Multiphonon sidebands of Fröhich polaron in metal halide perovskite quantum dots

We theoretically study the optical absorption of Fröhlich polaron in metal halide peovskite quantum dots based on the well-known Huang–Rhys model. We find that multiphonon sidebands are appeared in the absorption spectra when the energy of incident photon equaling to the multiple LO phonons, where the orders of phonon sideband and the strongest sideband depend on the radius of quantum dot sensitively, which indicates the average phonon numbers around a polaron could be evaluated by the orders of phonon sideband. Moreover, we discuss the temperature dependences of these phonon sidebands in details, giving the enlightenment for analyzing the carriers mobility affected by LO phonons scattering in recently experiments. These theoretical results not only provide an effective way to prove Fröhlich polaron states, but also enrich the knowledge for understanding the basic properties of polaron in metal halide perovskite nanostructures.