Ag and Si Codoped Phosphate Glasses: Plasmonic Nanocomposites with Enhanced UV Transparency

The use of silicon powder to produce plasmonic Ag nanocomposite phosphate glasses which also exhibit improved transparency in the ultraviolet (UV) is proposed. Ag₂O/Si codoped glasses were prepared in a barium‐phosphate matrix by a simple melt‐quench method in ambient atmosphere. The as‐prepared glasses exhibit enhanced UV transparency, whereby the surface plasmon resonance of Ag nanoparticles (NPs) is manifested for the glasses with higher Ag₂O contents. ³¹P nuclear magnetic resonance spectroscopy is consistent with the formation of P–O–Si bonds, thus suggesting their possible role on the improved UV light transmission. Consequently, a model was presented accounting for the influence of silicon on the polymerization of the phosphate network concomitant with the creation of highly reactive oxygen species. Further exploiting the proposed reactive species, a real‐time spectroscopic study of the plasmonic response of Ag NPs in Ag/Si codoped glass samples was carried out during an in situ thermal processing. The temperature dependence of the Ag particle precipitation was studied in the 400°C–430°C range, from which an Arrhenius‐type plot allowed for estimating the activation energy of the process at 3.42 (±0.38) eV. Ultimately, the vanishing of the luminescence ascribed to Ag⁺ ions was observed in a heat‐treated sample, consistent with the high reactivity acquired by the glass matrix. Silicon thus appears promising for producing UV transparent glasses for high‐performance optics and for the reduction of Ag⁺ ions to produce Ag nanocomposites valuable for photonic (nanoplasmonic) applications.     

A novel B2O3-Na2O-BaO-HgO glass system: Synthesis,physical, optical and nuclear shielding features

In the current paper, we investigated the impacts of HgO addition on optical, structural and radiation shielding properties of newly developed BNBH glass system, with nominal composition (60-x)B₂O₃+20Na₂O+20BaO + xHgO, where x = 0, 2.5, 5, 7.5, 10, 12.5 and 15. BNBH glasses were produced by traditional melt quenching technique. The structure of the produced glasses was estimated employing XRD and TEM analyses and their amorphous natures were verified. The material densities of the investigated glass samples increased nearly linearly as the HgO concentration increased. The UV–visible absorption spectra of the HgO doped glasses were obtained and it is noticed that the absorption coefficient varies with the increase of HgO concentration. The optical absorption spectra were also utilized to found optical energy band gaps, refraction indices and Urbach's tail energy of the prepared glasses. It was observed that the E_g decrease with the increase of HgO content. Moreover, nuclear radiation shielding parameters of BNBH glasses with HgO additive were obtained for photons, charged particles, and neutrons. It was perceived that the insertion of HgO was improved the protecting competences of the glasses against several nuclear radiation types. The results of this comprehensive study revealed that HgO can be used in the design of new glass systems for shielding studies.     

Gamma and neutron shielding characterizations of the Ag2O–V2O5–MoO3–TeO2 quaternary tellurite glass system with the Geant4 simulation toolkit and Phy-X software

Gamma and neutron shielding potential of the newly developed xAg₂O-(35-x)[0.5V₂O₅-0.5MoO₃]-65TeO₂ (x = 0, 5, 10, 15, 20 and 25 mol%) quaternary tellurite glass system were investigated computationally by means of Geant4 Monte Carlo simulations and Phy-X software. Gamma ray shielding capabilities were studied via the mass attenuation coefficient (μ_m), transmission fractions (T), effective atomic number (Z_eff), half value layer (HVL) and mean free path (MFP) parameters and for the photon energies of 0.284, 0.356, 0.511, 0.662, 1.173 and 1.330 MeV. Fast neutron removal cross-section (∑_R) parameter of the glasses was calculated to assess the neutron shielding capabilities. The results of this study revealed that tellurite glass containing 25% moles of Ag₂O has highest μ_m and Z_eff and lowest T, HVL and MFP values due to the high atomic number of Ag. In this study it was also seen that the ∑_R of the investigated glass system increases with the increase of Ag₂O fraction and ∑_R values of the studied glasses are higher than barite added concrete and close to the ∑_R of the PbO added borate glasses.     

The role of cadmium oxides in the enhancement of radiation shielding capacities for alkali borate glasses

The radiation shielding capacity of 80B₂O₃–(20-x) Na₂O–x CdO (where x = 0, 2, 4, 6, 8, 10, 12 and 14 mol%) cadmium-doped sodium borate glasses was evaluated. The linear attenuation coefficient (LAC) of the studied glasses was simulated using the Monte Carlo simulation code (MCNP-5) for gamma photons with energy between 0.01 and 15 MeV. Other pivotal gamma ray shielding parameters such as mass attenuation coefficient (MAC), half value layer (HVL), effective atomic number (Z_eff), and buildup factors (EBF and EABF) for the selected cadmium-doped sodium borate glasses were examined. The achieved data showed that, BNC 8 glass with CdO contents of 14 mol % possesses the highest LAC and varied between 0.0650 and 83.636 cm^-1 and also it has thinner HVL than other BNC glasses and varied between 0.008 and 10.686 cm for gamma ray energy between 0.01 and 15 MeV. Moreover, the removal cross sections of fast neutrons (Σ_R) were also calculated theoretically for the selected cadmium-doped sodium borate glasses. The obtained data shows that the insertion of CdO appears to enhance gamma ray and neutron shielding capacity. BNC8 with CdO content (14 mol%) was found to possess the best shielding parameters among the studied cadmium-doped sodium borate glasses.     

Synthesis and properties of tellurite based glasses containing Na2O,BaO, and TiO2: Raman,UV and neutron/charged particle shielding assessments

In this paper, 75TeO₂–5Na₂O–20BaO?xTiO₂ (TNB-Tix with x = 0, 05, 10, and 15) glasses were synthesized by the conventional melt-quench technique using analytic grade tellurium oxide (TeO₂), barium carbonate (BaCO₃), sodium carbonate (Na₂CO₃) and titanium oxide (TiO₂) as starting chemicals. The prepared glasses were studied for their physical features, Raman and UV spectra, and shielding performance against neutrons and charged particles. The optical property was investigated by UV–Vis spectrometry while the structural evolution of the glasses was studied through the Rahman spectra. Charged particles, slow and fast neutrons interaction parameters of the glasses were calculated theoretically and analyzed as well. The prepared glasses were yellowish without any flaws. The mass density of the glasses increased from 5.1 to 5.4 g/cm³ as TiO₂ content declined from 15 to 0 mol%. Also, an improvement in the optical bandgap from 2.89 to 3.2 eV was recorded as BaO content increased concerning TiO₂ while the refractive index declined from 2.43 to 2.35. Generally, the improvement in the TiO₂ content of the glasses produced a rise in the total and scattering cross section of thermal and slow neutrons respectively. In addition, the fast neutron cross section was enhanced from 0.1005 to 0.1015 cm^?1 for TNB-Ti00 – TNB-Ti15 glasses. The charged particle shielding parameters showed a strong dependence on the chemical structure of the glass system. The present glass system displayed good properties that could make them useful in optical and shielding applications.     

Synthesis,physical, optical,structural and radiation shielding characterization of borate glasses: A focus on the role of SrO/Al2O3 substitution

In a bid to expand the amount of information available on glass systems and their potential applications for radiation shielding design, glass samples with the compositions (30-x)SrO-xAl₂O₃–68B₂O₃–2V₂O₅(x = 5, 7.5, 10, 12.5&15 mol %) coded as SABV0 - 4 were prepared by the melt-quenching technique and analyzed for their optical, structural, physical, and radiation shielding features. The glassy (amorphous) nature of the SABV glass samples was affirmed by broad peaks of X-ray diffraction spectra. Calculated values of density and molar volume shown opposite behavior and the variation of these values were discussed as structural modifications in the glass matrix. From recorded optical absorption spectra optical band gap energy (Eg)-indirect transition, Urbach energy and optical basicity were estimated. FTIR spectra were recorded for all the samples in the range 400 cm^?1 to 4000 cm^?1. The FTIR absorbance spectra unveiled the SABV network structure mainly incorporating of BO₃ and BO₄ units. Raman spectroscopy is achieved to detect the structural changes and at higher wavenumber, B–O stretching modes in [BO₃] observed with one or two NBO's. The results of ESR spectra of glasses have indicated the highly covalent environment of vanadium ions. Analysis of the photon shielding parameters of the glasses which were obtained primarily from FLUKA Monte Carlo simulations and XCOM computations revealed photon energy and glass chemical composition dependence. The mass attenuation coefficient and effective atomic number ranged from 0.2668 to 0.3385 cm²g^-1 and 12.98–15.93 accordingly as the weight fraction of Sr increased from 16.06 to 26.72% in the glasses. Generally, photon shielding ability of the SABV glasses follows the trend: SABV0 > SABV1 > SABV2 > SABV3 > SABV4. The thermal neutron total cross section follows the same trend with values fluctuating between 71.9553 and 80.6268 cm^?1. However, SABV1 showed superior fast neutron moderating capacity among the glasses. The present SABV glasses showed outstanding photon shielding ability compared to common shields. The prepared glasses are thus suitable candidates for radiation protection applications.     

Selective preparation of Ag species on photoluminescence of Sm3+ in borosilicate glass via Ag+-Na+ ion exchange

Photoluminescence (PL) of rare earth ion-doped glasses could be enhanced by diverse Ag species such as Ag⁺ ions, Ag⁺-Ag⁺ pairs, Ag nano-clusters (NCs), and Ag nanoparticles (NPs). Selective preparation of silver species in rare earth ion-doped glasses is a crucial step to obtain the luminescence enhancement of rare earth ions caused by the different silver species. In this work, Ag⁺ ions and Ag NCs were selectively prepared in the Sm³⁺-doped borosilicate glass via the Ag⁺-Na⁺ ion exchange. The influence of AgNO₃/NaNO₃ ratio in the molten salt on the Ag existing states was investigated. The results demonstrate that the isolated Ag⁺ ions exist in the Sm³⁺-doped borosilicate glass when the ratio of AgNO₃/NaNO₃ is 1/1000. The Ag NCs are formed in the Sm³⁺-doped borosilicate glass when the AgNO₃/NaNO₃ ratio is 1/10. The influence of Ag⁺ ions or Ag NCs on the PL of Sm³⁺ was systematically investigated. The results show that the PL of Sm³⁺ was enhanced by the energy transfer from Ag⁺ ions or Ag NCs to Sm³⁺.     

Effect of bulk and nanoparticle Bi2O3 on attenuation capability of radiation shielding glass

The aim of this study is to examine the effect of Bi₂O₃ concentration and particle size on Bi₂O₃ glass. The tested glasses had the composition of SiO₂–Bi₂O₃–CaO–MgO–B₂O₃–K₂O–Na₂O–ZnO. Ordinary glass was compared with glasses with 10% Bulk Bi₂O₃, 10% Bi₂O₃ Nanoparticles (NPs), 20% Bulk Bi₂O₃, and 20% Bi₂O₃ nanoparticles. The mass attenuation coefficients (MACs) of all the investigated glasses were determined between 0.0595 MeV and 1.41 MeV. The results demonstrated that increasing the Bi₂O₃ content in the glass matrix improved their shielding capability, as well as showing that the NPs provided greater attenuation than the bulk Bi₂O₃ at the same concentration. The percent increase in the MAC between the bulk and nano Bi₂O₃ was also calculated and analyzed. From the MAC values, the LAC of the glass was determined and similar results were found compared to the MAC figure. The HVL and MFP of the glass were then analyzed and the results demonstrated that the glass with Bi₂O₃ NPs attenuated the same amount of photons at a smaller thickness, making the NP shield more effective. The heaviness of the samples illustrated that all the tested samples have a smaller weight than pure lead, making them more desirable. The attenuation factor of the glass (Att. Factor %) showed that increasing the Bi₂O₃ content in the samples and increasing the thickness of the shields both improve the shielding capability of the glass. Lastly, the d_lead of the glasses was determined, indicating that the greatest reduction in thickness occurs near the K-absorption edge of bismuth. Overall, the glass with 20% Bi₂O₃ NPs demonstrated to have the greatest potential for radiation shielding applications.     

Gamma radiation attenuation characteristics for lithium-zinc-tellurite glasses using Geant4 code and PDS computer software

Six glass samples with the composition of TeO₂-Li₂O-ZnO were analyzed for their radiation shielding properties. The radiation shielding factors for the lithium-zinc-tellurite glasses were reported using the Geant4 code and Phy-X/PSD program. The transmission factor (TF) was determined for different thicknesses and the results revealed that the TF decreases with increasing the thickness of the glass. For TeLiZ1, increasing the thickness of the sample from 0.4 cm to 1.6 cm led to decrease the transmission of the photon from 0.84 to 0.48 at 0.5 MeV and from 0.94 to 0.76 at 4 MeV. The radiation protection efficiency (RPE) results showed that a thicker glass sample absorbs a higher number of photons, implying that lower radiation pass among the glass, increasing RPE. Also, the glass coded as TeLiZ6 has higher RPE than that of TeLiZ1 glass which suggests that at higher content of TeO₂ (85 mol%), the more efficient the glass is at shielding the incoming photons. The linear attenuation coefficient (LAC) obtained by both methods (Geant4 and Phy-X/PSD showed a good agreement for all the glasses and at all investigated energies. The LAC indicates a strong energy dependence, especially at low energies. The LAC also increases as more TeO₂ is added to the glasses. TeLiZ6 (85TeO₂-15Li₂O, ρ = 5.164 g/cm₃) has the highest RPE and lowest TF, while TeLiZ1 (60TeO₂-15Li₂O-25ZnO, ρ = 4.976 g/cm³) has the lowest RPE and highest TF. The tenth value layer (TVL) was also determined and it was observed that TVL increases with increasing energy, reaching a maximum value at 10 MeV and varying between 12.919 and 13.808 cm. By contrast, the minimum TVL is reported at 15 keV and varies between 0.0106 and 0.0112 cm. The addition of TeO₂ decreases the TVL, with TeLiZ6 having the least TVL.     

Luminescence Enhancement of CdS Quantum Dots in Glass by Ag+ Ion Exchange

Luminescence of CdS quantum dots (QDs) enhanced by the induction of Ag nanoparticles (NPs) in glasses was investigated. Ag⁺ ions diffused into glasses containing CdS QDs by ion exchange, then formed Ag NPs after subsequent heat treatment. Luminescence intensity of CdS QDs increased approximately three times when the ion‐exchange duration was 1 min, but was severely quenched when the duration was extended to 30 min. Increasing the amount of Ag⁺ ions increased the number of Ag NPs and decreased the average distance between Ag NPs and CdS QDs. This decrease in the average distance induced the changes of luminescence intensity.     

Enhanced non-linear optical properties of Eu3+ activated glasses by embedding silver nanoparticles

Tri-positive lanthanide ion (Eu³⁺) activated glasses doped with different concentrations of silver (Ag0₎ nanoparticles obtained using thermal reducing agent were fabricated by applying the method of melt quench. The formation of Ag⁰ nanoparticles in glasses was revealed by the surface plasmon resonance (SPR) peak in the absorption spectra. Transmission electron microscopic measurements confirmed the presence of spherically shaped Ag⁰ nanoparticles of different size distribution. The absorption spectra showed a red–shift of the SPR peak with an increase in AgNO₃ concentration occurring through Ostwald's ripening process because of the growth of particle size (as evidenced from microscope images). The non-linear optical (NLO) and optical limiting measurements were performed in the near infrared spectral region and femtosecond pulse excitation. The non-linear parameters were found to increase as the AgNO₃ concentration increased to 0.6 mol %, however, the parameters subsequently decreased at higher doping level. The optical limiting threshold values demonstrated a reverse trend. The increase in non-linear optical properties regarding Ag nanoparticles concentration attributed to the enhancement of polarizabilities of glasses that occurred through local field stimulated by SPR of Ag nanoparticles when exposed to laser radiation of high energy. The increase in NLO coefficients (particularly the non-linear absorption coefficient) and the decrease in optical limiting threshold values with AgNO₃ concentration (up to 0.6 mol %) indicated that these glasses containing 0.6 mol % AgNO₃ are useful for the construction of the power optical limiters that function at the infrared region in the femtosecond pulse regime.     

Newly developed BGO glasses: Synthesis,optical and nuclear radiation shielding properties

In this research paper, we studied the optical and nuclear shielding efficiency of newly developed BGO glasses with the following compositions (in wt%): 32Bi₂O₃–68GeO₂, 42Bi₂O₃–58GeO₂, 47Bi₂O₃–53GeO₂, 52Bi₂O–48GeO₂, 62Bi₂O₃–38GeO₂. BGO glasses were prepared by traditional melt quenching method. To obtain the band gap values of fabricated BGO glasses, optical absorption spectra were used for evaluation of optical properties. The mass attenuation coefficients (μ/ρ) were achieved for prepared glasses at 0.015–15 MeV photon energies employing MCNPX Monte Carlo code and WinXcom program. Moreover, broad-range of nuclear shielding parameters for gamma ray, neutrons and charged particles such as mass attenuation coefficient, half value layer, effective atomic number, buildup factors, mass stopping powers, projected ranges, fast neutron removal cross sections and damage factors were calculated. The refractive index is calculated from E_opt, As Bi₂O₃ concentration is enhanced, E_opt is also increased as well as the optical electronegativity and consequently the refractive index. In addition, the results showed that BIGE5 glass sample with highest Bi₂O₃ contribution has excellent nuclear radiation shielding ability among the other fabricated glass samples.     

Physical Properties,Optical band gaps and Radiation Shielding Parameters Exploration for Dy<Superscript>3+</Superscript>-doped Alkali/Mixed Alkali Multicomponent Borate Glasses

Six compositions of 1 mol % Dy³⁺-doped multicomponent borate glasses containing single Li₂O, Na₂O, K₂O and mixed Li₂O–Na₂O, Li₂O–K₂O, and Na₂O–K₂O oxides have been synthesized by well-known melt-quenching technique. Following the measured density and refractive index values, various physical parameters were estimated for all the glass samples and differences in them are correlated with structural changes. To explore optical properties like absorption edge (λ_cut-off), optical band gap energy (E_opt), and Urbach energy (ΔE), optical absorption spectra were recorded for all the glasses. The E_g has been calculated using Davis and Mott theory for direct allowed, and indirect allowed transitions and the results were reported. The E_g values are also estimated using absorption spectrum fitting (ASF) method. The optical parameters variations have also been associated with the structural changes occurring in the glasses with different alkali/mixed alkali oxides content presence. The shielding properties of the prepared glasses were studied in terms of effective atomic numbers (Z_eff), mean free path (MFP), half value layer (HVL) and macroscopic effective removal cross-section (Σ_R). From these results, it was found that Potassium (K) glass shows superior gamma ray shielding properties due to a higher value of Z_eff and lower values of both MFP and HVL. These results indicate that the prepared glasses might be utilized in place of some common shielding materials to shield γ-rays and neutrons.     

Bioactivity and antibacterial activity against E-coli of calcium-phosphate-based glasses: Effect of silver content and crystallinity

In this work we developed improved bioactive glasses and glass-ceramics for biomedical applications, investigating their in vitro bioactivity, biocompatibility and antibacterial properties against E-Coli. A melt-quenched bioactive glass of the SiO₂-CaO-P₂O₅-MgO system was modified with the addition of 1 and 2 mol% Ag₂O and the 1 mol% Ag₂O-containing glasses were then heat treated to produce glass-ceramics. Surface modifications after soaking in SBF and ionic concentration changes showed that addition of silver and crystallization did not affect bioactivity although crystalline phases promoted a decrease in the degradation rate.Biocompatibility of all Ag-containing glasses and glass-ceramics was confirmed for certain samples concentrations. The antibacterial activity of the glasses against E-Coli was generally improved with decreasing particle size or increasing Ag₂O. The Ag-containing glass-ceramics with higher content of crystalline phase appears as a promising biocompatible biocidal material with potential applications in bone-related diseases.     

CdS Quantum Dots in Glass: “Modification of Photoluminescence by Silver Doping”

Silicate glasses containing CdS and Ag₂O were made by the melt-quenching method. CdS quantum dots (QDs) were precipitated inside the glass matrix by heat treatment at 570–590 °C for 10 h, and the influence of Ag on photoluminescence (PL) of CdS QDs was investigated. The emission located at 478–493 nm in wavelength originated from the direct recombination of electron/hole pairs was quenched due to charger transfer between Ag and CdS QDs. Modification of PL from CdS QDs by Ag provides potentials toward developing the color changing materials for light-emitting diodes (LEDs).     

Influence of Bi2O3/WO3 substitution on the optical,mechanical, chemical durability and gamma ray shielding properties of lithium-borate glasses

Six different lithium bismuth boro-tungstate glasses with chemical composition 20Li₂O-(20-x)Bi₂O₃-xWO₃-60B₂O₃ (x = 0, 1, 2, 3, 4 and 5 mol%) were produced by the quenching method. Then, the glasses were investigated by means of their optical, mechanical, chemical durability and gamma ray shielding properties. Measured values of density and ultrasonic velocities were used to determine the elastic properties of the glasses. The optical band gap determined using the absorbance spectrum fitting (ASF) model was found to decrease under Bi₂O₃/WO₃ substitution. The presence of BO₃, BO₄, BiO₆, and WO₄ structural groups in the glasses was confirmed by Fourier transform infrared spectroscopy (FTIR). The dissolution rate in the glass 20Li₂O–15Bi₂O₃–5WO₃–60B₂O₃ (LBWB5) was found to be 10 times lower than 20Li₂O-20Bi₂O₃– 60B₂O₃. Mass attenuation coefficients (MAC) values of the produced glasses were determined using the MCNPX Monte Carlo code and Phy-X/PSD program. The photon attenuation parameters such as half value layer (HVL), mean free path (MFP), effective atomic number (Z_eff), exposure buildup factor (EBF) and energy absorption buildup factor (EABF) were also studied. The obtained results showed that Bi₂O₃/WO₃ substitution has a direct impact on the photon attenuation abilities of produced glasses. More specifically, HVL values increased from 0.252 × 10^?2 cm for LBWB0 glass to 0.275 × 10^?2 cm for LBWB5 glass. However, different trends were observed for the photon buildup factors for the produced glasses. It can be concluded that the produced glasses have promising structural, optical, and photon attenuation properties to be used for gamma shielding applications.     

Preparation and characterization of SiO2/polydopamine/Ag nanocomposites with long-term antibacterial activity

Silver nanoparticles (Ag NPs) with diameter of approximately 10 nm were prepared by the reduction of silver nitrate using green synthesis, an eco-friendly approach. The synthesized Ag NPs were homogeneously deposited on silicon dioxide (SiO₂) particles modified with dopamine, leading to the formation of SiO₂/polydopamine (PD)/Ag nanocomposites (NCs) with a core–shell–satellite structure investigated by transmission electron microscopy. The Ag content of SiO₂/PD/Ag NCs determined by inductively coupled plasma optical emission spectrometry was approximately 5.92 wt%. The antibacterial properties of both Ag NPs and SiO₂/PD/Ag NCs against Vibrio natriegens (V. natriegens) and Erythrobacter pelagi sp. nov. (E. pelagi) were investigated by bacterial growth curves and inhibition zone. Compared to Ag NPs, the SiO₂/PD/Ag NCs exhibited superior long-term antibacterial activity, attributed to its controlled release of Ag⁺ ions.     

Effects of Ag additive on structure and crystallization behaviors of As2(Se15Te85)3 glasses

In this work, glass samples of compositions of As_40-0.4x(Se₁₅Te₈₅)_60-0.6xAg_x (x = 0, 10, 16.7, 20, 25 at%) are prepared. The structural transformations of glasses are deduced from the variations of glass densities and Raman spectra with the addition of Ag. Differential scanning calorimetry is applied to determine the characteristic temperatures, evaluate the thermal stabilities against crystallization, and investigate the crystallization kinetics under non-isothermal conditions. Thermal treatment of the as-prepared glass samples is carried out at both low (190 °C) and high (260 °C) crystallization temperatures. X-ray diffraction patterns demonstrate that crystals precipitated from glass matrices are pure As-Te(Se) phases free of Ag. The results are consistent with the Raman spectra. The relevant mechanism can be understood based on the dual chemical role of the Ag addition on the variations of glass network.     

Improved broadband near-infrared luminescence in Nd3+/Tm3+ co-doping tellurite glass with Ag NPs

The near-infrared (NIR) luminescence in S+E+O bands of tellurite glasses doped with Nd³⁺/Tm³⁺ and Ag nanoparticles (NPs) was investigated. The tellurite glasses were prepared by melt-quenching and heat-treated techniques. Under the excitation of 808 nm laser, Nd³⁺/Tm³⁺ doped tellurite glasses produced three NIR luminescence bands of 1.33, 1.47 and 1.85 μm, originating from Nd³⁺:⁴F_3/2→⁴I_13/2, Tm³⁺:³H₄→³F₄ and Tm³⁺:³F₄→³H₆ transitions respectively. Interestingly, a broadband luminescence spectrum ranging from 1280 to 1550 nm with the FWHM (full width at half maximum) about 201 nm was obtained due to the overlapping of the first two NIR bands. Further, the peak intensity of this broadband luminescence was increased by 75% after the introduction of Ag NPs with diameter in 10–20 nm. The analysis of fluorescence decay shows that compared with the enhanced local electric field, the energy transfer from Ag species to Nd³⁺ and Tm³⁺ ions plays a major role in luminescence enhancement. The findings in this work indicate that tellurite glass co-doped with Nd³⁺/Tm³⁺ and Ag NPs is a potential gain material applied in the S+E+O-band photonic devices.     

The nonlinear optical properties of silver nanoparticles decorated glass obtained from sintering mesoporous powders

Silver nanoparticles (Ag NPs) have excellent third-order nonlinear optical properties but it is still difficult to obtain silica glass containing Ag NPs with homogenous dispersion and small particle size. Herein, silica glass with homogenously distributed Ag NPs in its matrix was derived from sintering a famous type of mesoporous silica (FDU-12) encapsulated with Ag NPs (Ag NPs/FDU-12) through Spark Plasma Sintering (SPS) technique. Benefited from the low-temperature sintering property of the Ag NPs/FDU-12 powders (~930°C within 5 min), the Ag NPs can be directly trapped in the derived silica glass with small particle size (<3.0 nm) and without mass loss. The as-prepared Ag NPs/glass showed a typical reverse saturable absorption curve, which is measured via the Z-scan method by using a 532 nm nanosecond laser. The nonlinear coefficient and imaginary third-order susceptibility were calculated as 11.46 cm/GW and 2.22 × 10⁻¹² esu, respectively, indicating the excellent third-order nonlinear optical properties of the Ag NPs/glass. This study demonstrates a great potential for preparing silica glasses functionalized with well dispersed ultrafine functional particles, which is appealing in photonic field.