Surface effects in quantum dots

Surface effects play a major role in shaping optical and electronic properties of quantum dots given their high surface/volume ratio. Yet they remain poorly understood and have not been the object of intense investigation in the academic community. We are currently working on a simple model based on semi-classical electron transfer and a single surface state, which differs from the traditional model that views the surface as a broad distribution of mid-gap defects states. We are testing this model on white light emitting dots synthesized in our lab as well as other commercial samples. Linking surface effects to the debate about multiexcitons and its implications for photo-voltaics, we have also shown that surface-induced charge trapping processes are at the origin of the signals that had been interpreted as the signature of multi-excitons generation by other studies.