CdTe Quantum Dot Fluorescence Modulation by Spin Crossover

Nanocomposite materials containing Cadmium Telluride (CdTe) nanocrystals and [Fe(H-trz)(2)(trz)]BF4 nanoparticles were synthesized and investigated for the coupling between their photoluminescent and spin crossover properties. The bright CdTe emission around 550 nm was found to decrease reversibly when switching the ferrous complex from the high spin (HS) to the low spin (LS) state, which was attributed to the spectral overlap of the luminescence with the absorption of the complex in the latter electronic configuration. A significant irreversible change of the luminescence signal (photobleaching) was also observed both in emission intensity and lifetime measurements.