Papers by Author: Tito Trindade

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Authors: Sandra G. Cruz, Penka I. Girginova, Márcia C. Neves, Petr Smolka, Robert Kusak, Madalena Caldeira, José Teixeira-Dias, Julio Pedrosa, Tito Trindade
Abstract: An overview of the chemical strategies developed in our laboratories to obtain welldefined BiVO4 particles is presented. The methods rely on the thermal treatment (including hydrothermal conditions) of aqueous solutions containing bismuth(III) cations, vanadium(V) species and organic ligands. The use of distinct polyaminocarboxylates and cyclodextrins as possible morphological modifiers was investigated. NMR spectroscopic techniques were applied to the distinct chemical baths in order to have a better insight on the nature of the solute precursors.
Authors: M. Lehocký, L. Lapčík,Jr., Márcia C. Neves, Tito Trindade, L. Szyk-Warszynska, P. Warszynski, David Hui
Authors: G. Costa, M.J. Ribeiro, Tito Trindade, Joao A. Labrincha
Abstract: The preparation of ceramic pigments using industrial waste, a galvanizing sludge from the Cr/Ni plating process, as primary source is here reported. The ceramic pigments were prepared using the common solid state reaction process, investigating the optimal formulation, milling and firing conditions. The main focus will be given on the synthesis of chrome-tin red malayaite Ca(Cr,Sn)SiO5 pigment that was fully characterised and then tested in a standard ceramic glaze. Typical working conditions and colour development will be also reported.
Authors: Márcia C. Neves, Angela S. Pereira, Marco Peres, Andréi L. Kholkin, Teresa Monteiro, Tito Trindade
Abstract: Cadmium chalcogenide quantum dots (QD’s) were synthesised using a single source approach while zinc oxide QD’s were obtained by a colloidal technique. In both situations the dots were surface capped with tri-octylphosphine oxide (TOPO) hence leading to nanodispersed systems in organic solvents such as toluene. The organically capped QD’s (CdSe, CdS and ZnO) were used as building-units to fabricate LbL (layer-by-layer) films on glass and quartz substrates. A linear increase in the visible light absorbance (due to the QD’s) with the number of deposited layers indicates that multi-layered systems have been fabricated. In order to investigate the effect of the LbL manipulation on the integrity of the QD’s, comparative studies on the optical properties of the starting QD’s and the nanostructured films have been performed. The observation of quantum size effects in both cases suggests minimal degradation of the QD’s though clustering had probably occurred, a point which was further confirmed by AFM analysis.
Authors: Filipa L. Sousa, Paula C.R. Soares-Santos, Helena I.S. Nogueira, Rute A. Sá Ferreira, Ana M.V. Cavaleiro, Luís D. Carlos, Tito Trindade
Abstract: A layer-by-layer assembly method was employed to fabricate multilayered films containing the terbium heteropolyanions K6[Tb(BW11O39)(H2O)3]·32H2O and Ky[Tb(XW11O39)2]·nH2O (X = Si and P) and the polyelectrolytes poly(4-styrenesulfonate) and poly(allylamine hydrochloride). A comparative study on the optical properties of the films containing distinct polyoxometalates and different types of multilayers was carried out. The photoluminescence of the solid polyoxometalates and of the resulting films was investigated.
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