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1.
Int J Biol Macromol ; 272(Pt 2): 132883, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38838898

ABSTRACT

Glycyrrhiza glabra extract is widely known for its antioxidant and anti-inflammatory properties and can improve the wound healing process. The aim of this work was to shorten the time of the healing process by using an eco-sustainable wound dressing based on Spanish broom flexible cellulosic fabric by impregnation with G. glabra extract-loaded ethosomes. Chemical analysis of G. glabra extract was performed by LC-DAD-MS/MS and its encapsulation into ethosomes was obtained using the ethanol injection method. Lipid vesicles were characterized in terms of size, polydispersity index, entrapment efficiency, zeta potential, and stability. In vitro release studies, biocompatibility, and scratch test on 3T3 fibroblasts were performed. Moreover, the structure of Spanish broom dressing and its ability to absorb wound exudate was characterized by Synchrotron X-ray phase contrast microtomography (SR-PCmicroCT). Ethosomes showed a good entrapment efficiency, nanometric size, good stability over time and a slow release of polyphenols compared to the free extract, and were not cytotoxic. Lastly, the results revealed that Spanish broom wound dressing loaded with G. glabra ethosomes is able to accelerate wound closure by reducing wound healing time. To sum up, Spanish broom wound dressing could be a potential new green tool for biomedical applications.


Subject(s)
Bandages , Cellulose , Glycyrrhiza , Plant Extracts , Spartium , Wound Healing , Animals , Mice , Glycyrrhiza/chemistry , Plant Extracts/chemistry , Plant Extracts/pharmacology , Wound Healing/drug effects , Cellulose/chemistry , Cellulose/pharmacology , Spartium/chemistry , 3T3 Cells
2.
Inorg Chem ; 62(31): 12392-12402, 2023 Aug 07.
Article in English | MEDLINE | ID: mdl-37478498

ABSTRACT

The influence of manganese modification on the spectroscopic features of manganese-doped CeO2 systems synthesized by the microwave-assisted hydrothermal route and their correlation with the presence of O defective structures were verified, focusing on their interaction with poisonous atmospheres. Raman and electron paramagnetic resonance studies confirmed the presence of defective clusters formed by dipoles and/or quadrupoles. The number of paramagnetic species was found to be inversely proportional to the doping concentration, resulting in an increase in the Mn2+ signal, likely due to the reduction of Mn3+ species after the interaction with CO. X-ray photoelectron spectroscopy data showed the pure system with 33% of its cerium species in the Ce3+ configuration, with an abrupt decrease to 19%, after the first modification with Mn, suggesting that 14% of the Ce3+ species are donating one electron to the Mn2+ ions, thus becoming nonparamagnetic Ce4+ species. On the contrary, 58% of the manganese species remain in the Mn2+ configuration with five unpaired electrons, corroborating the paramagnetic feature of the samples seen in the electron paramagnetic resonance study.

3.
Front Rehabil Sci ; 4: 1110552, 2023.
Article in English | MEDLINE | ID: mdl-36873816

ABSTRACT

Introduction: Children with Cerebral Palsy (CP) functioning at Gross Motor Function Classification System (GMFCS) levels IV and V require "on time" identification and intervention. Interventions offered continue to be a challenge, in high-, but even more so in middle-, and low-income countries. Aim: To describe the methods developed to explore the ingredients of published studies on early interventions in young children with cerebral palsy (CP) at highest risk of being non-ambulant based on the "F-words for child development framework" and the design of a scoping review exploring these ingredients. Method: An operational procedure was developed through expert panels to identify ingredients of published interventions and related F-words. After sufficient agreement among researchers was reached, a scoping review was designed. The review is registered in the Open Science Framework database. The "Population, Concept and Context" framework was used. Population: young children (0-5 years with CP and at highest risk for being non-ambulant (GMFCS levels IV or V); Concept: non-surgical and non-pharmacological early intervention services measuring outcomes from any ICF domain; Context: studies published from 2001 to 2021. After duplicated screening and selection, data will be extracted and quality will be assessed with the American Academy for Cerebral Palsy and Developmental Medicine (AACPDM) and Mixed Methods Appraisal (MMAT) tools. Results: We present the protocol to identify the explicit (directly measured outcomes and respective ICF domains) and implicit (intervention features not explicitly intended or measured) ingredients. Conclusion: Findings will support the implementation of the F-words in interventions for young children with non-ambulant CP.

4.
Nanoscale ; 15(5): 2223-2233, 2023 Feb 02.
Article in English | MEDLINE | ID: mdl-36625389

ABSTRACT

Two-dimensional (2D) van der Waals (vdW) ferromagnetic metals FexGeTe2 with x = 3-5 have raised significant interest in the scientific community. Fe5GeTe2 shows prospects for spintronic applications since the Curie temperature Tc has been reported near or higher than 300 K. In the present work, epitaxial Fe5-δGeTe2 (FGT) heterostructures were grown by Molecular Beam Epitaxy (MBE) on insulating crystalline substrates. The FGT films were combined with Bi2Te3 topological insulator (TI) aiming to investigate the possible beneficial effect of the TI on the magnetic properties of FGT. FGT/Bi2Te3 films were compared to FGT capped only with AlOx to prevent oxidation. SQUID and MOKE measurements revealed that the growth of Bi2Te3 TI on FGT films significantly enhances the saturation magnetization of FGT as well as the Tc well above room temperature (RT) reaching record values of 570 K. First-principles calculations predict a shift of the Fermi level and an associated enhancement of the majority spin (primarily) as well as the total density of states at the Fermi level suggesting that effective doping of FGT from Bi2Te3 could explain the enhancement of ferromagnetism in FGT. It is also predicted that strain induced stabilization of a high magnetic moment phase in FGT/Bi2Te3 could be an alternative explanation of magnetization and Tc enhancement. Ferromagnetic resonance measurements evidence an enhanced broadening in the FGT/Bi2Te3 heterostructure when compared to FGT. We obtain a large spin mixing conductance of g↑↓eff = 4.4 × 1020 m-2, which demonstrates the great potential of FGT/Bi2Te3 systems for spin-charge conversion applications at room temperature.

5.
Disabil Rehabil ; 45(2): 376-390, 2023 01.
Article in English | MEDLINE | ID: mdl-35188861

ABSTRACT

PURPOSE: This review aims to identify the barriers and facilitators to knowledge use and Knowledge Translation (KT) strategies in rehabilitation in low, lower-middle, and upper-middle-income countries (LMICs). MATERIALS AND METHODS: A scoping review of studies of KT in rehabilitation in LMICs contexts using the Arksey and O'Malley Framework was conducted. A comprehensive search of MEDLINE and 10 other databases was undertaken to identify studies conducted primarily in LMICs. RESULTS: From the initial 15.606 titles identified; 27 articles were included for final analysis. Our analysis identified the following themes: Professional culture and context; KT interventions; and the conceptualization and application of KT and Evidence Based Practice (EBP). Individual-level barriers to KT included lack of skills, knowledge about EBP and English language, lack of motivation, and decision-making power. Facilitators to KT included positive attitudes and motivation. Organization-level barriers included lack of time, lack of financial resources, limited access to scientific journals, and applicability of research to rural settings. Facilitators included adequate financial and physical resources, a supportive management environment, and the existence of training and continuing education programs. CONCLUSION: This review identified common and unique barriers and facilitators to KT in LMICs when compared to KT studies conducted in high-income settings.IMPLICATIONS FOR REHABILITATIONKnowledge Translation from academic institutions to rehabilitation clinical practice in low and upper-middle-income countries is important to support evidence-based practice and patient outcomes.Barriers at the individual level include professionals' ability to understand English and knowledge of the evidence-based practice.Organization-level barriers included lack of time to access and implement new practices, lack of financial and personal resources, limited access to scientific journals, and applicability of research to rural settings.Training and continuing education programs are needed to support rehabilitation professionals' efforts to achieve the application of evidence-based practice in clinical practice.


Subject(s)
Developing Countries , Translational Science, Biomedical , Humans
6.
Dalton Trans ; 51(46): 17700-17710, 2022 Nov 29.
Article in English | MEDLINE | ID: mdl-36345782

ABSTRACT

This study consists of the synthesis of zinc-doped Bi2WO6 obtained by the sonochemical method. The XRD results indicated that the samples showed an orthorhombic phase with the P21ab space group without the presence of secondary phases, demonstrating success in the doping process. The results of the photocatalytic tests under the photodegradation of methylene blue showed better performance for the pure sample with 80% degradation during 2 hours of exposure to radiation. The high rate of photogenerated charges accompanied by the low recombination rate of the pairs and e-/h+ were responsible for forming hydroxyl radicals, the predominant oxidative agent of the mechanism. The increase in Zn2+ concentration in the Bi2WO6 matrix promoted inhibition of the photocatalytic properties by the appearance of oxygen vacancies that acted as a charge recombination center. In contrast, photoluminescence was improved by doping with Zn2+. The Bi2WO6:8% Zn2+ sample showed the highest PL intensity. The characteristics of the emitted colors are modulated from the emission spectra and are quantified in terms of the photometric parameters: chromaticity coordinates (x, y), color reproduction index (CRI), luminous radiation efficiency (LER), and purity of color (%) of samples. The adjustment in the colors is promoted as a function of the increase in the Zn2+ concentration observing the transition from: yellow → orange → green. PL is favored by the effect of the dopant (Zn2+) in the matrix, which allows Bi2WO6:Zn2+ to be considered a promising candidate for applications in optical devices. In addition, Bi2WO6 constitutes a high performance photocatalyst for the degradation of methylene blue.

7.
Dalton Trans ; 51(46): 17919, 2022 Nov 29.
Article in English | MEDLINE | ID: mdl-36377748

ABSTRACT

Correction for 'Synthesis and evaluation of photocatalytic and photoluminescent properties of Zn2+-doped Bi2WO6' by L. X. Lovisa, et al., Dalton Trans., 2022, https://doi.org/10.1039/d2dt03175b.

8.
Sci Rep ; 12(1): 3891, 2022 Mar 10.
Article in English | MEDLINE | ID: mdl-35273194

ABSTRACT

Recently, the topological insulators (TIs) antimony telluride (Sb2Te3) and bismuth telluride (Bi2Te3) are attracting high interest for applications based on spin-charge interconversion mechanisms. Aiming to make a step toward the technology transfer, it is of major importance to achieve and investigate epitaxial quality-TIs on large area Si-based substrates. In view of that, we report here magnetotransport and angle-resolved photoemission spectroscopy (ARPES) studies on Sb2Te3 and Bi2Te3 thin films grown by metal organic chemical vapor deposition (MOCVD) on top of 4″ Si(111) substrates. Clear weak antilocalization (WAL) effects are observed in both TIs, proving the existence of quantum transport mechanism, and the data are successfully interpreted in the framework of the Hikami-Larkin-Nagaoka model. Further, by dedicated magnetotransport experiments, it has been confirmed that the investigated WAL originates from two-dimensional (2D) topological states. ARPES has been performed ex-situ, and in both TIs the gapless Dirac cones have been observed and attributed to the topological surface states. Combining the proofs of the existence of quantum 2D transport as deduced from the analysis of the magnetoconductance curve with the direct observation of the Dirac-like band structure revealed by the ARPES spectra, it is possible to unambiguously confirm the topological nature of our Sb2Te3 and Bi2Te3 thin films. The results obtained on thin films grown by MOCVD on 4'' Si(111) substrate mark an important step towards the technology transfer of the topological insulators studied in this work.

9.
Sci Rep ; 12(1): 3341, 2022 02 28.
Article in English | MEDLINE | ID: mdl-35228568

ABSTRACT

This study reports the synthesis of hybrid nanostructures composed of cerium dioxide and microcrystalline cellulose prepared by the microwave-assisted hydrothermal route under distinct temperature and pH values. Their structural, morphological and spectroscopic behaviors were investigated by X-Rays Diffraction, Field Emission Gun Scanning Electron Microscopy, High-Resolution Transmission Electron Microscopy, and Fourier-Transform Infrared, Ultraviolet-Visible, Raman and Positron Annihilation Lifetime spectroscopies to evaluate the presence of structural defects and their correlation with the underlying mechanism regarding the biocide activity of the studied material. The samples showed mean crystallite sizes around 10 nm, characterizing the formation of quantum dots unevenly distributed along the cellulose surface with a certain agglomeration degree. The samples presented the characteristic Ce-O vibration close to 450 cm-1 and a second-order mode around 1050 cm-1, which is indicative of distribution of localized energetic levels originated from defective species, essential in the scavenging of reactive oxygen species. Positron spectroscopic studies showed first and second lifetime components ranging between 202-223 ps and 360-373 ps, respectively, revealing the presence of two distinct defective oxygen species, in addition to an increment in the concentration of Ce3+-oxygen vacancy associates as a function of temperature. Therefore, we have successfully synthesized hybrid nanoceria structures with potential multifunctional therapeutic properties to be further evaluated against the COVID-19.


Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/chemical synthesis , COVID-19 Drug Treatment , Cerium/chemistry , Nanostructures/chemistry , SARS-CoV-2/chemistry , Antiviral Agents/therapeutic use , Humans
11.
Radiol Bras ; 54(2): 123-129, 2021.
Article in English | MEDLINE | ID: mdl-33854267

ABSTRACT

Placental magnetic resonance imaging (MRI) has been increasingly requested, especially for the evaluation of suspected cases of placental adhesive disorders, generally known as placenta accreta. Abdominal radiologists need to become familiar with normal placental anatomy, anatomical variations, the current terminology, and major placental diseases that, although rare, are important causes of maternal and fetal morbidity and mortality. The aim of this didactic pictorial essay is to illustrate various findings on placental MRI, as well as to emphasize the importance of communication between radiologists and obstetricians in the search for best practices in the management of the affected patients.


A ressonância magnética placentária tem sido cada vez mais solicitada, sobretudo na avaliação de casos suspeitos de acretismo. Os radiologistas abdominais precisam se familiarizar com a anatomia placentária normal, variações anatômicas, terminologias atuais e principais doenças placentárias que, embora raras, são causas importantes de morbimortalidade materno-fetal. O objetivo deste ensaio é ilustrar, de maneira didática, diferentes achados placentários e enfatizar a importância da comunicação entre radiologistas e obstetras na busca da melhor conduta para as pacientes.

12.
Radiol. bras ; 54(2): 123-129, Jan.-Apr. 2021. tab, graf
Article in English | LILACS-Express | LILACS | ID: biblio-1155242

ABSTRACT

Abstract Placental magnetic resonance imaging (MRI) has been increasingly requested, especially for the evaluation of suspected cases of placental adhesive disorders, generally known as placenta accreta. Abdominal radiologists need to become familiar with normal placental anatomy, anatomical variations, the current terminology, and major placental diseases that, although rare, are important causes of maternal and fetal morbidity and mortality. The aim of this didactic pictorial essay is to illustrate various findings on placental MRI, as well as to emphasize the importance of communication between radiologists and obstetricians in the search for best practices in the management of the affected patients.


Resumo A ressonância magnética placentária tem sido cada vez mais solicitada, sobretudo na avaliação de casos suspeitos de acretismo. Os radiologistas abdominais precisam se familiarizar com a anatomia placentária normal, variações anatômicas, terminologias atuais e principais doenças placentárias que, embora raras, são causas importantes de morbimortalidade materno-fetal. O objetivo deste ensaio é ilustrar, de maneira didática, diferentes achados placentários e enfatizar a importância da comunicação entre radiologistas e obstetras na busca da melhor conduta para as pacientes.

13.
Phys Chem Chem Phys ; 22(44): 25876-25891, 2020 Nov 18.
Article in English | MEDLINE | ID: mdl-33156308

ABSTRACT

In this work PbMoO4 and Pb1-2xCaxSrxMoO4 (x = 0.1, 0.2, 0.3, 0.4 and 0.5) solid solutions have been successfully prepared, for the first time, by a simple co-precipitation method and the as-synthesized samples were subjected to a water-based reflux treatment. Structural characterization of these samples was performed using X-ray diffraction with Rietveld refinement analysis and Raman spectroscopy. Their optical properties were investigated by UV-Vis absorption spectroscopy and PL emissions, and the photocatalytic activity of the as-synthesized samples for the degradation process of Rhodamine B has been demonstrated. The surface structure and morphologies were characterized by field emission scanning electron microscopy. To complement and rationalize the experimental results, the geometry, electronic structures, and morphologies of as-synthesized samples were characterized by first-principles quantum-mechanical calculations at the density functional theory level. By using Wulff construction, based on the values of the surface energies for the (001), (100), (110), (111), (011) and (112) surfaces, a complete map of the available morphologies for PbMoO4 was obtained and a good agreement between the experimental and theoretical predicted morphologies was found. The structural and electronic changes induced by the substitution of Pb by Ca and Sr allow us to find a relationship among morphology, the electron-transfer process at the exposed surfaces, optical properties, and photocatalytic activity. We believe that our results offer new insights regarding the local coordination of superficial Pb/Ca/Sr and Mo cations (i.e., clusters) on each exposed surface of the corresponding morphology, which dictate the photocatalytic activities of the as-synthesized samples, a field that has so far remained unexplored. The present study, which combines multiple experimental methods and first-principles calculations, provides a deep understanding of the local structures, bonding, morphologies, band gaps, and electronic and optical properties, and opens the door to exploit the electrical, optical and photocatalytic activity of this very promising family of materials.

14.
Biomed Opt Express ; 11(10): 5506-5517, 2020 Oct 01.
Article in English | MEDLINE | ID: mdl-33149967

ABSTRACT

Thanks to its non-invasive nature, X-ray phase contrast tomography is a very versatile imaging tool for biomedical studies. In contrast, histology is a well-established method, though having its limitations: it requires extensive sample preparation and it is quite time consuming. Therefore, the development of nano-imaging techniques for studying anatomic details at the cellular level is gaining more and more importance. In this article, full field transmission X-ray nanotomography is used in combination with Zernike phase contrast to image millimeter sized unstained tissue samples at high spatial resolution. The regions of interest (ROI) scans of different tissues were obtained from mouse kidney, spleen and mammalian carcinoma. Thanks to the relatively large field of view and effective pixel sizes down to 36 nm, this 3D approach enabled the visualization of the specific morphology of each tissue type without staining or complex sample preparation. As a proof of concept technique, we show that the high-quality images even permitted the 3D segmentation of multiple structures down to a sub-cellular level. Using stitching techniques, volumes larger than the field of view are accessible. This method can lead to a deeper understanding of the organs' nano-anatomy, filling the resolution gap between histology and transmission electron microscopy.

15.
Sci Rep ; 9(1): 9927, 2019 07 09.
Article in English | MEDLINE | ID: mdl-31289314

ABSTRACT

The ability to manipulate the structure and function of promising systems via external stimuli is emerging with the development of reconfigurable and programmable multifunctional materials. Increasing antifungal and antitumor activity requires novel, effective treatments to be diligently sought. In this work, the synthesis, characterization, and in vitro biological screening of pure α-Ag2WO4, irradiated with electrons and with non-focused and focused femtosecond laser beams are reported. We demonstrate, for the first time, that Ag nanoparticles/α-Ag2WO4 composite displays potent antifungal and antitumor activity. This composite had an extreme low inhibition concentration against Candida albicans, cause the modulation of α-Ag2WO4 perform the fungicidal activity more efficient. For tumor activity, it was found that the composite showed a high selectivity against the cancer cells (MB49), thus depleting the populations of cancer cells by necrosis and apoptosis, without the healthy cells (BALB/3T3) being affected.


Subject(s)
Antifungal Agents/pharmacology , Antineoplastic Agents/pharmacology , Candida albicans/drug effects , Electrons , Metal Nanoparticles/chemistry , Oxides/chemistry , Silver/chemistry , Tungsten/chemistry , Urinary Bladder Neoplasms/drug therapy , Animals , Apoptosis , BALB 3T3 Cells , Cell Proliferation , Humans , Metal Nanoparticles/administration & dosage , Metal Nanoparticles/radiation effects , Mice , Oxides/radiation effects , Silver/radiation effects , Tumor Cells, Cultured , Tungsten/radiation effects , Urinary Bladder Neoplasms/pathology , Xenograft Model Antitumor Assays
16.
Ultrason Sonochem ; 56: 14-24, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31101248

ABSTRACT

In the present work, Sr0.9-x-y-zCa0.1In2O4:(xEu3+, yTm3+, zTb3+) particles were synthesized by the ultrasonic spray pyrolysis (USP) method to obtain a single-phase white phosphorus formed by six different cations in solution within the lattice (superstructure). The samples were also structurally and morphologically characterized by X-ray diffraction (XRD) techniques and by field emission scanning electron microscopy (FE-SEM). The photoluminescent behavior and the characteristics of the emitted colors were studied by the variation in the co-doping of the rare earth elements. The Sr0.9Ca0.1In2O4 sample showed a near blue color emission, but all co-doped samples showed emission in white with very close chromaticity coordinates to the standard white (x = 0.33 and y = 0.33). The Tm3+ → Tb3+ (ET1), Tm3+ → Eu3+ (ET2) and Tb3+ → Eu3+ (ET3) Energy Transfers were proposed and are considered necessary for adjusting and controlling the desired color properties.

17.
Phys Chem Chem Phys ; 20(45): 28382-28392, 2018 Nov 21.
Article in English | MEDLINE | ID: mdl-30177981

ABSTRACT

In order to achieve deep insight into the multiferroic behavior and electronic properties of intrinsic oxygen vacancies in ATiO3 (A = Mn, Fe, Ni), first-principles calculations based on hybrid density functional theory were carried out for bulk and non-polar (110) surface models. We found that the formation of an oxygen vacancy is accompanied by structural and electronic disorders in the constituent clusters of [TiO6] and [AO6] in ATiO3, that become [TiO5] and [AO5], respectively. This perturbation contributes to the generation of intermediary energy levels in the band gap region, thus narrowing the required excitation energy. In addition, the remaining electrons are mainly trapped in the empty 3d orbitals of the Ti cations neighboring the oxygen vacancy, generating [TiO5]' (3d1) that mediates an antiferromagnetic to ferromagnetic transition in MnTiO3 and FeTiO3 materials. In particular, MnTiO3 surfaces show exposed [TiO4]' species that are responsible for its half-metallic behavior. The present work provides compelling evidence that controlling oxygen vacancies can be a valuable strategy to tailor the multiferroic properties of ATiO3 materials.

18.
Phys Chem Chem Phys ; 20(3): 1923-1937, 2018 Jan 17.
Article in English | MEDLINE | ID: mdl-29297523

ABSTRACT

The present joint experimental and theoretical work provides in-depth understanding on the morphology and structural, electronic, and optical properties of ZnWO4 nanocrystals. Monoclinic ZnWO4 nanocrystals were prepared at three different temperatures (140, 150, and 160 °C) by a microwave hydrothermal method. Then, the samples were investigated by X-ray diffraction with Rietveld refinement analysis, field-emission scanning electron microscopy, transmission electronic microscopy, micro-Raman and Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and photoluminescence measurements. First-principles theoretical calculations within the framework of density functional theory were employed to provide information at the atomic level. The band structure diagram, density of states, Raman and infrared spectra were calculated to understand the effect of structural order-disorder on the properties of ZnWO4. The effects of the synthesis temperature on the above properties were rationalized. The band structure revealed direct allowed transitions between the VB and CB and the experimental results in the ultraviolet-visible region were consistent with the theoretical results. Moreover, the surface calculations allowed the association of the surface energy stabilization with the temperature used in the synthesis of the ZnWO4 nanocrystals. The photoluminescence properties of the ZnWO4 nanocrystals prepared at 140, 150, and 160 °C were attributed to oxygen vacancies in the [WO6] and [ZnO6] clusters, causing a red shift of the spectra. The ZnWO4 nanocrystals obtained at 160 °C exhibited excellent photodegradation of Rhodamine under ultraviolet light irradiation, which was found to be related to the surface energy and the types of clusters formed on the surface of the catalyst.

19.
Data Brief ; 14: 41-47, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28765830

ABSTRACT

This data article presents the results from quality control experiments including N-terminal sequencing, SEC-MALS and Mass Spectrometry for purified VanSA used in experiments described in (Hughes et al., 2017) [1]; in addition to ligand interaction measurements and thermal melting curves of VanSA in the presence of screened ligands from circular dichroism measurements as well as UV-vis absorbance spectra for the binding interaction of VanSA in the presence of screened ligands.

20.
Ultrason Sonochem ; 38: 256-270, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28633825

ABSTRACT

Copper tungstate (CuWO4) crystals were synthesized by the sonochemistry (SC) method, and then, heat treated in a conventional furnace at different temperatures for 1h. The structural evolution, growth mechanism and photoluminescence (PL) properties of these crystals were thoroughly investigated. X-ray diffraction patterns, micro-Raman spectra and Fourier transformed infrared spectra indicated that crystals heat treated and 100°C and 200°C have water molecules in their lattice (copper tungstate dihydrate (CuWO4·2H2O) with monoclinic structure), when the crystals are calcinated at 300°C have the presence of two phase (CuWO4·2H2O and CuWO4), while the others heat treated at 400°C and 500°C have a single CuWO4 triclinic structure. Field emission scanning electron microscopy revealed a change in the morphological features of these crystals with the increase of the heat treatment temperature. Transmission electron microscopy (TEM), high resolution-TEM images and selected area electron diffraction were employed to examine the shape, size and structure of these crystals. Ultraviolet-Visible spectra evidenced a decrease of band gap values with the increase of the temperature, which were correlated with the reduction of intermediary energy levels within the band gap. The intense photoluminescence (PL) emission was detected for the sample heat treat at 300°C for 1h, which have a mixture of CuWO4·2H2O and CuWO4 phases. Therefore, there is a synergic effect between the intermediary energy levels arising from these two phases during the electronic transitions responsible for PL emissions.

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