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International audience; Since the invention and further development of lasers in the 1960s, photonics has grown into a field that permeates virtually every aspect of modern life. As photonics deals with the generation, transmission, modulation, amplification, conversion, and detection of light, glasses have played crucial and central roles in a multitude of applications given glasses' diverse range of composi-tions, properties, and forms. They are also low-cost materials, recyclable and generally easy to fabricate. In homage to the United Nations International Year of Glass 2022, this paper reviews the past, present, and future of photonic glasses.

Made available in DSpace on 2022-04-28T17:20:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-07-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) CeRTEV Tellurite glasses are considered a potential alternative for applications not achieved by SiO2-based glasses, presenting interesting optical properties, such as high linear and nonlinear refractive indexes, extended optical window, being also suitable for metallic nanoparticle growth, like Te-0. When doped with sulfide species, it can benefit the reduction of Te4+ to Te-0, which can be advantageous to synthesize in-situ chalcogenide nanoparticles and quantum dots. This work presents investigations on the reduction of Te4+ to Te-0 in tellurite glasses doped with PbS and PbO/ZnS, and aims to control this redox process through the processing with pulsed fs-laser. Tellurite glass samples were synthesized by melt-quenching technique and the thermal and structural properties were explored by different techniques, such as DSC, Raman scattering spectroscopy and mapping experiment, TEM and SAED. Reduction of tellurium to Te-0 nanocrystals into tellurite glass after laser irradiation was studied in detail and confirmed by the presence of bands at similar to 120 and 140 cm(-1) in Raman spectroscopy and mapping, assigned to the Te-Te vibrational modes, which suggest that S2- induces in-situ Te4+ reduction. Moreover, quasi spherical tellurium nanoparticles were observed through TEM and confirmed their chemical nature and crystallization by SAED. The study of tellurium reduction in the vitreous matrix becomes particularly important and promising for some applications, since its reduction generates changes in the refractive index by precipitation of Te-0 nanoparticles, allowing the fabrication of waveguides and as photosensitive material for tridimensional data storage. (C) 2021 Published by Elsevier B.V. Univ Sao Paulo, Sao Carlos Inst Chem IQSC, Sao Carlos, SP, Brazil Univ Sao Paulo, Sao Carlos Inst Phys IFSC, Sao Carlos, SP, Brazil Univ Sao Paulo, Sao Carlos Sch Engn EESC, Sao Carlos, SP, Brazil Sao Paulo State Univ, Inst Chem, Araraquara, SP, Brazil Univ Fed Alfenas, Grp Quim Mat, Pocos De Caldas, MG, Brazil Sao Paulo State Univ, Inst Chem, Araraquara, SP, Brazil FAPESP: 2018/164076 FAPESP: 2018/11283-7 FAPESP: 2018/16126-7 CeRTEV: 2013/077936

Historical research of public spaces provides a better understanding of the social formation and preserve cultural and landscaping heritage. José Bonifácio Square, located in Picacicaba, São Paulo State, Brazil, is an important public space. We carried out a historical survey in the archives of municipal public institutions and a landscape record was done by identifying tree species implanted in the square. We verified a strong church influence in the development of the square landscape project. The first landscaping work occurred in 1885, and it became known as City Public Garden. It presented naturalistic features, using exotic and native species, mainly trees, for landscaping composition. Several modifications and reforms were made from 1885 to 2005. José Bonifácio Square was considered highly diverse (H’ = 3.18) with 151 individuals, distributed in 36 species belonging to 14 botanical families. The native species from Atlantic Forest represented 82.6% of Bignoniaceae, Arecaceae, and Fabaceae species. The high diversity of native species found in José Bonifácio Square allowed us to infer a lower ecological fragility and a higher environmental balance than other Brazilian squares. The analysis of historical information from the years 1885 to 2019 and the analysis of the square’s floristic composition in contemporary times demonstrated José Bonifácio Square’s relevance in forming and conserving Piracicaba’s urban identity. Resumo As pesquisas em espaços públicos históricos ajudam a entender a formação das sociedades e a preservar o patrimônio cultural e paisagístico. A Praça José Bonifácio, localizada em Piracicaba, no estado de São Paulo, é um espaço público importante na história da cidade. Um levantamento histórico foi realizado nos arquivos das instituições públicas do município e o registro da paisagem foi feito através da identificação das espécies arbóreas implantadas na Praça. Foi verificada uma forte influência da igreja no desenvolvimento do projeto da Praça estudada. O primeiro projeto paisagístico foi implementado em 1885 e o espaço ficou conhecido como Jardim Público da Cidade, com cenários naturalistas com árvores exóticas e nativas. Foram realizadas muitas reformas e modificações na praça, no período de 1885-2005. Em relação à vegetação, a Praça José Bonifácio foi considerada altamente diversa (H ‘ = 3,18) com 151 indivíduos identificados, distribuídos em 36 espécies pertencentes a 14 famílias botânicas. As espécies botânicas nativas apresentaram frequência de 82,6%, predominantemente da Mata Atlântica, sendo maior a frequência de espécies de Bignoniaceae, Arecaceae e Fabaceae, que também são frequentemente encontradas em outras praças brasileiras. A alta diversidade florística de espécies nativas encontradas na praça José Bonifácio infere a um equilíbrio ambiental quando comparada a outras praças brasileiras. A análise de informações históricas dos anos de 1885 a 2019, e a análise da composição florística da praça na contemporaneidade demonstrou a relevância da Praça José Bonifácio na formação e conservação da identidade urbana de Piracicaba.

New glass compositions containing high concentrations of Tb3+ ions were developed aiming at the production of magneto-optical (MO) fibers. This work reports on the structural and MO properties of a new glass composition based on (100 − x)(41GeO2–25B2O3–4Al2O3–10Na2O–20BaO) − xTb4O7. Morphological analysis (HR-TEM) of the sample with the highest concentration of Tb3+ ions confirmed the homogeneous distribution of Tb3+ ions and the absence of nanoclusters. All the samples presented excellent thermal stability against crystallization (ΔT > 100 °C). An optical fiber was manufactured by a fiber drawing process. The UV–Vis spectra of the glasses showed Tb3+ electronic transitions and optical windows varying from 0.4 to 1.6 μm. The magneto-optical properties and the paramagnetic behaviors of the glasses were investigated using Faraday rotation experiments. The Verdet constant (VB) values were calculated at 500, 650, 880, 1050, 1330, and 1550 nm. The maximum VB values obtained at 650 and 1550 nm for the glass with x = 18 mol% were -128 and − 17.6 rad T−1 m−1, respectively. The VB values at 500 and 1550 nm for the optical fiber containing 8 mol% of Tb4O7 were − 110.2 and − 9.5 rad T−1 m−1, respectively, while the optical loss at around 880 nm was 6.4 dB m−1.

Knowledge of relaxation processes is fundamental in glass science and technology because relaxation is intrinsically related to vitrification, tempering as well as to annealing and sev-eral applications of glasses. However, there are conflicting reports -- summarized here for different glasses -- on whether the structural relaxation time of glass can be calculated using the Maxwell equation, which relates relaxation time with shear viscosity and shear modulus. Hence, this study aimed to verify whether these two relaxation times are comparable. The structural relaxation kinetics of a lead metasilicate glass were studied by measuring the re-fractive index variation over time at temperatures between 5 and 25 K below the fictive temperature, which was initially set 5 K below the glass transition temperature. Equilibrium shear viscosity was measured above and below the glass transition range, expanding the current knowledge by one order of magnitude. The Kohlrausch equation described very well the experimental structural relaxation kinetics throughout the investigated temperature range and the Kohlrausch exponent increased with temperature, in agreement with studies on other glasses. The experimental average structural relaxation times were much longer than the values computed from isostructural viscosity, as expected. Still, they were less than one order of magnitude higher than the average relaxation time computed through the Maxwell equation, which relies on equilibrium shear viscosity. Thus, these results demon-strate that the structural relaxation process is not controlled by isostructural viscosity, and that equilibrium shear viscosity only provides a lower boundary for structural relaxation kinetics., 19 pages, 8 figures. Changed title. Minor updates to the text

Glass is a familiar material that requires abundant mineral sources, with devastating consequences for the environment. Rice husk ash (RHA) presents a very high silica content (&gt, 95%) and it can be a very promising alternative source for silica in silica-based glass. However, impurities like manganese and iron, which depend on the rice harvest, might limit RHA use, particularly in the production of optical transparent glasses. In this work, we discussed how Mn and Fe can affect the coloring of the produced glass, and how the effect of these impurities can be removed. First, the RHA was treated with acid solutions, leading to the production of a soda-lime glass with similar transparency to commercial glass (&gt, 70%). Secondly, another simpler approach was studied: a small amount of antimony oxide was added in the composition of the glass, obtaining a transparent glass (&gt, 80%, same thickness) with RHA.

Made available in DSpace on 2020-12-12T01:15:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The challenge to obtain stable glasses containing monodisperse magnetic nanoparticles with controlled size and shape is an exciting and almost unexplored field of research. Such new materials can be used in magneto-photonics or ultra-sensitive magnetic sensors. In this work, for the first time, colorless and transparent bulk glasses containing monodisperse 20 nm Fe3−δO4 nanoparticles were prepared by a melt-quenching route. Magnetic nanoparticles were synthesized by thermal decomposition and covered with a stellate mesoporous silica shell in order to protect them against dissolution during the glass melting process. The incorporation of nanoparticles into glasses and the ideal parameters obtained for this system are discussed. The new nanocomposite materials were characterized in order to investigate the structure, thermal, and magnetic properties. Such an original approach is a very promising way to incorporate a wide panel of nanoparticles, including metallic, bimetallic and metal oxide nanoparticles, into a variety of glasses providing new properties to these materials. São Paulo State University - UNESP Institute of Chemistry, P. O. Box 355 Université de Strasbourg CNRS Institut de Physique et Chimie des Matériaux de Strasbourg UMR 7504 São Paulo State University - UNESP Institute of Chemistry, P. O. Box 355 CNPq: 153762/2018-7 FAPESP: 2013/07793-6 FAPESP: 2018/07727-7 FAPESP: 2019/19609-1 CAPES: 88881.134870/2016-01

Made available in DSpace on 2020-12-12T01:24:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-08-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) A set of glass samples with composition based on ternary 50P2O5–30Na2O–20ZnO (PNZ) matrix doped with different MnO contents was prepared via melt-quenching technique. Thermal, structural and spectroscopic properties were investigated by differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), Raman spectroscopy, UV–visible absorption, photoluminescence (PL) and by electron paramagnetic resonance (EPR) using Mn2+ as probe. Glass compositions (100-x)PNZ:xMn (0.01 ≤ x ≤ 1.0 in mol% of MnO) were characterized as glasses after careful analysis of the thermal and structural data. While DSC curves show the presence of the glass transition phenomenon (Tg), XRD analysis identified the non-crystalline arrangement, compatible with glass structure. Raman spectra of PNZ:xMn samples showed that the successive increase in Mn2+ content leads to rise of vibrational modes assigned to phosphate Q1 units, suggesting the breakdown of phosphate glass network chains. UV–Vis absorption spectra of glasses presented absorption bands centered at 250, 318, 341, 358 and 408 nm attributed to the Mn2+ electronic transitions. Glass samples containing above 0.06 mol% of MnO presented a broadband absorption centered at 511 nm assigned to the presence of traces of Mn3+. Additionally, UV–Vis, PL and EPR data showed that Mn2+ ions are occupying octahedral arrangements. Besides, EPR results suggest that the increase in MnO concentration influences on the EPR signal and hyperfine splitting constant suggests the presence of a moderately ionic bond between Mn2+ and PNZ glass network. Instituto de Química de Araraquara Universidade Estadual Paulista UNESP, P.O. Box 355 Instituto de Química de São Carlos Universidade de São Paulo IQSC–USP, P.O. Box 780 Departamento de Física Universidade Federal de São Carlos, Rod. Washington Luis Km. 235 Instituto de Física de São Carlos Universidade de São Paulo IFSC-USP, P.O. Box 369 Instituto de Química de Araraquara Universidade Estadual Paulista UNESP, P.O. Box 355 FAPESP: 2016/16900-9 FAPESP: CERTEV-2013/07793-6

The coacervation process of Graham’s Salt Na(PO3)n enabled the preparation of polyphosphate coacervates (CPPs) by adding different metallic ions (Mn+), and/or low-molecular-weight solvents at a specific solution, which resulted in a phase separation. The more viscous phase is termed as CPP and the less viscous one is the supernatant. CPPs have been extensively studied in recent years as a glass precursor at room temperature. Preparation at room temperature allows the preservation of the physicochemical properties of a wide range of active principles that may be used in controlled drug-delivery systems. Despite the present limitations of CPPs in terms of high hygroscopicity, this vulnerability to water is considered one of the great advantages of this material regarding applications in the controlled release of drugs and tissue engineering. Thus, in the presence of water, CPPs will dissolve in calcium and phosphate ions, which are the major inorganic constituents of bone and hydroxyapatite (HAP). It is believed that, in contact with body fluids, CPPs will degrade and, as this process occurs, they will be replaced by HAP. Therefore, CPPs configure a potential biomaterial that offers excellent properties with a wide range of biomedical applications that will be discussed and reviewed in this paper, including the structural properties and the recent improvements of materials based on CPPs and related devices.

Made available in DSpace on 2020-12-12T02:33:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 In this study an impedimetric immunosensor was developed in order to determine ciprofloxacin (CIP) in wastewater samples, an emergent contaminant widely found in wastewater. To achieve this, an anti-ciprofloxacin antibody was immobilized on the surface of a printed carbon electrode. Then, the developed immunosensor was applied in wastewater samples from Université Laval residences (Québec, Canada) through the load transfer resistance (Rct) using [Fe(CN)6]3-/4- as a redox probe, and the average CIP concentration was found to be 2.90 × 10-4 μg mL-1. The observed Rct changes presented a linear relationship from CIP concentrations of 10-5 to 1.0 μg mL-1, with detection and quantification limits of 2.50 × 10-6 and 7.90 × 10-6 μg mL-1, respectively. The immunosensor presented high selectivity and repeatability, as well as a good recovery rate in wastewater samples (97%). Significant interference with other compounds was not observed. The proposed method requires only 30 μL of sample without the use of organic solvents or preceding sample preparation and/or extraction techniques. Moreover, the method is fast: only 20 min of incubation followed by 2 min of analysis time was sufficient to obtain the CIP concentration. The method's estimated cost is U$ 2.00 per sample. Center for Optics Photonics and Laser (COPL) Université Laval UNESP Natl. Inst. for Alternative Technol. of Detection Toxicological Eval. and Removal of Micropollutants and Radioactives Institute of Chemistry São Paulo State University-UNESP, P.O. Box 355 Department of Chemical Engineering Universidade Federal de Minas Gerais (UFMG) Institute of Chemistry São Paulo State University (UNESP), P.O. Box 355 UNESP Natl. Inst. for Alternative Technol. of Detection Toxicological Eval. and Removal of Micropollutants and Radioactives Institute of Chemistry São Paulo State University-UNESP, P.O. Box 355 Institute of Chemistry São Paulo State University (UNESP), P.O. Box 355

A study of nonlinear refractive index (n2) of terbium-doped germanate glass was done. A large optical transparency window was observed, and average value of n2 of 7.5x10-20 m2W-1 was obtained.

Made available in DSpace on 2022-04-28T19:41:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-11-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Horizon 2020 Framework Programme Agence Nationale de la Recherche Glass forming regions in the system GaO3/2 – GeO2 – LaO3/2 – BaO have been explored using aerodynamic levitation coupled to laser heating synthesis technique. Structure property relationships have been established between the thermal and optical properties of the resulting glass thanks to Raman and Infrared vibrational spectroscopies. The germano-gallate glass networks are mainly made of three-dimensional interconnected corner shared GeO4 and GaO4 tetrahedra forming Ge – O – Ge and Ga – O− – Ge bridges in which gallium tetrahedral GaO4 units are charged-compensated by barium and lanthanum cations. In GeO2-rich compositions, the excess of positive charges produces mainly non-bridging oxygens on germanate moieties, leading to a depolymerization of the glass network. In the case of gallium rich compositions, the infrared cut-off is red-shifted as compared to the germanate glasses, in accordance with the disappearance of germanium associated entities such as germanium and gallium bridges or germanium sites with non-bridging oxygen both vibrating at higher wavenumber. Institut de Chimie de la Matière Condensée de Bordeaux Université de Bordeaux, 87 Avenue du Dr Schweitzer Conditions Extrêmes et Matériaux Haute Température et Irradiation UPR3079 Université d'Orléans 1 Avenue de la Recherche Scientifique Institut des Sciences Moléculaires UMR 5255 Université́ de Bordeaux 351 cours de la Libération Institute of Chemistry São Paulo State University-UNESP Rua Prof. Francisco Degni, 55, CEP 14800-060 Institute of Chemistry São Paulo State University-UNESP Rua Prof. Francisco Degni, 55, CEP 14800-060 FAPESP: 2013/07793-6 FAPESP: 2019/01223-0 Horizon 2020 Framework Programme: 823941 Agence Nationale de la Recherche: ANR-10-IDEX-03-02 Agence Nationale de la Recherche: ANR-18-CE08-0004-02

Made available in DSpace on 2019-10-06T15:19:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-15 In this work, glass compositions in the system NaPO3 - Sb2O3 – CuO (PSbCu) containing different concentrations of CuO and Sb2O3 were prepared through the melt - quenching methodology. Thermal, structural and optical properties of the PSbCu glasses were systematically studied by differential scanning calorimetry (DSC), X – ray powder diffraction (XRD) and Raman, UV–Visible and Photoluminescence (PL) spectroscopies, besides electron paramagnetic resonance (EPR) measurements. The DSC curves for all samples presented the glass transition phenomenon (Tg), while the XRD patterns showed the presence of an amorphous halo, which confirmed the glassy nature of all samples analyzed. UV–Vis spectra of the glasses showed a transparent window from 450 to 800 nm. The EPR signals intensities were investigated as a function of the copper concentration and Sb2O3 content in the (PySb0.5Cu) (20 ≤ y ≤ 80) and (PSb80xCu) (0.25 ≤ x ≤ 1.25) glasses. The EPR results showed that the increase of Sb2O3 concentration on the PySb0.5Cu glasses decreased the Cu2+ signals, which suggests the Sb3+ oxidizing to Sb5+, also transferring electrons to Cu2+ species to create the EPR a silent Cu+ specie. According to EPR parameters and PL spectra (excited at 380 nm) of PySb0.5Cu glasses, the ions Cu2+ ions were preferentially found in a distorted octahedral geometry, while Cu+ is in a square planar geometry according to the Jahn-Teller effect. Instituto de Química da Araraquara Universidade Estadual Paulista — UNESP, P. O. Box 355 Departamento de Química Instituto de Ciências Exatas Universidade Federal de Juiz de Fora Instituto de Física de São Carlos Universidade de São Paulo Departamento de Física Universidade Federal de São Carlos Instituto de Química da Araraquara Universidade Estadual Paulista — UNESP, P. O. Box 355

Strain engineering is a powerful tool for generating single-photon emitters in monolayer (ML) transition metal dichalcogenides. Here, we report on a simple method for generating sharp emission lines (linewidths ≈ 150–500 μeV) in a monolayer (ML) WSe2 on nano-roughness regions of Tb3+-borogermanate glasses. We performed a polarization-resolved magneto-luminescence study in WSe2/glass at low temperature. Remarkably, we observed several stable and linearly polarized doublet emission peaks in strained regions that are associated with a fine structure splitting due to the anisotropic electron–hole exchange interaction with g-factors of ∼8.4–9.8. Our results indicate that strain engineering on glass substrates is a promising tool for generating quantum dot-like emitters in ML WSe2 for possible integration with photonics systems for quantum information technology.

Made available in DSpace on 2021-06-25T11:03:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-13 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Instituto Nacional de Fotônica Bacterial nanocellulose (BNC) is a natural biopolymer obtained by gram-negative bacteria by means of a green and inexhaustible biotechnological process using glucose as producing source. BCN hydrogels is formed by cellulose nanofibrils that maintain an open network structure, an ideal matrix to produce new class of organic-inorganic nanocomposites (OIN) for multifunctional applications. The polyoxometalates (POMs) are complex molecules with several metallic ions sharing oxide ions, forming a highly symmetrical metal oxide cluster. Phosphotungstic acid (PWA), H3PW12O40 photoreduction process activated under ultraviolet irradiation, promoting color change. In this work, photochromic organic-inorganic nanocomposites were prepared by soaking phosphotungstic acid (H3PW12O40) in wet BNC membranes mats at room temperature. Semi-transparent and free-standing BNC/PWA nanocomposite with paper-like aspect were obtained. BNC network was able to control, stabilize and disperse PWA particles in a narrow nanometric distribution, and FTIR spectra indicated that the primary Keggin structure was also preserved in the nanocomposites, independently on the PWA content. The nanoparticles present a narrow distribution of around 16 nm, independently on the PWA concentration. BNC/PWA nanocomposites showed reversible photochromic behavior characteristic of the equilibrium between different tungsten oxidation states. PWA reduction (W6+→ W5+) and organic matrix oxidation is proposed to occur through a radical process involving the interaction of one electron from the oxygen atom of the PWA and one hydrogen from BNC matrix. The photochromic effect vanishes almost completely after 5 h. This mechanism is real in the presence of oxygen, however, if the membranes are left in nitrogen or under vacuum the blue color remains longer than 45 days. Photo-electrochemical behavior was studied by spectroelectrochemistry measurements. It is worth noting that all processes were still reversible in the timescale of the experiment and color changes were observed in several cycles. Institute of Chemistry São Paulo State University (UNESP) Laboratório de Biopolímeros e Biomateriais (BioPolMat) Universidade de Araraquara Instituto de Química – Universidade de São Paulo USP Departamento de Física Instituto de Ciências Exatas Universidade Federal de Juiz de Fora (UFJF) Deparment of Chemistry Federal University of São Departamento de Física Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio) Institute of Chemistry São Paulo State University (UNESP) FAPESP: 2013/07793-6 FAPESP: 2013/24725-4 FAPESP: 2014/12424-2 FAPESP: 2016/11591-8 FAPESP: 2018/25512-8 FAPESP: 2020/04509-9 Instituto Nacional de Fotônica: 407822/2018-6

Made available in DSpace on 2021-06-25T11:13:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-01 New magnetic glass compositions, based on system (100-x) (60GeO2 -25B2O3 -4Al2O3 -10Na2O-1PbO) - xTb4O7 were prepared by the melt-quenching technique. The materials were systematically characterized with respect to their structural (XRD, EXAFS, XANES and Raman), thermal (DSC), morphological, optical, magnetic and magneto-optical (MO) properties. Morphological and magnetic measurements show the homogeneous distribution of the Tb3+ ions as the magnetic susceptibility increases proportionally to the rare earth content. The optical window covers the range from 0.5 up to 1.6 μm, limited by absorption due to 4f8 -> 4f7 5 d 1and 4f8 -> 4f8 transitions of Tb3+. XANES and EXAFS measurements at the Ge-K edge show that the germanium atoms are always tetrahedrally coordinated, while results at the Tb-LIII edge shows terbium atoms to be eight-coordinated and exclusively present in the oxidation state 3+ independently of the glass composition. MO measurements show that the Verdet constant (VB) increases linearly with the Tb3+ concentration reaching the value of -83.9 rad T-1m-1 at 650 nm for glass containing 8 mol% of Tb4O7. Good thermal stability (ΔT = 200 °C) allowed obtaining an optical fiber of a glass containing 4 mol% of Tb4O7 featuring VB values of -37.9, -23.6 and -5.89 rad T-1 m-1, at 500, 650 and 1550 nm, respectively. Institute of Chemistry São Paulo State University UNESP Institute of Physics Applied Physics Center University of Brasília São Carlos Institute of Physics São Paulo University USP Department of Materials Engineering (DEMa) Federal University of São Carlos UFSCar Centre d'Optique Photonique et Laser Université Laval Institute of Chemistry São Paulo State University UNESP

New glass compositions containing high concentrations of Tb3+ ions were developed aiming at the production of magneto-optical (MO) fibers. This work reports on the structural and MO properties of a new glass composition based on (100-x)(41GeO2-25B2O3-4Al2O3-10Na2O-20BaO) – xTb4O7. Morphological analysis (HR-TEM) of the sample with the highest concentration of Tb3+ ions confirmed the homogeneous distribution of Tb3+ ions and the absence of nanoclusters. All the samples presented excellent thermal stability against crystallization (ΔT > 100 oC). An optical fiber was manufactured by a fiber drawing process. The UV-Vis spectra of the glasses showed Tb3+ electronic transitions and optical windows varying from 0.4 to 1.6 µm. The magneto-optical properties and the paramagnetic behaviors of the glasses were investigated using Faraday rotation experiments. The Verdet constant (VB) values were calculated at 500, 650, 880, 1050, 1330, and 1550 nm. The maximum VB values obtained at 650 and 1550 nm for the glass with x = 18 mol% were − 128 and − 17.6 rad T− 1 m− 1, respectively. The VB values at 500 and 1550 nm for the optical fiber containing 8 mol% of Tb4O7 were − 110.2 and − 9.5 rad T− 1 m− 1, respectively, while the optical loss at around 880 nm was 6.4 dB m− 1.

Made available in DSpace on 2022-04-28T19:40:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-11-01 Ho3+-doped YNbO4 and Y3NbO7 phosphors were synthesised via a co-precipitation synthesis route. Structural characterisation and spectroscopic properties were performed as a function of the Ho3+ concentration. The Rietveld type-refinement confirms the stabilisation of the pure monoclinic Fergusonite YNbO4 phase at the highest temperatures, but the quadratic phase is stabilised for the lowest temperature, whereas a pure cubic fluorite Y3NbO7 phase was observed for all of the heat treatments. Raman and infrared spectroscopies were used to compare the cation-oxygen vibrational modes. Emission spectra and up-conversion processes were obtained under excitation at 445 and 975 nm respectively. For a similar Ho3+ content, the energy transfers observed show differences between the two crystalline compounds that are related to a stronger interaction between the holmium cations in the fluorite host lattice. CNRS Univ. Bordeaux, Bordeaux INP, ICMCB, UMR 5026 ISM - Institute of Molecular Science UMR 5255 CNRS-University of Bordeaux Université de Bordeaux CNRS Laboratoire des Composites ThermoStructuraux, UMR 5801 Chemistry Institute São Paulo State University – UNESP Chemistry Institute São Paulo State University – UNESP

Made available in DSpace on 2020-12-12T02:47:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-25 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Glasses are materials with highly flexible compositions and high chemical and physical durability. These characteristics make them suitable materials for hosting nanoparticles for different purposes. Hybrid glasses containing magnetic nanoparticles have been highlighted due to their potential for application as ultra-sensitive magnetic sensors and magnetic devices. In this work, phosphate bulk glasses containing 0.5%, 1.0%, and 2.0% in mass of metallic CoPt alloy nanoparticles were prepared by melt-quenching technique. The CoPt nanoparticles were synthesized by reducing metal precursors in a high temperature organic solvent and, in the second step, they were covered with a silica layer in order to protect the nanoparticles for the subsequent melting. The nanoparticles were treated at different temperatures. Heat treatment at 900 °C showed the highest values of saturation magnetization and coercivity, and for that reason these nanoparticles were chosen for incorporation into glass. In the transmission electron microscopy images of the glass containing 2.0% in mass of nanoparticles, the interplanar distance of 0.21 nm was identified and indexed to the 111 plane of CoPt, confirming that the nanoparticles were successfully embedded into the matrix. The UV–Vis spectra presented Co2+ characteristic bands at 528, 578, and 626 nm, indicating that these ions are tetrahedrally coordinated in the matrix. Themagnetic measurements presented behavior close to ferromagnetic, showing that it is possible to prepare a magnetic glass containing bimetallic nanoparticles. Institute of Chemistry - São Paulo State University - UNESP, P. O. Box 355 Federal University of Sao Carlos (UFSCar) Graduate Program in Materials Science and Engineering Department of Materials Engineering Instituto de Física Núcleo de Física Aplicada Universidade de Brasília Instituto Federal Goiano Institute of Chemistry - São Paulo State University - UNESP, P. O. Box 355 CAPES: 001 FAPESP: 2013/07793-6 FAPESP: 2018/07727-7 FAPESP: 2019/19609-1 CAPES: 88882.332718/2019-01

Made available in DSpace on 2020-12-12T01:28:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-25 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Financiadora de Estudos e Projetos Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Transparent Eu3+-doped tantalum phosphate glass-ceramics containing Na2Ta8O21 nanocrystals were successfully obtained by a two-step heat treatment. Structural analyses were performed using X-ray diffraction, Transmission Electron Microscopy, Nuclear Magnetic Resonance and Raman spectroscopy. Due to the high Ta/P ratio (= 2) the glass network is built from a mixed 3D PO4–TaO6 chain in which TaO6-rich regions are inserted and responsible for crystallization of an alkali tantalum oxide phase Na2Ta8O21. Eu3+ and their optical properties was used as a sensitive probe to study it site structure in the host matrix. The radiative properties of Eu3+ emission levels were predicted using the Judd-Ofelt theory. The chemical environment and local phonon energy around the rare-earth ions have been proposed based on phonon side band associated with the 7F0 → 5D2 transition, 5D0 → 7F2/7F1 relative intensity and narrowing of the emission bands. High tantalum content precursor glass exhibits high photoluminescence quantum efficiency due to low phonon energy and high refractive index (1.9461 at 633 nm). A perovskite-like bronze crystalline structure is formed in the glass-ceramic (nucleated at 925 °C for 0.5 h and grown at 940 °C for different times) and is considered promising for nonlinear optical applications and studies. Institute of Chemistry Sao Paulo State University - UNESP Sao Carlos Institute of Chemistry University of Sao Paulo, São Carlos Grupo de Química de Materiais Universidade Federal de Alfenas Campus Poços de Caldas, Poços de Caldas Institute of Chemistry Sao Paulo State University - UNESP CNPq: 156420/2018-0 FAPESP: 2013/07793-6 FAPESP: 2018/16126-7

Made available in DSpace on 2021-06-25T10:15:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-05 Glasses in the system (85-x)GeO2-(x)B2O3-10Na2O-4Al2O3-1PbO, which are used as matrices for rare-earth ion containing magneto-optic glasses have been prepared and their thermal and structural properties have been characterized by differential scanning calorimetry, Raman scattering, and solid state NMR spectroscopies. Besides showing the features of the corresponding borogermanate binary glasses, the Raman spectra also reveal new features consistent with the occurrence of B-O-Ge connectivities. One- and two-dimensional 23Na, 27Al, and 11B NMR spectra reveal monotonic structural changes as a function of composition, reflecting the competition of the three network former species for charge compensation by the network modifier cations. Aluminum is found in a predominantly four-coordinated environment. Its anionic functionalization and, with second priority, that of the boron oxide component take precedence over that of the germanium oxide component. The glass transition temperature decreases with increasing B2O3 content and shows an excellent correlation with the average network connectivity deduced from the NMR data. Institute of Chemistry São Paulo State University-UNESP, R. Prof. Francisco Degni, 55 São Carlos Institute of Physics São Paulo University - USP, Av. Trabalhador Sãocarlense 400 Institut für Physikalische Chemie Westfälische Wilhelms-Universität, Corrensstraße 28-30 Institute of Chemistry São Paulo State University-UNESP, R. Prof. Francisco Degni, 55

Made available in DSpace on 2021-06-25T11:07:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-03 Emerging contaminants, including pharmaceutical compounds, are receiving research attention as a result of their widespread presence in effluents and wastewater treatment plants (WWTPs). The antibiotic ciprofloxacin (CIP) is extensively employed to treat infections in animal and human medicine. Both CIP and its metabolites are common contaminants found in WWTPs. In this study, a label-free ultrasensitive U-bent optical fiber-based immunosensor for the determination of CIP in wastewater samples was developed using the properties of the conducting polymer polyaniline (PANI). The anti-CIP immunoglobulin G (IgG) was deposited on a silica optical fiber surface previously functionalized with PANI. Scanning electron microscopy and micro-Raman spectroscopy were used to investigate the surface of the immunosensor. The analysis of CIP in wastewater was performed without the use of an organic solvent or sample preparation steps, with only the sample dilution in saline buffer (pH = 7.4). The linear range for CIP was from 0.01 to 10,000 ng L-1. The detection limit was 3.30 × 10-3 ng L-1 and the quantification limit was 0.01 ng L-1. The immunosensor provided a high average recovery of 91% after spiking wastewater samples with CIP at a concentration of 9,100 ng L-1. The method was applied in triplicate to wastewater samples from Quebec (Canada), obtaining concentrations of 549 and 267 ng L-1. A comparison with a reference method showed no significant difference (t-test at 95% confidence). The new technique developed is selective, allowing a quantitative analysis of CIP in wastewater. Center for Optics Photonics and Laser (COPL) Université Laval National Institute for Alternative Technologies of Detection Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM) Institute of Chemistry São Paulo State University (UNESP) Institute of Chemistry São Paulo State University (UNESP) National Institute for Alternative Technologies of Detection Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM) Institute of Chemistry São Paulo State University (UNESP) Institute of Chemistry São Paulo State University (UNESP)

Made available in DSpace on 2020-12-12T02:36:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Herein we report the synthesis of highly-doped silver nanocluster in fluorophosphate glasses through the melting-quenching method in order to achieve sensitization with Tm3+ and Mn2+ ions. Blue and red emission belonging to Tm3+ (470 to 490 nm) and Mn2+ (550 to 750 nm) ions could be obtained via non-resonant excitation of Tm3+ and Mn2+. Slight decrease of the fluorescence decay times confirmed an energy transfer as a possible mechanism to explain the Tm3+ and Mn2+ emission. The composition of 5 mol% of AgNO3, 0.4 mol% of Tm2O3 and 0.2 mol% of MnF2 in our sample leads to distance between donor (silver nanoclusters) and acceptor (Tm3+-Mn2+) as short as 11 Å, which suggests that the main mechanism for blue and red emission from Tm3+ and Mn2+ is Förster Resonance Energy Transfer (FRET). The results presented here show that the studied material has potential application for multicolor generation as luminophore in white light emitting diodes (W-LED). Institute of Chemistry - São Paulo State University - UNESP Department of Chemical Physics and Optics Faculty of Mathematics and Physics Charles University, Ke Karlovu 3 Department of Chemistry and Chemical Engineering Chalmers University of Technology Institute of Chemistry - São Paulo State University - UNESP FAPESP: #2013/07793-6 FAPESP: #2016/16343-2 FAPESP: #2016/16900-9

Made available in DSpace on 2020-12-12T01:30:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-10-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ASCRS Research Foundation Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) A series of new transparent and magnetic germanoborate glasses in the system (100-x)[60GeO2–25B2O3–10Na2O–4Al2O3–1PbO] – (x) Gd2O3, with x = 0, 1, 2, 5, 10, 15 and 20 mol%, was prepared and studied with respect to their thermal and structural changes in the presence of Gd2O3. Based on Differential Scanning Calorimetre (DSC) analysis, a glass with 5% of Gd2O3 showed a high thermal stability, which progressively decreases for samples with higher content of Gd2O3. By the analysis of Raman and Fourier Transform Infrared (FTIR) spectra, it was possible to identify that by increasing the amount of Gd2O3, a progressive depolymerization of 6-membered Ge[IV] rings is promoted, concomitant with an increase of Ge[IV] tetrahedra units with non-briding oxygens. The structural analysis through the local-sensitive techniques EXAFS (Extended X-ray Absorption Fine Structure) and XANES (X-ray Absorption Near Edge Structure) showed that the short-range structural modification around the elements Ge and Gd3+ does not change with the addition of Gd2O3 and the presence of germanium four-fold coordination [GeIV] and Gd3+ states, respectively. A simulation of the coordination number (N), the interatomic distance (R) of Ge–O and Gd–O bonds and the Debye-Waller factor was also carried out. The microstructure, after crystallization, of the sample with 15 mol% of Gd2O3 was evaluated using optical and electron microscopes. Finally, the paramagnetic behaviour and ion probe quantification of Gd3+ ions were obtained based on magnetic susceptibility measurements. São Paulo State University (Unesp) Institute of Chemistry São Carlos Institute of Physics University of São Paulo (USP) ICMCB CNRS Université de Bordeaux São Paulo State University (Unesp) Institute of Chemistry FAPESP: 2013/07793-6 FAPESP: 2019/01223-0

Made available in DSpace on 2021-06-25T10:16:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-19 Bismuth-containing rare-earth codoped fluoride phosphate glasses are promising materials for superbroadband near-infrared (NIR) emission with potential applications in optical amplification. To elucidate their structural organization, this contribution develops a comprehensive multinuclear solid-state single and 31P/19F double resonance NMR strategy, applied to glasses in the system (BiF3)y(50NaPO3-20Ba(PO3)2-20NaF-10BaF2)100-y (y = 0, 5, 10, 20, 30, 40). To separately assess the influence of bismuth and fluorine constituents on the network structure, an additional set of (NaPO3)50-2x(Ba(PO3)2)20-x(NaF)20+2x(BaF2)10+x (x = 0, 2.5, 5.0, 7.5) glasses was also investigated. Introduction of alkali fluoride ions into phosphate glasses is shown to follow a new network modification scheme involving depolymerization of polyphosphate chains under the formation of F-bonded fluorophosphate units. However, a significant part of the fluoride stays separate, interacting exclusively with metal-ion species. 23Na MAS and 23Na{31P} double resonance NMR results are consistent with a local sodium ion environment dominated by phosphate ions in the Bi-free system, whereas in the BiF3-containing glasses, the successive reduction of the dipolar second moment M2(Na-P) with increasing BiF3 content reflects the expected dilution effect, accompanied by increasing competition of the fluoride ions for ligation with the Na+ ions. São Carlos Institute of Physics São Paulo University-USP, Avenida Trabalhador Saocarlense 400 Institut für Physikalische Chemie Westfälische Wilhelms-Universität Münster, Corrensstrasse 30 Institute of Chemistry São Paulo State University-UNESP, Avenida Professor Francisco Degni, 55 Institute of Chemistry São Paulo State University-UNESP, Avenida Professor Francisco Degni, 55