TY - JOUR
T1 - Photoconductivity studies on nanoporous TiO2/dopamine films prepared by sol-gel method
AU - Valverde-Aguilar, G.
AU - Prado-Prone, G.
AU - Vergara-Aragón, P.
AU - Garcia-Macedo, J.
AU - Santiago, Patricia
AU - Rendón, Luis
N1 - Funding Information:
The authors acknowledge the financial supports of ICyTDF No. PICSA12-124, DGAPA IT20083, DGAPA IN221507, DGAPA IN223809, SIP 20130459, UCMEXUS-CONACyT CN-12-513, CONACyT 166354 and CONACyT 79781. We thank to Jaqueline Cañetas-Ortega (SEM) and Diego Quiterio (preparation of samples for SEM) for their technical assistance.
PY - 2014/9
Y1 - 2014/9
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84906313863&partnerID=8YFLogxK
U2 - 10.1007/s00339-013-8187-0
DO - 10.1007/s00339-013-8187-0
M3 - Artículo
SN - 0947-8396
VL - 116
SP - 1075
EP - 1084
JO - Applied Physics A: Materials Science and Processing
JF - Applied Physics A: Materials Science and Processing
IS - 3
ER -