Fullerene modification of WO₃ electron transport layer toward high‐efficiency MA‐free perovskite solar cells with eliminated light‐soaking effect

In perovskite solar cells (PSCs), the light-soaking effect, which means device performance changes obviously under continuous light illumination, is potentially harmful to loaded devices as well accurately assessing their efficiency. Herein, chemically stable tungsten trioxide (WO3) with high electron mobility used transport material in methylamine (MA)-free PSCs. However, effect observed apparently our devices. A fullerene derivative, C60 pyrrolidine Tris-acid (CPTA), introduced modify interface between WO3 and (PVK) layers, can bond PVK simultaneously, leading passivation of defect suppression trap-assisted nonradiative recombination. What more, introduction CPTA enhance built-in electric field thereby facilitating extraction inhibiting carrier accumulation at interface. Consequently, WO3-based PSCs has been eliminated, power conversion efficiency boosted from 17.4% for control 20.5% WO3/CPTA-based PSC enhanced stability. This study gives guidance design interfacial molecules eliminate effect.