Impact of Bychkov-Rashba Spin Splitting on Dual Emissions for Lead Halide Perovskite Nanowires.

Bychkov-Rashba spin-orbit coupling (SOC) is decisive for photoinduced photoluminescence (PL) in terms of double emissions. It turns out to be remarkable for one-dimensional lead halide perovskite nanowires (PeNWs). This is primarily due to large surface to volume ratios and structural symmetry breaking fields in the reduced dimension. Systematic studies of the effect of Rashba SOC on PL and its discrimination with the self-trapped exciton in wide temperature and illumination intensity ranges are considerably important and, heretofore, have not been performed. Here, highly crystalline methylammonium lead triiodine (MAPbI3) PeNWs are demonstrated to be able to produce remarkable dual emissions at low temperatures. With extensive analyses by a photoelectrical device-based spin-photogalvanic effect and magnetophotoluminescence, the Rashba effect is proven to be the only factor that governs the dual emissions. We believe a complete understanding of the PL character of PeNWs is beneficial for the development of novel perovskite nanophotonic devices.