Caracterização de nanoestruturas de óxido de estanho como sensores de gás

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Eletrodos nanoestruturados de 'TI' 'O IND.2' aplicados na degradação fotoeletrocatalítica de aminas aromáticas e desenvolvimento de dispositivo fotovoltaico 'TI 'O IND.2' / 'SB IND.2' 'S IND.3' / 'P3' 'HT'

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Polymer brush modified electrode with switchable selectivity triggered by pH changes enhanced by gold nanoparticles

In this work, a sensor was built up with smart material based on polymer brush and gold nanoparticles. The modified electrode functionalized with polyacrylic acid (PAA) tethered to indium tin oxide (ITO) and covered with gold nanoparticle (ITO/PAA/Au) demonstrated switchable interfacial properties discriminating different pHs. The switchable electrochemical and plasmonic process was characterized by cyclic voltammetry (CV), electrochemistry impedance spectroscopy (EIS), and localized surface plasmon resonance (LSPR).

Amperometric glucose biosensor based on layer-by-layer films of microperoxidase-11 and liposome-encapsulated glucose oxidase

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Melanin as an active layer in biosensors

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

SeP hole injection layer for devices based on organic materials

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Electrical properties of highly conducting Sno2:Sb nanocrystals synthesized using a nonaqueous sol gel method

This work describes the synthesis of highly conducting antimony-doped tin oxide (ATO) nanocrystals prepared via a nonaqueous sol–gel route in the size range of 4–6 nm and provides insights into its electrical properties. The antimony composition was varied from 1 to 18 mol% and the lowest resistivity (4.0 × 10−4Ω·cm) was observed at room temperature in the SnO2:8.8 mol% Sb composition. The samples were evaluated by X-ray diffraction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscope, and resistivity measurements were taken in the four-probe mode in the temperature range of 13–300 K. The results show highly crystalline nanoparticles in a monodisperse colloidal system, dependence on the shape of ATO nanoparticles as a function of Sb distribution, low resistivity, and semiconductor–metal transition.

SnO2 dense ceramic microwave sintered with low resistivity

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

High activity photocatalyst powder formed by three ceramic oxides

A Photocatalyst ceramic powder that presented high photoactivity based on TiO2 modified with 25% molar of SnO2 and up to 5% molar of Ag2O was obtained in the present work. The aforementioned ceramic powder was obtained using all commercial oxides as well as the oxides mixture technique. The powders were ground in high energy mill for one hour with subsequent thermal treatment at 400°C for four hours. They were, furthermore, characterized using surface area of around 6m2/g, where the X-Ray diffraction results provided evidence for the presence of anatase and rutile phases, known to be typical characteristics of both the TiO2 and SnO2 used. During the thermal treatment, Ag2O was reduced to metallic silver. The photodegradation rehearsals were carried out using a 0.01 mmol/L Rhodamine B solution in a 100mg/L photocatalyst suspension in a 500ml beaker, which was irradiated with 4W germicide Ultraviolet light of 254nm. In addition, samples were removed after duration of about 10 minutes to an hour, where they were analyzed thoroughly in UV-vis spectrophotometer. The analysis of the results indicated that for the compositions up to 2.5% molar of Ag2O, the photoactivity was found to be greater than that of Degussa P25 photocatalyst powder, and as such it was then used as a reference. Taking into account 90% degradation of Rhodamine B, a duration period of 11 minutes was obtained for the developed photocatalyst powder compared to the 38 minutes observed for the Degussa P25. FEG-SEM micrographies enabled the verification of the morphology as well as the interaction of the oxide particles with the metallic silver, which led us to propose a model for the increase in photoactivity observed in the photocatalyst powder under investigation.

Monitoramento de danos estruturais utilizando sensores de nanocompósitos

Pós-graduação em Engenharia Mecânica - FEIS

Estudo das propriedades estímulo responsivas dos polímeros escovas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparative gas sensor response of SnO2, SnO and Sn3O4 nanobelts to NO2 and potential interferents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synergy between polyaniline and OMt clay mineral in Langmuir-Blodgett films for the simultaneous detection of traces of metal ions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photoelectrochemical properties of FTO/p-NiO electrode induced by UV light irradiation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Propriedades ópticas e elétricas de materiais híbridos de sílica/orgânico à base de GPTS:TEOS preparados pelo método sol-gel

Fabrication of optoelectronic devices requires the employment of at least one transparent electrode. Usually, commercially transparent electrodes have been made by deposition of indium tin oxide (ITO) films by RF-Sputtering technique. These commercial electrodes have sheet resistance of about 100 Ω/sq and optical transmittance of 77% at the wavelength of 550 nm. The poly(3,4-ethylenedioxythiophene):polystyrene-sulfonate (PEDOT:PSS) is an alternative material to fabricate transparent electrodes due to its high conductivity (about 600 S/cm) and solubility in water. Soluble conductive materials exhibits advantages for processing of electrode layers, however there is a disadvantage during devices fabrication once materials with the same solvent of the electrode material cannot be coated one over the other. Alternatively, organic/Silica hybrid materials prepared by sol-gel process allow producing bulks and films with high chemical durability. In order to obtain transparent electrodes with high chemical durability, we introduced a blended material comprising the high UV-VIS transparency of organic/Silica sol-gel material and a high conductivity polymer PEDOT:PSS. The organic/Silica sol was obtained using two different molar concentrations (1:1 and 4:1), of tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTS). Amounts of PEDOT:PSS solutions were added to the sol material, resulting in different weight fractions of sol and polymer. G:T/P:P were deposit onto glass substrates by spray-coating. In order to perform electrical characterization of the blended material, gold electrodes were thermally evaporated onto the films. The electrical characterization was performed using a Keithley 2410 source/meter unity and the optical characterization, using a Cary50 UV-Vis spectrophotometer. The absorption coefficient and electric conductivity of the different compositions blends, as function of the PEDOT:PSS concentration, were...