Strong Electronic Coupling and Ultrafast Electron Transfer between PbS Quantum Dots and TiO2 Nanocrystalline Films

Hot carrier and multiple exciton extractions from lead salt quantum dots (QDs) to TiO2 single crystals have been reported. Implementing these ideas on practical solar cells likely requires the use of nanocrystalline TiO2 thin films to enhance the light harvesting efficiency. Here, we report 6.4 +/- 0.4 fs electron transfer time from PbS QDs to TiO2 nanocrystalline thin films, suggesting the possibility of extracting hot carriers and multiple excitons in solar cells based on these materials.