Glasses with compositions (52.5 - x/2)B2O3:(12.5 - x/2)SiO2:25La2O3:5ZnO:5CaO:0.5Eu2O3:xWO3, x = 0, 2.5, 5, 7.5, 10, 20 (mol%) were prepared by conventional melt-quenching method and investigated by X-ray diffraction analysis, DSC analysis, DR-UV-Vis spectroscopy and photoluminescence spectroscopy. Physical parameters like density, molar volume, oxygen molar volume and oxygen packing density were also determined. Their values, as well as DR-UV-Vis spectroscopy results, indicate that the tungstate ions incorporate into the base borosilicate glass as tetrahedral WO4 and octahedral WO6 groups. With increasing WO3 content over 5 mol%, WO6 units are progressively linked to each other by W-O-W bonds, leading to the formation of a more connected and homogeneous glass network. Glasses are characterized by a high glass transition temperature (over 650 °C) and good thermal stability. The emission intensity of the Eu3+ ion increases with the introduction of WO3 due to the occurrence of non-radiative energy transfer from the tungstate groups to the active ion. The most intense luminescence peak observed at 612 nm suggests that the glasses are potential materials for red emission.

The pure and xDy(3+)-doped SrMoO4 series (x = 0.5, 1.0, 1.5 and 2.0 at.%) were synthesized using a direct mechanochemical route. We found that a milling speed of 850 rpm and a milling time of 30 min result in a complete chemical reaction at different concentrations of dopant ions. The phase formation, structural units, and optical properties of the obtained samples were investigated by XRD, IR, UV-Vis and PL analyses. It has been established that Dy2O3 mainly influences the lattice parameters, unit cell volumes, crystallite sizes, and microstrains. The symmetry of MoO4 groups was investigated using IR spectroscopy, and it showed that pure and Dy3+-doped SrMoO4 samples are built up of deformed structural units. The calculated optical band gap of the obtained crystal phases decreases with increasing concentrations of Dy3+ ions. The host SrMoO4 matrix shows broad blue emission centered at 430 nm under an excitation wavelength of 230 nm. All doped samples display a strong yellow emission at 570 nm, belonging to the F-4(9/2) -> H-6(13/2) transition of Dy3+ ions. The highest luminescence intensity was observed when the concentration of the Dy3+ ion was 0.5 at.%. The mechanism of concentration quenching was mainly caused by the electric dipole-dipole interaction. The calculated CIE chromaticity coordinates of the doped samples fall in the yellow range. This study demonstrates that mechanochemical treatment is an appropriate route for the fast preparation of yellow phosphors.

Eu3+ incorporated barium borate and zinc borate glasses of composition: (35- 0.50x)BaO-(65- 0.50x)B2O3xEu2O3 and (50-0.50x)ZnO-(50-0.50x)B2O3-xEu2O3 (x = 0-5 mol%) were synthesized by the melt quenching in the temperature range: 1200-1400 degrees C. Structural, thermal and optical properties of glasses were studied by X-ray diffraction (XRD), Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Colorimetry (DSC), 11B Magic Angle Spinning (MAS) Nuclear Magnetic Resonance (NMR), Vickers' hardness tests, UV-visible and photoluminescence studies. The density of barium borate and zinc borate glass samples increase from 3.614 to 3.891(+/- 0.005) g center dot cm- 3 and from 3.393 to 3.804(+/- 0.005) g center dot cm-3 respectively, upon increasing Eu2O3 concentration from 1 to 5 mol%. The glass transition temperature of both series increases with increasing Eu2O3 concentration. Raman and FTIR spectra show stretching and bending vibrations of B-O-B linkages in the BO4 and BO3 structural units. The hardness of barium borate and zinc borate glasses are 4.91 (+/- 0.21) and 4.63(+/- 0.18) GPa respectively. The concentration of tetrahedral borons in barium borate and zinc borate glasses are 46(+/- 1) % and 29(+/- 1) % respectively. UV-visible spectra of glasses exhibit absorption bands due to transitions of Eu3+ from the 7F0,1 ground states to the excited states of Eu3+. The emission spectra of the samples containing Eu2O3 were measured at an excitation wavelength of 392 nm. Glasses emit intense red light and quenching of luminescence is observed at 3 and 4 mol% Eu2O3 concentration in barium borate and zinc borate glasses respectively. The emission intensity of barium borate glasses is found to be significantly higher than that of zinc borate glasses.

In this study, the effects of ball milling conditions on the phase formation, symmetry of structural units and photoluminescence features of SrMoO 4 were investigated.

The aim of this study is synthesising nano-sized BaTiO 3 (BTO) particles by pulsed laser ablation (PLA) in water colloid. The BTO target is prepared by initial mechano-chemical treatment of BaCO 3 and rutile powders and further high-temperature solid-state synthesis. The BTO targets are characterized by powder X-ray diffraction (XRD). The PLA processes are carried out by irradiating by a pulsed nanosecond Nd:YAG laser at the wavelength of 266 nm and various laser pulse energies. Several techniques, as XRD, UV-vis absorption spectroscopy (UV-Vis) and scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX) are employed to characterize the particles’ phase composition, optical properties, morphology and size.

Applying the melt quenching method (cooling rate 101–102 K/s), new multicomponent vanadate glasses were synthesized, containing different amounts of MoO3 at the expense of B2O3 with the composition 20Li2O:(30 − x)B2O3:50V2O5:xMoO3, x = 10, 20 mol%. The obtained samples were characterized by X-ray diffraction, infrared spectroscopy, differential scanning calorimetry and impedance spectroscopy. The density of the glasses was measured by the Archimedes method, on the basis of which the physicochemical parameters molar volume, oxygen molar volume and oxygen packing density were calculated. It was found that the replacement of B2O3 with MoO3 leads to changes in electrical conductivity, which are a consequence of the increase in non-bridging oxygen atoms in the amorphous structure. The electrochemical characterization of the 20Li2O:(30 − x)B2O3:50V2O5:20MoO3 glass obtained was performed by assembling an all-solid-state cell, employing 20Li2O:(30 − x)B2O3:50V2O5:20MoO3 glass as a cathode active material. The obtained results show that the studied glass compositions are interesting in view of their potential application as cathode materials in all-solid-state lithium-ion batteries.

Two modifications of ZnMoO4 were successfully obtained by mechanochemical treatment with two milling speeds applied at 500 and 850 rpm. The phase formation was monitored by XRD analysis. The metastable monoclinic ß-ZnMoO4 was directly synthesized at room temperature using the higher milling speed of 850 rpm. The thermodynamically stable triclinic α-ZnMoO4 was obtained by combining heat treatment t 600 °C and ball milling at the lower milling speed of 500 rpm. The IR spectra contain typical vibration bands and confirm the formation of both ZnMoO4 polymorphs. UV-Vis absorption and photoluminescence (PL) spectroscopy are used to study the optical properties of the as-prepared samples. The calculated optical band gaps for α- and ß-ZnMoO4 are 4.09 and 3.02 eV. The photoluminescence emission spectrum of both samples shows peaks with different maximum intensity at 615 and 403 nm for α and ß phase, respectively. CIE co-ordinates are located in the orange and blue range of the color diagram.

This work investigated the optical characteristics of BaWO4 nanoparticles that were produced through direct mechanochemical synthesis at varying speeds and times. This research expands upon our previous study. We demonstrated that the mechanochemical activation of the precursor of BaCO3 and WO3, at elevated milling speeds (850 rpm), facilitates the formation of tetragonal BaWO4 in a reduced reaction time. The final products were characterized by scanning electron microscopy (SEM), as well as Raman, infrared (IR), UV-Vis diffuse reflectance, and photoluminescence spectroscopies. The crystallite sizes and particles shapes were determined by X-ray diffraction and SEM analysis. Round particles with a size below 50 nm formed under different milling conditions. The Raman spectra of the synthesized samples confirmed the presence of a scheelite-type structure with the typical six distinct vibrational peaks. The symmetry of the structural WO4 groups was determined by IR spectroscopy. The absorption spectra of both samples exhibited intensive peaks at 210 nm, and the calculated optical band gaps of BaWO4 were 5.10 eV (3 h/500 rpm) and 5.24 eV (1 h/850 rpm). A strong (400 nm) and weak (465 nm) emission were observed for the BaWO4 that was obtained at a higher milling speed, while wider emission at 410 nm was visible for the BaWO4 that was prepared at a lower milling speed. The CIE coordinates of the mechanochemically synthesized BaWO4 were located within the blue area, exhibiting various positions.

The present paper deals with the synthesis, characterization, and properties of sol-gel-derived TiO2/TeO2/Nb2O5 nanopowders. The gels were prepared using a combination of organic [Ti (IV) n-butoxide, Nb (V) ethoxide (C10H25NbO5)] and inorganic [telluric acid (H6TeO6)] precursors. The aging of gels was performed in air for several days in order to enable further hydrolysis. The phase formation of the gels was investigated by XRD upon heating in the temperature range of 200–700 °C. It was established that the gels heat-treated up to 300 °C exhibited a predominantly amorphous phase in all binary and ternary compositions. The amount of amorphous phase gradually decreased with increasing temperature, and the first TiO2 (anatase) crystals were detected at about 400–500 °C. The average crystallite size of TiO2 (anatase) in the powdered samples heat-treated at 400 °C was about 10 nm. By DTA, it was established that the decomposition of organics is accompanied by strong weight loss occurring in the temperature range of 200–300 °C. The completeness of the hydrolysis-condensation reactions was verified by IR and UV–Vis analyses. The UV–Vis spectra of the as-prepared gels exhibited red shifting of the cut-off. Photoluminescence spectra exhibited a change in intensity with varying temperature and composition. The performed photocatalytic tests showed that all powders possess photocatalytic activity toward Malachite green organic dye. The obtained nanopowders exhibited good antibacterial properties against E. coli ATCC 25922. The obtained samples can be considered as prospective materials for use as environmental catalysts.

In this paper, the crystallization behavior of 52WO3:22B2O3:26La2O3:0.5Eu2O3 glass has been investigated in detail by XRD and TEM analysis. The luminescent properties of the resulting glass-ceramics were also investigated. By XRD and TEM analysis, crystallization of β-La2W2O9 and La2WO6 crystalline phases has been proved. Photoluminescent spectra showed increased emission in the resulting glass-ceramic samples compared to the parent glass sample due to higher asymmetry of Eu3+ ions in the obtained crystalline phases, where the active Eu3+ ions are incorporated. Also, in the glass-ceramics, the crystalline particles are embedded in the amorphous matrix and more of them are separated from each other which improves the light scattering intensity from the free interfaces of the nanocrystallites, resulting in the enhancement of the PL intensity. It was established that the optimum emission intensity is registered for glass-ceramic samples obtained after an 18 h heat treatment of the parent glass. After 21 h of glass crystallization, the amount of crystallite particles is high enough, and they are in close proximity to each other, and hence, the average distance between europium ions decreases, resulting in quenching of Eu3+ and a decrease in the emission intensity. Additionally, at 21 h of glass crystallization, formation of new crystalline phase—La2WO6 is established. A redistribution of Eu3+ ions in the different crystalline compounds is most likely taking place, which is also not favorable for the emission intensity.

Dy3+ single-doped and Dy3+/Eu3+ co-doped ZnO:B2O3:WO3:Nb2O5 glass was successfully synthesized using the melt quenching method. The amorphous character of the prepared samples was confirmed by X-ray diffraction (XRD). The glass transition and crystallization temperatures were examined by differential scanning calorimetry (DSC). Raman spectroscopy was applied to investigate the glass microstructure. Physical properties like the density, molar volume, oxygen molar volume and oxygen packing density of the glass were also determined. The photoluminescence excitation (PLE) and emission (PL) spectra of the resultant glass types were measured. The obtained Dy3+ single-doped glass was characterized by strong luminescence at 482 and 574 nm, corresponding to the 4F9/2 → 6H15/2 (blue) and 4F9/2 → 6H13/2 (yellow) transitions, respectively, and weak luminescence at 663 nm and 753 nm due to the 4F9/2 → 6H11/2 (red) and 4F9/2 → 6H9/2 + 6F11/2 (red) transitions. The luminescence results indicate that energy transfer from the Dy3+ to Eu3+ ions occurs in the proposed glass system. The emitted light from the Dy3+ single-doped glass was found to be yellow-orange. The Dy3+/Eu3+ co-doped samples emitted darker orange light. The obtained results show that the investigated types of glass have the potential to be used as orange light-emitting materials.

Nanocrystalline CoWO4 sampled were synthesized using a simple mechanochemical approach and a solid-state reaction, respectively. The formation of nanocrystalline CoWO4 was characterized by X-ray diffraction (XRD) and infrared spectroscopy (IR). The optical properties of the obtained samples were explored by diffuse reflectance UV–visible (DRS) and photoluminescence (PL) techniques. A milling speed of 850 rpm led to the direct synthesis of monoclinic CoWO4 with a short reaction time (1 h). The complete reaction did not occur in the solid-state synthesis. The obtained samples had monoclinic crystal systems with different lattice parameters. The average crystallite sizes of CoWO4 were in the range of 20 to 180 nm. The TEM investigation showed that the morphology of the CoWO4 particles differed depending on the preparation conditions. The values of the determined optical bandgap of CoWO4 were the range of 1.89 to 2.18 eV, according to diffusion reflectance spectroscopy in the ultraviolet-to-visible range. Broader blue–green emission spectra with peaks at 430 nm were observed for samples prepared via both routes. The CIE color coordinates of the CoWO4 samples lay in the blue and purple regions. The quantum yields of the CoWO4 samples synthesized after 1 h and 5 h milling times at 850 rom were 0.34 and 0.67%, respectively. This study proposes an affordable mechanochemical approach for blue–green phosphors that could possibly be used in various light-emitting diodes (LEDs).

Calcium molybdate (CaMoO4) and Dy3+ doped CaMoO4 (Dy3+=0.5, 1, 1.5, 2 and 2.5 at.%) nanoparticles were successfully obtained by mechanochemical approach. The influence of Dy3+ ion concentration on the structure, morphology, and photoluminescent properties were investigated. The CaMoO4 and Dy3+ doped CaMoO4 phases with tetragonal structure were completely prepared after 30 min milling time with applied milling speed of 850 rpm. TEM analysis shows that the synthesized samples consist of mainly spherical particles with narrow particle size distribution. According to both XRD and TEM analysis, the average particles size is below 40 nm. The UV-vis absorption spectra show one peak at 240-245 nm. The calculated optical band gap of pure CaMoO4 is 3.96 eV and it decreases to 3.65 eV with increasing the concentration of Dy3+ ion up to 2.5 at %. The excitation spectra of the Dy3+-doped CaMoO4 samples contain absorption peaks corresponding to the MoO4 group and to the Dy3+ ion. The green and blue light emissions were observed for pure CaMoO4 and Dy3+ doped CaMoO4 samples under different wavelengths excitation (250 and 350 nm) typical for absorption of the host matrix. Emission spectra of all doped powders consist of the characteristic peaks of Dy3+ in the blue (∼480 nm) and yellow (∼575nm) regions which are assigned to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions, respectively. The weak peak at 660 nm also is observed due to 4F9/2 →6H11/2 transition of Dy3+ ion. The highest photoluminescence emission intensity was detected when the sample is doped with 1.5 at.% Dy3+ concentration. It was found that the color coordinates (x and y) of 1.5 at.% and 2at.% Dy3+-doped CaMoO4 fall close to the white light region in the CIE diagram. The results indicate that the mechanochemically obtained Dy3+ doped CaMoO4 nanoparticles can find application in different optical instruments.

The effect of the addition of Nb2O5 (up to 5 mol%) on the structure and luminescent properties of ZnO-B2O3 glass doped with 0.5 mol% (1.32 × 1022) Eu2O3 was investigated by applying infrared (IR), Raman and photoluminescence (PL) spectroscopy. Through differential thermal analysis and density measurements, various physical properties such as molar volume, oxygen packing density and glass transition temperature were determined. IR and Raman spectra revealed that niobium ions enter into the base zinc borate glass structure as NbO4 tetrahedra and NbO6 octahedra. A strong red emission from the 5D0 level of Eu3+ ions was registered under near UV (392 nm) excitation using the 7F0 → 5L6 transition of Eu3+. The integrated fluorescence intensity ratio R (5D0 → 7F2/5D0 → 7F1) was calculated to estimate the degree of asymmetry around the active ion, suggesting a location of Eu3+ in non-centrosymmetric sites. The higher Eu3+ luminescence emission observed in zinc borate glasses containing 1–5 mol% Nb2O5 compared to the Nb2O5-free zinc borate glass evidences that Nb2O5 is an appropriate component for modifying the host glass structure and improving the emission intensity.

Novel multicomponent glasses with nominal compositions of (50−x)MoO3:xWO3:25La2O3:25B2O3, x = 0, 10, 20, 30, 40, 50 mol% doped with 3 mol % Eu2O3 were prepared using a conventional melt-quenching method. Their structure, thermal behavior and luminescent properties were investigated by Raman spectroscopy, differential thermal analysis and photoluminescence spectroscopy. The optical properties of the glasses were investigated by UV–vis absorption spectroscopy and a determination of the refractive index. Physical parameters such as density, molar volume, oxygen molar volume and oxygen packing density were determined. The glasses are characterized by a high glass transition temperature. Raman analysis revealed that the glass structure is built up mainly from tetrahedral (MoO4)2− and (WO4)2− units providing Raman bands of around 317 cm−1, 341–352 cm−1, 832–820 cm−1 and 928–935 cm−1. At the same time, with the replacement of MoO3 with WO3 some fraction of WO6 octahedra are produced, the number of which increases with the increasing WO3 content. A strong red emission from the 5D0 level of Eu3+ ions was registered under near-UV (397 nm) excitation using the 7F0 → 5L6 transition of Eu3+. Photoluminescence (PL) emission gradually increases with increasing WO3 content, evidencing that WO3 is a more appropriate component than MoO3. The integrated fluorescence intensity ratio R (5D0 → 7F2/5D0 → 7F1) was calculated to estimate the degree of asymmetry around the active ion, suggesting a location of Eu3+ in non-centrosymmetric sites. All findings suggest that the investigated glasses are potential candidates for red light-emitting phosphors.

Glasses with the compositions in mol % of 50ZnO:(50 − x)B2O3:0.5Eu2O3:xWO3, x = 0, 1, 3, 5 and 10 were obtained by applying the melt-quenching method and investigated by Raman spectroscopy, DSC analysis and photoluminescence (PL) spectroscopy. Raman spectra revealed that tungstate ions incorporate into the base zinc borate glass as tetrahedral [WO4]2− groups, and octahedral [WØ4O2]2− species with four bridging and two non-bridging oxygen atoms. There are also metaborate, [BØ2O]− and pyroborate units, [B2O5]4−, in the glass networks. The glasses are characterized by good transmission in the visible region, at about 80%. Photoluminescence (PL) spectra evidenced that WO3 is an appropriate constituent for the modification of zinc borate glass structure and for enhancing the Eu3+ luminescent intensity. The most intense luminescence peak observed, at 612 nm, suggests that the glasses are potential materials for red emission.

The current study aims to synthesize and analyze both pure and La-doped TiO2, and evaluate the photocatalytic and antibacterial activity of as-prepared samples. Doped and undoped samples were prepared by the non-hydrolytic sol–gel method from titanium(IV) chloride, benzyl alcohol, and lanthanum(III) nitrate followed by thermal treatment. Lanthanum content in synthesized samples was 0.4, 1, and 5 mol%. The resulting nanopowders’ structure and morphology were described using XRD, IR, and UV–Vis analysis. The average particle sizes of pure and doped TiO2 were about 6–15 nm and anatase was found to be a dominant crystalline phase in the samples. It was observed that particle sizes decreased on increasing La content. The photocatalytic activity of the pure and La-doped sol–gel powders was estimated in the decomposition of paracetamol in distilled water using ultraviolet light illumination. Doping with lanthanum ions has been shown to increase the photocatalytic properties on the degradation of paracetamol. Furthermore, the annealed catalysts (pure and La3+ doped) showed increased photocatalytic activity and degradation of the analgesic in comparison with non-annealed materials. In both cases, the highest photocatalytic efficiency is observed at the optimal La3+ (1 mol%) concentration. The antimicrobial activity of 1 mol% La/TiO2 was tested against a reference strain E. coli in the presence of ultraviolet light and in dark conditions. The number of viable bacterial cells was determined by a spread plate method, and kill curves were performed. The results showed that photoactivated 1 mol% La/TiO2 exhibited a strong bactericidal effect, and in concentration, 1 mg/mL efficiently killed bacteria at an initial cell density of about 105 colony forming units in 1 mL within 15 min.

In this study, pure TiO2 gels were synthesized by applying the sol–gel method, using Ti(IV) butoxide with the addition of two different solvents, namely ethylene glycol (EG) and isopropanol (isop), with only air moisture present. It was established using XRD that the gel prepared with the addition of EG was amorphous even at 400 °C, while the other gel was amorphous up to 300 °C. It was found that TiO2 (anatase) had a dominant crystalline phase during heating to 600 °C, while at 700 °C, TiO2 (rutile) appeared. The as-obtained powdered materials were annealed at 500 °C and subsequently underwent photocatalytic tests with paracetamol. Additionally, the TiO2 samples were modified with Ag+ co-catalysts (10−2 M), using photofixation by UV illumination. The photocatalytic activity of the Ag-modified powders was also tested in the photodegradation of a commonly used paracetamol in aqueous solution under UV light illumination. The obtained data exhibited that the annealed samples had better photocatalytic efficiency and decomposed paracetamol faster in comparison to the non-annealed sol–gel powders. The highest degradation efficiency was observed for the TBT/isop/Ag material, with degradation efficiencies average values of 65.59% and 75.61% paracetamol achieved after the third cycle of photocatalytic treatment. The co-catalytically modified powders had higher photocatalytic efficiency in comparison to the pure nanosized powders. Moreover, the sol–gel powders of TBT/EG, TBT/EG/Ag (10−2 M), TBT/isop, and TBT/isop/Ag (10−2 M) demonstrated the ability to retain their photocatalytic activity even after three cycles of use, suggesting that they could find practical use in the treatment of pharmaceutical wastewater. The observed photocatalytic efficiency and positive impact of silver make the prepared powders a desirable choice for pharmaceutical drug degradation, helping to promote environmentally friendly and effective wastewater treatment technology.

TiO2 based powders containing B2O3 and Nb2O5 were obtained through an aqueous sol-gel method. The as prepared gels were step wisely heated in the temperature range 200°C - 500°C and subsequently characterized by XRD, IR and UV-Vis analysis. The TiO2 (anatase) is the single crystalline phase which has been detected up to 500°C. Photocatalytic tests showed that the investigated samples possess photocatalytic activity toward Malachite green organic dye and TiO2/Nb2O5 exhibited higher photocatalytic activity than TiO2/B2O3 sample. The compositions exhibited good antimicrobial activity against E. coli NBIMCC K12 407 and Bacillus subtilis NBIMCC 3562.

This work demonstrates that ultrashort laser ablation of Eu3+-doped glass results in the formation of nanoparticles manifesting the same luminescence properties as the native bulk material. The initial glass is 50ZnO-40B(2)O(3)-5WO(3)-5Nb(2)O(5) (mol %) doped with Eu ions. A laser emitting pulses with 75-fs duration at the wavelength of 800 nm is used to ablate the material with the ejected species collected on a substrate in a standard pulsed-laser deposition scheme in air at atmospheric pressure. The deposited material consists of nanoparticles with a size distribution in the range from a few nanometers to several tens on nanometers with the most probable value being about 11 nm. The analyses performed indicate that it is in amorphous phase with the domination of the Eu3+ state preserved as in the bulk. The ablation of the glass causes a reduction of the W and Nb oxidation states in comparison to the initial glass, as well as to an increase of the nonbridging oxygen amount.