Exhibition of Förster resonance energy transfer from CdSe/ZnS quantum dots to zinc porphyrazine studied in solution

Abstract

Molecular level interaction between CdSe/ZnS core-shell quantum dots (QD) and zinc porphyrazine (1) is studied in solution by means of UV–vis spectroscopy, steady state emission and time-resolved fluorescence decay measurements. Appreciable value of red shift of the Soret absorption band of 1 (~4 nm) in presence of QD is indicative of ground state interaction between these two species in solution. Photoluminescence (PL) of QD is quenched considerably in presence of 1 upon formation of QD–1 system and average value of lifetime of QD is reduced considerably following the addition of 1 in increasing concentration. The PL quenching mechanism may be identified as Förster resonance energy transfer from QD to 1 in solution. Evaluation of bimolecular quenching constant (kq) value of QD–1 system (kq (av) ~ 3.2 × 1012 dm3·mol−1·sec−1) establishes that static quenching mechanism predominates over diffusion controlled pathway behind quenching of PL of QD in presence of 1 in solution. The results demonstrate that 1 may be selectively employed as an energy accepting unit in combination with quantum dots for possible application in organic photovoltaics.