Hot Carrier Relaxation in CsPbBr-Based Perovskites: A Polaron Perspective.

Long-standing interpretations for the exceptional photovoltaic and optoelectronic properties showcased by the perovskite family pertain to the underlying complicated interplay of polaron formation and hot carrier cooling. This Perspective primarily focuses on reassessing the existing status of polaron studies conducted on CsPbBr-based systems in particular, in the framework of transient absorption investigations. The role of the key aspect that is ultimately accountable for deciding the fate of polaron formation, i.e., the carrier-longitudinal optical phonon coupling, has been comprehensively evaluated in terms of diverse factors which affect this Fröhlich interaction-mediated coupling. The study provides a detailed discussion regarding the alterations in lattice polarity, surrounding dielectric medium, lattice temperature, and system dimensionality which can influence the charge screening extent and thereby the polaron formation. Such studies concerning strategies for achieving easily attainable modulations in polaron formation in CsPbBr-based systems are highly relevant for technological advancement.