Eu-Doped BaTiO3 Powder and Film from Sol-Gel Process with Polyvinylpyrrolidone Additive

Transparent BaTiO3:Eu3+ films were prepared via a sol-gel method and dip-coating technique, using barium acetate, titanium butoxide, and polyvinylpyrrolidone (PVP) as modifier viscosity. BaTiO3:Eu3+ films ~500 nm thick, crystallized after thermal treatment at 700 ºC. The powders revealed spherical and rod shape morphology. The optical quality of films showed a predominant band at 615 nm under 250 nm excitation. A preliminary luminescent test provided the properties of the Eu3+ doped BaTiO3

Synthesis and characterization of two new TiO2-containing benzothiazole-based imine composites for organic device applications

The effect of the presence of titanium dioxide in two new imines, (E,E)-(butane-1,4-diyl)bis(oxybutane-4,1-diyl) bis(4- {[(benzo[d][1,3]thiazol-2-yl)methylidene]amino}benzoate) (SP1) and (E)-N-[(benzo[d][1,3]thiazol-2-yl)methylidene]-4-dodecylaniline (SP2), on the properties and stability of imine:TiO2 composites for organic device applications were examined. The investigated titanium dioxide (in anatase form, obtained via the sol–gel method) exhibited a surface area of 59.5 m2 /g according to Brunauer–Emmett–Teller theory, and its structure is a combination of both meso- and microporous. The average pore diameter calculated by the Barrett–Joyner–Halenda method was 6.2 nm and the cumulative volume of pores was 0.117 m3 /g. The imine SP1 exhibited columnar organization (Col), while SP2 revealed a hexagonal columnar crystalline phase (Colhk). The imine:TiO2 mixtures in various weight ratio (3:0, 3:1, 3:2, 3:3) showed a lower energy gap and HOMO–LUMO energy levels compared to pure TiO2 . This implies that TiO2 provides not only a larger surface area for sensitizer adsorption and good electron collection, but also causes a shift of the imine energy levels resulting from intermolecular interaction. Also the temperature of the phase transition was slightly affected with the increase of TiO2 concentration in imine-based composites. The changes observed in the Fourier transform middle-infrared absorption (FT-MIR) spectra confirmed the significant influence of TiO2 on structural properties of both investigated imines. Similar interactions of oxygen vacancies existing on the TiO2 surface with SP1 and SP2 were observed. The imine:TiO2 mixtures showed good air stability and reusability, which demonstrates its potential for organic device applications

Graphene Oxide Carboxymethylcellulose Nanocomposite for Dressing Materials

Sore, infected wounds are a major clinical issue, and there is thus an urgent need for novel biomaterials as multifunctional constituents for dressings. A set of biocomposites was prepared by solvent casting using different concentrations of carboxymethylcellulose (CMC) and exfoliated graphene oxide (Exf-GO) as a filler. Exf-GO was first obtained by the strong oxidation and exfoliation of graphite. The structural, morphological and mechanical properties of the composites (CMCx/Exf-GO) were evaluated, and the obtained composites were homogenous, transparent and brownish in color. The results confirmed that Exf-GO may be homogeneously dispersed in CMC. It was found that the composite has an inhibitory activity against the Gram-positive Staphylococcus aureus, but not against Gram-negative Pseudomonas aeruginosa. At the same time, it does not exhibit any cytotoxic effect on normal fibroblasts

Graphene coating obtained in a cold-wall CVD process on the Co-Cr Alloy (L-605) for medical applications

Graphene coating on the cobalt-chromium alloy was optimized and successfully carried out by a cold-wall chemical vapor deposition (CW-CVD) method. A uniform layer of graphene for a large area of the Co-Cr alloy (discs of 10 mm diameter) was confirmed by Raman mapping coated area and analyzing specific G and 2D bands; in particular, the intensity ratio and the number of layers were calculated. The effect of the CW-CVD process on the microstructure and the mor-phology of the Co-Cr surface was investigated by scanning X-ray photoelectron microscope (SPEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Nanoindentation and scratch tests were performed to determine mechanical properties of Co-Cr disks. The results of microbiological tests indicate that the studied Co-Cr alloys covered with a graphene layer did not show a pro-coagulant effect. The obtained results confirm the possibility of using the developed coating method in medical applications, in particular in the field of cardiovascular diseases

Synthesis and characterization of two new TiO2-containing benzothiazole-based imine composites for organic device applications

The effect of the presence of titanium dioxide in two new imines, (E,E)-(butane-1,4-diyl)bis(oxybutane-4,1-diyl) bis(4- {[(benzo[d][1,3]thiazol-2-yl)methylidene]amino}benzoate) (SP1) and (E)-N-[(benzo[d][1,3]thiazol-2-yl)methylidene]-4-dodecylaniline (SP2), on the properties and stability of imine:TiO2 composites for organic device applications were examined. The investigated titanium dioxide (in anatase form, obtained via the sol–gel method) exhibited a surface area of 59.5 m2/g according to Brunauer–Emmett–Teller theory, and its structure is a combination of both meso- and microporous. The average pore diameter calculated by the Barrett–Joyner–Halenda method was 6.2 nm and the cumulative volume of pores was 0.117 m3/g. The imine SP1 exhibited columnar organization (Col), while SP2 revealed a hexagonal columnar crystalline phase (Colhk). The imine:TiO2 mixtures in various weight ratio (3:0, 3:1, 3:2, 3:3) showed a lower energy gap and HOMO–LUMO energy levels compared to pure TiO2. This implies that TiO2 provides not only a larger surface area for sensitizer adsorption and good electron collection, but also causes a shift of the imine energy levels resulting from intermolecular interaction. Also the temperature of the phase transition was slightly affected with the increase of TiO2 concentration in imine-based composites. The changes observed in the Fourier transform middle-infrared absorption (FT-MIR) spectra confirmed the significant influence of TiO2 on structural properties of both investigated imines. Similar interactions of oxygen vacancies existing on the TiO2 surface with SP1 and SP2 were observed. The imine:TiO2 mixtures showed good air stability and reusability, which demonstrates its potential for organic device applications

Sicilian byzantine icons through the use of non-invasive imaging techniques and optical spectroscopy: The case of the madonna dell’elemosina

The iconographic heritage is one of the treasures of Byzantine art that have enriched the south of Italy, and Sicily in particular, since the early 16th century. In this work, the investigations of a Sicilian Icon of Greek-Byzantine origin, the Madonna dell’Elemosina, is reported for the first time. The study was carried out using mainly non-invasive imaging techniques (photography in reflectance and grazing visible light, UV fluorescence, infrared reflectography, radiography, and computed tomography) and spectroscopic techniques (X-ray fluorescence and infrared spectroscopy). The identification of the constituent materials provides a decisive contribution to the correct historical and artistic placement of the Icon, a treasure of the Eastern European historical community in Sicily. Some hidden details have also been highlighted. Most importantly, the information obtained enables us to define its conservation state, the presence of foreign materials, and to direct its protection and restoration

Graphene Coating Obtained in a Cold Wall CVD Process on the Co Cr Alloy L 605 for Medical Applications

Graphene coating on the cobalt chromium alloy was optimized and successfully carried out by a cold wall chemical vapor deposition CW CVD method. A uniform layer of graphene for a large area of the Co Cr alloy discs of 10 mm diameter was confirmed by Raman mapping coated area and analyzing specific G and 2D bands; in particular, the intensity ratio and the number of layers were calculated. The effect of the CW CVD process on the microstructure and the morphology of the Co Cr surface was investigated by scanning X ray photoelectron microscope SPEM , atomic force microscopy AFM , scanning electron microscopy SEM , and energy dispersive X ray spectroscopy EDS . Nanoindentation and scratch tests were performed to determine mechanical properties of Co Cr disks. The results of microbiological tests indicate that the studied Co Cr alloys covered with a graphene layer did not show a pro coagulant effect. The obtained results confirm the possibility of using the developed coating method in medical applications, in particular in the field of cardiovascular disease

Synthesis and down conversion emission property of Eu3+ doped LaAlO3 CsAlO2 and LiLaO2 phosphors

[EN] LaAlO3:Eu3+, CsAlO2:Eu3+ and LiLaO2:Eu3+ phosphors with varying concen- trations of Eu3+ from 3 to 10 mol% were prepared by combustion synthesis method and the samples were further heated to 1,000ºC to improve the crystallinity of the materials. The structure and morphology of materials have been examined by X-ray diffraction and scan- ning electron microscopy. SEM images depicted that the morphology of crystallites have no uniform shapes and sizes. Small and coagulated particles of irregular shapes of different sizes are obtained. The characteristic emissions of Eu3+ were clearly observed at nearly 580, 592, 650, 682 to 709 (multiplet structure) nm for 5D - 7 Fn transitions where n = 0, 1, 3, 4 respectively, including the strongest emission peaks at 614 and 620 nm for 5 D0 - 7 F2 transitions in CsAlO2:Eu3+ and LiLaO2:Eu3+ host lattices. The intensity of emission peak corresponding to 5 D0 !→ 7 F1 transitions in LaAlO3 :Eu3+ material is comparable to that of 5D0 5D-7F2 transitions which is also a singlet. Photoluminescence intensity follows the order as in LiLaO2 > LaAlO3 > CsAlO2 lattices. Remarkable high photoluminescence intensity with 7 mol% doping of Eu3+ in LiLaO2 makes it a strong contender for red colored display applications.This work was supported by the European Commission through Nano CIS project (FP7-PEOPLE-2010-IRSES ref. 269279).Marí Soucase, B.; Singh, KC.; Moya Forero, MM.; Singh, I.; Om, H.; Chand, S. (2015). Synthesis and down conversion emission property of Eu3+ doped LaAlO3 CsAlO2 and LiLaO2 phosphors. Optical and Quantum Electronics. 47(7):1569-1578. https://doi.org/10.1007/s11082-014-9997-9S15691578477Abbattista, F., Vallino, M.: Remarks on the $$\text{La}_{2}\text{O}_{3}-\text{Li}_{2}\text{O}$$ La 2 O 3 - Li 2 O binary system between 750 and 1,000  $$^{\circ}$$ ∘ C. Ceram. Int. 9, 35–38 (1983)Bae, Y., Lee, K., Byeon, S.: Synthesis and $$\text{Eu}^{3+}$$ Eu 3 + concentration-dependent photoluminescence of $$\text{Gd}_{\rm 2-x}\text{Eu}_{\rm x}\text{O}_{3}$$ Gd 2 - x Eu x O 3 nanowires. J. Lumin. 129, 81–85 (2009)Blasse, G., Grambier, B.: Luminescent Materials, vol. 43. Springer, Berlin, pp. 43–46 (1994)Dereń, P., Krupa, J.: Spectroscopic investigations of $$\text{LaAlO}_{3}$$ LaAlO 3 : $$\text{Eu}^{3+}$$ Eu 3 + . J. Lumin. 102–103, 386–390 (2003)Ekambaram, S., Patil, K.: Synthesis and properties of $$\text{Eu}^{2+}$$ Eu 2 + activated blue phosphors. J. Alloys Compd. 248, 7–12 (1997)Gao, X., Lei, L., Lv, C., Sun, Y., Zheng, H., Cui, Y.: Preparation and photoluminescence property of a loose powder, $$\text{Ca}_{3}\text{Al}_{2}\text{O}_{6}$$ Ca 3 Al 2 O 6 : $$\text{Eu}^{3+}$$ Eu 3 + by calcination of a layered double hydroxide precursor. J. Solid State Chem. 181, 1776–1781 (2008)Hayakawa, T., Kamt, N., Yamada, K.: Visible emission characteristics in $$\text{Tb}^{3+}$$ Tb 3 + -doped fluorescent glasses under selective excitation. J. Lumin. 68, 179–186 (1996)Hreniak, D., Strek, W., Dereń, P., Bednarkiewicz, A., Łukowiak, A.: J. Alloys Compd. 408, 828–830 (2006)Huang, Y., Jiang, C., Cao, Y., Shi, L., Seo, H.: Luminescence and microstructures of $$\text{Eu}^{3+}$$ Eu 3 + -doped in triple phosphate $$\text{Ca}_{8}\text{MgR}(\text{PO}_{4})_{7}$$ Ca 8 MgR ( PO 4 ) 7 (R = La, Gd, Y) with whitlockite structure. Mater. Res. Bull. 44, 793–798 (2009)Kharbache, H., Mahiou, R., Boutinaud, P., Boyer, D., Zakaria, D., Deren, P.: Experimental evidence of $$\text{Eu}^{3+}$$ Eu 3 + pairs in $$\text{K}_{2}\text{EuF}_{5}$$ K 2 EuF 5 . Opt. Mater. 31, 558–561 (2009)Kijima, T., Shinbori, T., Sekita, M., Uota, M., Sakai, G.: Abnormally enhanced $$\text{Eu}^{3+}$$ Eu 3 + emission in $$\text{Y}_{2}\text{O}_{2}\text{SO}_{4}$$ Y 2 O 2 SO 4 : $$\text{Eu}^{3+}$$ Eu 3 + inherited from their precursory dodecylsulfate-templated concentric-layered nanostructure. J. Lumin. 128, 311–316 (2008)Liu, G., Hong, G., Wang, J., Dong, X.: Hydrothermal synthesis of spherical and hollow $$\text{Gd}_{2}\text{O}_{3}$$ Gd 2 O 3 : $$\text{Eu}^{3+}$$ Eu 3 + phosphors. J. Alloys Compd. 432, 200–204 (2007)Mączka, M., Bednarkiewicz, A., Mendoza-Mendoza, E., Fuentes, A.F., Kępiński, L.: Optical properties of Eu and Er doped $$\text{LaAlO}_{3}$$ LaAlO 3 nanopowders prepared by low-temperature method. J. Solid State Chem. 194, 264–269 (2012)Mao, Z., Wang, D., Lu, Q., Yu, W., Yuan, Z.: Tunable single-doped single-host full-color-emitting $$\text{LaAlO}_{3}$$ LaAlO 3 : $$\text{Eu}$$ Eu phosphor via valence state-controlled means. Chem. Commun. 3, 346–348 (2009)Mao, Z.Y., Wang, D.J., Liu, Y.H., Fei, Q.N., Zheng, X., Xu, S.C., Qiu, K.: Tuning the color purity of $$\text{LaAlO}_{3}$$ LaAlO 3 : $$\text{Eu}^{3+}$$ Eu 3 + red phosphor by the cross relaxation. Opto Electron. Lett. 6, 116–119 (2010)Marí, B., Singh, K., Sahal, M., Khatkar, S., Taxak, V., Kumar, M.: Preparation and luminescence properties of $$\text{Tb}^{3+}$$ Tb 3 + doped $$\text{ZrO}_{2}$$ ZrO 2 and $$\text{BaZrO}_{3}$$ BaZrO 3 phosphors. J. Lumin. 130, 2128–2132 (2010)Marí, B., Singh, K.C., Cembrero-Coca, P., Singh, I., Singh, D., Chand, S.: Red emitting $$\text{MTiO}_{3}$$ MTiO 3 (M = Ca & Sr) phosphor doped with $$\text{Eu}^{+3}$$ Eu + 3 or $$\text{Pr}^{+3}$$ Pr + 3 with some cations as co-dopands. Displays 34, 346–351 (2013)Ningthoujam, R., Sudarsan, V., Kulshreshtha, S.: $$\text{SnO}_{2}$$ SnO 2 : $$\text{Eu}$$ Eu nanoparticles dispersed in silica: A low-temperature synthesis and photoluminescence study. J. Lumin. 127, 747–756 (2007)Ogasawara, K., Watanabe, S., Toyoshima, H., Brik, M.G.: Handbook on Physics and Chemistry of Rare Earths, vol. 1. Elsevier, Amsterdam (2007)Pereyra-Perea, E., Estrada-Yañez, M.R., García, M.: Preliminary studies on luminescent terbium-doped ZrO2 thin films prepared by the sol-gel process. J. Phys. D 31, 7–10 (1998)Perez, D., Vegas, A.: The Zintl-Klemm concept applied to cations in oxides. I. The structures of ternary aluminates. Acta Cryst. B 59, 305–323 (2003)Pieterson, L., Heeroma, M., Heer, E., Meijerink, A.: Charge transfer luminescence of $$\text{Yb}^{3+}$$ Yb 3 + . J. Lumin. 91, 177–193 (2000)Shi, C., Shi, J., Deng, J., Han, Z., Zhou, Y., Zhang, G.: Excitation states of $$\text{RE}^{3+}$$ RE 3 + -pentaphosphates in VUV and UV range. J. Electron. Spectros. Relat. Phenomena 79, 121–124 (1996)Singh, V., Watanabe, S., Gundu Rao, T.K., Chubaci, J.F.D., Kwak, H.-Y.: Characterization, photoluminescence, thermally stimulated luminescence and electron spin resonance studies of $$\text{Eu}^{3+}$$ Eu 3 + doped $$\text{LaAlO}_{3}$$ LaAlO 3 phosphor. Solid State Sci. 13, 66–71 (2011)Solovyev, O.V., Malkin, B.Z.: Modeling of electron-vibrational $$4\text{f}^{\rm n}-4\text{f}^{{\rm n}-1}5\text{d}$$ 4 f n - 4 f n - 1 5 d spectra in $$\text{LiYF}_{4}$$ LiYF 4 : $$\text{RE}^{3+}$$ RE 3 + crystals. J. Mol. Struct. 838, 176–181 (2007)Zhang, Y., Li, W., Jingjun, X.: Structure and photoluminescence properties of $$\text{KSr}_{4}(\text{BO}_{3})_{3}$$ KSr 4 ( BO 3 ) 3 : $$\text{Eu}^{3+}$$ Eu 3 + red-emitting phosphor. Opt. Mater. Express 2(2012), 92–102 (2012)Zhou, L., Yan, B.: Sol-gel synthesis and photoluminescence of $$\text{CaSiO}_{3}$$ CaSiO 3 : $$\text{Eu}^{3+}$$ Eu 3 + nanophosphors using novel silicate sources. J. Phys. Chem. Solids 69, 2877–2882 (2008

Synthesis, structure and luminescence of Er3+-doped Y3Ga5O12 nano-garnets

A novel Y3(1-x)Er3xGa5O12 nanocrystalline garnet has been synthesized by a sol-gel technique and a complete structural, morphological, vibrational, and optical characterization has been carried out in order to correlate the local structure of the Er3+ ions with their optical properties. The synthesized nanocrystals are found in a single-phase garnet structure with an average grain size of around 60 nm. The good crystalline quality of the garnet structure is confirmed by FTIR and Raman measurements, since the phonon modes of the nano-garnet are similar to those found in the single crystal garnet. Under blue laser excitation, intense green and red visible and 1.5 mu m infrared luminescences are observed, whose relative intensities are very sensitive to the Er3+ concentration. The dynamics of these emissions under pulsed laser excitations are analyzed in the framework of different energy transfer interactions. Intense visible upconverted luminescence can be clearly observed by the naked eye for all synthesized Er3+-doped Y3Ga5O12 nano-garnets under a cw 790 nm laser excitation. The power dependency and the dynamics of the upconverted luminescence confirm the existence of different two-photon upconversion processes for the green and red emissions that strongly depend on the Er3+ concentration, showing the potential of these nano-garnets as excellent candidates for developing new optical devices.This work has been partially supported by Ministerio de Ciencia e Innovacion of Spain (MICCIN) under The National Program of Materials (MAT2010-21270-C04-02; -03; -04), The Consolider-Ingenio 2010 Program (MALTA CSD2007-0045), and The National Infrastructure Program, by Ministerio de Economia y Competitividad of Spain (MINECO) within The Indo-Spanish Joint Programme of Cooperation in Science and Technology (PRI-PIBIN-2011-1153/DST-INT-Spain-P-38-11), and by the EU-FEDER funds (UCAN08-4E-008). S.F. Leon-Luis and V. Monteseguro wish to thank MICINN for the FPI grants (BES-2008-003353 and BES-2011-044596). Dr V. Venkatramu is grateful to DAE-BRNS, Government of India for the award of DAE Research Award for Young Scientists (no. 2010/20/34/5/BRNS/2223).Venkatramu, V.; León-Luis, SF.; Rodriguez-Mendoza, UR.; Monteseguro, V.; Manjón, FJ.; Lozano-Gorrín, AD.; Valiente, R.... (2012). Synthesis, structure and luminescence of Er3+-doped Y3Ga5O12 nano-garnets. Journal of Materials Chemistry. 22:13788-13799. doi:10.1039/c2jm31386cS13788137992

Synthesis of yttrium aluminum garnet nanoparticles in confined environment III: Cerium doping effect

Cerium yttrium aluminum garnet (Ce:YAG, CexY3-xAl5O12) nanoparticles doped with different cerium amount were obtained by calcining the precursors synthesized via co-precipitation in w/o microemulsion for 1\u202fh\u202fat 900\u202f\ub0C. The structural and morphological properties were investigated by using X-ray Diffraction (XRD), Infrared Spectroscopy (IR) and Transmission Electron Microscopy (TEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS) in order to investigate the effect of doping level on formation and microstructure of obtained nanoparticles. It was found that the composition of the final products strongly depends on the concentration of cerium. The formation of single YAG phase was observed only at 0.5% cerium. For other concentrations, a mixture of YAG and yttria phases was obtained indicating an effect of the cerium on stabilization of sesquioxide phase. Optical properties of the single phase powder were also investigated in details