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(NH2)(2)](1-x)[CH3NH3](x)PbI3 (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 photo-luminescence (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)PhI(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 mu s. These results suggest that mixed cation FA(1-x)MA(x)PbI(3) perovskites are promising for high-efficiency photovoltaics and other optoelectronic applications.