Energy transfer in the system of PbS quantum dots

This work is devoted the investigation of the process of nonradiative energy transfer via FRET mechanism between lead sulphide QDs of different size in the porous matrix and on the glass surface at both room and decreased temperatures. As a result, we observed quenching of photoluminescence (PL) for donors together with flare-up of PL of acceptors, which was accompanied by significant increasing of lifetimes of acceptors up to values characteristic for donors. This unexpected effect can be explained using three-level model which based on a complex energy structure of PbS quantum dots-donors, which are involved in the energy transfer. The observed effect can lead to a significant change in the dynamic characteristics of the charge carriers in quantum dot solar cells