Magnesium Zinc Sulfophosphate Glass Research Articles

Titanium Nanoparticles Modified NIR Emission of Neodymium Doped Magnesium Zinc-Sulfophosphate Glass: Effect of Heat Treatment on Surface Plasmon Resonance Bands

New type plasmonic sensitizer, titanium nanoparticles (Ti NPs) shown potential in enhancing photoluminescence of rare-earth ions (REIs) as doped into magnesium zinc-sulfophosphate (MZS) glass for optical to optic application. Here, neodymium ions (Nd3+)-doped MZS glass with Ti NPs inclusion gone heat treatment (HT) at 450°C for 6 and 12 hours in order to tune the NPs size and tailor their plasmonic strength. The sample was characterized using X-ray diffractometer (XRD), high-resolution transmission electron microscope (HRTEM), and photoluminescence (PL) spectrometer. Heat treatment (HT) grows Ti NPs with a mean size ≈ 16 nm. The SPR bands are probed around 585and 739 nm. The SPR band intensities change with HT duration. The NIR PL bands were perceived around 878 nm, 1050 nm and 1322 nm corresponding to 4F3/2→4I9/2, 4F3/2→4I11/2 and 4F3/2→4I13/2 transitions, accordingly. The PL transition 4F3/2→4I9/2 (878 nm) and 4F3/2→4I13/2 (1322 nm) is enhanced about 1.44 and 1.52 times respectively, after 12 hours HT. The results show that HT enhances PL through SPR amplification. These findings may be useful in developing solid-state lasers and optical materials.

Altering coupled mode of surface plasmon resonance mediated by silver and gold nanoparticles through heat treatment: Judd ofelt, racah and NIR-luminescence of neodymium doped magnesium–zinc-sulfophosphate glass

Manipulating surface plasmon resonance (SPR) of silver (Ag) and gold (Au) nanoparticles (NPs) in amorphous material may open new possibilities in optic and photonic fields. Driven by this fact, heat treatments (HT) were used to tune the excitation mode of SPR. The Nd3+ doped magnesium-zinc-sulfophosphate glasses embedded with Ag and Au NPs were heat-treated at 450 °C for 6 and 12 h and characterized using X-ray diffractometer (XRD), high-resolution transmission electron microscope (HRTEM), UV–Vis–NIR absorption and photoluminescence (PL) spectrometer. The mean size of NPs was slightly reduced (4.68 nm→ 4.35 nm) after 12 h of HT due to the elastic ripening process, causes by internal pressure within NPs. Unusual multiple SPR bands were evidence around 419, 481, 613, 676, 776, 848 and 939 nm after the glass (AgAu6h) is heat-treated for 6 h. Thirteen absorption bands are recorded within 326–875 nm, corresponding to the Nd3+ ion transitions. The NIR PL bands of Nd3+ ion were detected around 878 nm, 1050 nm, and 1322 nm corresponding to 4F3/2 → 4I9/2, 4F3/2 → 4I11/2, and 4F3/2 → 4I13/2 transitions, respectively. Overall, sample coded AgAu12 h disclosed the highest bandwidth gain of 0.09, 1.14, and 3.06 ( × 10−22 cm3) assigned to transition 4F3/2 → 4I9/2, 4F3/2 → 4I11/2, and 4F3/2 → 4I13/2, respectively, with a quantum efficiency of 21.06% (for transition 4F3/2 → 4I11/2). The HT can modify the intensity of PL through different NPs assemblies (single, dimer, trimer) and bonding modes (e.g: longitudinal dipolar or quadrupolar coupling mode). The unique optical feature discovered may be useful in customizing solid-state laser materials.

Correlation of mechanical properties and crystal field parameters of europium-doped magnesium–zinc–sulfophosphate glasses

Europium-doped magnesium–zinc–sulfophosphate glasses of molar composition (65 − x) P2O5–20MgO–15ZnSO4–xEu2O3 (x = 0.0, 0.5, 1.0, 1.5 and 2.0) were prepared via melt-quenching method. The synthesized glasses were characterized at room temperature to determine the relationship between Racah and mechanical properties. The FTIR spectra of glasses in the range of 4000–400 cm−1 revealed the presence of characteristic functional groups. The Young’s, shear and bulk moduli of glasses were observed to enhance with the increase in Eu3+ contents. The ratio increased from 0.710 to 0.747 which confirms the increase in the degree of centrality of the glasses. Racah parameters evaluated from first three major absorption bands were reduced from 72.3906 to 60.1111 cm−1 with the increase in Europium contents, thus signifying the weakening in f–f electrons repulsion. Crystal field parameters decrease from 42.2445 to 35.2397 cm−1 denoting strong covalent character of ligand bond of the synthesized glass system. The synthesized glasses have potential for the development of hard surface engineering.

Synergistic effects of Nd3+ and Ag nanoparticles doping on spectroscopic attributes of phosphate glass

Abstract Efficient, inexpensive and eye−safe new host glass as up−conversion (UC) emission solid−state laser media became demanding. Nanoparticles (NPs) of various noble metals have been inserted into the phosphate−based amorphous host matrix to enhance the rare-earth ions (REIs) stimulated emission cross−section. Furthermore, only a few reports exist on the combined influences of neodymium ions (Nd3+) and pure silver (Ag) NPs on the structural and optical response of magnesium zinc sulfophosphate (MZSP) glasses. In this view, a series of MZSP glasses were doped by Nd3+ ions and pure Ag NPs (at different concentrations) to improve their structural and optical properties. Such melt−quench synthesized glasses were characterized at room temperature using diverse analytical measurement tools. The XRD pattern of as−quenched samples approved their amorphous nature. The FTIR and Raman spectra of glasses revealed the presence of characteristic bonding vibrations of different functional groups. The TEM images showed the existence of spherical Ag NPs (mean size of 8.34 nm) in the host glass matrix. The surface plasmon resonance (SPR) band of Ag NPs was detected around 451 nm. The UV–Vis–NIR absorption and PL emission spectra of glasses were utilized to evaluate the Judd−Ofelt (JO) intensity parameters ( Ω 2 , Ω 4 and Ω 6 ) and radiative properties. The observed fluctuation in the Ω 2 values with the increase in Ag NPs contents was attributed to the dynamic change of ligands symmetry around Nd3+ inside the glass network. Variations in the Ω 4 and Ω 6 values with the increase in Ag NPs contents indicated a considerable reduction in the glass rigidity. The PL spectra of glasses exhibited a prominent band around 576–584 nm corresponding to the 2G7/2 +4G5/2 → 4I9/2 transition in Nd3+. Glass prepared with 0.5 mol% of Ag NPs disclosed the highest PL enhancement (≈19 times) and largest emission cross−section (≈4.35 × 10−24 cm2) which was ascribed to the synergism between Ag NPs SPR mediated strong local field effect (LFE) and the subsequent energy transfer to Nd3+ appeared in the proximity of NPs. It was concluded that the proposed glass composition can lead to the development of UC solid−state laser compared to many other reported glass system.

Luminescence of Neodymium Ion-Activated Magnesium Zinc Sulfophosphate Glass: Role of Titanium Nanoparticles Sensitization

Abstract A series of neodymium ion (Nd3+)-activated magnesium zinc sulfophosphate glasses sensitized with various contents of titanium nanoparticles (Ti NPs) were prepared via the melt-quenching method and characterized. The influence of Ti NPs on the optical characteristics of the glasses was determined. The XRD patterns of the as−quenched samples verified their amorphous nature. The differential thermal analyses (DTA) of the samples showed their good thermal stability against crystallization. The HRTEM image of the samples exhibited the formation of Ti3O5 NPs inside the amorphous network. The SPR bands of Ti3O5 NPs were probed at 587 nm and 730 nm. The ESR spectra of the glasses disclosed the existence of the singlet oxygen induced by the surface plasmon resonance (SPR) effect of Ti3O5 NPs. The absorption spectra of the glasses revealed twelve characteristic bands of Nd3+. The Judd-Ofelt calculations were performed to support the experimental spectroscopic results. The up−conversion (UC) photoluminescence (PL) emission spectra of the glasses revealed an intense yellow band at approximately 585 nm due to the 4G5/2 + 2G7/2 → 4I9/2 transition in Nd3+. The glass prepared with 0.4 mol% of Ti NPs displayed the highest PL intensity enhancement and maximum gain bandwidth. In short, the overall properties of the glasses were sensitive to the contents of Ti NPs. The observed improvement in the optical traits of the proposed glasses was attributed to the Ti NPs SPR-induced local field effect (LFE) in the proximity of Nd3+. Present findings could contribute to the development of the proposed glass-based solid−state laser and photonic devices.

Spectroscopic properties of neodymium doped magnesium zinc sulfophosphate glass: Synergistic effects of titanium and silver nanoparticles embedment

Abstract Synergistic effects of two distinct metal/semiconductor nanoparticles (NPs) upon incorporation into different materials medium have shown to open up a new frontier in material research. In this view, two series of neodymium ions (Nd3+) doped magnesium zinc−sulfo phosphate glass glasses composition 58.5P2O5–20MgO–20ZnSO4–1.5Nd2O3–0.5AgNPs−yTi NPs (where y = 0.1, 0.2, 0.3 and 0.4 mol% in excess) and 58.5P2O5–20MgO–20ZnSO4–1.5Nd2O3–0.4TiNPs−xAg NPs (where x = 0.1, 0.2, 0.3, 0.4 and 0.5 mol% in excess) were prepared via melt−quenching method. The as-synthesized samples were characterized to determine the combined effects of silver (Ag)/titanium (Ti) NPs inclusion on their spectroscopic properties. XRD analyses of as-quenched samples confirmed their amorphous nature. The FTIR and the Raman spectra revealed the presence of characteristic vibration bonds inside the studied glass network. The HRTEM images verified the nucleation of both Ag and Ti3O5 NPs inside the host matrix. The occurred twelve absorption bands centred at 352, 430, 458, 473, 512, 526, 582, 626, 682, 745, 802 and 875 nm were assigned to the respective transitions from the ground state (4I9/2) to the excited states of 2D1/2+4D3/2+4D5/2, 2P1/2, 4G11/2, 2D3/2+2P3/2+2G9/2, 4G9/2+2K13/2, 4G7/2, 4G5/2+2G7/2, 2H11/2, 4F9/2, 4F7/2+4S3/2, 4F5/2+2H9/2 and 4F3/2 in Nd3+. The probed surface plasmon resonance (SPR) band of Ag NPs (at 442 nm) and Ti3O5 NPs (at 585 and 730 nm) indicated their successful embedment within the glass matrix. Meanwhile, the SPR bands of both NPs disclosed a slight red−shift when embedded together inside the glass compared to their individual incorporation which was ascribed to the near field effect mediated alteration in natural frequency of the oscillator. The observed prominent yellow band around 585 nm in the photoluminescence (PL) spectra of glasses was approved to the transition of 2G7/2+4G5/2 → 4I9/2. The NIR PL spectra depicts bands around 874 nm, 1050 nm and 1322 nm, corresponding to 4F3/2 → 4I9/2, 4F3/2 → 4I11/2 and 4F3/2 → 4I13/2 transitions respectively. The evidenced PL intensity quenching in the glass prepared bands around with both Ag and Ti3O5 NPs was attributed to the effect of metallic NPs mediated local heating. Judd-Ofelt (JO) theory was used to evaluate the spectroscopic properties of the glass and make contact with experimental findings. Sample embedded with 0.4 mol% of Ti NPs together with 0.3 mol% of Ag NPs showed highest stimulated emission cross−section (4.78 × 10−24 cm2) for transition 2G7/2+4G5/2 → 4I9/2. It was established that the synergistic effects of two types of metal NPs embedded inside the Nd3+ doped proposed host glass may be useful to achieve customized spectroscopic properties required for solid state laser and photonic application.

Nd3+ doped magnesium zinc sulfophosphate glass: New candidate for up-conversion solid state laser host

Abstract Phosphate based glasses with neodymium ions (Nd3+) doping are advantageous for high energy short pulse up−conversion (UC) solid−state laser applications. In this work, the magnesium zinc sulfophosphate glass systems with composition of (60−x)P2O5–20MgO–20ZnSO4−xNd2O3 (where x = 0.0, 0.5, 1.0, 1.5 and 2.0 mol%) were prepared via melt−quenching method. Structures of as−quenched samples were characterized at room temperature using Fourier-transform infrared spectrometer FTIR and Raman measurements. Thermogravimetry−differential thermal analyses (TG−DTA) confirmed the thermal stability (>100 °C) of selected glasses. Ultraviolet–visible near-infrared (UV–Vis–NIR) absorption and photoluminescence (PL) spectroscopy were used to evaluate the optical properties of the proposed glasses. Absorption spectra of glasses revealed thirteen characteristic bands in the range of 328–875 nm which were assigned to the ground state to various excited states transitions in Nd3+ ions. The reliability of the Judd−Ofelt (JO) evaluation was authenticated via the attainment of the very low value of root mean square deviation (0.18 × 1020 to 0.63 × 1020 cm2). The spectroscopic quality factors of glasses were enhanced from 1.51 to 2.07 with the increase in Nd3+ ions doping contents. Glass containing 1.5 mol% of Nd3+ ions displayed a slight reduction of Ω2 value, validating the improvement of symmetrical environment around Nd3+ ions in the glass network. Meanwhile, the observed enhancement in the Ω4 and Ω6 values with increasing Nd3+ ions content was ascribed to the improvement of glass viscosity and rigidity. The achieved green−yellowish PL band around 580 nm (emerged from 2G7/2 → 4I9/2 transition) exhibited large branching ratio (83–84%), indicating efficient lasing transition with improved emission cross−section (3.25–4.70 × 10−25 m2) in the glass system. Based on results, the proposed glass system was effective to be used in UC solid−state laser applications.

Correlation of Optical and Mechanical Properties of Silver Nanoparticles Sensitized Europium Doped Magnesium Zinc Sulfophosphate Glasses

Magnesium-zinc-sulfophosphate glasses with various concentration of Silver nanoparticles (AgNPs) of molar composition 63.5P2O5–20MgO –15ZnSO4–1.5Eu2O3 –yAgNps (y = 0.0, 0.1, 0.3, 0.5, 0.7,0.9 and 1.1 g in excess) were prepared via melt-quenching method. As-synthesized glasses were characterized at room temperature to determine the relationship between structural and mechanical properties. Densities of glasses were increased from 3.0720 to 4.3304 g.cm-3 with increase in AgNPs embedding levels, suggesting the network shrinkages and enhanced compactness. The Young’s, shear and bulk modulus of glasses were observed to enhance with the increase in AgNPs contents. The Poisson’s ratio of the studied glasses was increased from (0.0978 to 0.1416) while the values of both Vickers hardness (from 0.0658 to 0. 0.0682 GPa) as well as (from 0.8350 to 0.8916) were increased. The proposed glass composition may be useful for the development of hard surface engineering.

Europium Doped Magnesium Zinc Sulfophosphate Glass as Potential Red Laser Host

Demand for rare earth ions (REIs) doped inorganic glasses have been ever-increasing for diverse photonic applications. Synthesis of these glasses needs the appropriate choice of suitable host matrices, modifiers, and REIs as dopants to improve their spectroscopic traits. In this realization, a new series of magnesium-zinc-sulfophosphate glasses were prepared with varied europium ions (Eu3+) doping contents (0 to 2.0 mol%). Such melt-quench synthesized glasses were characterized at room temperature by diverse analytical techniques to determine their physical and optical properties. XRD pattern of as-quenched samples confirmed their amorphous nature. Densities of the glass system were observed to increase from 2.540 to 2.788 g.cm−3 with the increase in Eu3+ doping contents from 0 to 2.0 mol% which were attributed to the generation of more bridging oxygen atoms and enhanced network compactness. Photoluminescence (PL) emission spectra of glasses exhibited four characteristic peaks positioned at 593, 613, 654 and 701 nm assigned to corresponding 5D0→7F0, 5D0→7F2, 5D0→7F3, and 5D0→7F4 transitions in Eu3+, in which the intensity of the peak at 613 nm (red) was highest. Emission intensities of all peaks were enhanced with the rise in Eu3+ content up to 1.5 mol% and quenched thereafter. It was affirmed that the physical and optical traits of these glass compositions can be improved by adjusting the Eu3+ doping contents. The proposed glass compositions may be potential for the development of varied photonic devices especially for eye safe solid-state red laser and fibre sensors.

Optical Properties of Neodymium Doped Magnesium Zinc Sulfo- Phopshate Glass: Impact of Gold Nanoparticles Inclusion

Gold (Au) nanoparticles (NPs) incorporated in magnesium zinc sulfo-phosphate glass with the molar composition of (58.5P_2O_5–20MgO–20ZnSO_4–1.5Nd_2O_3–xAu NPs (where x = 0.0, 0.1, 0.2, 0.3, and 0.4 mol%) were prepared via melt quench technique. The effect of Au NPs as incorporated in Nd^3+ doped glasses were studied using X‒ray diffraction (XRD), High Resolution-Transmission Electron Microscope (HR‒TEM), UV‒Visible-NIR absorption spectrometer and photoluminescence spectrometer. The amorphous nature of glass is confirmed via XRD measurements and existence of Au NPs inside the glass is reveal by HR-EM. The typical absorption bands of Nd^3+ are attained which positioned around 352, 430, 459, 474, 512, 525, 581, 626, 682, 744, 801and 875 nm. Up-conversion (UC) photoluminescence (PL) demonstrated six prominent emission bands located around 420, 445, 460, 484, 515 and 545 nm corresponding transition 2P_1/2--> 4I_9/2, 2D_5/2-->4I_11/2, 2P_1/2-->4I_11/2, 2D_5/2-->4I_13/2, 2K_15/2,4G_7/2-->4I_11/2,4I_9/2 and 2D_5/2-->4I_15/2 respectively. Glass containing 0.1 mol% of Au NPs shows utmost PL enhancement and the emission decrease beyond 0.1 mol% of Au NPs depicts re-absorption of SPR and increase of non-radiative channel. The improvement of PL intensity attributed to local field effect of Au NPs that altered the environment in proximity Nd^3+ ions. The proposed glass could be potential for improvement of solid state laser design.

Samarium doped calcium sulfate ultra-phosphate glasses: Structural, physical and luminescence investigations

Luminescence mechanism of RE doped glasses is significant in optical devices, the glasses of compositions (80-x) P2O5-20CaSO4-(x) Sm2O3 with 0.3 ≤ x ≤ 1.5 mol% have been prepared by melt-quench method. The result of XRD patterns affirmed the amorphous nature of the samples. The structure was investigated successfully using FTIR, NMR and Raman in order to examine the molecular vibrational modes and to verify the de-polymerization process. Absorption and photoluminescence spectra of Sm2O3 doped calcium ultra-phosphate glasses have been reported. Three emission band of Sm3+ centered at 4G5/2→6H9/2 (642 nm), 4G5/2→6H7/2 (597 nm) and 4G5/2→6H5/2 (559 nm) have been observed at λexc = 402 nm. The spectroscopic research reveals the de-polymerization pattern in P2O5 glass structure by conversion of Q3→Q2→Q1 and to Qo units. Physical and optical properties were investigated, doped ions were successfully position at interstice spaces in CSP, the physical properties such as, density, Polarizability, Molar refractivity, and refractive index etc, have been estimated. The absorption spectra in the wavelength range 900–1700 nm were determined, the spectra consist of seven absorption peaks corresponds to transitions from 6H5/2 ground state to excited state. From the absorption edge spectra, the band gap (direct and indirect) and the Urbach energy (ΔE) values were evaluated. The conventional JO (Judd-Ofelt) intensity parameters (Ω2, Ω4 and Ω6) and root mean square (δrms) deviation have been evaluated and discussed with respect to Sm3+ concentration. Obtained result goes along with the Sm3+ doped magnesium zinc sulfo-phosphate glasses for advancement of many functional glasses.

On the optical properties of Er3+ ions activated magnesium zinc sulfophosphate glass: Role of silver nanoparticles sensitization

Effects of silver (Ag) nanoparticles (NPs) on the physical and optical properties of erbium ions (Er3+) doped magnesium zinc sulfophosphate glasses of composition (59.5-x)P2O5-20.0MgO-20.0ZnSO4-0.5Er2O3-xAgCl (where x ≤ 1.5 mol%) were examined. Transparent bubble free glasses were prepared using melt quenching method. As-quenched samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), ultraviolet-visible (UV–Vis) absorption and photoluminescence (PL) spectroscopy to determine the feasibility of achieving their improved optical properties useful for photonic devices. Furthermore, Judd-Ofelt intensity and radiative parameters were evaluated to complement the experimental observations. XRD patterns of as-quenched samples confirmed their amorphous nature. TEM images of glasses revealed the nucleation of Ag NPs with average size of 10 nm. UV–Vis spectra of glasses exhibited nine absorption bands assigned to 4f-4f transitions of Er3+ ions. An enhancement in the PL emission intensities corresponding to the 2H11/2→4I15/2 and 4S3/2→4I15/2 transitions by a factor of 6 and 5 were achieved. Such enhancement was attributed to the local field effect (LFE) stimulated by the surface plasmon resonance (SPR) of Ag NPs alongside energy transfer mechanism among Er3+ ions and Ag NPs.

Tailored optical properties of Dy3+ doped magnesium zinc sulfophosphate glass: Function of silver nanoparticles embedment

Glasses with composition (59.5-x)P2O5–20.0MgO-20.0ZnSO4–0.5Dy2O3-xAgCl (0.0≤x≤ 0.5 mol%) were prepared by melt-quenching method and characterized thoroughly. The role of silver nanoparticles (Ag NPs) inclusion on the spectroscopic and the physical properties of the synthesized glasses were determined. Judd-Ofelt (J-O) theory was used to complement the experimental optical data. TEM images confirmed the existence of Ag NPs of average size ≈4.5 nm. The absorption spectra showed eleven bands aroused from the ground state (6I15/2) to various excited states transitions of dysprosium (Dy3+) ion. The surface plasmon resonance (SPR) peak of Ag NPs was probed around 446 nm. The calculated J-O parameter (Ω2) for the glass without Ag NPs incorporation was the highest, indicating the strong metal-ligand covalence bond. Irrespective of Ag NPs contents, the emission spectra of the studied glasses revealed two intense photoluminescence bands centered at 480 nm (blue: 4F9/2→6H15/2) and 574 nm (yellow: 4F9/2→6H13/2) accompanied by two very weak red bands positioned at 662 and 752 nm. The luminescence intensity of both blue and yellow band was enhanced by a factor of 2 and it was 1.5 fold for the red bands. This enrichment in the luminescence intensity was attributed to the Ag NPs mediated SPR effect and subsequent energy transfer from the Ag NPs to the nearsighted Dy3+ ions.

Spectroscopic traits of holmium in magnesium zinc sulfophosphate glass host: Judd – Ofelt evaluation

Basic understanding on the spectroscopic behaviour of holmium ion (Ho3+) doped in magnesium zinc sulfophosphate glass host is essential for the development of inexpensive and eye–safe infrared solid state laser. To achieve this goal, six such glass samples were prepared using melt quenching method at varying Ho3+ ions contents. FTIR and Raman spectra were recorded to determine the structural properties of the synthesized glasses. Samples were characterized using UV–Vis–NIR absorption and photoluminescence (PL) spectroscopy to determine the Ho3+ ions concentration dependent spectral properties. The absorption spectra of the studied glasses revealed seven peaks which were allocated to the transition from the ground state (5I8) to the excited states (3H6, 5G5, 5G6, 3K8, 5F3, 5F4+5S2, 5F5, 5I6, and 5I7) of Ho3+ ion. Judd–Ofelt (J–O) intensity parameters (Ω2, Ω4, and Ω6) and radiative parameters such as transition probabilities, fluorescence branching ratio, and radiative lifetime were calculated from the measured optical spectra. The nephelauxetic ratio shows negative value signifying ionic bond between REI and the ligand. The value of J–O parameters Ω2, Ω4, Ω6 and spectroscopic quality factor were varied in the range of (4.10 − 8.05) ×10−20 cm2, (1.96−2.77) ×10−20 cm2, (1.95−2.31) ×10−20 cm2 and (1.01 − 1.25), respectively. The small of Ω2 indicated high symmetry around Ho3+ ions while the large value of Ω4 and Ω6 signified the occurrence of high rigidity of the glasses. PL emission spectra of the synthesized glasses disclosed two significant bands assigned to 5F4 → 5I8 (green) and 5F5 → 5I8 (red) transitions. The stimulated emission cross–section for the green and red luminescence was ranged respectively between (8.60 − 10.79) ×10−21 cm2 and (9.35 − 11.62) ×10−21 cm2. The proposed glasses was established to be beneficial for solid state laser application.

Improved absorbance of holmium activated magnesium-zinc-sulfophosphate glass

Constant efforts are dedicated to overcome the limitations of phosphate based glass system, where sulfophosphate glasses (SPGs) played a key role. Rare earth ions (REIs) doped magnesium zinc SPG (MZSPG) systems are technologically prospective due to their several unique attributes. Construction of integrated light amplifier and solid state laser needs the maximum gain within small component dimensions. Thus, Ho3+ ions doped SPGs are believed to meet this demand. Ho3+ ions having sharp optical absorption peaks in the spectral range of 200–900 nm is useful for diversified applications. Conversely, SPGs comprising of oxides of sulphur, phosphorous and at least one other component with SO42- ions contents lower than PO43- with low melting temperature makes them a distinctive class of technologically potential disordered system. In this view, modification of Ho3+ ions absorbance inside SPGs network is challenging. To achieve this goal, following melt-quenching route we prepared a series of Ho3+-doped MZSPG system of composition (60-x)P2O5-(20)ZnSO4-(20)MgO–(x)Ho2O3, where x = 0.0, 0.5, 1.0, 1.5 2.0, and 2.5 mol%. The influence of Ho2O3 concentration on the density, refractive index, and optical absorption properties of the synthesized glass system is examined. The density and refractive index is found to increase with increasing Ho2O3 concentration. The absorption spectra revealed nine prominent peaks centered at 387, 418, 450, 484, 538, 642, 1148 and 1945 nm. The glass absorbance is enhanced with increasing Ho3+ contents. Optical band gap energy is found to range from 3.847 to 3.901 eV. The reduction of Urbach energy from 0.257 to 0.191 eV with increasing Ho3+ contents verified the shrinkage of glass network structure and lowering of defect mediated disorder. In-depth investigations on the structural and optical properties of MZSPG system are underway to achieve the milestones set for photonic devices.

Structural and physical properties of $$\hbox {Sm}^{3+}$$ Sm 3 + doped magnesium zinc sulfophosphate glass

Samarium (\(\hbox {Sm}^{3+})\) doped magnesium zinc sulfophosphate glass system of composition (60–\(x)\hbox {P}_{2}\hbox {O}_{5}\)–20MgO–20ZnSO\(_{4}\)–\(x\hbox {Sm}_{2}\hbox {O}_{3}\) (\(x =\) 0.0, 0.5, 1.0, 1.5 and 2.0 mol%) were synthesized using melt-quenching technique. The structure and physical properties of prepared glass samples were characterized. The X-ray diffraction pattern verified their amorphous nature. The physical properties such as density, refractive index, molar volume, rare earth ion concentration, etc. were calculated. The decrease in the optical bandgap energy with increasing \(\hbox {Sm}_{2}\hbox {O}_{3}\) contents was attributed to the alteration in the glass network structures. Fourier transformed infrared spectra and Raman analyses manifested the depolymerization of \(\hbox {ZnSO}_{4}\) in the phosphate host matrix. The present findings may be beneficial for the advancement of functional glasses.

Spectroscopic attributes of Sm3+ doped magnesium zinc sulfophosphate glass: Effects of silver nanoparticles inclusion

We report the modified optical properties of Sm3+ doped magnesium zinc sulfophosphate glass system with silver nanoparticles (Ag NPs) inclusion. Three glass samples were prepared using melt quenching method and characterized. TEM images revealed the nucleation of Ag NPs with average diameter ≈12.50 nm. The UV–Vis–NIR spectra showed thirteen absorption bands. The surface plasmon resonance (SPR) band of Ag NPs was manifested at 446 nm. FTIR spectra disclosed the bonding vibrations for P-O bonds, P-O-P linkages, and PO2 units. Ag NPs concentration dependent bonding parameters and Judd-Ofelt (JO) intensity parameters were calculated. The JO parameter Ω2 was reduced with the increase of Ag NPs contents, indicating the ionicity and symmetry enhancement between Sm3+ ions with their surrounding ligands. The emission spectra of all samples under the excitation wavelength of 402 nm exhibited four significant peaks centered at 562, 599, 644 and 702 nm which are allocated to 4G5/2→6H5/2, 6H7/2, 6H9/2 and 6H11/2 transitions, respectively. Inclusion of Ag NPs was discerned to augment the luminescence intensity by a factor of two, which was majorly ascribed to the local field effect of Ag NPs and subsequent energy transfer from the NPs to Sm3+ ions.

Spectral characteristics of Er 3+ doped magnesium zinc sulfophosphate glasses

This paper evaluates the spectroscopic properties of the Erbium (Er3+) ions doped magnesium zinc sulfophosphate glass system synthesized via melt-quenching method. Prepared glass samples are characterized using UV–Vis–NIR absorption and photoluminescence (PL) spectroscopy to determine the Er3+ ions concentration dependent spectral characteristics. The absorption spectra displayed nine prominent absorption bands aroused from the ground state (4I15/2) to the excited state (4I13/2, 4I11/2, 4I9/2, 4F9/2, 2H11/2, 4F7/2, 4F3/2, 2H9/2 and 4G11/2) transitions of Er3+ ion. The intensity parameters (Ω2,Ω4andΩ6) and radiative properties associated to the spectral transitions of Er3+ ion are calculated using Judd-Ofelt (JO) expressions. Room temperature PL spectra revealed two significant emission bands centered at 541 and 654 nm. Appearance of luminescence intensity quenching beyond 1 mol% of Er3+ is attributed to the cross-relaxation mechanism. The value of stimulated emission cross-section for 4S3/2→4I15/2 spectroscopic transition in Er3+ ion is found to be very high (85.8211 × 10−22 cm2). Present glass composition is demonstrated to be advantageous for various photonic applications.

Optical transitions in Dy3+-doped magnesium zinc sulfophosphate glass

Dy3+-doped magnesium zinc sulfophosphate glasses with composition of (60−x)P2O5–20MgO–20ZnSO4–xDy2O3 (x=0.0, 0.5, 1.0, 1.5 and 2.0mol%) were synthesized using melt-quenching technique and characterized via emission and absorption measurements. The UV–Vis-NIR absorption spectra in the wavelength range of 320–2000nm revealed eleven absorption peaks which were assigned to the transitions from the ground level (6H15/2) to several excited energy levels of Dy3+ ion. The Judd-Ofelt (JO) intensity parameters (Ω2,Ω4,andΩ6) were evaluated to predict the radiative properties including transition probability, radiative lifetime, and branching ratios. Emission spectra of the prepared glass under 452nm (6H15/2→4I15/2) excitation wavelength consisted of four bands centered at 480, 574, 662 and 752nm which were originated from 4F9/2→6HJ (J=15/2, 13/2, 11/2 and 9/2) transitions. Emission spectra were further used to determine the effective bandwidth, the stimulated emission cross-section, and branching ratios.