Mitigating the Heterointerface Driven Instability in Perovskite Photovoltaics

Abstract

Metal halide perovskites have the potential to revolutionize the field of photovoltaics, though limited stability has impeded commercial exploitation. The soft heterointerface between the perovskite and charge-transporting layer is one of the major bottlenecks that limits operational stability. Here, we present rationally designed molecular modulators that synergistically improve the stability of the α-FAPbI₃-based perovskite solar cells while retaining power conversion efficiency (PCE) of 24.0% with a high open-circuit voltage (V_OC) of ～1.195 V. The interfacially modified photovoltaic cells exhibit high operational stability, whereby the champion device retains ～88% of initial performance after 2000 h of maximum power point tracking at 40 °C and 1 sun illumination. The molecular origins of such enhanced stability and device performance are corroborated by multiscale characterization techniques and modeling, providing insights into the origins of performance and stability enhancements.