Phonon-assisted exciton absorption in CdSe/CdS colloidal nanoplatelets

The features of the nonresonant absorption of CdSe nanoplatelets with a CdS shell are studied in the case of excitation to the exciton absorption edge by high-power nanosecond laser pulses. It is shown that the exciton-phonon interaction plays a key role in the processes of nonresonant absorption of photons in colloidal nanoplatelets. The observed features of the nonlinear change in absorption are explained by the effect of the partial filling of the exciton phase space owing to the interaction with longitudinal optical phonons.