Rare earth ion Dy3+-doped tellurite glasses were synthesised in the system of (75-x)TeO2-15Sb2O3-10WO3-xDy2O3 (TSWD glasses). XRD and FTIR characterizations were used to find the crystalline and ...structural properties. The intensities of the electronic transitions and the ligand environment around the Dy3+ ion were determined using the Judd-Ofelt (J-O) theory on the absorption spectra of the glasses. The measured luminescence spectra exhibit intense emissions at 574 and 484nm along with less intense emissions around 662 and 751nm. Various radiative properties of the 4F9/2 excited level of Dy3+ ion were calculated for the glasses. Decay profiles were measured to find the life times and quantum efficiencies. Yellow to blue intensity ratio (Y/B), CIE chromaticity coordinates and correlated color temperature (CCT) values are calculated using the emission spectra to evaluate the emitted light. The obtained results suggest the utility of the glasses for potential yellow laser and white LED's applications.
PL spectra and CIE chromaticity diagram of dysprosium ion doped TSWD glasses. Display omitted
•Dy3+ ions doped TeO2 based heavy metal oxide glasses were prepared.•Judd-Ofelt Ωλ (λ=2, 4, 6) and bonding parameters determined by absorption spectra.•PL intensities of the glasses observed to increase up to 0.8mol% of Dy3+ ions.•Radiative properties have been determined from the 4F9/2 excited level of Dy3+ ion.•CIE diagram recommending the glasses for laser and white LED applications.
A series of novel π-electron rich fluoranthene derivatives (P1–P3) adorned with symmetrical and unsymmetrical alkoxy chains were developed using Diels-Alder reaction. The use of peripheral ...triethyleneglycol (TEG) chains on fluoranthene enhances its electron donating ability and furnishes decrease in their energy levels and optical band gap. The intense sky-blue fluorescence exhibiting fluoranthene ensembles have been investigated as potential fluorescent chemosensors for the detection of explosive nitroaromatics (NACs). Fluorescence studies demonstrate that emission intensity of P1–P3 was efficiently decreased upon interaction with picric acid (PA) in a dominant static quenching phenomena which is attributed to photoinduced electron transfer process. The limit of detection (LOD) was found to be in the range of 2–20 ppb. The vapour phase sensing study involving thin films of P1–P3 showed efficient quenching response and sensing process is found to be highly reversible. Surface morphology of thin films significantly varied with the type of alkyl chain present on fluoranthene. The thin films are highly selective towards PA in aqueous medium containing commonly interfering nitro-explosives. Contact mode approach using silica gel substrates allows femto-gram detection of trinitrotoluene (TNT) and PA makes these materials as potential chemosensors for real time applications.
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•High blue fluorescent novel fluoranthene derivatives with varied nature of alkyl chains•Selective detection of 2,4,6-trinitrophenol in aqueous and vapour phase methods•Porous nature thin films enhance the sensitivity and selectivity.•Good reversibility and recycling of thin films•Femto-gram detection of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol by contact method
The emission and life time decay characteristics of Eu3+ ions in barium boro-phosphate glasses mixed with different concentrations of Al2O3 are studied. The emission spectra exhibited bands due to ...5D0→7F0, 7F1, 7F2, 7F3, 7F4 transitions of Eu3+ ions. The highest intensity of these transitions is observed when the glasses are mixed with 3.0mol% of Al2O3. Using the emission spectra, the Judd–Ofelt (J–O) parameters and the radiative parameters viz., emission probability, A, the radiative lifetime, τ, and the fluorescent branching ratio, β of different transitions originated from 5D0 level of Eu3+ ions are evaluated. The results have been analyzed as a function of Al2O3 concentration with the aid of IR spectral data. The IR spectral data have indicated that Al3+ ions participate in larger proportions in octahedral positions in the glasses mixed with 3.0mol% of Al2O3, which induce bonding defects, de-cluster the Eu3+ ions and facilitate for minimizing the emission losses due to quenching. The quantitative analysis of these results further indicated that 3.0mol% of Al2O3 is optimal for achieving the highest luminescence efficiency in these glasses.
•Eu3+: BaO–B2O3–P2O5 glasses mixed with variable concentration of Al2O3 were prepared•Luminescence spectra of Eu3+ ions in the visible region is recorded.•Enhancement in the quantum efficiency is observed due to increase of Al2O3 content.•The increase is understood due to the declusterization of Eu3+ ions by Al3+ ions.
Li2O–MO–B2O3 (MO=ZnO, CaO and CdO) glasses doped with europium are prepared by using the melt quenching technique to study their absorption and luminescence properties to understand their lasing ...potentialities. The XRD pattern of the glasses confirmed the amorphous nature and the IR spectra reveal the presence of BO3 and BO4 units in the glass network. Judd–Ofelt intensity parameters Ωλ (λ=2, 4, 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. The J–O parameters have been used to calculate transition probabilities (A), lifetime (τR), branching ratios (βR) and stimulated emission cross-section (σP) for the 5D0→7FJ (J=1–4) transitions of the Eu3+ ions. The decay from the 5D0 level of Eu3+ ions in these glasses has been measured and analysed. Branching ratios and stimulated emission cross-sections measured for all these glasses show that the 5D0→7F1 transition under investigation has the potential for laser applications. The high stimulated emission cross-section and branching ratios from the present glasses suggests their potential for infra red lasers. The study of the thermoluminescence is also carried out and the data suggests that the CdBEu glass is suitable for thermoluminescence emission output among the three Eu3+ doped glasses.
•GeSbNa:B novel glass system was developed by the conventional melt quenching method.•Energy band gap (Eg) values increased with the content of B2O3 (mol%).•Ed, n and So values enhanced with the ...increase of boron ions in the glass network.•Enhanced K value or optical conductivity of the glasses were observed.•Obtained low phonon energy (0.073–0.102 eV) in comparison to tellurite glasses.
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Borate incorporated novel germanium based glass system was fabricated by traditional melt-quenching technique and is used as a probe for the generation of efficient lasers. In this context, we have explored in detail the impact of B2O3 addition on optical properties of GeSbNa (germanate-antimono-sodium) glass composition. The optical absorption spectra reveal that the cut-off edge of the glasses is shifted to lower wavelengths, due to smaller number of (NBO’s) non-bridging oxygen atoms. Using optical energy band gap values, the phonon energy (EΩ) of the glass system was calculated. Extinction coefficient (k) values were found to decrease in the wavelength range of 290–335 nm which is used for low loss optical devices. The refractive index (RI) of the glasses decreased, indicating that the entire B2O3 doped GeSbNa glass system obeys the normal dispersion mechanism. In addition, the boron mixed GeSbNa glass system shows low phonon energy, making it ideal for rare earth ion hosting glass systems for laser rods and promising candidate for manufacturing optical fibers.
This research delves into the influence of red lead content on the red and NIR emission characteristics of Pr
3+
ions within a nonconventional antimony silicate glass system. The glasses were ...synthesized across a composition spectrum of (40 − x) Pb
3
O
4
‒49Sb
2
O
3
‒(10 + x)SiO
2
:1Pr
2
O
3
, where x ranged from 0 to 35 mol%. Characterization was carried out using XRD, DSC, XPS, and IR spectroscopy. These analyses unveiled the presence of antimony ions in both Sb
3+
and Sb
5+
states and lead ions in Pb
4+
and Pb
2+
states within these glass compositions. Optical absorption and emission spectra (at λ
exc
= 445 nm) were recorded within the wavelength range of 400‒1800 nm. Luminescence decay profiles of two pivotal transitions, namely,
3
P
0
→
3
F
2
(red emission) and
1
G
4
→
3
H
5
(1.3 µm NIR emission), were also recorded. Various radiative parameters from these spectra were extracted using the J–O theory. The findings indicated that, as the Pb
3
O
4
content declined from 40 to 10 mol%, the covalent nature of the samples diminished, resulting in a remarkable amplification in the intensity of both the red and NIR emission bands of Pr
3+
ions. The glass containing 10 mol% of Pb
3
O
4
exhibited the most elevated radiative parameters and quantum efficiency. This augmentation was attributed to the reduction of Pb
4+
and Sb
5+
ions within the glass network or the augmentation of Pb
2+
ions, serving as modifiers that mitigated phonon losses. Consequently, glasses with 10 mol% Pb
3
O
4
demonstrate great potential for telecommunications applications, owing to their significant enhancement in PL emission for the
3
P
0
→
3
F
2
and
1
G
4
→
3
H
5
transitions.
In this study, we have attempted to amplify green and orange emissions of Sm3+ and Ho3+ ions due to co-doping in zinc strontium phosphate glasses by adding different concentrations of red lead. The ...preliminary structural investigations like EPR and optical absorption spectra of rare earth free glasses have indicated that the lead ions do exist in Pb3+ state and the covalent character of PbO bond gradually decreased with increase of Pb3O4. The optical absorption (OA) spectra of Sm3+ and Ho3+ individually doped glasses exhibited conventional bands in the visible and NIR regions. The spectra were characterized using J-O theory. The value of Ω2 exhibited decreasing trend with increase of Pb3O4 concentration up to 8.0 mol%. The photoluminescence spectra of Sm3+, Ho3+ and co-doped glasses were recorded at an excitation wavelength of 401 nm. The Sm3+ doped glasses exhibited feeble green and orange emission bands due to 4G5/2 → 6H52, 6H9/2 transitions in addition to strong 4G5/2 → 6H7/2 emission at about 600 nm. The visible emission spectra of Ho3+ doped glasses exhibited green and orange emission bands due to 5F4 + 5S2 → 5I8 and 5F5 → 5I8, respectively. These two bands observed to have been overlapped with 4G5/2 → 6H52 (green) and 4G5/2 → 6H9/2 (orange) bands of Sm3+ ions, respectively, in the co-doped glasses. The intensity of green and orange emission lines of co-doped glasses mixed with 8.0 mol% of Pb3O4 seemed to have been intensified nearly two times when compared with that of Sm3+ individually doped glasses. The increased efficiency of these two emissions is attributed to the decreasing covalent character of glass network due to the increasing concentration of Pb3O4 and the mutual energy transfer between the two co-dopant ions. The emission process is further analyzed using rate kinetic equations and the resultant emission intensities are found to be proportional to the life time of the corresponding excited state.
Photoluminescence spectra of ZnO‒Pb3O4‒SrO‒P2O5: Sm3O4 and Ho2O3 co-doped glasses. Display omitted
•Green, orange emissions of Sm3+−Ho3+ in ZnO-SrO-P2O5: Pb3O4 glasses investigated.•8.0 mol% of Pb3O4 is the optimal concentration for getting intense G and R lines.•Increased efficiency of G and R lines is attributed to the decreasing covalent character.•EPR, OA spectra of RE free glasses indicated that lead ions do exist in Pb3+ state.
Boro silica phosphate glasses with Na2O and CaO as modifiers, mixed with different concentrations of ZrO2 are developed by melt-quenching technique. Simulated body fluid (SBF) solution with pH 7.2 ...was prepared by the Kokobo method. The prepared glasses were immersed in simulated body fluid (SBF) solution for a period of 30days. The weight loss and the pH of the residual solution are carried out at specific intervals during this period. The post-immersed samples are characterized by XRD and SEM techniques. These studies confirm the formation of crystalline hydroxyapatite layer (HA) on the surface of the glasses. For understanding the influence of ZrO2 on the magnitude of HA layer formation and degradability of the samples, the spectroscopic studies viz. optical absorption and IR spectral studies on post- and pre-immersed samples were undertaken. The results of spectroscopic studies, coupled with bioactive studies, are analyzed as a function of ZrO2 concentration. The analysis indicated that the glasses containing low quantities of ZrO2 exhibit better bioactive characteristics.
•Bioactive boro silica phosphate glasses mixed with ZrO2 are developed.•Bioactivity of the glasses is studied by immersing them in SBF solution.•XRD, SEM and spectroscopic studies are carried out.•The analysis of results indicated the formation of HA layer on the glass surface.•Bioactive nature is found to be higher with low content of ZrO2.
Zirconium doped calcium phosphate-based bioglasses are the most prominent bioactive materials for bone and dental repair and regeneration implants. In the present study, a 8ZnO–22Na2O–(24 − ...x)CaO–46P2O5–xZrO2 (0.1 ≤ x ≤ 0.7, all are in mol%) bioglass system was synthesized by the conventional melt-quenching process at 1100 °C. The glass-forming ability and thermal stability of the glasses were determined by measuring the glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm), using differential thermal analysis (DTA). The biological activity of the prepared samples was identified by analyzing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-energy dispersive spectra (SEM-EDS), before and after immersion in simulated body fluid (SBF) for various intervals of 0, 1 and 5 days, along with the magnitude of pH and the degradation of glasses also evaluated. The obtained results revealed that the glass-forming ability and thermal stability of glasses increased with the increase in zirconia mol%. The XRD, FTIR, and SEM-EDS data confirmed a thin hydroxyapatite (HAp) layer over the sample surface after incubation in SBF for 1 and 5 days. Furthermore, the development of layer found to be increased with the increase of incubation time. The degradation of the glasses in SBF increased with incubation time and decreased gradually with the increase content of ZrO2 mol% in the host glass matrix. A sudden rise in initial pH values of residual SBF for 1 day owing to ion leaching and increase of Ca2+ and PO43− ions and then decreased. These findings confirmed the suitability of choosing material for bone-related applications.
Strontium Bismuth Borosilicate (SrBiBS as N) glasses doped with Tb3+ ions (N: Tb) and co-doped with Sm3+/Tb3+ (N: SmTb) were synthesized through the process of classical melt quenching. The ...structural and optical properties are investigated through energy dispersive spectroscopy; X-ray diffraction, Differential thermal analysis (DTA) and Fourier transform infrared spectra (FTIR), Optical absorption (OA) and photoluminescence (PL) spectral studies. X-ray diffraction indicates amorphous nature of glass. DTA curves explained the thermal stability and stress parameters of glasses. FTIR spectrum indicates existing vibrations of borate and silicate units. The absorption spectra have shown nine absorption bands of Tb3+ ions in the visible and NIR regions, due to transitions from ground state 7F6. In visible region, absorption spectra of co-doped glasses exhibited two bands of Tb3+ and three bands of Sm3+ with hyper sensitive transitions at 375 nm (7F6 → 5G6) and 401 nm (6H5/2 → 6P3/2). Photo Luminescence (PL) spectra of N: Tb and N: SmTb glasses is recorded at 375 nm excitation. N: Tb glasses have shown green emission corresponding to 5D4 → 7F5 transition. In all N: SmTb glasses, addition of Tb3+ ions has enhanced Sm3+ emission which is connected to quenching of Tb3+ emission. Moreover, 0.8 mol% of Tb3+ ions in co-doped glass (N: SmTb8) has shown maximum emission. The energy transfer process was inferred from shortening of decay times observed in N: SmTb glasses. The decay profiles fitted with Inokuti-Hirayama model suggests that the electric dipole-dipole interaction(S = 6) between Sm3+ and Tb3+ might dominate in energy transfer mechanism with probability PET and energy transfer parameter Q of 113–173 S−1 and 9.9–12.0 respectively. The color chromaticity (CIE) coordinates from PL emission of N: Tb & N: SmTb glasses have covered Green, Orange red and yellow (warm-light) regions with coordinates in ranges of x = 0.39–0.62 and y = 0.34–0.56.The color temperatures in range of 1713 K–4258 K.
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•Tb3+, Sm3+/Tb3+ co-doped SrBBiS glasses by melt quench technique•FTIR show different units of vibration and DTA profile show thermal stability.•PL and I-H model to fit non exponential curve confirm energy transfer.•PL CIE coordinates show RGY emission for emitting devices.•CCT values show transformation of cool to warm emission.
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