Carrier Decay Properties of Mixed Cation Formamidinium–Methylammonium Lead Iodide Perovskite [HC(NH2)2]1–x[CH3NH3]xPbI3 Nanorods

Organic–inorganic lead iodide perovskites are efficient materials for photovoltaics and light-emitting diodes. We report carrier decay dynamics of nanorods of mixed cation formamidinium and methylammonium lead iodide perovskites [HC(NH 2 ) 2 ] 1– x [CH 3 NH 3 ] x PbI 3 (FA 1– x MA x PbI 3 ) synthesized through a simple solution method. The structure and FA/MA composition ratio of the single-crystal FA 1– x MA x PbI 3 nanorods are fully characterized, which shows that the mixed cation FA 1– x MA x PbI 3 nanorods are stabilized in the perovskite structure. The photoluminescence (PL) emission from FA 1– x MA x PbI 3 nanorods continuously shifts from 821 to 782 nm as the MA ratio ( x ) increases from 0 to 1 and is shown to be inhomogeneously broadened. Time-resolved PL from individual FA 1– x MA x PbI 3 nanorods demonstrates that lifetimes of mixed cation FA 1– x MA x PbI 3 nanorods are longer than those of the pure FAPbI 3 or MAPbI 3 nanorods, and the FA 0.4 MA 0.6 PbI 3 displays the longest average PL lifetime of about 2 μs. These results suggest that mixed cation FA 1– x MA x PbI 3 perovskites are promising for high-efficiency photovoltaics and other optoelectronic applications.