Spin-polarized excitonic luminescence of oriented cesium lead bromine nanowires near the quantum confinement regime

Perovskite nanowires with unique properties, including strong spin–orbit coupling and bright excitonic photoluminescence, are promising for spin-photonics. However, the link between their spin-related optical properties and anisotropic quantum confinement is unclear. Here, we investigate this relationship by measuring the circularly polarized magneto-optical spectra in cesium lead bromine nanowires with widths near the excitonic Bohr diameter. Results show that in the Faraday mode, only thicker nanowires show spin-polarized excitonic emission. In the Voigt mode, thicker nanowires display unexpected spectral broadening with increasing magnetic field, while thinner ones show large singlet–triplet splitting, with minimal magnetic field dependence. These insights highlight the potential of perovskite nanomaterials for advanced spin-optical applications.