Exciton-Resolved Phonon Coupling and Energy Dissipation Pathways in CsPbBr 3

microcrystals using photoluminescence, Raman, and reflectance spectroscopy at low temperature, revealing the simultaneous presence of high-energy and Rashba excitons, each accompanied by distinct phonon replica series. High-energy exciton replicas are uniquely spaced by approximately 9 meV, whereas Rashba exciton replicas exhibit a characteristic approximately 6 meV spacing, indicating the specificity of the exciton-phonon coupling. k-means clustering applied to a large low-temperature photoluminescence data set reveals these replica features are prevalent. With increasing temperature, replica features broaden and merge, evolving into a dominant longitudinal optical phonon coupling regime at room temperature. This work establishes direct spectroscopic evidence for concurrent, exciton-specific phonon coupling within a single material, offering pathways to engineer light-matter interactions for optoelectronic and phonon-photon-based quantum device applications.