Photoconductivity studies on nanoporous TiO2/dopamine films prepared by sol-gel method
Por:
Valverde-Aguilar G., Prado-Prone G., Vergara-Aragón P., Garcia-Macedo J., Santiago P., Rendón L.
Publicada:
1 sep 2014
Resumen:
Dopamine was encapsulated into nanoporous amorphous TiO2 matrix by sol-gel method under atmospheric conditions. A second sample was obtained by the addition of the crown-ether 15C5 in this previous sample. Thin films were spin-coated on glass wafers. No heat treatment was employed in both films. All films were characterized using infrared spectroscopy, high resolution transmission electronic microscopy, X-ray diffraction, optical absorption and scanning electronic microscopy. Despite the films prepared with 15C5 were no calcined, a partial crystallization was identified. Anatase and rutile nanoparticles with sizes of 4-5 nm were obtained. Photoconductivity technique was used to determine the charge transport mechanism on these films. Experimental data were fitted with straight lines at darkness and under illumination wavelengths at 320, 400, and 515 nm. It indicates an ohmic behavior. Photovoltaic and photoconductivity parameters were determined from the current density vs. the applied-electrical-field results. Amorphous film has bigger photovoltaic and photoconductive parameters than the partially crystalline film. Results observed in the present investigation prove that the nanoporous TiO2 matrix can protect the dopamine inhibiting its chemical instability. This fact modifies the optical, physical and electrical properties of the film, and is intensified when 15C5 is added. © 2013 Springer-Verlag Berlin Heidelberg.
Filiaciones:
Valverde-Aguilar G.:
CICATA Unidad Legaria, Instituto Politécnico Nacional, Legaria 694, Col Irrigación, Miguel Hidalgo, C. P. 11500 Ciudad de México, Mexico
Prado-Prone G.:
Department of Solid State, Instituto de Física, Universidad Nacional Autónoma de México, C.P. 04510 Mexico City, D.F., Mexico
Vergara-Aragón P.:
Physiology Department, Faculty of Medicine, Universidad Nacional Autónoma de México, C.P. 04510 Mexico City, D.F., Mexico
Garcia-Macedo J.:
Department of Solid State, Instituto de Física, Universidad Nacional Autónoma de México, C.P. 04510 Mexico City, D.F., Mexico
Santiago P.:
Departamento de Materia Condensada, Instituto de Física, Universidad Nacional Autónoma de México, C.P. 04510 Mexico City, D.F., Mexico
Rendón L.:
Departamento de Materia Condensada, Instituto de Física, Universidad Nacional Autónoma de México, C.P. 04510 Mexico City, D.F., Mexico
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