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Luminescence properties of pHEMA-TiO2 gels based hybrids materials

Authors :: Pavlo Gorbovyi
Clément Sanchez
Andrei Kanaev
Luc Museur
Laurence Rozes
Mamadou Kaba Traoré
Laboratoire de Physique des Lasers (LPL)
Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)
Laboratoire des Sciences des Procédés et des Matériaux (LSPM)
Université Paris 13 (UP13)-Institut Galilée-Université Sorbonne Paris Cité (USPC)-Centre National de la Recherche Scientifique (CNRS)
Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP)
Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Source :: Journal of Luminescence, Journal of Luminescence, 2012, 132 (5), pp.1192-1199. ⟨10.1016/j.jlumin.2011.12.072⟩
Publication Year :: 2012
Publisher :: Elsevier BV, 2012.
Abstract: International audience; Photoluminescence (PL) of photochromic pHEMA-TiO2 gels-based hybrids was studied by means of time- and energy-resolved spectroscopy at temperatures between 300 K and 10 K. The PL band at 485 nm is assigned to S0←T1 transition of methoxyphenol (organic molecule added to the commercial monomer hydroxyethyl methacrylate, HEMA and used as an inhibitor of spontaneous polymerisation) in the polymer environment, while the PL band at 600 nm is assigned to the self-trapped exciton onto octahedral TiO6 site of the inorganic component. The mechanisms of the excited states population are discussed. In particular it is shown that both singlet-triplet energy transfer in methoxyphenol and methoxyphenol–TiO2 charge transfer are strongly affected by the material composition and temperature. The hypothesis about the photoexcited holes annihilation with the trapped electrons is confirmed to be one of main mechanisms limiting the Ti3+ centres concentration.