Nanowire Lasers of Formamidinium Lead Halide Perovskites and Their Stabilized Alloys with Improved Stability

The excellent intrinsic optoelectronic properties of methyl ammonium lead halide perovskites (MAPbX(3), X = Br, I), such as high photoluminescence quantum efficiency, long carrier lifetime, and high gain coupled with the facile solution growth of nanowires make them promising new materials for ultralow-threshold nanowire lasers. However, their photo and thermal stabilities need to be improved for practical applications. Herein, we report a low-temperature solution growth of single crystal nanowires of formamidinium lead halide perovskites (FAPbX(3)) that feature red-shifted emission and better thermal stability compared to MAPbX(3). We demonstrate optically pumped room-temperature near-infrared (similar to 820 nm) and green lasing (similar to 560 nm) from FAPbI(3) (and MABr-stabilized FAPM(3)) and FAPbBr(3) nanowires with low lasing thresholds of several microjoules per square centimeter and high quality factors of about 1500-2300. More remarkably, the FAPbI(3) and MABr-stabilized FAPbI(3) nanowires display durable room temperature lasing under similar to 10(8) shots of sustained illumination of 402 nm pulsed laser excitation (150 fs, 250 kHz), substantially exceeding the stability of MAPbI(3) (similar to 10(7) laser shots). We further demonstrate tunable nanowire lasers in wider wavelength region from FA-based lead halide perovskite alloys (FA,MA)PbI3 and (FA,MA)Pb(I,Br)(3) through cation and anion substitutions. The results suggest that formamidinium lead halide perovskite nanostructures could be more promising and stable materials for the development of light-emitting diodes and continuous-wave lasers.