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Admittance spectroscopy of Cu2ZnSnS4 based thin film solar cells
Fernandes, P. A.; Sartori, A. F.; Salomé, P. M. P.; Malaquias, J.; Cunha, A. F. da; Graça, M. P. F.; González, J. C.In this report, we propose an AC response equivalent circuit model to describe the admittance measurements of Cu2ZnSnS4 thin film solar cell grown by sulphurization of stacked metallic precursors. This circuit describes the contact resistances, the back contact, and the heterojunction with two trap levels. The study of the back contact resistance allowed the estimation of a back contact barrier of 246 meV. The ...
Growth and characterization of Cu2ZnSn(S,Se)4 thin films for solar cells
Salomé, P. M. P.; Malaquias, J.; Fernandes, P. A.; Ferreira, M. S.; Cunha, A. F. da; Leitão, J. P.; González, J. C.; Matinaga, F. M.Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) with their band gap energies around 1.45 eV and 1.0 eV, respectively, can be used as the absorber layer in thin film solar cells. By using a mixture of both compounds, Cu2ZnSn(S,Se)4 (CZTSSe), a band gap tuning may be possible. The latter material has already shown promising results such as solar cell efficiencies up to 10.1%. In this work, CZTSSe thin films were grown in...
Assessment of the potential of tin sulphide thin films prepared by sulphurizati...
Malaquias, J.; Fernandes, P. A.; Salomé, P. M. P.; Cunha, A. F. daIn this work, SnxSy thin films have been grown on soda-lime glass substrates by sulphurization of metallic precursors in a nitrogen plus sulphur vapour atmosphere. Different sulphurization temperatures were tested, ranging from 300 °C to 520 °C. The resulting phases were structurally investigated by X-Ray Diffraction and Raman spectroscopy. Composition was studied using Energy Dispersive Spectroscopy being then...
Experimental Adhesion Prevention Studies: A Comparative Study in a Rabbit Model
Background: Adhesions formation after abdominal surgery is a problem that causes many complications in the patient’s future life. In this study we compare the possible individual effects of Ringer ́s lactate, Adept® and Mesofol® and the combined effects of Adept® and Mesofol® in the prevention of post surgical adhesions formation in a standardised rabbit model.Materials and Methods: 90 rabbits were divided into...
Growth pressure dependence of Cu2ZnSnSe4 properties
Salomé, P. M. P.; Fernandes, P. A.; Cunha, A. F. da; Leitão, J. P.; Malaquias, J.; Weber, A.; González, J. C.; Silva, M. I. N. daIn this work, we show a set of growth conditions, for the two step process, with which the growth of CZTSe is successful and reproducible. The properties of the best CTZSe thin films grown by this method were examined by SEM/EDS, XRD, Raman scattering, AFM/EFM, transmittance and reflectance measurements, photoluminescence (PL) measurements and hot point probe. A broad emission band was observed in the photolumi...
Mo bilayer for thin film photovoltaics revisited
Salomé, P. M. P.; Malaquias, J.; Fernandes, P. A.; Cunha, A. F. daThin film solar cells based on Cu(In,Ga)Se2 as an absorber layer use Mo as the back contact. This metal is widely used in research and in industry but despite this, there are only a few published studies on the properties of Mo. Properties such as low resistivity and good adhesion to soda lime glass are hard to obtain at the same time. These properties are dependent on the deposition conditions and are associat...
Avaliação da comunicação interna: um diagnóstico dos veículos de comunicação na...
MALAQUIAS, J. V.; GAMA, L. C.; PELUFE, M. S.; ARAUJO, S. da L. S.; FONSECA, R. B.; ARAUJO, G. P. de; RIVERA, A. S. P.; COSTA, C. A.; CHERUBINI, M. Y.2009
Effect of anode flow field design in direct methanol fuel cells: preliminary st...
Schock, L.; Silva, R. A.; Malaquias, J.; Pinto, A. M. F. R.; Rangel, C. M.The direct methanol fuel cells are promising candidates for portable power sources due to their high energy density, however studies continue in order to give solutions for a number of drawbacks that affect cell performance and efficiency. Achieving good fuel cell performance requires that the flowing streams of fuel and oxidizer are evenly distributed over the entire surface of the catalyst layer and also an e...
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