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Here, we demonstrate that quasi self-standing Au nanorod arrays prepared with plasma polymerisation deposited SiO2 dielectric spacers support surface enhanced fluorescence (SEF) while maintaining high signal reproducibility. We show that it is possible to find a balance between enhanced radiative and non-radiative decay rates at which the fluorescent intensity is maximized. The SEF signal optimised with a 30 nm spacer layer thickness showed a 3.5-fold enhancement with a signal variance of <15% thereby keeping the integrity of the nanorod array. We also demonstrate the decreased importance of obtaining resonance conditions when localized surface plasmon resonance is positioned within the spectral region of Au interband transitions. Procedures for further increasing the SEF enhancement factor are also discussed. [ABSTRACT FROM AUTHOR]

Highly resolved fluorescence and excitation fluorescence spectra for C70(CH3)8 were recorded in a solid toluene solution at 5 K. The addition of eight methyl groups to the fullerene cage induces a blue shift of about 1300 cm−1 of the C70 fluorescence. By comparison with the spectra of C70 in toluene, the observed structures are assigned to arise from a partially dipole allowed S1→S0 transition and a dipole allowed S2→S0 transition only separated by 65 cm−1. [Copyright &y& Elsevier]

We present some preliminary results on the photophysical properties of a new supramolecular assembly C60–H2TPP, studied at low temperatures by optical spectroscopy. While the absorption spectrum in the long wavelength range reflects the dominant contribution of the porphyrin moiety, the fluorescence spectrum is dominated by the emission coming from the pyrrolidino[60]fullerene moiety. No fluorescence line narrowing effect was observed when exciting within the lowest absorption band assigned to the porphyrin moiety. However, the demonstration that narrow spectral holes can be burnt in this band reveals that the excited state of the porphyrin moiety is not strongly affected by electron–phonon coupling with the host despite its covalent link with a bulky fullerene. [Copyright &y& Elsevier]

We have recorded the dispersed fluorescence and phosphorescence spectra of C70 in toluene matrices at 5 K upon excitation with the green Ar+ laser line (λ=514 nm), along with phosphorescence excitation spectra and also site selected phosphorescence spectra. The dispersed phosphorescence spectrum shows spectral features that originate from at least 14 distinct different sites for C70 within the toluene matrix. Selective excitation of the lowest singlet–singlet transition at 665.8 nm generated a spectrum from a single phosphorescent site which shows prominent Herzberg–Teller induced e1′ and e2′ modes in a 3A2′–1A1′ transition. The dispersed fluorescence spectrum showed Herzberg–Teller induced e1′ and a1″ modes that were inferred to originate from a 1A2′–1A1′ transition as well as bands in the origin region that were interpreted to come from 1E1′–1A1′ and 1A2″–1A1′ transitions. The selective phosphorescence excitation spectra revealed that the character, the absolute energy and the order of the two lowest excited singlet states 1A2′ and 1E1′ are site dependent. An orbitally allowed and thermally activated T2 state lying 240 cm−1 higher in energy from the T1 state is revealed by temperature dependent experiments. Site selective phosphorescence excitation spectra showed evidence of phonon sidebands 12–14 cm−1 from the corresponding zero-phonon line. The energy difference between the S1 and T1 states was determined to be about 2936 cm−1, however the exact splitting energy is matrix and site dependent. [Copyright &y& Elsevier]

We examine the potential of cadmium sulfide when combined with plasmonic nanostructures to support photo-induced catalysis. Super-bandgap irradiation of a silver nanowire and cadmium sulfide composite for the probe molecule p-aminothiophenol (PATP) showed the formation of dimercaptoazobenzene (DMAB) from PATP. Our results demonstrate that cadmium sulfide can be used as an alternative material to semiconductors, such as titanium dioxide, for plasmonic photocatalysis applications. [ABSTRACT FROM AUTHOR]

The development of new catalysts for oxidation reactions is of central importance for many industrial processes. Plasmonic catalysis involves photoexcitation of templates/chips to drive and enhance oxidation of target molecules. Raman-based sensing of target molecules can also be enhanced by these templates. This provides motivation for the rational design, characterization, and experimental demonstration of effective template nanostructures. In this paper, we report on a template comprising silver nanoparticles on aligned peptide nanotubes, contacted with a microfabricated chip in a dry environment. Efficient plasmonic catalysis for oxidation of molecules such as p-aminothiophenol results from facile trans-template charge transfer, activated and controlled by application of an electric field. Raman detection of biomolecules such as glucose and nucleobases are also dramatically enhanced by the template. A reduced quantum mechanical model is formulated, comprising a minimum description of key components. Calculated nanotube-metal-molecule charge transfer is used to understand the catalytic mechanism and shows this system is well-optimized. Plasmonic nanomaterials offer new frontiers as photocatalysis and sensor materials, yet elucidating factors controlling each is a challenge. Here, authors examine the role of electric fields in photocatalysis and biomolecule sensing abilities of peptide-nanotubesupported silver nanoparticles. [ABSTRACT FROM AUTHOR]