Minimal Effect of the Hole-Transport Material Ionization Potential on the Open-Circuit Voltage of Perovskite Solar Cells

Hole-transport material optimization is an important step toward maximizing the efficiency of perovskite solar cells. Here, we investigate the role of one hole-transport material property, the ionization potential, on the performance of perovskite solar cells. We employ a device architecture that allows us to systematically tune the ionization potential while avoiding any impact to other device parameters, and we find that for a wide range of ionization potentials the photovoltaic performance is minimally affected. This finding relaxes the requirement for the development of hole-transport materials with particular ionization potentials, allowing for the optimization of hole-transport materials that can improve performance in differing ways such as through increased stability or decreased parasitic absorption.