title: Enhanced nonlinear optical responses in donor-acceptor ionic complexes via photo induced energy transfer.
abstract: By complexion of donor and acceptor using ionic interactions, the enhanced nonlinear optical responses of donor-acceptor ionic complexes in aqueous solution were studied with 7-ns laser pulses at 532 nm. The optical limiting performance of negatively charged gold nanoparticles or graphene oxide (Acceptor) was shown to be improved significantly when they were mixed with water-soluble, positively-charged porphyrin (Donor) derivative. In contrast, no enhancement was observed when mixing with negatively-charged porphyrin. Transient absorption studies of the donor-acceptor complexes confirmed that the addition of energy transfer pathway were responsible for excited-state deactivation, which results in the observed enhancement. Fluence, angle-dependent scattering and time correlated single photon counting measurements suggested that the enhanced nonlinear scattering due to faster nonradiative decay should play a major role in the enhanced optical limiting responses.
authors.affiliation: Department of Physics, National University of Singapore, 117542, Singapore.
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Mamidala
authors.forename: Lakshminarayana
authors.initials: L
authors.lastname: Polavarapu
authors.forename: Janardhan
authors.initials: J
authors.lastname: Balapanuru
authors.forename: Kian Ping
authors.initials: KP
authors.lastname: Loh
authors.forename: Qing-Hua
authors.initials: QH
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
mesh_terms: D004579:Electron Transport; D004735:Energy Transfer; D006108:Graphite / Q000737:chemistry* / Q000528:radiation effects; D007477:Ions; D008027:Light; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D017711:Nonlinear Dynamics; D055672:Static Electricity
chemical_list: D007477:Ions; D006108:Graphite