Low-Temperature Observation of Photoinduced Electron Transfer from CdTe Nanocrystals

Photoinduced electron transfer from a CdTe nanocrystal (NC) to a photoluminescence quencher, 1,2,4,5-tetracyanobenzene (TCNB), has been studied with both steady-state photoluminescence spectroscopy and low-temperature time-resolved photoluminescence spectroscopy. The photoluminescence of CdTe NCs is quenched by TCNB mainly through a static electron transfer process and apparently slow quenching decay in nanosecond order is also observed below 50 K. Characteristic temperature dependence of charge separation rate constant at low temperature is discussed on the basis of exciton fine structure of the CdTe NC generated by an electron-hole exchange interaction.