Circularly-Polarized Excitons and Spin-Orbital Coupling Ordering Effects in Chiral-Structured Organic-Inorganic Hybrid Perovskites

Chiral-structured semiconducting materials have shown emerging phenomena such as chirality-induced spin selection, namely CISS. Here, we utilize magnetic field effects of circularly polarized photoluminescence (MFE-CPL) to probe circularly-polarized excitons and spin-orbital coupling (SOC) ordering effects based on chiral-structured metal-halide hybrid perovskite films where the chiral-structured 1D S-MBAPbBr₃ dispersed in nonchiral-structured 3D MAPbBr₃ matrix. The chiral-structured perovskites can demonstrate right-handed (s⁺) and left-handed (s^-) CPL upon applying right-handed and left-handed circularly polarized excitations. This observation indicates that right-handed/left-handed circularly polarized lights can selectively excite the respective handed chiral structures. Interestingly, applying the magnetic field of 0.9 T can clearly increase the circular polarization of CPL at room temperature. Here, these magnetic field effects provide three fold critical information. First, light-emitting excitons can indeed exhibit circularly polarized orbital momentum, leading to circularly polarized excitons in the chiral perovskite structures. Second, the chiral structures are essentially formed with helically-ordered SOC, presenting SOC ordering effects towards generating CPL. Third, applying a magnetic field enhances the SOC ordering effects, consequently increasing the circular polarization of CPL by decreasing the dephasing of circularly polarized excitons in chiral structures. This presentation will discuss circularly-polarized excitons formed through spin-orbital coupling ordering effects in chiral-structured perovskites.