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Aurora Amparo Flores-Caballero

Bio: Aurora Amparo Flores-Caballero is an academic researcher from Instituto Politécnico Nacional. The author has contributed to research in topics: Crystallite & X-ray photoelectron spectroscopy. The author has an hindex of 1, co-authored 2 publications receiving 7 citations.

Papers
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Journal ArticleDOI
01 May 2020-Vacuum
TL;DR: In this paper, the ternary solid solution (CdS1-xSex) thin films were deposited by Chemical Solution onto ITO/glass substrates at 90 degrees C. The results revealed good crystalline quality of CBD films as an effect of ITO substrate and deposition temperature.

9 citations

Journal ArticleDOI
15 Feb 2021
TL;DR: In this article, Boron and cerium-doped titania (Anatase) were prepared via sol-gel method and phase composition and morphology were assessed by X-ray diffraction (XRD), scanning electronic microscopy (SEM), BET, diffuse reflectance spectra (DRS), and XPS.
Abstract: Boron- and cerium-doped titania (Anatase) were prepared via sol-gel method. Phase composition and morphology were assessed by X-ray diffraction (XRD), scanning electronic microscopy (SEM), BET, diffuse reflectance spectra (DRS), and XPS. Photo-electrochemistry of these materials, deposited onto fluorine-doped SnO2 (FTO), was investigated in acid and acid-containing methanol. The boron-doped sample showed the best opto-electronic properties among the investigated samples. On the other hand, the cerium-doped titania samples annihilate to a certain extent the titania surface states, however, photogenerated charge separation was limited, and certainly associated to surface Ce3+/Ce4+ species. The substitutional effect of boron ions for O sites and interstitial sites was confirmed by XRD and XPS analyses.

2 citations


Cited by
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01 Jan 2005
TL;DR: A series of cerium ion-doped titanium dioxide (Ce 3+ -TiO2) catalysts with special 4 f electron configuration was prepared by a sol-gel process and characterized by Brunauer-Emmett-Teller method as discussed by the authors.
Abstract: A series of cerium ion-doped titanium dioxide (Ce 3+ –TiO2) catalysts with special 4 f electron configuration was prepared by a sol–gel process and characterized by Brunauer-Emmett-Teller method, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), and also photoluminescence (PL) emission spectroscopy. The photocatalytic activity of Ce 3+ –TiO2 catalysts was evaluated in the 2-mercaptobenzothiazole (MBT) degradation in aqueous suspension under UV or visible light illumination. The experimental results demonstrated that the overall photocatalytic activity of Ce 3+ –TiO2 catalysts in MBT degradation was signigicantly enhanced due to higher adsorption capacity and better separation of electron-hole pairs. The experimental results verified that both the adsorption equilibrium constant (Ka) and the saturated adsorption amount (Gmax) increased with the increase of cerium ion content. The results of XPS analysis showed that the Ti 3+ ,C e 3+ , and Ce 4+ ions reside in the Ce 3+ –TiO2 catalysts. The results of DRS analysis indicated that the Ce 3+ –TiO2 catalysts had significant optical absorption in the visible region between 400 and 500 nm because electrons could be excited from the valence band of TiO2 or ground state of cerium oxides to Ce 4 f level. In the meantime, the dependence of the electron-hole pair separation on cerium ion content was investigated by the PL analysis. It was found that the separation efficiency of electron-hole pairs increased with the increase of cerium ion content at first and then decreased when the cerium ion content exceeded its optimal value. It is proposed that the formation of two sub-energy levels (defect level and Ce 4 f level) in Ce 3+ –TiO2 might be a critical reason to eliminate the recombination of

367 citations

Journal ArticleDOI
TL;DR: In this paper, CdSxSe1−x (0 ≤ x ≤ 1) films were deposited on p-Si via thermal co-evaporation method with Cs and CdSe as source materials.

11 citations

Journal ArticleDOI
TL;DR: In this article, a study of optical, structural and chemical properties of semiconducting CdSe nanoparticles with an organic shell prepared by laser fragmentation of acetone dispersed CdSE powder was performed during 30min at different power intensities.

6 citations

Journal ArticleDOI
01 May 2021-Vacuum
TL;DR: In this paper, a ternary magnetic photocatalyst MnxZn1-xFe2O4/BiVO4/MnO2 (MZF/BVO/MO) was developed with a practical and reliable hydrothermal method.

5 citations

Journal ArticleDOI
TL;DR: In this article , a multi-length scale and multi-method approach was proposed to deepen insights into the photoluminescence properties and (photo)chemical reactivity of cadmium reds in oil paintings by combining both well established and new non-invasive/non-destructive analytical techniques, including macro-scale vis-NIR and vibrational spectroscopies and micro-nano-scale advanced electron microscopy mapping and X-ray methods employing synchrotron radiation and conventional sources.
Abstract: Abstract Cadmium red is the name used for denoting a class of twentieth century artists’ pigments described by the general formula CdS 1− x Se x . For their vibrant hues and excellent covering power, a number of renowned modern and contemporary painters, including Jackson Pollock, often used cadmium reds. As direct band gap semiconductors, CdS 1− x Se x compounds undergo direct radiative recombination (with emissions from the green to orange region) and radiative deactivation from intragap trapping states due to crystal defects, which give rise to two peculiar red-NIR emissions, known as deep level emissions (DLEs). The positions of the DLEs mainly depend on the Se content of CdS 1− x Se x ; thus, photoluminescence and diffuse reflectance vis–NIR spectroscopy have been profitably used for the non-invasive identification of different cadmium red varieties in artworks over the last decade. Systematic knowledge is however currently lacking on what are the parameters related to intrinsic crystal defects of CdS 1− x Se x and environmental factors influencing the spectral properties of DLEs as well as on the overall (photo)chemical reactivity of cadmium reds in paint matrixes. Here, we present the application of a novel multi-length scale and multi-method approach to deepen insights into the photoluminescence properties and (photo)chemical reactivity of cadmium reds in oil paintings by combining both well established and new non-invasive/non-destructive analytical techniques, including macro-scale vis–NIR and vibrational spectroscopies and micro-/nano-scale advanced electron microscopy mapping and X-ray methods employing synchrotron radiation and conventional sources. Macro-scale vis–NIR spectroscopy data obtained from the in situ non-invasive analysis of nine masterpieces by Gerardo Dottori, Jackson Pollock and Nicolas de Staël allowed classifying the CdS 1− x Se x -paints in three groups, according to the relative intensity of the two DLE bands. These outcomes, combined with results from micro-/nano-scale electron microscopy mapping and X-ray analysis of a set of CdS 1− x Se x powders and artificially aged paint mock-ups, indicated that the relative intensity of DLEs is not affected by the morphology, microstructure and local atomic environment of the pigment particles but it is influenced by the presence of moisture. Furthermore, the extensive study of artificially aged oil paint mock-ups permitted us to provide first evidence of the tendency of cadmium reds toward photo-degradation and to establish that the conversion of CdS 1− x Se x to CdSO 4 and/or oxalates is triggered by the oil binding medium and moisture level and depends on the Se content. Based on these findings, we could interpret the localized presence of CdSO 4 and cadmium oxalate as alteration products of the original cadmium red paints in two paintings by Pollock. Graphical abstract

5 citations