Synergic Influence of Reverse Micelle Confinement on the Enhancement in Photoinduced Electron Transfer to and from Carbon Nanoparticles

Abstract

The photoexcited behavior of carbon nanoparticles (CNPs) and the effect of confinement on photoinduced electron transfer (PET) to and from the CNPs have been examined by confining the nanoparticles and electron donor–acceptor systems in aerosol OT (AOT)/hexane/water reverse micelles (RMs). The CNPs and the electron donor dimethylaniline (DMA) are captured in the nonpolar environment of the RMs, while methyl viologen (MV2+), the electron acceptor, readily goes into the water pool. This confined medium facilitates experimentation on the electron transfer dynamics between two different phases. PET from DMA to MV2+ via CNPs is the expected phenomenon. The ultrafast photogenerated MV•+ cation radical acts as an electron sink scavenging electrons from DMA. PET has been confirmed from steady-state and time-resolved fluorescence along with ultrafast transient absorption measurements. The kinetic details of PET in the DMA–CNP–MV2+ assembly in a confined RM medium provide prospects toward development of light energy conversion devices.