Proceedings of International Conference on Perovskite and Organic Photovoltaics and Optoelectronics (IPEROP19)
Publication date: 23rd October 2018
Recently, the eco-friendly halide perovskites, mainly lead-free perovskites, have attracted extensively attention due to their low toxicity. The Sn-based perovskite is a one of potential candidates for efficient perovskite solar cells (PSCs). However, the oxidation of Sn2+ to Sn4+ under ambient air degrades the Sn-based perovskite and the device photovoltaic performance. Here, we dope SnF2 as reducing agent and introduce bulky organic cation of ethylenediammonium diiodide (EDAI2) as additive to stabilize formamidinium tin iodide (FASnI3) perovskite. When the commonly-used hole transport material (HTM) of spiro-OMeTAD is covered on the perovskite active layer, spiro-OMeTAD accelerates the oxidation of perovskite and the perovskite film will decompose within 30 min. Hence, HTM-free Tin-based perovskite is fabricated and presents stability for at least 12 hr under air. When FASnI3 is doped with 0.1 M EDAI2, open-circuit voltage for the PSC is significantly enhanced compared to pure FASnI3 counterpart, indicating that addition of EDAI2 is an efficient strategy to improve the photovoltaic performance.