Understanding polaron dynamics in CeO2 for advanced catalytic material design

Abstract

Understanding electronic transport in materials is crucial for both fundamental and applied physics, as it directly affects key properties such as carrier mobility in semiconductors and conversion efficiency in photoelectric materials. In defect-free CeO₂, the formation of polarons induced by intrinsic electron–phonon coupling deviates from traditional defect-induced mechanisms, offering a new physical perspective for tuning carrier mobility and photoresponse in materials. This study systematically investigates the electron–phonon interactions in CeO₂ using ab initio polaron equations. We identify a striking electron–hole asymmetry: electrons primarily exhibit Holstein polaron characteristics, while holes predominantly behave as Fröhlich polarons. This distinction provides insights into charge transport mechanisms during photoelectrical conversion reactions. Our analysis reveals that the transport of Fröhlich polarons in CeO₂ is governed by electron–phonon scattering mechanisms, with holes mainly modulated by acoustic deformation potentials and high-frequency longitudinal optical phonons. This work provides a microscopic understanding of carrier transport in CeO₂ and offers new strategies for designing efficient CeO₂-based photoelectrochemical conversion materials, including defect engineering, heterostructure integration, and nanostructure design to optimize charge transport.