Sign of the Gap Temperature Dependence in CsPb(Br,Cl)₃ Nanocrystals Determined by Cs-Rattler-Mediated Electron-Phonon Coupling.

ABSTRACT: So far, the striking sign reversal in the near-ambient slope of the gap temperature dependence of colloidal CsPbCl₃ perovskite nanocrystals (NCs) compared to its Br counterpart remains unresolved. Pure bromide NCs exhibit a linear gap increase with increasing temperature, to which thermal expansion and electron-phonon interaction equally contribute. In contrast, the temperature slope for the chlorine compound gap is clearly negative. By combining temperature- and pressure-dependent photoluminescence on a series of CsPb(Br_1-xCl_x)₃ NCs, we unravel the origin of such inversion. The electron-phonon interaction is solely responsible, undergoing a sudden change in sign and magnitude due to activation of an anomalous electron-phonon coupli

SUBMITTER: Fasahat S 

PROVIDER: S-EPMC11915369 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature