A-Site Cation Effect on Growth Thermodynamics and Photoconductive Properties in Ultrapure Lead Iodine Perovskite Monocrystalline Wires

Among the various building blocks beyond polycrystalline thin films, perovskite wires have attracted extensive attention for potential applications including nanolasers, waveguides, field-effect transistors, and more. In this work, millimeter-scale lead iodine-based perovskite wires employing various A-site substitutions, namely, Cs, methylammonium (MA), and formamidinium (FA), have been synthesized via a new type solution method with nearly 100% yield. All of the three millimeter scale perovskite wires (MPWs) compositions exhibit relatively high quality, and CsPbI3 is proven to be monocrystalline along its entire length. Furthermore, the growth thermodynamics of the APbI3 MPWs with respect to A-site cation effect were studied thoroughly by various characterization techniques. Finally, single MPW photodetectors have been fabricated utilizing the APbI3 MPWs for studying the photoconductive properties, which show different sensitivities under illumination. This systematic synthesis method of solution-proces...