Perovskite solar cells with power conversion efficiencies exceeding 16% at AM 1.5G one sun illumination are developed using the black polymorph of formamidnium lead iodide, HC(NH2)(2)PbI3. Compared with CH3NH3PbI3, HC(NH2)(2)PbI3 extends its absoprtion to 840 nm and shows no phase transition between 296 and 423 K. Moreover, a solar cell based on HC(NH2)(2)PbI3 exhibits photostability and little I-Vhysteresis.