▎ 摘　　要

The charge separation and recombination processes between CdSe quantum dot (QD) and graphene oxide (GO) composites with linking molecule methylene blue (MB+) were studied by femtosecond transient absorption spectroscopy. Anchoring MB+ molecules on GO results in significant changes in steady-state and transient absorption spectra, where the exciton dissociation time in the CdSe QD-MB+-GO composite was determined to be 1.8 ps. Surprisingly, the ground state bleaching signal increased for MB+-GO complex was found to be 5.2 ps, in relation with electron transfer from QD to GO. On the other hand, the strong electronic coupling between MB center dot-GO radical and GO prolonged charge recombination process (>= 5 ns) in QD-MB+-GO composites. Charge separation and recombination processes at the interface between semiconductor QDs and graphene can thus be modulated by the functionalized dye molecules.