Amorphous Silica Matrix Research Articles

Volcanic Eruption in the Nanoworld: Efficient Oxygen Exchange at the Si/SnO2 Interface.

Here, a phenomenon of efficient oxygen exchange between a silicon surface and a thin layer of tin dioxide during chemical vapor deposition is presented, which leads to a unique Sn:SiO2 layer. Under thermodynamic conditions in the temperature range of 725-735°C, the formation of nanostructures with volcano-like shapes in "active" and "dormant" states are observed. Extensive characterization techniques, such as electron microscopy, X-ray diffraction, synchrotron radiation-based X-ray photoelectron, and X-ray absorption near-edge structure spectroscopy, are applied to study the formation. The mechanism is related to the oxygen retraction between tin(IV) oxide and silicon surface, leading to the thermodynamically unstable tin(II)oxide, which is immediately disproportionate to metallic Sn and SnO2 localized in the SiO2 matrix. The diffusion of metallic tin in the amorphous silicon oxide matrix leads to larger agglomerates of nanoparticles, which is similar to the formation of a magma chamber during the natural volcanic processes followed by magma eruption, which here is associated with the formation of depressions on the surface filled with metallic tin particles. This new effect contributes a new approach to the formation of functional composites but also inspires the development of unique Sn:SiO2 nanostructures for diverse application scenarios, such as thermal energy storage.

Identification and Dynamics of Microsecond Long-Lived Charge Carriers for CsPbBr3 Perovskite Quantum Dots, Featuring Ambient Long-Term Stability.

We analyze the stability and photophysical dynamics of CsPbBr3 perovskite quantum dots (PeQDs), fabricated under mild synthetic conditions and embedded in an amorphous silica (SiOx) matrix (CsPbBr3@SiOx), underscoring their sustained performance in ambient conditions for over 300 days with minimal optical degradation. However, this stability comes at the cost of a reduced photoluminescence efficiency. Time-resolved spectroscopic analyses, including flash-photolysis time-resolved microwave conductivity and time-resolved photoluminescence, show that excitons in CsPbBr3@SiOx films decay within 2.5 ns, while charge carriers recombine over approximately 230 ns. This longevity of the charge carriers is due to photoinduced electron transfer to the SiOx matrix, enabling hole retention. The measured hole mobility in these PeQDs is 0.880 cm2 V-1 s-1, underscoring their potential in optoelectronic applications. This study highlights the role of the silica matrix in enhancing the durability of PeQDs in humid environments and modifying exciton dynamics and photoluminescence, providing valuable insights for developing robust optoelectronic materials.

Simulant molten core–concrete interaction experiments in view of understanding Fukushima Daiichi Nuclear Power Station Cs-bearing particles generation mechanism

The Fukushima Daiichi accident resulted in the release of a novel form of radioactive Cs contamination into the environment, called Cs-bearing microparticles (CsMP). CsMPs constitute a substantial portion of the radioactive pollution near the nuclear power station and traveled beyond several hundred kilometers. Extensive characterization of the CsMPs revealed an amorphous silica matrix, along with Cs and other minor or trace elements such as Fe and Zn. This study explores the unclear generation mechanism of CsMPs by conducting experimental molten core concrete interactions (MCCI) as a source of Si and analyzing the resultant aerosols. The findings demonstrate that MCCI is in capacity to produce spherical submicronic and micronic particles, primarily composed of amorphous silica and incorporating elements akin to CsMPs. A humid atmosphere is found to favour an even closer chemical composition. Examination of the internal structure of the synthesized particles unveils pores and numerous crystalline nanoinclusions possibly serving as nucleation sites for CsMP formation through the condensation of Si-rich vapors.

SBA-15- and SBA-16-Functionalized Silicas as New Carriers of Niacinamide.

Amorphous silica as a food additive (E 551) is used in food materials (e.g., sweeteners, dairy products) for its anti-caking properties. The physicochemical properties of SiO2 also make it suitable to serve as a carrier of active substances in functional foods, dietary supplements, and drugs. Deficiency of niacinamide (vitamin B3, niacin) leads to several pathologies in the nervous system and causes one of the nutritional diseases called pellagra. The present study focuses on the use of hybrid ordered mesoporous silicas (SBA-15/SBA-16) functionalized with amino groups introduced through grafting or co-condensation with (N-vinylbenzyl)aminoethylaminopropyltrimethoxysilane (Z-6032) as novel carriers of niacinamide. They combine the characteristics of a relatively stable and chemically inert amorphous silica matrix with well-defined structural/textural parameters and organic functional groups that give specific chemical properties. The highest degree of carrier loading with niacinamide (16 wt.%) was recorded for the unmodified SBA-15. On the other hand, the highest degree of niacinamide release characterizes the functionalized SBA-15 sample (60% after 24 h), indicating that the presence of amino groups affects the release profile of niacinamide from the structure of the mesoporous silica.

The Study of the Influence of ZrO2 Precursor Type and the Temperature of Annealing on the Crystallization of the Tetragonal Polymorph of ZrO2 in Zirconia-Silica Gels.

Materials of the ZrO2-SiO2 system were obtained by the sol-gel method applying two different types of ZrO2 precursors: zirconium (IV) n-propoxide Zr(OC3H7)4 and zirconium (IV) acetate Zr(OOC2H3)4 (organic acetic acid salt) while commonly used tetraethoxysilane TEOS was selected as SiO2 introducing one. ZrO2 concentration in synthesized samples varied from 20% to 50% (mol.). After drying for 28 days, all gels were annealed at 500 °C, 1000 °C, and 1200 °C in air. FTIR spectroscopy together with XRD diffraction was selected as the two main structure research methods. SEM microscopy was applied to analyze the local chemical compositions of samples and to observe the morphology of gels' surfaces. The analysis of FTIR spectra and XRD diffraction patterns allowed us to recognize different ZrO2 polymorphs which appeared in the samples depending strongly as well on ZrO2 precursor type as on the temperature of annealing. Samples synthesized by using the zirconium (IV) n-propoxide contained both cubic and tetragonal zirconia phases in general but showed the tendency of the increasing t-ZrO2 content in gels richer in ZrO2 and heated up to 1200 °C. However, in materials obtained applying zirconium (IV) acetate, the first detected at 500 °C phase was t-ZrO2 which was then conversing to m-ZrO2 form with the increasing temperature in case of samples rich in ZrO2. Meanwhile, t-ZrO2 was the predominant phase in samples of the lower content of ZrO2 but annealed at higher temperatures. By the analysis of changes in band profiles and positions, one can draw conclusions that the structure of studied samples is mostly built up of an amorphous silica matrix, in which different types of zirconia polymorphs create their own crystal lattice. The presence of the particular polymorph depends strongly on the type of zirconia precursor and the temperature of annealing.

Dependence of Exchange Bias on Interparticle Interactions in Co/CoO Core/Shell Nanostructures.

This article reports the dependence of exchange bias (EB) effect on interparticle interactions in nanocrystalline Co/CoO core/shell structures, synthesized using the conventional sol-gel technique. Analysis via powder X-Ray diffraction (PXRD) studies and transmission electron microscope (TEM) images confirm the presence of crystalline phases of core/shell Co/CoO with average particle size ≈ 18 nm. Volume fraction () is varied (from 20% to 1%) by the introduction of a stoichiometric amount of non-magnetic amorphous silica matrix (SiO) which leads to a change in interparticle interaction (separation). The influence of exchange and dipolar interactions on the EB effect, caused by the variation in interparticle interaction (separation) is studied for a series of Co/CoO core/shell nanoparticle systems. Studies of thermal variation of magnetization () and magnetic hysteresis loops () for the series point towards strong dependence of magnetic properties on dipolar interaction in concentrated assemblies whereas individual nanoparticle response is dominant in isolated nanoparticle systems. The analysis of the EB effect reveals a monotonic increase of coercivity () and EB field () with increasing volume fraction. When the nanoparticles are close enough and the interparticle interaction is significant, collective behavior leads to an increase in the effective antiferromagnetic (AFM) CoO shell thickness which results in high and . Moreover, in concentrated assemblies, the dipolar field superposes to the local exchange field and enhances the EB effect contributing as an additional source of unidirectional anisotropy.

Synthesis of Sorption Materials from Low Grade Titanium Raw Materials.

In this paper, a universal technology is proposed for processing low-titanium mineral raw material—apatite-nepheline ore waste, including its treatment with sulfuric or hydrochloric acid in a two-stage mode with a sequential increase in the concentration. This technique allowed us to remove nepheline and apatite in the first stage and achieve a titanium mineral content of TiO2 of more than 30%; in the second stage, we were able to convert the titanium into its precursors—titanyl sulfate monohydrate TiOSO4·H2O and a hybrid rutile-silica composition. The key stage in the sorbent synthesis is the reaction of the precursor with a phosphoric acid solution. The preferred sequence of operations begins with the mechanical activation of the precursor, causing morphological changes in it, and subsequent treatment with phosphoric acid at different concentrations under atmospheric conditions and in an autoclave, accompanied by phase transformations. Conditions for the chemical reactions which regulated the composition and structure of the final product and, accordingly, its sorption activity were found. With the help of XFA, the phase compositions of the sorbents were identified, including the individual crystalline phase α-TiP obtained from TS or the crystalline phase αTi(HPO4)2∙H2O, which is in an amorphous silica matrix obtained from a rutile–silica composition.

Silica-induced electron loss of silver nanoparticles.

Despite the frequent use of silver nanoparticles (Ag NPs) embedded in materials for medical or optical applications, the effect of the matrix on the nanoparticle properties remains largely unknown. This study aims to shed light on the effect of an amorphous silica matrix on the structure and charge distribution of 55- and 147-atom silver nanoparticles by means of dispersion-corrected DFT calculations. Particular attention is paid to nanoparticle size and concentration effects and to the impact of the presence of native defects in the matrix. Covalent bonding between the silver nanoparticles and the matrix is found to occur at the interface. Such interface reconstruction involves the breaking of Si-O bonds, which systematically leads to the formation of Ag-Si bonds, and in some cases, to the formation of Ag-O ones. Interestingly, these interface reconstructions are accompanied by electron depletion of the nanoparticles, a substantial number of electrons being transferred from the two outer shells of the Ag NPs to the surrounding silica medium. The electrons lost by the nanoparticles are captured by the Si atoms involved in the interface bonds, but also, unexpectedly, by the undercoordinated silica defects that act as electron pumps and by the atoms of the silica network inside a few angströms spherical shell around the silver nanoparticle. The numbers of interface bonds and electrons transferred to the surrounding silica shell appear to be proportional to the surface area of the Ag NP. The electronic extension within silica goes beyond that attributable to the Ag NP spill-out. The presence of additional electrons in the matrix, especially on defects, is consistent with the experimental literature.

Synthesis and Characteristics of Multifunctional Magneto-luminescent Nanoparticles by an Ultrasonic Wave-assisted Stӧber Method

Multifunctional magneto-luminescent nanoparticles (NPs) were synthesised by an ultrasonic wave-assisted Stöber method. The multifunctional NPs are composed of magnetic NPs (Fe3O4) and photoluminescent quantum dots (QDs) (ZnS:Mn) in amorphous silica (SiO2) matrix, which was confirmed by X-ray diffraction, Raman scattering spectroscopy, and transmission electron microscopy (TEM). The multifunctional NPs have high saturation magnetisation at room temperature simultaneously with strong photoluminescence (PL) in visible light, which is promising for biomedical applications.

Cryogenic magnetocaloric effect in Gd2O3 nanoparticles studied by heat capacity

Structural characteristics and magnetic properties with respect to magnetocaloric effect was studied in the nanocomposite systems consisting of Gd2O3 nanoparticles embedded in the regular pores of amorphous silica matrix. The particles of size 2–16 nm were prepared by nanocasting method within the pores of periodic silica matrices of hexagonal (SBA15 type) and cubic (SBA16 type) symmetries. Magnetocaloric response of the systems was examined in the applied fields up to 9 T in the low temperature region ranging from 0.4 K to 55 K. The data obtained from the measurements of the heat capacity Cp(H,T) revealed a peak at temperature below 10 K. Taking into account the superposition principle, the contributions corresponding to the lattice and the magnetic subsystem heat capacities were analyzed separately. The high value of magnetic entropy change |ΔSM| = ~27 JK−1kg−1 and |ΔSM| = 37 JK−1kg−1 for the systems with hexagonal and cubic matrices, respectively were observed at the temperature close to 2 K under field change from 0 to 9 T. The evidence on considerable high |ΔSM| values along with the large surface area of mesoporous silica, easy and reproducible preparation manifest some extra advantages over the conventional refrigeration technology.

Athermal Solid Phase Reaction in Pt/SiO x Thin Films Induced by Electron Irradiation.

Microelectronics based on Si requires metal silicide contacts. The ability to form platinum silicide (Pt2Si) by electronic excitation instead of thermal processes would benefit the field. We studied the effects of electron irradiation on Pt2Si formation in composite films—composed of Pt and amorphous silicon oxides (a-SiOx)—by transmission electron microscopy and electron diffraction. Pt2Si formed in Pt/a-SiOx bilayer and a-SiOx/Pt/a-SiOx sandwiched films by 75 keV electron irradiation, at 298 and 90 K. The reaction is attributable to dissociation of SiOx triggered by electronic excitation. In a-SiOx/Pt/a-SiOx sandwiched films, reflections of pure Pt were not present after irradiation, i.e., Pt was completely consumed in the reaction to form Pt2Si at 298 K. However, in Pt/a-SiOx bilayer films, unreacted Pt remained under the same irradiation conditions. Thus, it can be said that the extent of the interfacial area is the predominant factor in Pt2Si formation. The morphology of Pt islands extensively changed during Pt2Si formation even at 90 K. Coalescence and growth of metallic particles (Pt and Pt–Si) are not due to thermal effects during electron irradiation but to athermal processes accompanied by silicide formation. To maintain the reaction interface between metallic particles and the dissociation product (i.e., Si atoms) by electronic excitation, a considerable concomitant morphology change occurs. Elemental analysis indicates that the decrease in Si concentration near Pt is faster than the decrease in O concentration, suggesting formation of a Si depletion zone in the amorphous silicon oxide matrix associated with formation of Pt2Si.

Synthesis, characterization and magnetic properties of ε-Fe2O3 nanoparticles prepared by sol-gel method

Nanoparticles of ε-Fe2O3 in an amorphous silica matrix were prepared by the sol–gel method without using a precursor. X-ray diffraction patterns reflect a completely amorphous state for the samples even after heat-treated up to 600 °C, while at higher temperatures the formation of crystalline iron oxide phases was observed. Transmission electron microscopy analysis showed a wide size distribution of nanoparticles from 3±0.5 to 46±0.8 nm. The occurrence of ε-Fe2O3 particles depends on several factors like annealing temperature, particle size and iron concentration in initial chemicals. Based on the 57Fe Mössbauer spectra, three octahedral and one tetrahedral iron site were identified for ε-phase. The optimized conditions for the preparation of ε-Fe2O3 rich sample were confirmed and ~ 90% of the ε-Fe2O3 phase was obtained with the particle size of 15±0.6 nm. The high coercivity of ~ 1.18 T at room temperature was confirmed for our nanoparticle system.

Pleiotropic action of pH-responsive poly(pyridine/PEG) copolymers in the stabilization of silicic acid or the enhancement of its polycondensation

In this paper the effect of two synthetic, pH-responsive co-polymers, U-PVPyPEGMA-H and Q-PVPyPEGMA-H, with pyridine and polyethylene glycol grafts, on silicic acid polymerization is presented. The scope of this work was to evaluate the impact of several experimental parameters, such as working pH, polymer MW, polymer concentration, state of the pyridine ring (non-protonated, protonated, quaternized) on the anticipated inhibitory and/or enhancement activity with regards to silicic acid autocondensation to produce amorphous silica. It was found that pH substantially influences the silicification reaction, either in the absence or presence of the polymers. pH also affects the protonation state of the pyridine N atom. For example, pH switching from 5.0 to 7.0 transforms U-PVPyPEGMA-H from a silica formation catalyst (pH = 5.0) to a silicic acid stabilizer (pH = 7.0). Concentration enhances the role of the polymers, either as silicic acid stabilizers or catalysts. Polymer MW appears to have no effect on their activity either as stabilizers or catalysts. Polymer entrapment in the precipitated amorphous silica matrix occurs under these experimental conditions, affecting particle size, morphology and tendency for aggregation. The state of the N atom on the pyridine ring (non-protonated, protonated, quaternized) exhibits a profound effect on silicic acid autocondensation to produce amorphous silica. Based on our results, a “free” (non-protonated) pyridine ring induces silica inhibition, whereas protonation or quaternization enhances silica formation.

Synthesis of functionalized mesoporous Ni-SBA-16 decorated with MgO nanoparticles for Cr (VI) adsorption and an effective catalyst for hydrodechlorination of chlorobenzene

In this research work the impact of MgO promoter tested on Ni-SBA-16 efficiency in aqueous media as an adsorbent for Cr(VI) and an effective catalyst for hydrodechlorination of chlorobenzene. New hydrothermal procedures were applied for the synthesis of Ni-SBA-16 and MgO/Ni-SBA-16 respectively. Results revealed that nanocomposites containing Ni nanocrystals of an average size distributed homogeneously within the pores of the amorphous silica matrix and also MgO was effectively coated on Ni-SBA-16 mesoporous silica walls, and that the mesoporous Ni-SBA-16 structure has been well preserved upon modification of MgO. The catalyst analysis results showed high interaction of unpromoted and MgO promoted catalyst Ni-SBA-16 as hydrodechlorination of chlorobanzene (≈ 96%) remained stable for 6 hours. The synthesized nanostructures were tested against Cr(VI) removal. 100% Cr(VI) adsorption was noted using 4 g/L and 200 mg/L of nanostructure and Cr(VI) respectively at temperature 75 °C, contact time 100 min and pH 3.

Structural, Thermal and Luminescence Study of Ceria Nanocrystals Dispersed in Silica Matrix

Ceria (CeO2) nanocrystals dispersed in silica were prepared by sol-gel, a very suitable method for large-scale production. The formation of cubic fluorite structure of CeO2 nanocrystals was confirmed by XRD, TG-DTA and TEM. The average nanocrystalline size has been calculated ~3-5 nm using Debye-Scherrer formula for different annealed samples. The calculated nanocrystalline sizes were compared with W-H plot and TEM histograms. Different structural parameters like microstrain, lattice constant, dislocation density, X-ray density and activation energy were also calculated for all prepared samples. We have examined the photoluminescence (PL) due to defect centers and Ce3+ ions present in prepared nanopowder which were excited at two different wavelengths. PL study revealed the effect of annealing on the emission spectra and resulted that the emission efficiency of direct excitation at λex = 325 nm was enhanced with respect to the indirect λex = 250 nm. The emission produced from CeO2 nanocrystals dispersed in amorphous silica matrix has been influenced by many factors such as the modification of the ligand field around the Ce3+ ions in silica, presence of hydroxyl ions and annealing temperature also. Detailed Energy transfer mechanism has been explained with all possible transition lines.

Trace Level Detection and Quantification of Crystalline Silica in an Amorphous Silica Matrix with Natural Abundance 29Si NMR.

A protocol for the detection of trace amounts of quartz in amorphous silica gels by NMR spectroscopy was developed and tested on commercially available samples. Using natural abundance 29Si MAS NMR spectroscopy with CPMG acquisition and standard addition of crystalline quartz, quantitative detection of quartz concentrations down to 0.1% wt. was achieved. CPMG permitted to suppress the amorphous silica-derived signal, benefitting from the extremely long T2 relaxation time of quartz in 29Si and hence dramatically increasing the sensitivity. Dedicated post-processing exploiting the known CPMG spikelet frequencies allowed to probe the near-absence of quartz in commercial, 100% silica samples, enabling assessment of conformity of unknown samples to EU legislation (REACH).

A mesostructured hybrid CTA\u2013silica carrier for curcumin delivery

Curcumin is a natural active principle with antioxidant, antibacterial and anti-inflammatory properties. Its use is limited by a low water solubility and fast degradation rate, which hinder its bioavailability. To overcome this problem, curcumin can be delivered through a carrier, which protects the drug molecule and enhances its pharmacological effects. The present work proposes a simple one-pot sol–gel synthesis to obtain a hybrid carrier for curcumin delivery. The hybrid consists of a mesostructured matrix of amorphous silica, which stabilizes the carrier, and hexadecyltrimethylammonium (CTA), a surfactant where curcumin is dissolved to increase its water solubility. The carrier was characterized in terms of morphology (FESEM), physicochemical properties (XRD, FTIR, UV spectroscopy) and release capability in pseudo-physiological solutions. Results show that curcumin molecules were entrapped, for the first time, in a silica-surfactant mesostructured hybrid carrier. The hybrid carrier successfully released curcumin in artificial sweat and in a phosphate buffer saline solution, so confirming its efficacy in increasing curcumin water solubility. The proposed drug release mechanism relies on the degradation of the carrier, which involves the concurrent release of silicon. This suggests strong potentialities for topical administration applications, since curcumin is effective against many dermal diseases while silicon is beneficial to the skin.A simple one-pot sol–gel organic-solvent-free synthesis, at room temperature, leads to the formation of a hybrid mesostructured CTA–silica containing curcumin. When in pseudo-physiological solutions, the hybrid releases curcumin (enclosed in surfactant micelles), with enhanced solubility, and silicates. This material is a promising candidate for topical administration of drugs, since curcumin is effective against several dermatological diseases and silicon is beneficial to skin.

Magnetocrystalline and Surface Anisotropy in CoFe2O4 Nanoparticles.

The effect of the annealing temperature Tann on the magnetic properties of cobalt ferrite nanoparticles embedded in an amorphous silica matrix (CoFe2O4/SiO2), synthesized by a sol-gel auto-combustion method, was investigated by magnetization and AC susceptibility measurements. For samples with 15% w/w nanoparticle concentration, the particle size increases from ~2.5 to ~7 nm, increasing Tann from 700 to 900 °C. The effective magnetic anisotropy constant (Keff) increases with decreasing Tann, due to the increase in the surface contribution. For a 5% w/w sample annealed at 900 °C, Keff is much larger (1.7 × 106 J/m3) than that of the 15% w/w sample (7.5 × 105 J/m3) annealed at 700 °C and showing comparable particle size. This indicates that the effect of the annealing temperature on the anisotropy is not only the control of the particle size but also on the core structure (i.e., cation distribution between the two spinel sublattices and degree of spin canting), strongly affecting the magnetocrystalline anisotropy. The results provide evidence that the magnetic anisotropy comes from a complex balance between core and surface contributions that can be controlled by thermal treatments.

Tantalum doped SiO2-CaO-P2O5 based bioactive glasses: Investigation of in vitro bioactivity and antibacterial activities

AbstractMultifunctionality can be achieved for bioactive glasses by endowing them with multiple other properties along with bioactivity. One way to address this topic is by doping these glasses with therapeutic metallic ions. In this work, we put under investigation a series of bioactive glasses doped with tantalum. We aim to study the effect of tantalum, on the structure, bioactivity and antibacterial property of a ternary bioactive glass composition based on SiO2-CaO-P2O5. Fourier Transformed Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and Electron Scanning Microscopy (SEM) were used to assess the structural and morphological properties of these glasses and monitor their changes after in vitro acellular bioactivity test. Antibacterial activity was tested against gram positive and negative bacteria. Characterization results confirmed the presence of calcium carbonate crystallites along with the amorphous silica matrix. The assessment of bioactivity in SBF indicated that all compositions showed a fast bioactive response after only six hours of immersion period. However, analytical characterization revealed that tantalum introduced a slight latency in hydroxyapatite deposition at higher concentrations (0.8-1 %mol). Antibacterial test showed that tantalum ions had an inhibition effect on the growth of E. coli and S. aureus. This effect was more pronounced in compositions where mol% of tantalum is superior to 0.4%. These results proved that tantalum could be used, in intermediate proportions, as a promising multifunctional dopant element in bioactive glasses for bone regeneration applications.

Effect of Ag nanoparticles on the Judd–Ofelt and radiative parameters of Sm[formula omitted] ions in sol–gel silica matrix

Sm3+ singly doped and Sm3+ co-doped with varying concentrations of silver nanoparticles (Ag NPs) in silica matrix were fabricated via sol–gel route and investigated by structural and spectroscopic techniques. Structural characterizations were done by XRD, EDX and TEM techniques. The XRD and TEM studies reveal the presence of nanosized Ag particles in the amorphous silica matrix whereas EDX confirms the atomic percentage of Sm and Ag respectively as 1.43 and 0.08 in the present matrix. Spectroscopic studies were performed through UV–visible absorption, excitation, emission and time co-related photoluminescence decay spectra of the fabricated samples. The dependence of Judd–Ofelt intensity parameters and the radiative parameters of Sm3+ on the concentration of Ag NPs in the studied matrix were evaluated. Significantly higher value of Ω2 obtained for the present system reveals effective network modifying nature of the Ag NPs as well as the effectiveness of the silica host. The photoluminescence behavior shows strong dependence on the concentration of Ag NPs and possesses highest intensity and yield for Ag concentration of 0.03 wt%. The emission transition 4G5∕2→6H9∕2 of Sm3+ corresponding to the red color observed at 640 nm for the present silica matrix shows excellent radiative behavior compared to other popular hosts. The radiative behavior is explained in terms of LSPR phenomena, network modifying role of Ag NPs and energy transfer between Sm3+ ions and Ag NPs.