Efficient and Stable Perovskite Solar Cells based on Nitrogen‐Doped Carbon Nanodots

The role of graphitic and amorphous nitrogen‐doped carbon dots (N‐CDs) as additives for perovskite solar cells (PSCs) is investigated. A detailed study of N‐CDs: perovskite (PVSK) blends through X‐ray diffraction, nuclear magnetic resonance, field emission scanning electron microscopy, UV–vis, and photoluminescence spectroscopy reveals the existence of interactions between N‐CDs and PVSK. The amorphous or graphitic nature of these carbon nanoforms, as well as the interactions between CDs and PVSK, clearly determines the photovoltaic outcome of the PSCs. Thus, a small amount of graphitic carbon dots (g‐N‐CDs) leads to more‐stable PSCs, while maintaining and even improving the power conversion efficiency (PCE). In addition, the long‐term evaluation of the g‐N‐CDs‐containing cells shows improvement of the PCE over time, up to 109% of the initial efficiency after 40 days while the reference performance is dropped to 86%.