Supramolecular Macrocyclic Iodine Adsorbents Enable Photothermally Stable Perovskite Solar Cells

In this study, the design and synthesis of two novel diazapentacene-based macrocycles (M3 and M4) is reported via a one-pot Yamamoto coupling reaction. These macrocycles are constructed by π-extension of a dihydrophenazine core, maintaining its excellent redox activity while offering enlarged cavities and enhanced electron-donating properties. As a result, M3 and M4 exhibit strong electron-rich characteristics and well-defined cavities, enabling their use as efficient iodine adsorbents to mitigate photo-thermal-induced iodine loss and perovskite degradation in solar cells. The macrocycles demonstrate dual-mode iodine capture: physical adsorption through cavity confinement and chemical adsorption via charge-transfer interactions, both of which show excellent reversibility. Addressing the critical issue of operational instability in perovskite solar cells (PSCs), caused by iodine escape and Pb⁰ defect formation, these macrocycles effectively trap volatile iodine species and suppress defect generation. Notably, PSCs incorporating macrocycle M4 achieve a high efficiency of 26.13% and outstanding operational stability, retaining ≈95.85% of their initial efficiency after 1000 h of maximum power point (MPP) tracking at 85 °C under the International Summit on Organic Photovoltaic Stability-Light-Soaking Test at 65/85 °C (ISOS-L-2) protocol.