Time-resolved photoluminescence and transient absorption spectroscopy are used to examine the influence that long excited state lifetimes of Mn-doped nanocrystals have on the mechanisms of photoinduced electron transfer (PET) in photocatalytic systems. Mn-doped ZnSe nanocrystals can undergo PET over their nearly millisecond excited state lifetime, which enables electron transfer to viologens in solution over large encounter distances in comparison to molecular length scales. The long excited state lifetimes also enable diffusion of the excited nanocrystals over hundreds of nanometers in solution, allowing them to react with molecular species at nanomolar concentrations. The ability to capture and sustain optical energy in spin-forbidden transitions among crystal field states of the Mn ions opens opportunities to explore the influence that long excited state lifetimes have on photocatalytic reaction mechanisms involving molecular species such as CO2 that can be difficult to concentrate or attach to nanocrystal surfaces.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films