Methylammonium (CH3 NH3+ ) and formamidinium ((NH2 )2 CH+ ) based lead iodide perovskites are currently the two commonly used organic-inorganic lead iodide perovskites. There are still no alternative organic cations that can produce perovskites with band gaps spanning the visible spectrum (that is, <1.7 eV) for solar cell applications. Now, a new perovskite using large propane-1,3-diammonium cation (1,3-Pr(NH3 )22+ ) with a chemical structure of (1,3-Pr(NH3 )2 )0.5 PbI3 is demonstrated. X-ray diffraction (XRD) shows that the new perovskite exhibits a three-dimensional tetragonal phase. The band gap of the new perovskite is about 1.6 eV, which is desirable for photovoltaic applications. A (1,3-Pr(NH3 )2 )0.5 PbI3 perovskite solar cell (PSC) yields a power conversion efficiency (PCE) of 5.1 %. More importantly, this perovskite is composed of a large hydrophobic cation that provides better moisture resistance compared to CH3 NH3 PbI3 perovskite.
Keywords: ammonium; band gap; organic cations; perovskite solar cells; stability.
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