The evolution of perovskite-based solar cells to their maximum efficiency

Abstract

Device fabrication techniques and the photovoltaic performance of organic-inorganic hybrid solar cells are reviewed with a focus on lead organohalide perovskite and mesoscopic TiO₂-based solid-state solar cells, which have demonstrated a high conversion efficiency that has exceeded 15% since our first report of the perovskite photovoltaic material in 2009. The hybridization of organic and inorganic materials in these solid-state mesoscopic structures enables the enhancement of the photovoltage up to 1.2 V by minimizing the Gibbs energy (voltage) loss from carrier transfers at heterogeneous interfaces. The unique physical properties of carrier conduction and the future potential for efficiency enhancements are discussed for the perovskite-based photovoltaics. Another topic that is a focus is the metal-ligand complex as a photo-absorber on mesoporous TiO₂, which is capable of a high voltage of 1.18 V in combination with perylene as a crystalline hole conductor. The review emphasizes the importance of a voltage enhancement in the development of higher performance as well as material innovation for solution-printable processes during the R&D of organic photovoltaics.