Ion-Migration Inhibitor for Spiro-OMeTAD/Perovskite Contact toward Stable Perovskite Solar Cells

This is the authors' abstract. We don't add key points for this paper.

Dopants are utilized to enhance the mobility and optimize energy levels of hole-transporting layers in perovskite solar cells (PSCs), which are crucial to achieving high power conversion efficiencies (PCEs) of normal PSCs. However, the traditional method of doping 2,2′,7,7′-tetrakis(N,N-di(4-methoxyphenyl)amino)-9,9-spirobifluorene (Spiro-OMeTAD) with lithium bis(trifluoromethylsulfonyl)imide (Li-TFSI) can cause inward migration of Li-ions to perovskite, which is one of the main factors affecting the long-term stability of PSCs. In this study, we utilized a multifunctional ion-migration inhibitor at the Spiro-OMeTAD/perovskite interface to control ion migration. As a result, both Spiro-OMeTAD and perovskite were safeguarded and the device's operational stability was enhanced. The optimized devices with 4-methanesulfonyl-benzamidine hydrochloride exhibited an improved PCE of up to 25.3%. Meanwhile, we documented 520-h T90 under continuous 1-sun illumination, 740-h T80 heating at 60 ± 5 °C, and 1000-h T92 at maximum power point tracking at 50 ± 5 °C under continuous 1-sun illumination.