School of Chemistry - Research Publications

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    Concentrating Aggregation-Induced Fluorescence in Planar Waveguides: A Proof-of-Principle
    Banal, JL ; White, JM ; Ghiggino, KP ; Wong, WWH (NATURE PORTFOLIO, 2014-04-10)
    The photophysical properties of fluorescent dyes are key determinants in the performance of luminescent solar concentrators (LSCs). First-generation dyes--coumarin, perylenes, and rhodamines--used in LSCs suffer from both concentration quenching in the solid-state and small Stokes shifts which limit the current LSC efficiencies to below theoretical limits. Here we show that fluorophores that exhibit aggregation-induced emission (AIE) are promising materials for LSC applications. Experiments and Monte Carlo simulations show that the optical quantum efficiencies of LSCs with AIE fluorophores are at least comparable to those of LSCs with first-generation dyes as the active materials even without the use of any optical accessories to enhance the trapping efficiency of the LSCs. Our results demonstrate that AIE fluorophores can potentially solve some key limiting properties of first-generation LSC dyes.
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    A Transparent Planar Concentrator Using Aggregates of gem-Pyrene Ethenes
    Banal, JL ; White, JM ; Lam, TW ; Blakers, AW ; Ghiggino, KP ; Wong, WWH (WILEY-V C H VERLAG GMBH, 2015-10-07)
    The luminescence properties of pyrene ethenes, both as monomer and aggregate species, are found to depend on the regioisomer structure. Systematic shifts in absorption, emission, and excitation spectra of the gem‐pyrene ethenes, both in solution and in rigid polymer hosts, are consistent with weakly interacting H‐aggregate formation. This aggregation leads to excimer‐like emission with Stokes shifts greater than 1 eV. Planar concentrators fabricated from gem‐pyrene diphenylethenes show comparable performance to previously reported inorganic phosphors. The UV absorption and emission properties of the planar concentrator devices exhibit potential for transparent solar concentrators or visible–blind photodetector applications. This is the first demonstration of exploiting the unusual photophysics of molecular aggregates in planar concentrators.
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    Energy Migration in Organic Solar Concentrators with a Molecularly Insulated Perylene Diimide
    Banal, JL ; Soleimaninejad, H ; Jradi, FM ; Liu, M ; White, JM ; Blakers, AW ; Cooper, MW ; Jones, DJ ; Ghiggino, KP ; Marder, SR ; Smith, TA ; Wong, WWH (AMER CHEMICAL SOC, 2016-06-23)