Lead Leakage Preventable Fullerene-Porphyrin Dyad for Efficient and Stable Perovskite Solar Cells

Designing functional fullerenes with roles beyond defect passivation and electron-transporting for perovskite solar cells (PSCs) is essential to the development of fullerenes and PSCs. Here, the authors design and synthesize a functional fullerene, FPD, composed of a C-60 cage, a porphyrin ring, and three pentafluorophenyl groups. The structure features of FPD enable it can form chemical interactions with the perovskite lattices. These interactions enhance the defect passivation effect and prevent the decomposition of perovskite under irradiation. As a result, the FPD-based device yields an improved power conversion efficiency of 23% with substantially enhanced operational stability (T-80 > 1500 h). Furthermore, once got damaged, the FPD can prevent lead leakage by forming a stable and water-insoluble complex (FPD-Pb). Their findings provide a novel strategy to achieve high-performance and eco-friendly PSCs with functional fullerene materials.