Noelio Oliveira Dantas

Noelio Oliveira Dantas
Universidade Federal de Uberlândia (UFU) | UFU

About

220
Publications
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3,354
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June 1994 - November 2014
Universidade Federal de Uberlândia (UFU)
Position
  • Diretor de Pesquisa

Publications

Publications (220)
Article
Wounds treated with TiO2 nanoparticles (TiO2-NPs) show an improvement in healing time. However, little is known about the parameters that can contribute to this result. On the other hand, the treatment of wounds with polyphenols is widely known. These compounds are found in the peel of Annona crassiflora fruit and have antioxidant, analgesic and an...
Article
In this work measurements of photoluminescence quantum efficiency (η) in CdS nanocrystals embedded in phosphate glass matrix was performed using the thermal lens technique. The study was performed, using two different excitation wavelengths, in three samples with average sizes of 5.1, 6.3 and 6.7 nm and emission around 980 nm. The emission was stro...
Article
In this work, lithium-boron-aluminum (LBA) glasses doped with Eu³⁺ were produced by the traditional melting method. These precursor glasses (PG) were heat treated at 400 and 450 °C for 6 h to produce glass-ceramics (GC). The X-ray diffraction measurements showed the formation of a crystalline phase. In the LBA GCs, crystal growth is nucleated at th...
Article
This work presents a detailed investigation of the blue and near infrared (NIR) emission of Tm³⁺ and Yb³⁺ ions in ZnTe doped oxide glasses. Absorption, luminescence and lifetime measurements were performed in order to optimize the luminescent properties of Yb³⁺ and Tm³⁺. The influence of ZnTe and Yb³⁺ concentration on the enhancement and quenching...
Article
The Eu³⁺ and Gd³⁺ doped Y2O3 nanomaterials were prepared at room temperature by a coprecipitation method. The luminescence materials were characterized by XRD, Raman spectroscopy, and photoluminescence (PL). The materials display reddish color under UV excitation because of the intraconfigurational 4f transitions from Eu³⁺ ions. Photoluminescent ma...
Article
Optical emission and energy-transfer Eu3+↔Ho3+ process is investigated in Eu3+/Ho3+-codoped 60TeO2:40ZnO glass. Absorption and excitation spectra were collected, and photoluminescence was investigated as a function of concentration using excitations at 394 and 438 nm. The emissions were sensitive to the excitation wavelength, which determined the d...
Article
The structural and optical properties of zinc tellurite glasses doped with Ho³⁺ and Pr³⁺ using Raman spectroscopy are investigated. The Raman spectroscopy identified changes in glass phonon energy and structural disorder caused by the chemical bond breaks with addition of rare earth ions in the host matrix. The glass composition and rare earth conc...
Article
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The structural and optical properties of the TiO2 nanocrystals (NCs) samples pure and doped with Nd³⁺ ions were studied as a function of temperature. These properties were studied by using the Raman spectroscopy, steady-state and time-resolved photoluminescence. A structural transformation is observed by a systematic study as a function of the temp...
Article
Full-text available
The study of the interaction of the herbicide glyphosate with zinc oxide (ZnO) nanocrystals (NCs) was investigated under controlled pH conditions. These changes alter the various chemical groups’ vibrational frequencies of the glyphosate molecule according to the infrared spectra. Scanning electron microscopy (SEM), and atomic force microscopy (AFM...
Article
This work reports on the preparation and photoluminescence properties of the phosphate glass matrix based on P2O5-Al2O5-Na2O-K2O (PANK) doped with Yb3+, Eu3+ and Er3+ with different amount of Nb2O5 prepared by the conventional melting process. The Raman bands assigned to the Nb2O5 indicating the insertion of this oxide in the glass. Under UV excita...
Article
In this study, structural and thermal features of phosphate glasses doped with diluted magnetic semiconductors are investigated. The samples were ZnTe nanocrystals doped with different concentrations of Cr and Mn. UV-visible absorption spectra showed the presence of Cr²⁺ and Cr³⁺ ions into the matrix. Depolymerization of the phosphate network is ob...
Article
The thermal and structural properties of a Li2O ⋅ B2O3 ⋅ Al2O3 glass matrix with the addition CaF2 or LiF were investigated by XRD and DTA. The results showed that the samples are glasses. The thermal analysis also showed a trend of the glass transition temperature shifting to lower temperatures, and the shift or new peaks of crystallization is obs...
Article
Diluted magnetic semiconductor Pb1-xCoxS nanocrystals with nominal concentrations of Co (x = 0.00, 0.10 and 0.16) embedded in a chalcogenide glass matrix were synthesized by the low-cost fusion-nucleation method that allows for the manipulation, control, and tuning of the structural, optical, and electronic properties. Transmission electron microsc...
Article
Zinc Oxide (ZnO) and simonkolleite (SM) have been extensively studied separately in several technological applications. However, the cytotoxicity of SM has not yet been investigated, nor has the synergism between SM and ZnO. In this work, we investigated both the synergism of SM with ZnO in the physico-chemical properties and cytotoxicity in breast...
Chapter
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https://www.intechopen.com/online-first/doped-semiconductor-nanocrystals-development-and-applications
Chapter
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Mass testing for COVID-19 is essential to defining patient management strategies, choosing the best clinical management, and dimensioning strategies for controlling viral dissemination and immunization strategies. Thus, it is of utmost importance to search for devices that allow a quick and reliable diagnosis of low cost that can be transposed from...
Article
In this study, magnetic-optical properties of Zn1−xCoxO NCs were modulated with x-content. The optical, structural, morphological, and magnetic properties were investigated by optical absorption (OA), fluorescence (FL), X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and electronic paramagnetic resonance (EPR). The...
Article
Full-text available
In this study, structural and thermal features of phosphate glasses doped with diluted magnetic semiconductors are investigated. The samples were ZnTe nanocrystals doped with different concentrations of Cr and Mn. UV-visible absorption spectra showed the presence of Cr2+ and Cr3+ ions into the matrix. Depolymerization of the phosphate network is ob...
Chapter
https://www.intechopen.com/online-first/diluted-magnetic-semiconductors-nanocrystals-saturation-and-modulation
Article
In this work, we investigated the structural and optical properties of zinc tellurite glass matrices doped with Tm³⁺ and Dy³⁺. Raman spectra show the structural units and vibrational modes of two glass matrices composed of TeO2 and ZnO. The chemical composition of the glass and the doping with the rare earth ion changed the frequency and intensity...
Article
Full-text available
Glyphosate detection and quantification is still a challenge. After an extensive literature review, we have observed that the Fourier Transform Infrared Spectroscopy (FTIR) practically had not been used for detection or quantification yet. The interaction of zinc oxide (ZnO), silver oxide (Ag2O), and Ag-doped ZnO nanocrystals (NCs), as well as nano...
Article
In this work, we report a potential optical nanothermometer (NTh) based on Nd³⁺ doped TiO2 nanocrystals, operating within the biological windows. The Nd³⁺ emissions at around 900, 1060, and 1340 nm were used upon excitation at 808 nm. The fluorescence intensity ratio (FIR) corresponding to the emissions at 1060 nm and 1340 nm (FIR = I1060 nm/I1340...
Article
Study of the optical and structural properties of the phosphate glass doped with CdS nanocrystals and co-doped with Nd 3+ ions, Abstract: In this work, a study of the optical and structural properties of a phosphate glass (P 2 O 5-Al 2 O 3-Na 2 O-K 2 O) doped with cadmium sulfide (CdS) nanocrystals and co-doped with Nd 3+ ions produced by the fusio...
Article
In this work, we synthesized the phosphate glass pure and doped with erbium ions (Er³⁺) and investigated the effect of the controlled atmosphere and fluoride incorporation on the optical properties of Er³⁺ ions using the Judd-Ofelt theory. The PAN and PANK glass matrices with nominal compositions 60P205·10Al2O3·30Na2O (mol%) and 40P2O5·20Al2O3·35Na...
Article
Full-text available
Visceral leishmaniasis is a reemerging neglected tropical disease with limitations for its diagnosis, including low concentration of antibodies in the serum of asymptomatic patients and cross-reactions. In this context, this work proposes an electrochemical immunosensor for the diagnosis of visceral leishmaniasis in a more sensitive way that is cap...
Article
The Tm³⁺/Tb³⁺/Sm³⁺ doped 60TeO2·40ZnO glass were prepared and white light generation under 355 nm excitation were investigated. The glass samples were produced adjusting the ions concentrations in order to achieve the red-green-blue relative intensity ratios pursuing white light emission. The overall emission light chromaticity coordinates sweeped...
Article
Luminescence and energy-transfer mechanisms in 60TeO2:40ZnO glass codoped with Dy³⁺and Pr³⁺ is investigated. Two sets of Dy³⁺/Pr³⁺ codoped samples were synthetized, each with a fixed donor-ion concentration. The photoluminescence under UV-VIS excitation revealed emissions in 437, 485, 528, 540, 613, 644, 684, 706, and 730 nm (Pr³⁺), and in 480, 574...
Article
The optical and structural properties of Cr-doped Bi2S3 nanocrystals embedded in host glass were investigated. Transmission electron microscopy images and energy dispersive X-ray spectroscopy confirm the formation of the Bi2−xCrxS3 nanocrystals and the presence of the Bi, S and Cr elements. Raman spectroscopy reveal changes of structural crystallin...
Article
In this work, we report the study of Zn1-xNixTe nanocrystals in a glassy matrix, synthesized by a new protocol based on the fusion-nucleation method. Optical absorption spectra, analyzed based on the crystalline field theory, evidenced the substitutional incorporation of Ni²⁺ ions in the ZnTe semiconductor lattice with tetrahedral symmetry. Transmi...
Article
We have studied the optical properties of channel waveguides written using a femtosecond laser in tellurite-zinc glasses doped with metallic silver (%TeO2%ZnO:Ag). Our findings showed that the tellurium dioxide glasses could be significantly affected by the silver presence, even with low silver concentration. By properly choosing the parameters and...
Article
Semimagnetic chalcogeneide Pb1-xMnxS nanocrystals were grown in borosilicate glass host and their optical, structural and magnetic properties were investigated. Transmission electron microscopy images confirms the growth of the Pb1-xMnxS nanocrystals. Uv–Vis-Nir spectroscopy measurements of these nanocrystals revealed band-gap shifting from 0.94 eV...
Chapter
The optical properties of nanocrystal (NC) colloidal quantum dots (QDs) largely depend on their size and shape. These properties can be easily tuned by temperature and the concentration of ligands during their synthesis to generate QD particles with different optical features. However, the enormous complexity of these QD systems limits the understa...
Article
This article presents a successfully development of hybrid functional nanomaterials composed of Protoporphyrin-IX/Halloysite nanotubes (PpIX/HNTs), in which the PpIX molecules were adsorbed on the surface of the HNTs at different degree of aggregation. This article also presents a possible explanation for the PpIX adsorption by the HNTs surface and...
Chapter
In the present work we review the most important results obtained concerning the influence of thermo-optical parameters of nanocomposite glasses doped with rare earth ions and Metallic or semiconductor nanoparticles. Glassy hosts doped with Rare Earth ions present optical properties that have been widely investigated due to their applicability in o...
Article
Two sets of Er³⁺/Sm³⁺ co-doped 80TeO2:20ZnO (mol%) glass samples were synthetized and their luminescence properties investigated under VIS (532 nm) and NIR (980 nm) excitation. Emissions around 530, 550, 660, 800, and 850 nm from Er³⁺ and 560, 600, 645, and 700 nm from Sm³⁺ were generated via energy down-conversion (532 nm excitation), and up-conve...
Article
The temperature dependence of the photoluminescence spectra and the lifetime of a phosphate glass (P2O5–Al2O3–Na2O–K2O) doped with different concentrations of Nd³⁺ ions was studied. The emission intensities of the (²S3/2, ⁴F7/2), (²H9/2,⁴F5/2),⁴F3/2 → ⁴I9/2 transitions were measured in a wide range of temperature from 80 up to 480 K. The changes in...
Article
Chromium-doped bismuth telluride (Bi2−xCrxTe3) diluted magnetic semiconductor nanocrystals were successfully synthesized in a glass matrix by the fusion method with nominal Cr concentrations of x = 0.00, 0.05, and 0.10. Transmission electron microscopy confirmed the growth of nanocrystals with an average diameter of ~5.0 nm. Shifts in X-ray diffrac...
Article
Full-text available
P2O5–Al2O3–Na2O–K2O phosphate glasses with various K2O/Al2O3 ratios were synthesized using the melt quenching technique. Raman and absorption spectra were measured to investigate the effects of these ratios on the structures and spectroscopic properties of the glasses. As the K2O/Al2O3 ratio increases, the Raman spectra show shifts of some of the s...
Article
A series of Tm³⁺/Dy³⁺ co-doped TeO2:ZnO glass samples were synthetized via fusion method and frequency up- and down-conversion (FUC and FDC) luminescence properties was investigated. A characterization through Raman spectrum and optical absorption of the glass host was first performed, followed by optical absorption and excitation spectra of the Tm...
Article
Full-text available
Nanostructured materials have exhibited great potential applications in the field of (bio)sensing. In particular, the capacitive electrolyte‐insulator‐semiconductor (EIS) sensor is a suitable field‐effect device for integration of film‐based nanostructures as sensing units. In this study, the fabrication of a hybrid nanostructured film using the la...
Article
The effect of ion concentration on the saturation intensity, Is, was investigated and its effect on the evaluation of nonlinear optical properties was discussed. The suggested experimental approach points out a more accurate way to obtain Is. The value of Is in the limit of low concentration and low incident intensity was obtained as (266 ± 14) KW/...
Article
Phospholipases A2 represent a family of enzymes with important application in medicine. However, direct tracking is difficult due to the absence of a stable, effective and specific marker for these enzymes. Magic-sized quantum dots (MSQDs) are inorganic semiconducting nanocrystals with unique physical properties. They have the ability to conjugate...
Article
Full-text available
Tellurite-based (TeO2) glass systems are known to have relatively high chemical and thermal stability, high transmittance in the infrared region as well as low light dispersion. Parallel to the investigations of the optical properties of the TeO2-based glasses, there is a growing interest in the manufacture of transparent oxides containing specific...
Article
This paper reports on the optical, morphological, structural and magnetic properties of Zn1-xCuxTe nanocrystals, doped with Cu (x varying from 0.000 to 0.100) and grown by thermal annealing at 500 °C in a P2O5–ZnO–Al2O3–BaO–PbO glass system that had been synthesized by fusion. At higher levels of Cu-doping, optical absorption (OA) showed that Cu²⁺...
Article
The effect of Cr co-doping on the optical properties of Mn-doped ZnTe nanocrystals (NCs) embedded in a glass matrix is studied in this paper. The substitutional incorporation of Cr²⁺ ions into these semiconducting NCs was strongly evidenced by optical absorption and crystal field theory analyses, which showed the characteristic transitions of Cr²⁺...
Article
Bayesian inference was used as a new approach to calculate of rare earth (RE) ion spectroscopic parameters within the Judd−Ofelt theory using the Li2O-B2O3-Al2O3 glass system doped with Nd2O3 and TiO2. This system was synthesized by the fusion method, and the physical properties of the as-synthesized material were investigated. Optical absorption,...
Article
Frequency upconversion luminescence in Yb³⁺/Tm³⁺ co-doped 60P2O5·15ZnO·5Al2O3·10BaO·10PbO glass (PZABP) excited at 980 nm is reported. Pump power dependence, lifetime measurements, and the absorption spectra of the Tm³⁺ ions in the visible to IR region are investigated as a function of sensitizer (Yb³⁺) concentration. Blue light at 475 nm and red l...
Article
Full-text available
The incorporation of nanomaterials that are biocompatible with different types of biological compounds has allowed the development of a new generation of biosensors applied especially in the biomedical field. In particular, the integration of film-based nanomaterials employed in field-effect devices can be interesting to develop biosensors with enh...
Article
Successful fabrication of glass-based hybrid nanocomposites (GHNCs) incorporating Ag, core-shell CdSe/CdS and CdSxSe1-x nanoparticles (NPs) is herein reported. Both metallic (Ag) and semiconductor (CdSe/CdS) NPs were pre-synthesized, suspended in colloids and added into the sol-gel reaction medium which was used to fabricate the GHNCs. During fabri...
Article
CdS quantum dots (QDs) embedded in a phosphate glass matrix were investigated. The time-resolved Z-scan technique was used to determine the nonlinear refraction and absorption for different concentrations of CdS QDs. The results indicate that the nonlinear absorption presents a reverse saturable character, which is a desirable feature in the design...
Article
Full-text available
Iron-doped bismuth sulphide (Bi2-xFe x S₃) nanocrystals have been successfully synthesized in a glass matrix using the fusion method. Transmission electron microscopy images and energy dispersive spectroscopy data clearly show that nanocrystals are formed with an average diameter of 7-9 nm, depending on the thermic treatment time, and contain Fe in...
Article
The OSL characteristics of three different borate glass matrices containing magnesia (LMB), quicklime (LCB) or potassium carbonate (LKB) were examined. Five different formulations for each composition were produced using a melt-quenching method and analyzed in terms of both dose-response curves and OSL shape decay. The samples were irradiated using...
Article
Full-text available
Semiconductor nanocrystal quantum dots have been the subject of extensive investigations in different areas of science and technology in the past years. In particular, there are few studies of magic-sized quantum dots (MSQDs), even though they exhibit features such as extremely small size, fluorescence quantum efficiency, molar absorptivity greater...
Article
Full-text available
Semimagnetic Pb1-xCoxSe nanocrystals were synthesized by a fusion protocol in a glass matrix and characterized by optical absorption (OA), transmission electron microscopy (TEM), and photoluminescence (PL) techniques. OA spectra and TEM images strongly indicated the formation of Pb1-xCoxSe magnetic phases in the glass system and the quantum dot siz...
Article
In this work was investigated the luminescence quantum efficiency, η, of Nd-doped phosphate glasses, as a function of temperature (298–438 K), using the normalized lifetime thermal lens technique. This system presents high quantum efficiency at low Nd3+ concentration and at ambient temperature, 98%. In the temperature interval from 298 to 313 K, η,...
Article
Anthocyanins are the most important natural dye structure, which are contained in the orange-red-blue colors of several plants, fruits, vegetables and roots. Anthocyanins derived from ornamental plants have shown a higher degree of acylation that corresponds to a greater chemical stability. This work presents the absorption and fluorescence spectro...