Optical Characteristics and Operational Principles of Hybrid Perovskite Solar Cells (Phys. Status Solidi A 12∕2018)

Perovskite Solar Cells The crystal structure of the CH 3 NH 3 PbI 3 organic‐inorganic hybrid perovskite with direct band gap formation in the crystal and the operating principle of a CH 3 NH 3 PbI 3 solar cell are shown on the cover, referring to article number 1700730 by Hiroyuki Fujiwara and co‐workers. In this article, the optical characteristics and operational principles of hybrid perovskite solar cells are reviewed. In particular, the unique optical properties of various hybrid perovskite materials, as revealed by experimental characterization and first‐principles calculations, are described in detail. Moreover, from the photocurrent characterization results, the fundamental operating principles of the perovskite cells based on a simple p–n junction formation are discussed. The high short‐circuit current observed in the solar cells is further interpreted by the suppressed parasitic light absorption and efficient optical confinement in the solar cells. This article provides renewed principles for the optical processes and operation of hybrid perovskite solar cells.