Charged quantum dots for high-efficiency photovoltaics and IR sensing

Charging of quantum dots (QDs) provides an effective way for managing 3D nanoscale potential profiles, which in turn control photoelectron processes. Dot charging creates local potential barriers around randomly distributed single dots, and collective barriers around dot clusters, rows etc. if the QDs form specific structures or arrays. The nanoscale potential barriers provide an effective tool for the suppression of fast capture processes of photocarriers by QDs. This allows one to increase the photocarrier lifetime and reduce recombination losses. The charging of dots also enhances the electron coupling to infrared radiation and multi-step absorption of sub-bandgap photons. Nanomaterials with charged QDs have a number of features attractive for photovoltaic and sensing applications.