Rapid synthesis of amine cross-linked epoxy and methyl co-modified silica aerogels by ambient pressure drying

The silica aerogels were synthesized by sol–gel method via ambient pressure drying. Tetraethyl orthosilicate (TEOS) was used as a main silica source, methyltriethoxysilane (MTES) as a co-precursor silica source and (3-Glycidoxypropyl)trimethoxysilane (GPTMS) as a silane coupling agent. The silica aerogels obtained were further undergoing cross-linking epoxy from GPTMS with amine from diethylenetriamine (DETA) which played a dual role of base catalyst and reagent. The cumulative volumes for open pores of the cross-linked aerogels were evaluated to be 1.4 cm³/g. The Young's modulus and maximum compression strength were 25.4 MPa and 6.17 MPa, respectively. The addition of MTES accelerated the solvent exchange of alcohol within the pores with n-hexane and reduced the shrinkage of aerogels network during the ambient pressure drying. The formation of organic network enhanced the strength of the cross-linked aerogels to prevent the crack generation and the subsequent failure of the monolith during the ambient drying, therefore, protected the nanoporous structure of aerogels.     

Melting enthalpy ΔHm for describing glass forming ability of bulk metallic glasses

A new melting enthalpy ΔH_m criterion for the prediction of glass forming ability (GFA) of alloys is proposed and five Zr–Al–Ni–Cu bulk metallic glasses (BMG) with critical dimension Z_max up to ? 7.5 mm are also developed by us in the light of the optimum ΔH_m of Zr–Al–Ni–Cu alloy system. And then, we researched the relationships between ΔH_m and two GFA parameters (critical cooling rate R_c and Z_max) of five bulk metallic glass (BMG) systems, such as Mg–Ni–Nd, Pd–Cu–Si, La–Al–Ni–Cu, Zr–Al–Ni–Cu and Zr–Ti–Ni–Cu–Be, respectively. The results show that the relationships between ΔH_m and R_c are all concave upward parabolas, and the optimum ΔH_ms for Mg–Ni–Nd, Pd–Cu–Si, Zr–Al–Ni–Cu, Zr–Ti–Ni–Cu–Be and La–Al–Ni–Cu are 10.3960 kJ mol^?1, 21.2202 kJ mol^?1, 19.7146 kJ mol^?1, 18.1455 kJ mol^?1 and 13.1558 kJ mol^?1, respectively. On the contrary, the relationships between ΔH_m and Z_max are all concave downward parabolas, and the optimum ΔH_ms for Mg–Ni–Nd, Pd–Cu–Si, Zr–Al–Ni–Cu, Zr–Ti–Ni–Cu–Be and La–Al–Ni–Cu are 10.5530 kJ mol^?1, 21.0830 kJ mol^?1, 19.6603 kJ mol^?1, 19.7231 kJ mol^?1 and 13.1173 kJ mol^?1, respectively. Furthermore, other BMGs’ R_cs or Z_maxs predicted by above-mentioned relationships satisfactorily agree with the tested results, which indicates that these relationships are reliable. However, the predicted results are reliable only if the main components are similar with the fitted BMGs or the additive is sparkle enough that the alloy’s character does not change. On the whole, the ΔH_m can act as a criterion for quickly predicting the alloy’s GFA and be helpful for the development of new BMGs.     

Fabrication and optimization of single-junction nc-Si:H n–i–p solar cells using Si:H phase diagram concepts developed by real time spectroscopic ellipsometry

In this study, we have developed and applied deposition phase diagrams in the plane of the bulk layer thickness d_b and the H₂-dilution ratio R = [H₂]/[Si₂H₆] for Si:H materials deposited by 70 MHz VHF PECVD from [H₂] + [Si₂H₆] mixed gases on c-Si/(native-oxide)/n-layer substrates. To establish the phase diagrams, series of Si:H depositions having different R values over the range of 60–150 were measured in real time using a rotating-compensator multichannel ellipsometer. Using phase diagram concepts for guidance, we have fabricated high efficiency single-junction nc-Si:H n–i–p solar cells with ～3 Å/s intrinsic layers using the VHF PECVD process. We have found that the nc-Si:H solar cells with the best performance are obtained by incorporating i-layers deposited in the single-phase nanocrystalline silicon regime near the transition boundary to mixed-phase (a + nc)-Si:H. Applying insights from real time spectroscopic ellipsometry moreover, we have investigated in detail the effects of the phase of the underlying n-layer on the phase evolution of the overdeposited Si:H i-layer and on the overall device performance. With the strategy developed here, a stabilized efficiency of η = 9.46% (V_oc = 0.516 V, J_sc = 24.65 mA/cm², FF = 0.744) has been achieved for nc-Si:H solar cells (0.25 cm² in active area) fabricated with an i-layer deposition rate of ～2.2 Å/s.     

Structural and optical spectroscopy of LiNbO3:Tm nanocrystals embedded in a SiO2 glass matrix

Transparent SiO₂:Li₂O:Nb₂O₅ glass doped with Tm³⁺ has been prepared by the sol–gel method, and heat-treated in air (HT) at temperatures between 500 and 800 °C. X-ray diffraction (XRD) patterns and Raman spectroscopy show SiO₂ and LiNbO₃ phases in samples HT above 650 °C, and a NbTmO₄ phase for T > 750 °C. The XRD SEM analysis show increasing particle size and number with the increase of HT temperature. Intra-4f¹² transitions due to Tm³⁺ ion dispersed in the matrix are observed in samples with T > 650 °C. The luminescence is dominated by the ¹G₄ → ³F₄ (～650 nm), ¹D₂ → ³F₃ (～780 nm), ³H₄ → ³H₆ (～800 nm), ³H₅ → ³H₆ (～1200 nm) and ³H₄ → ³F₄ (～1500 nm) transitions under resonant excitation to the ion levels.     

Sol–gel synthesis and photoluminescence of RE3BO6: Eu3+/Tb3+ (RE = Y, Gd) microcrystalline phosphors from hybrid precursors

Novel phosphors of Eu³⁺/Tb³⁺ doped RE₃BO₆ (RE = Y, Gd) have been prepared using an original modified in situ sol–gel synthesis route. Different optimized organic media were mixed with rare earth coordination polymers, and tri-n-butyl borate was added to assemble inorganic/organic multi-component hybrid precursors. After calcinations of the resulting precursors at 1000 °C, target phosphors were obtained. The microstructure and morphology information of the phosphors were investigated via the technique of X-ray powder diffraction (XRD) and scanning electronic microscopy, and it has been shown that these phosphors present symmetrical distribution and high packing density, whose grain sizes were around 200 nm. Analyzed by luminescent spectra, these phosphor particles show narrow lines of emissions respectively originating from their characteristic transitions, and the dominating emission peak is due to the hypersensitive transition. The RE₃BO₆: Eu³⁺/Tb³⁺ (RE = Y, Gd) phosphors can be expected to gain more practical applications in commercial phosphors and other luminescent materials used in advanced devices.     

Structure of rare-earth phosphate glasses by X-ray and neutron diffraction

Previous diffraction studies of the structures of rare-earth phosphate glasses (R₂O₃)_x(P₂O₅)_1−x are extended to glasses with smaller R³⁺ ions with R = Sm, Gd, Dy, Er, Yb, Y for x = ∼0.25 and with R = Nd, Sm, Gd for x = ∼0.15. Parameters for the P–O, R–O and O–O first-neighbor peaks were obtained by Gaussian fitting. P–P and R–P distances were estimated from the positions of peak maxima. Effects of residual silica or alumina contents present as a result of glass processing were taken into account for selected samples. The P–O coordination number, N_PO, and the P–O, O–O, P–P distances are consistent with the presence of phosphate tetrahedra and are insensitive to the R species and the R₂O₃ content. Rare-earth coordination numbers, N_RO, decrease from ∼8 to ∼6.5 when x is increased from ∼0.15 to ∼0.25. N_OO and N_PP decrease with increasing R₂O₃ content indicating the network disintegration. The numbers N_RO of the metaphosphate glasses (x = ∼0.25) decreases from ∼7 to ∼6 when R is changed from La to Yb. This change is also indicated by the behavior of the R–O distances and by constant number densities of atoms. The decrease in N_RO with increasing R₂O₃ content is due to the reduction in the number of terminal O (O_T) available for coordination of the R³⁺ ions (six at metaphosphate composition). Especially for smaller R³⁺ ions sharing O_T between two R sites is not favored. The decrease by ∼0.04 nm of the prominent R–R first-neighbor distance with a change of R from La to Yb at the metaphosphate composition is indicated by a shift to higher magnitude of scattering vector of the shoulder occurring in front of the first main diffraction peak.     

Thermal stability and glass-forming ability of new Ti-based bulk metallic glasses

New Ti-based metallic glass (Ti₅₃Cu₁₅Ni_18.5Al₇Si₃M₃B_0.5 (M = Sc, Hf, Ta, Nb)) alloys were prepared by melt spinning and copper mold casting. The effects of foreign atoms on the thermal stability and the glass-forming ability were investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and differential thermal analysis (DTA). The results show that the values of T_rgs are 0.619, 0.609, 0.606, 0.597 K and ΔT_xs are 58, 54, 85, 78 K, respectively. The foreign atom’s size factor (∥R_F − R_Ti∣/R_Ti − 0.12∣) and mixing heat factor (∑x_iH_iF/∑x_iW_i) are proposed to predict the glass-forming ability and thermal stability, respectively.     

ArF laser induced pulse absorption in fused silica (type III): Modeling the fluence and repetition rate dependence

At 193 nm, weak stationary bulk absorption coefficients α^stat in standard and experimental grade fused silica (type III) are measured in dependence on the laser fluence H and repetition rate f. The samples show non-linear increases α^stat(H) for 0.2 ? H ? 5 mJ cm^?2 pulse^?1 (f = const.) and α^stat(f) for 100 ? f ? 1000 Hz (H = const.). An absorption model, focussing on ArF laser induced E′ center generation and annealing, and the associated rate equations are applied to simulate the experimental data quantitatively. From the simulations, material parameters like the 2-photon absorption (TPA) coefficient, the E′ center absorption cross section σ_E′ and the hydrogen related E′ annealing rate are calculated. TPA coefficients values of 9.7 · 10^?9 cm/W (standard grade material) and 1.4 · 10^?8 cm/W (experimental grade material), E′ center cross sections of 4.5 · 10^?18 and 3.6 · 10^?18 cm² and hydrogen annealing rates of 1.5 s^?1 (standard grade) and 3.4 s^?1 (experimental grade) are found.     

EPR study of molybdenum-lead-phosphate glasses

The local symmetry and interaction between paramagnetic ions in xMoO₃(1 ? x)[2 P₂O₅PbO] glasses with 0.5 ? x ? 50 mol% are investigated by EPR spectroscopy. For x ? 10 mol% the isolated Mo⁵⁺ ions surrounded by five oxygen ligands in a square-pyramidal form (C_4v symmetry) prevail. The short range disorder in the environment of Mo⁵⁺ ions is not significantly (ΔR/R ≈ 2%). At high molybdenum content (x > 20 mol%) the dipole–dipole and superexchange coupled Mo⁵⁺ ions appear and their number increases with the MoO₃ content. These two aspects are also correlated with the network modifier and former role of molybdenum oxide in function of its concentration. Thus a strong depolymerization of the phosphate structure and the formation of P–O–Mo or Mo–O–Mo bonds in studied glasses appear.     

The effect of fluoride on the Fe2+/Fe3+-redox equilibrium in glass melts in the system Na2O/NaF/CaO/Al2O3/SiO2

Liquids with the base compositions (16 − x/2)Na₂O · xNaF · 10CaO · 74SiO₂ (x = 0, 1, 3, and 4) and (10 − x/2) · Na₂O · xNaF · 10CaO · yAl₂O₃ · (80 − y)SiO₂ (x = 0, 1, 3, 5 and y = 5 and 15) doped with 0.25 mol% Fe₂O₃ were studied by means of square-wave voltammetry in the temperature range from 1000 to 1500 °C. With increasing temperature, the redox equilibria were shifted to the reduced state. Also while increasing the alumina concentration, the Fe²⁺/Fe³⁺-redox equilibrium is shifted to the reduced state. In the soda-lime–silica melt the addition of fluoride shifts the equilibrium to the oxidized state, while in the aluminosilicate melts with 15 mol% Al₂O₃, the equilibrium is shifted to the reduced state. In the aluminosilicate melts with 5 mol% Al₂O₃, the equilibrium was not affected by the fluoride concentration. This is explained by the structure of the respective glass compositions.     

Influence of Ar/C2H2 ratio on the structure of hydrogenated carbon films

The amorphous hydrogenated carbon films (a-C:H) were obtained on Si (1 1 1) wafers by plasma jet chemical vapor deposition (PJCVD). a-C:H coatings have been prepared at 1000 Pa in argon/acetylene mixture. The Ar/C₂H₂ gas volume ratio varied from 1:1 to 8:1. It was demonstrated that by varying the Ar/C₂H₂ ratio the composition, growth rate of the coatings, and consequently the structure of the film, can be controlled. The growth rate and surface porosity of coatings deposited at Ar/C₂H₂ = 8:1 ratio decrease slightly with an increase in the distance between the plasma torch nozzle and substrate from 0.04 to 0.095 m. The transmittance of the coatings in the IR region of 2.5–25 μm slightly increases, while the absorption peaks at 2850–2960 cm^?1 related with sp³ CH_2–3 modes remain unchanged with an increase in the distance. The Raman spectroscopy indicated that the a-C:H coating formed at the Ar/C₂H₂ = 8:1 and 0.06 m has the highest sp³ C–C fraction. The proposed PJCVD technique allows to achieve the growth rates up to 300 nm/s.     

Photoluminescence of Sm3+, Dy3+, and Tm3+-doped transparent glass ceramics containing CaF2 nanocrystals

Photoluminescence properties of Sm³⁺, Dy³⁺, and Tm³⁺-doped transparent oxyfluoride silicate glass ceramics containing CaF₂ nanocrystals were reported. Emission bands of ⁴G_5/2 → ⁶H_5/2 (562 nm), ⁴G_5/2 → ⁶H_7/2 (598 nm), ⁴G_5/2 → ⁶H_9/2 (645 nm) and ⁴G_5/2 → ⁶H_11/2 (706 nm) for the Sm³⁺: glass and glass ceramic, with an excitation at ⁶H_5/2 → ⁴F_7/2 (402 nm) have been recorded. Of them, ⁴G_5/2 → ⁶H_7/2 (598 nm) has shown a bright orange emission. With regard to the Dy³⁺: glass, a bright fluorescent yellow emission at 575 nm (⁴F_9/2 → ⁶H_13/2) and blue emission at 481 nm (⁴F_9/2 → ⁶H_15/2) have been observed, apart from 662 nm (⁴F_9/2 → ⁶H_11/2) emission transition with an excitation at 386 nm (⁶H_15/2 → ⁴I_13/2 + ⁴F_7/2) wavelength. Emission bands of ¹G₄ → ³F₄ (650 nm) and ¹G₄ → ³H₅ (795 nm) transitions for the Tm³⁺: glass and glass ceramic, with an excitation at ³H₆ → ¹G₄ (467 nm) have been observed. Of them, ¹G₄ → ³F₄ (650 nm) has shown bright red emission. Decay lifetime measurements were also carried out for all the observed Sm³⁺, Dy³⁺, and Tm³⁺-doped glass and glass ceramic emission bands.     

Effect of illumination on hydrogenated amorphous silicon thin films doped with chalcogens

Hydrogenated amorphous silicon thin films doped with chalcogens (Se or S) were prepared by the decomposition of silane (SiH₄) and H₂Se/H₂S gas mixtures in an RF plasma glow discharge on 7059 corning glass at a substrate temperature 230 °C. The illumination measurements were performed on these samples as a function of doping concentration, temperature and optical density. The activation energy varied with doping concentration and is higher in Se-doped than S-doped a-Si:H thin films due to a low defect density. From intensity versus photoconductivity data, it is observed that the addition of Se and S changes the recombination mechanism from monomolecular at low doping concentration films to bimolecular at higher doping levels. The photosensitivity (σ_ph/σ_d) of a-Si, Se:H thin films decreases as the gas ratio H₂Se/SiH₄ increased from 10^?4 to 10^?1, while the photosensitivity of a-Si, S:H thin films increases as the gas ratio H₂S/SiH₄ increased from 6.8 × 10^?7 to 1.0×10^?4.     

The shoving model for the glass-former LiCl·6H2O: A molecular dynamics simulation study

Molecular dynamics (MD) simulations of LiCl·6H₂O showed that the diffusion coefficient D, and also the structural relaxation time <τ>, follow a power law at high temperatures, D^?1 ∝ (T ? T_o)^?μ, with the same experimental parameters for viscosity (T_o = 207 K, μ = 2.08). Decoupling between D and <τ> occurs at T_x ～ 1.1T_o. High frequency acoustic excitations for the LiCl·6H₂O model were obtained by the calculation of time correlation functions of mass current fluctuations. The temperature dependence of the instantaneous shear modulus, G_∞(T), was considered in the shoving model for supercooled liquids [J.C. Dyre, T. Christensen, N.B. Olsen, J. Non-Cryst. Solids 352 (2006) 4635] resulting in a linear relationship log (D^?1) vs. G_∞/T.     

Enhanced mid-IR luminescence of Tm3+ ions in Ga2S3 nanocrystals embedded chalcohalide glass ceramics

Chalcohalide glass with a composition of 65GeS₂–25Ga₂S₃–10CsI (in mol%) doped with 0.6 wt% Tm³⁺ ions was prepared by conventional melt–quench method. By heat treating the precursor glass at 20 °C above its glass transition temperature T_g for different durations, IR transparent glass ceramics were obtained. X-ray diffraction (XRD) and scanning electron microscope (SEM) showed that Ga₂S₃ crystallites were precipitated after heat treatment and their grain sizes were in nano-scale and increased with the elongation of heat treated time. Mid-IR luminescence properties of the glass and transparent glass ceramic samples were investigated. The emissions at 2.3 and 3.8 μm corresponding to optical transitions of ³H₄ → ³H₅ and ³H₅ → ³F₄ of Tm³⁺ ions were significantly enhanced by the presence of Ga₂S₃ nanocrystals and reached a maximum after 8 hours treatment.     

Bond character,optical properties and ionic conductivity of Li2O/B2O3/SiO2/Al2O3 glass: Effect of structural substitution of Li2O for LiCl

A glass of composition (20 ? x)Li₂O–xLiCl–65B₂O₃–10SiO₂–5Al₂O₃ where 0 ? x ? 12.5 wt% is prepared using the normal melt-quenching technique. The optical constants and electrical conductivity and their correlation are investigated, furnished and discussed with the substitution of Li₂O for LiCl. The mechanism of the optical absorption and the calculated Urbach energy follow the rule of phonon-assisted transitions. The ionic conduction mechanism is determined by activation energy process. Substitution up to 10 wt% LiCl provides high ionic conductivity (1.9 × 10^?2 Ω^?1 m^?1) due to the high average electronegativity of LiCl which increases the polarizability of lithium ions. The small cation–anion distance approach confirmed the enhancement in ionic conductivity of LiCl containing glass compared to that of Li₂O. Due to the large size of Cl^? ions, there is an expansion of the lattice which in turn broadens the available path windows. For 12.5 wt% LiCl, anomalous density behavior is observed and a reduction in conductivity is occurred, σ = 5.4 × 10^?3 Ω^?1 m^?1. Owing to the model of bond fluctuation, the reduction is attributed to the increase in the alkali halide concentration which creates bottlenecks that hinder the motion of Li⁺ ions. The ionic conductivity character is strongly supported by the behavior of the glass ionicity factor, density, molar volume, refractive index, average boron–boron separation, molar refraction, metallization criterion and non-bridging oxygen concentration of the studied glass.     

Formation of nanoclusters through silver reduction in glasses: The model

The system of equations describing the formation of silver nanoclusters through the reduction of ionic silver in the course of thermal processing of silver containing glasses in hydrogen is formulated and solved numerically. The processes of the clusterization of neutral silver within the glass and at the surface, and the growth of the nanoclusters are modeled with the account of different mobilities and concentrations of the participating species. The influence of the variation of diffusion coefficients of Ag⁰ atoms, Ag⁺ and H⁺ ions as well as concentration of Ag⁺ ions in the glass matrix. It is shown that concentration distribution of neutral hydrogen (H⁰) strongly depends on the relationship between concentration of Ag⁺ ions (C_Ag⁺) and concentration of neutral hydrogen at the glass surface (C₁), as well as between diffusion coefficients of silver and hydrogen ions. When D_Ag⁺ ≪ D_H⁺ and C_Ag⁺ ≫ C₁, the total hydrogen concentration profile (C_Htot = C_H⁰ + C_H⁺) is defined by silver ion diffusion coefficient D_Ag⁺. Concentration of neutral silver, C_Ag⁰, represents a bell-shaped depth distribution, whose maximum moves to the depth linearly with t^1/2 with the rate depending both on the diffusion coefficient of neutral silver, D_Ag⁰, and neutral hydrogen, D_H⁰. It is shown that the depth position of the maximum coincides with the frontier of the layer filled by clusters. The kinetics of the cluster radius growth in the bulk of the glass also depends both on D_Ag⁰ and D_H⁰ and essentially deviated from the kinetic law R² ∼ t predicted earlier in the assumption of time-independent oversaturation. The kinetics of Ag cluster growth on the glass surface turned out independent of the D_Ag0 diffusion coefficient.     

Sol–gel derived organic–inorganic hybrid electrolytes for thin film electrochromic devices

Sol–gel derived, lithium ion conducting organic–inorganic hybrid electrolytes for ambient temperatures applications, have been synthesized from tetraethyl orthosilicate (TEOS), poly(ethylene oxide) (PEO), propylene carbonate (PC), propylene oxide, butyl acrylate, butyl methacrylate, ethyl acetoacetate and LiClO₄ precursors. Mass fractions of the organic additions in the gels were of ca 30 mass% for gels 0/B, F–H and 40 mass% for gel J. The colorless transparent or translucent hybrid materials obtained in this work were aged at room temperature for at least three weeks and then dried at 80 °C for 3 h. The morphology and structure of all compositions were investigated by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM/EDX), Fourier transform infrared spectroscopy and ²⁹Si MAS nuclear magnetic resonance. Amorphous nature of the hybrids was confirmed by X-ray diffraction. SEM, FTIR and NMR analysis showed structural properties and [SiO₄] tetrahedrons poly-condensation process to be strongly influenced by organic additives have been employed. Room temperature ionic conductivities of the hybrid electrolytes were in a range of 9.84 × 10⁻⁴–1.56 × 10⁻³ Ω⁻¹ cm⁻¹.     

Optical properties and infrared-to-visible upconversion in Er3+-doped GeO2–Bi2O3 and GeO2–PbO–Bi2O3 glasses

Luminescence properties and upconversion studies of germanate glasses in ternary GeO₂–PbO–Bi₂O₃ and binary GeO₂–Bi₂O₃ systems containing Er₂O₃ (0.1–1.0 wt%) are presented for the first time. The Judd-Ofelt parameters found for these glasses are: Ω₂ = 4.50 × 10⁻²⁰ cm², Ω₄ = 1.55 × 10⁻²⁰ cm² and Ω₆ = 0.69 × 10⁻²⁰ cm² for binary glasses and Ω₂ = 4.44 × 10⁻²⁰ cm², Ω₄ = 1.82 × 10⁻²⁰ cm² and Ω₆ = 0.39 × 10⁻²⁰ cm² for ternary glasses. The refractive index of these glasses is found to be ∼2. The transition ⁴I_13/2 → ⁴I_15/2 is peaked at ∼1.53 μm and shows a radiative lifetime around 5 ms. Both systems exhibit similar emission cross-section at 1.53 μm around 0.8 × 10⁻²⁰ cm². Upconverted green emission at ∼530 nm (²H_11/2 → ⁴I_15/2) and ∼550 nm (⁴S_3/2 → ⁴I_15/2) and red emission at ∼668 nm (⁴F_9/2 → ⁴I_15/2) are observed under 980 nm cw excitation. Our results suggest that these glasses are promising candidates for applications in photonics.     

Efficient plasmonic coupling between Er3 +:(Ag/Au) in tellurite glasses

We report a systematic study of the localized surface plasmon resonance effects on the photoluminescence of Er^3 +-doped tellurite glasses containing Silver or Gold nanoparticles. The Silver and Gold nanoparticles are obtained by means of reduction of Ag ions (Ag⁺ → Ag⁰) or Au ions (Au^3 + → Au⁰) during the melting process followed by the formation of nanoparticles by heat treatment of the glasses. Absorption and photoluminescence spectra reveal particular features of the interaction between the metallic nanoparticles and Er^3 + ions. The photoluminescence enhancement observed is due to dipole coupling of Silver nanoparticles with the ⁴I_13/2 → ⁴I_15/2 Er^3 + transition and Gold nanoparticles with the ²H_11/2 → ⁴I_13/2 (805 nm) and ⁴S_3/2 → ⁴I_13/2 (840 nm) Er^3 + transitions. Such process is achieved via an efficient coupling yielding an energy transfer from the nanoparticles to the Er^3 + ions, which is confirmed from the theoretical spectra calculated through the decay rate.