Metal Halide Perovskites—From a Scientific Curiosity Toward an Industrialized Photovoltaic Technology
Photovoltaic (PV) solar energy is already the least expensive form of producing electricity in many geographic locations. The industry is set to increase in scale by at least another order of magnitude, and many technological innovations are being developed and implemented at the laboratory scale, implying that the roadmap for progress will continue to deliver efficiency and power output gains for decades to come. Altogether, it is inevitable that a significant fraction of our future, clean and sustainable power generation capacity will be met with PV. One of the most exciting new materials, poised to deliver significant efficiency gains for solar PV, is metal halide perovskites. These materials were only found to be remotely useful for solar energy conversion a little over a decade ago, and since then the performance of a solar cell fabricated with a single thin film of metal halide perovskites has reached the performance of the very best silicon PV cells, with multi-junction perovskite, or perovskite-on-silicon tandem cells, shooting past and beyond the efficiency levels that could ever be achieved with Silicon or even Gallium Arsenide alone. Despite the progress, there remain naysayers, largely pointing toward the unproven stability of metal halide perovskites and also the reliance upon lead in the most efficient and most stable perovskite materials. In this lecture, I will describe some of the key moments in the early development of metal halide perovskite PV, some of the key research challenges, opportunities and recent progress, and the industrial progress toward delivering a reliable, scalable and sustainable PV technology.