Browsing by Author "del Valle, M. A."

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    Capacitors Based on Polypyrrole Nanowire Electrodeposits
    (2022) Ramirez, A. M. R.; del Valle, M. A.; Ortega, E.; Diaz, F. R.; Gacitua, M. A.
    The electrochemical polymerization of polypyrrole nanowires is carried out using potentiodynamic and galvanostatic methods in order to enhance the performance of the modified electrodes as capacitor devices. The electrochemical, spectroscopic, and morphological properties are determined through cyclic voltammetry, Raman spectroscopy and scanning electron microscopy, respectively, corroborating the presence of PPy-nw in dimensions of 30 nm in diameter. Characterization as a capacitor revealed that the nanowire structure enhances key parameters such as specific capacitance with 60 times greater value than bulk polymer modification, in addition to a significant increase in stability. In this way, it is verified that electrodes modified with polypyrrole nanowires obtained in situ by electrochemical methods constitute an excellent candidate for the development of capacitors.
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    ZnO thin films fabricated by chemical bath deposition, used as buffer layer in organic solar cells
    (ELSEVIER SCIENCE BV, 2009) Lare, Y.; Godoy, A.; Cattin, L.; Jondo, K.; Abachi, T.; Diaz, F. R.; Morsli, M.; Napo, K.; del Valle, M. A.; Bernede, J. C.
    ZnO thin films synthetized by chemical bath deposition are used as buffer layer between the anode and the organic electron donor in organic solar cells. Films deposited from zinc nitrate solutions are annealed in room air at 300 degrees C for half an hour. The X-ray diffraction and microanalysis studies show that ZnO polycrystalline thin films are obtained. The solar cells used are based on the couple copper phthalocyanine as electron donor and (N, N-diheptyl-3,4,9,10-perylenetetracarboxylicdiimide-PTCDI-C7) as electron acceptor. It is shown that the presence of the ZnO buffer layer improves the energy conversion efficiency of the cells. Such improvement could be attributed to a better energy level alignment at the anode/electron donor interface. The anode roughness induced by the ZnO buffer layer can also transform the planar interface organic electron donor/electron acceptor into roughen topography. This increases the interface area, where carrier separation takes place, which improves solar cells performances. (C) 2009 Elsevier B. V. All rights reserved.