroughs to the cusp of commercialization within the last decade . Thus far, much focus has been aimed at improving the power-conversion efficiency of small-area cells-now approaching 26%, having already surpassed most other thin-film PV technologies (1). Efficiency is, however, only one of many requirements for a PV technology to succeed. Equally important is the capacity to retain performance over time, for up to 25+ years. On page 307 of this issue Zhao et al. (2) tackle this challenge of longterm stability of MHP solar cells through accelerated stress testing.