Acoustic phonon–exciton interaction by extremely strong exciton confinement and large phonon energy in CsPbBr3 perovskite

Abstract

Recently, CsPbX3 (X: halogen) materials have been considered as promising light-emitting materials, because of their good environmental durability and outstanding optoelectronic properties. Understanding the exciton and phonon behaviors in CsPbX3 is crucial in developing advanced optoelectronic devices. In this work, distinct acoustic phonon–exciton interaction, which was first observed in perovskite, was discovered in our established highly luminescent and durable CsPbBr3 film. The acoustic phonon–exciton coupling was induced by strong exciton confinement (∼70 meV exciton binding energy) and accompanied by large phonon energy ascribed to local vibration modes. We believe that our results will serve to in improve performance of the corresponding optoelectronic devices.