Tuning Band-Edge Spin–Orbit Coupling to Prolong Carrier Lifetime in CsPbBr 3 Perovskites

enhances spin polarization without introducing midgap trap states compared to the pristine system. This spin polarization reduces nonadiabatic coupling between band-edge states while activating additional spin-orbit coupling (SOC)-mediated spin-flip channels within CBM↑/CBM↓ and VBM↑/VBM↓. These channels enable dynamic charge redistribution among spin-resolved orbitals, thereby prolonging carrier lifetimes. Our study reveals how band-edge SOC governs charge recombination and spin relaxation dynamics in halide perovskites, providing design principles for high-performance optoelectronic devices.