title: Femtosecond dynamics of excitons and hole-polarons in composite P3HT/PCBM nanoparticles.
abstract: The dynamics of charge separation in aqueous suspensions of regioregular P3HT nanoparticles containing PCBM were investigated for the first time using femtosecond transient absorption spectroscopy. This investigation is supported by the recently reported use of regioregular P3HT/PCBM nanoparticles as charge trapping and storage devices. In this study, the presence of excited-state and charge-separated species, including singlet excitons, polymer polarons and free charges, generated in rr-P3HT/PCBM nanoparticles was identified through visible pump and visible/near-infrared probe femtosecond transient absorption spectroscopy at a range of electron acceptor concentrations. The decrease of the singlet exciton lifetime by charge transfer to PCBM is well described by a one-dimensional diffusion model with a P3HT domain size of approximately 5 nm for 5-50 wt % PCBM. This model also indicates that bimolecular recombination is the dominant charge recombination mechanism at 20 wt % PCBM and above.
authors: School of Chemistry & Physics, The University of Adelaide, Adelaide, South Australia 5005, Australia.
authors: Scott N
authors: SN
authors: Clafton
authors: David M
authors: DM
authors: Huang
authors: William R
authors: WR
authors: Massey
authors: Tak W
authors: TW
authors: Kee
mesh_terms: D004058:Diffusion; D037741:Fullerenes / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D013056:Spectrophotometry, Ultraviolet; D013876:Thiophenes / Q000737:chemistry*; D013997:Time Factors
chemical_list: C539575:(6,6)-phenyl C61-butyric acid methyl ester; D037741:Fullerenes; D013876:Thiophenes; C507295:poly(3-hexylthiophene)