Guilherme Lavareda

Here we report on the structural, optical, electrical and magnetic properties of Co-doped and (Co,Mo)-codoped SnO2 thin films deposited on r-cut sapphire substrates by pulsed laser deposition. Substrate temperature during deposition was kept at 500 degrees C. X-ray diffraction analysis showed that the undoped and doped films are crystalline with predominant orientation along the {[}1 0 1] direction regardless of the doping concentration and doping element. Optical studies revealed that the presence of Mo reverts the blue shift trend observed for the Co-doped films. For the Co and Mo doping concentrations studied, the incorporation of Mo did not contribute to increase the conductivity of the films or to enhance the ferromagnetic order of the Co-doped films. (C) 2012 Elsevier B.V. All rights reserved.

A fluorene-based pi-conjugated copolymer with on-chain dibenzoborole units was used in the development of a nanocoated gold interdigitated microelectrode array device which successfully detects fluoride in a broad range of concentrations (10(-11)-10(-4) M) in aqueous solution, upon impedance spectroscopy measurements. A calibration curve obtained over this range of concentrations and a new analytical method based on impedance spectroscopy measurements in aqueous solution is proposed. The sensor nanofilm was produced by spin-coating and diagnosed via spectroscopic ellipsometry, AFM, and electrically conductivity techniques. Changes in the conductivity due to the boron-fluoride complex formation seem to be the major mechanism behind the dependence of impedimetric results on the fluoride concentration. (C) 2010 Elsevier B.V. All rights reserved.