Squaraine-sensitized composite of a reduced graphene oxide/Tio2 photocatalyst π Stacking as a new method of dye anchoring

K. L.Vincent Joseph, Jonghun Lim, A. Anthonysamy, Hyoung Il Kim, Wonyong Choi, Jin Kon Kim

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24 Citations (Scopus)


We synthesized a near infra-red (NIR)-absorbing squaraine dye (VJ-S) showing strong absorption and emission maxima at 684 and 704 nm, respectively, with a high molar extinction coefficient (ε) of 1.277 × 105 M-1 cm-1 and a band gap of 1.77 eV. Its oxidation and reduction potentials were found to be 0.889 and -0.795 V, respectively, with HOMO and LUMO levels of -5.21 and -3.53 eV, respectively. We also prepared the self-assembled core/shell nanocomposite r-NGOT, where TiO2 is the core and reduced nano-sized graphene oxide (r-NGO) is the shell. When VJ-S was anchored on r-NGOT, it showed π-π stacking with r-NGO, which is confirmed by Fourier-transformed infrared spectroscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and electron energy loss spectroscopy. The optical absorption spectrum of the VJ-S/r-NGOT nanocomposite measured with diffuse reflectance UV/visible absorption spectroscopy covers the whole range of visible light wavelengths up to 800 nm. The photocatalytic activity of VJ-S/r-NGOT at visible light wavelengths (λ > 420 nm) is much higher than that of r-NGOT alone.

Original languageEnglish
Pages (from-to)232-239
Number of pages8
JournalJournal of Materials Chemistry A
Issue number1
Publication statusPublished - 2015 Jan 7

Bibliographical note

Publisher Copyright:
© The Royal Society of Chemistry 2015..

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)


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