Polymeric nanocomposites involving a physical blend of IR sensitive quantum dots and carbon nanotubes for photodetection

A photodetecting device with enhanced efficiency has been fabricated by using a blend of IR sensitive quantum dots (QDs) and carbon nanotubes (CNTs). Measurements on the facile physical mixtures of PbSe QDs, and CNTs in compatible solvents show quenching of the IR photoluminescence of QDs due to the presence of the CNTs. This effect, verified for QDs with emission at different wavelengths, is envisaged to originate from the electron transfer from QDs adsorbed on the surface of CNTs, similar to that occurring when the QDs are chemically conjugated to CNTs, as reported in the literature. An appreciable increase is observed in the photocurrent of the polymeric photodetector devices (made with P3OT as the polymer host) fabricated with a QDs/CNTs mixture when compared to PbSe:P3OT without CNTs. These studies demonstrate that electron transfer from QDs to CNT is achievable by simple physical mixing, apparently obviating the need of a cumbersome chemical process of conjugation between CNTs and QDs.