Exciton linewidth broadening induced by exciton–phonon interactions in CsPbBr3 nanocrystals
Buyang Yu, Chunfeng Zhang, Lan Chen, Xinyu Huang, Zhengyuan Qin, Xiaoyong Wang, Min Xiao
Abstract
Quantum dephasing of excitonic transitions in CsPbBr3 nanocrystals has been studied using two-dimensional electronic spectroscopy at cryogenic temperatures. The exciton–phonon interactions for acoustic and optical modes exhibit different effects on the coherent dynamics of excitonic transitions. The homogeneous linewidth shows a proportional dependence on the temperature, suggesting the primary dephasing channel of the elastic scattering between exciton and acoustic modes. The exciton–optical mode interaction is manifested as the beatings of off-diagonal signals in the population time domain at the frequencies of 29 and 51 cm−1, indicating phonon replicas of excitonic transitions arising from coherent exciton–phonon interaction. The insight information of exciton homogeneous broadening in perovskite nanocrystals is essential for the potential application of quantum light sources.