We developed a novel approach to the synthesis organic-inorganic hybrids joining oxide stability with the antenna sensitization of organic molecules. To this end we explored an original approach based on supersonic beams deposition of organic molecules [1] and oxide clusters [2]. Controlling size and energy of the clusters precursors to produce the assembled nano-oxides and the kinetic energy of the organic precursors, the interfaces can be tailored achieving a nanohybrids with novel and very promising sensing properties. The chemical physical properties of the nanohybrids, investigated by electron spectroscopies demonstrate formation of stable covalent bonds not present with more conventional deposition methods. To test functional properties of the novel nano-hybrids produced sensing devices have been developed and studied. chemosensors based on multilayers of nanostructured TiO2 and ZnPc have been developed. Below 200°C a p-type response and improved stability with respect to pure organic devices have been achieved with a quite good sensitivity to reducing gases known to be very poor for pure MPc films [3]. At higher temperatures our hybrid sensors evolve into an oxide-based transduction mechanism with a n-type response. Exposure to reducing and oxidizing species shows a quite different sensing response (compared to pure oxide) and confirms the ZnPc functionalization of TiO2. High stability is evidenced by the operation at temperatures up to 380°C. We envisage the formation of novel nano-hydrids induced by the co-deposition technique, as confirmed by XPS/UPS analysis.
Financial support by MIUR FIRB-SQUARE (RBNE01Y8C3_007), FUR-PAT NANOCOSHY and TASCA.
References
1-S. Iannotta and T. Toccoli,, J. Polym. Sci. B, 41 (2003), 2501- L.Casalis, M.F.Danisman, B.Nickel, G.Bracco, T.Toccoli, S.Iannotta, G.Scoles, Phys. Rev. Lett. 90, 206101 (2003)- Y. Wu, T.Toccoli, N.Koch, E.Iacob, A.Pallaoro, P.Rudolf and S.Iannotta P. R. L.. (2007 in press.)
2-T. Toccoli, et al., IEEE Sensors Journal, 3 (2005), 199
3-F. Siviero, N. Coppedè, A. M Taurino, T. Toccoli, P. Siciliano, S. Iannotta , Sens. Actuators B (2007) in press.
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