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Benavides, Vicente
Publications (3 of 3) Show all publications
Navarro Prado, F., Benetti, D., Benavides, V., Zhao, H., Cloutier, S., Castaño, V., . . . Rosei, F. (2017). Nanofiber-Structured TiO2 Nanocrystals as a Scattering Layer in Dye-Sensitized Solar Cells. ECS Journal of Solid State Science and Technology, 6(4), Article ID N32-N37.
Open this publication in new window or tab >>Nanofiber-Structured TiO2 Nanocrystals as a Scattering Layer in Dye-Sensitized Solar Cells
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2017 (English)In: ECS Journal of Solid State Science and Technology, ISSN 2162-8769, E-ISSN 2162-8777, Vol. 6, no 4, article id N32-N37Article in journal (Refereed) Published
Abstract [en]

We developed a scattering layer composed of TiO2 nanocrystals assembled into a densely packed three-dimensional network of nanofibers to localize light within a photoanode used in dye sensitized solar cells (DSSCs). The electro-netting approach was applied to obtain polyamide 6 nanofibers with bi-modal diameter distribution, followed by solvothermal synthesis for the coating of TiO2 nanocrystals on the polymer template. The resulting nanofiber-structured scattering layer (NFSL) is composed of TiO2 nanofibers (200-300 nm in diameter) supporting an ultrathin nanofiber network (diameters within 10-50 nm) and exhibits strong light scattering in the visible range (400 to 700 nm). This NFSL was applied on top of a transparent active TiO2 layer (TL) forming the photoanode in DSSCs. The performance of the bi-layered photoanode was compared to its analogue, fabricated with commercial scattering layers containing different sizes of nanoparticles. The DSSCs assembled with the NFSL showed an 18% enhancement in power conversion efficiency (PCE) compared to that of DSSCs whose photoanode contained only a TL. This enhancement factor was improved up to 31% when the bi-layered structure was post-treated with TiCl4. The PCE improvement was mainly associated with the light harvesting efficiency within the photoanode because of scattering from the NFSL and increased dye adsorption due to the addition of this top layer. These conclusions were inferred from diffuse reflectance behavior, dye loading measurements, external quantum efficiency and electrochemical properties. Our work demonstrates a promising approach without the requirement of time consuming and complicated procedures for the fabrication of a densely packed 3D nanofiber network scattering layer for diverse energy conversion devices and photocatalytic applications

Place, publisher, year, edition, pages
Electrochemical Society, 2017
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-62841 (URN)10.1149/2.0181704jss (DOI)000393988500011 ()
Note

Validerad; 2017; Nivå 2; 2017-04-03 (andbra)

Available from: 2017-04-03 Created: 2017-04-03 Last updated: 2018-11-20Bibliographically approved
Chernogorova, O. P., Drozdova, E. I., Ushakova, I. N., Bulychev, S., Ekimov, E., Benavides, V. & Soldatov, A. (2016). Indentation behaviour of superelastic hard carbon. Philosophical Magazine, 96(32-34), 3451-3460
Open this publication in new window or tab >>Indentation behaviour of superelastic hard carbon
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2016 (English)In: Philosophical Magazine, ISSN 1478-6435, E-ISSN 1478-6443, Vol. 96, no 32-34, p. 3451-3460Article in journal (Refereed) Published
Abstract [en]

Superelastic hard carbon particles widely varying in structure andproperties have been studied by instrumented microindentationtechnique. The carbon particles up to 200 μm in size were producedby fullerene collapse upon high-pressure high-temperature treatmentof metal–fullerene powder mixture with simultaneous sintering ofmetal matrix composite materials (CM) reinforced by the particles.The structure and properties of the carbon particles were controlledby changing synthesis parameters and the state (composition andstructure) of the parent fullerite crystals. The specific features of theinstrumented indentation behaviour of the particles were studied asa function of their hardness. Mechanical properties of the particlestested at loads of up to 1970 mN exhibit an indentation size effect,which becomes more pronounced with increasing hardness of thecarbon particles. Upon holding at a constant load, the fullerenederivedcarbon particles undergo unrecoverable deformation, and theindentation creep CIT increases with increasing particle hardness. Anincrease in hardness of the reinforcing carbon particles substantiallyimproves the wear resistance of the CM and decreases their frictioncoefficient.

National Category
Other Physics Topics
Research subject
Experimental physics
Identifiers
urn:nbn:se:ltu:diva-59920 (URN)10.1080/14786435.2016.1235802 (DOI)000388738500010 ()2-s2.0-84991278469 (Scopus ID)
Note

Validerad; 2016; Nivå 2; 2016-11-21(andbra)

Available from: 2016-10-24 Created: 2016-10-24 Last updated: 2018-07-10Bibliographically approved
Benavides, V., Chernogorova, O., Drozdova, E. I., Ushakova, I. N. & Soldatov, A. (2015). Raman and electron microscopy study of C60 collapse/transformation to a nanoclustered graphene-based disordered carbon phase at high pressure/temperature (ed.). Paper presented at . Physica status solidi. B, Basic research, 252(11), 2626-2629
Open this publication in new window or tab >>Raman and electron microscopy study of C60 collapse/transformation to a nanoclustered graphene-based disordered carbon phase at high pressure/temperature
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2015 (English)In: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 252, no 11, p. 2626-2629Article in journal (Refereed) Published
Abstract [en]

Transformation of C60 polymers to a superelastic hard carbon (nanoclustered graphene phase (NGP)) occurring in metal matrix at 5 GPa in a temperature interval of 1000–1100 K was studied by optical, scanning electron microscopy (SEM), and Raman spectroscopy. Raman spectral scan across the sample surface allowed us to identify different stages of the structural transformation. The SEM and Raman spectroscopy data testify for the NGP appearance at the defects concentration sites in the parent fullerite structure. We propose that the buckyballs collapse/formation of the NGP is governed by nucleation and growth (diffusive) mechanism unlike earlier discussed in the literature possibility of the martensitic-type (displacive) character of this transformation.

National Category
Other Physics Topics
Research subject
Experimental physics
Identifiers
urn:nbn:se:ltu:diva-6977 (URN)10.1002/pssb.201552665 (DOI)000364690400046 ()2-s2.0-84946434200 (Scopus ID)54debcfd-13d4-4b81-a6a0-24a4447f86f0 (Local ID)54debcfd-13d4-4b81-a6a0-24a4447f86f0 (Archive number)54debcfd-13d4-4b81-a6a0-24a4447f86f0 (OAI)
Note
Validerad; 2015; Nivå 2; 20151027 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
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