Glasses of the composition Pb2O3‒ZnO‒P2O5: Dy3+ mixed with three different modifier oxides viz., MgO, CaO and SrO are prepared. The influence of modifier oxide on the luminescence characteristics of ...Dy3+ ions has been investigated. Using the intensities of various absorption bands of Dy3+ ions, the Judd-Ofelt parameters Ω2, Ω4 and Ω6 have been evaluated. Together with the J‒O parameters and the luminescence spectra, various radiative properties like transition probability A, branching ratio βr, the radiative life time τr, and the emission cross-section σE for various emission levels of Dy3+ ions have been evaluated and reported. The values of these parameters were found to be influenced by modifier oxides. Among the three modifier oxides mixed glasses, the glasses mixed with CaO mixed glasses exhibited the highest luminescence efficiency. The results have been analyzed in the light of structural modifications taking place in the glass network with the help of IR spectral studies.
Emission spectra of Dy3+ doped MO (Mg, Ca & Sr)‒Pb3O4‒ ZnO‒P2O5 glass system. Display omitted
•Glasses of the composition Pb2O3‒ZnO‒P2O5‒MO: Dy3+ (M = Mg, Ca, Sr) were prepared.•Optical absorption and photoluminescence spectra were recorded.•Using J-O theory evaluated various radiative properties of Dy3+ ions were evaluated.•Analysis of results indicated CaO mixed glass exhibit better luminescence efficiency.
This work is focused on the amplification of green (G), orange (O) and NIR (1.5 μm) emissions of Er3+ ions by co-doping with varying contents (traces ≤ 0.1 mol%) of Au2O3 in an exotic PbO-B2O3-SeO2 ...glasses ceramic. The glasses were synthesized by conventional melt quenching method and were crystallized by heat-treating them at crystallization temperature for a period of 24 h. Initial characterization of the samples by means of SEM, XRD, XPS, IR and Raman studies suggested that the post-heated samples are entrenched with poly-crystal grains (with sizes varying from 100 to 500 nm). These studies have also revealed that the concentration of such nano-crystallites is increased with increased content of Au2O3 up to 0.075 mol%. The XRD studies, in particular, have indicated that the glass ceramics are composed of Au2(SeO3)2(SeO4) (crystal phase containing Se ions of mixed valence states) and Au0 nano particles. The XPS studies have also indicated the presence of Se and gold ions in different valence states in these samples. IR and Raman spectra have suggested increased degree of internal chaos in the glass ceramic with increasing concentration of Au2O3. Optical absorption (OA) spectra of Au2O3 doped glass ceramic samples (without Er3+ ions) exhibited a broad band in the visible region identified as surface plasmon resonance (SPR) band of gold metallic particles. The photoluminescence (PL) spectra of these samples exhibited an emission peak due to inter-band transition from sp to d energy bands of Au0 metallic particles. This emission is identified to play a crucial role in enhancing PL emission of Er3+ ions in the visible and NIR regions. Finally, we have recorded optical absorption, photoluminescence spectra and decay profiles of the Er3+ doped (with Au2O3 as co-dopant) glass ceramics. The spectra were characterized using J–O theory and different radiative parameters (viz., transition probabilities, branching ratios, radiative lifetime) of green, orange and NIR emission transitions of Er3+ ions were evaluated. The results indicated a significant reinforcement of green (4S3/2 → 4I15/2), orange (4F9/2 → 4I15/2) and NIR (4I13/2 → 4I15/2) emissions of Er3+ ions due to co-doping with Au2O3. Quantitative analysis of the results of PL emission indicated that 0.075 mol% of Au2O3 is the optimal concentration for achieving the highest quantum yield of these three emissions in this glass ceramic. Additional population of 4S3/2, 4F9/2 and 4I13/2 energy levels of Er3+ ions from the excited state of Au0 metallic particles is found to be the reason for such enhancement of quantum efficiency.
PL spectra of Au metallic particles in PbO-B2O3-SeO2-Er2O3 glass ceramics mixed with different concentrations of Au2O3along with energy scheme of gold particles. Display omitted
•Exotic PbO-SeO2-Er2O3: Au2O3 glass ceramics were synthesized.•Amplification of G, O and NIR emission emissions of Er3+ ions is investigated.•PL results suggested that EA75 sample exhibited the highest efficiency.•Energy transfer from Au0 particles is found to be the reason for such enhancement.
Sb2O3–Li2O–Er2O3glasses mixed with various modifier oxides viz., MgO, CaO and SrO have been prepared by the melt quenching technique in this present work. Optical absorption, photoluminescence and ...decay characteristics were measured at room temperature. The Judd-Ofelt (JO) parameters Ω2, Ω4 and Ω6 for Er2O3 mixed glasses were calculated using absorbance spectra. The emission spectra excited λexc = 380 nm exhibited emission transitions 4F7/2, 2H11/2, 4S3/2, 4F9/2 → 4I15/2 (Vis region) and 4I13/2 → 4I15/2 (NIR region) of Er3+ doped glasses. Numerous characteristics of radiative parameters viz., AR, βR, τR, and σEP for Er2O3 enriched glasses were analyzed and reported, based on JO parameters and the emission spectra. Overall, the results indicated that Er3+ mixed glasses exhibited a substantial increase in the green emission (2H11/2, 4S3/2 → 4I15/2) intensity of all glass samples. When compared with the other two glasses, the SrO mixed glass having the highest quantum efficiency (η = 88.2%) of green emission. The structural modifications of Er3+ ions due to modifier oxides were identified by IR spectral studies.
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•Sb2O3–Li2O‒MO (M = Mg, Ca & Sr): Er2O3 glasses were prepared.•The quantum efficiency of SrSbEr glass enriched was determined to be 88.2%.•Reasons for enhancement are enlightened on the basis of structural variations.
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.
Li2SO4–MgO–P2O5 glasses mixed with a varied quantity of NiO were prepared. Detailed spectroscopic investigations (viz., OA, IR and Raman) spectra were carried out. Optical absorption spectral results ...indicated that Ni2+ ions in the glass network reside in octahedral (Oh) as well as tetrahedral (Td) sites; these results have also pointed out the growing concentration of Ni2+ ions in Oh sites as NiO concentration is increased up to 0.8 mol%. Results of infrared and Raman spectral studies indicated increased internal chaos in the sulpho-phosphate glass network with an increase of NiO concentration up to 0.8 mol%. Values of dielectric permittivity (both real and imaginary components), a.c. conductivity, σac, are observed to be gradually increasing with NiO content in the concentration range 0–0.8 mol%. Electric moduli spectra have exhibited dipolar relaxation effects and the dipolar relaxation time τ estimated from these spectra exhibited a decreasing trend with the raise of NiO quantity up to 0.8 mol%. The complexes of octahedral Ni2+ ions with oxygen ions are predicted to be the possible dipoles responsible for the dipolar effects. Variation of σac with NiO content exhibited an increasing trend up to 0.8 mol%. Quantitative analysis of this observation indicated ionic contribution to σac is dominant in the glasses containing small quantities of NiO (< 0.8 mol%), whereas in the glasses containing higher quantities of NiO (> 0.8 mol%) polaronic contribution to the conductivity seems to be present. Overall, the results of dielectric properties of studied glass system indicted that the glass with low quantities of NiO (< 0.8 mol%) can be considered as useful material as electrolytes in the solid-state batteries.
An illustration of entrenchment of SO42− structural unit in the disrupted phosphate glass network consisting of PO43− (Q0) units. Display omitted
•Spectral studies of Li2SO4–MgO–P2O5:NiO glasses indicated Ni2+ ions act as modifiers.•ε and σac found to increase with NiO content due to increased internal chaos in glass.•Dielectric studies indicated glasses with NiO (<0.8 mol%) are useful as electrolytes.
SeO2 based glasses of the composition 39 PbO–(60-x) B2O3– xSeO2:1.0 Yb2O3 (with 10 ≤ x ≤ 50) was synthesized. Analysis of the results of structural studies of the samples revealed that the glass ...network consists of SeO42− and SeO32− units; the studies further indicated an increasing fraction of SeO32− units and decreasing concentration of SeO42− groups with increase of SeO2 content. Optical Absorption (OA) and photoluminescence (PL) spectra have exhibited bands due to 2F7/2 → 2F5/2 and 2F5/2 → 2F7/2 transitions, respectively. Evaluated absorption and emission cross-sections and lifetime of the excited state of Yb3+ ions exhibited an increase with increase of SeO2 content. Results of PL studies indicated nearly fourfold increase of PL output with increase of SeO2 content up to 50%. Such increase is attributed to the increased concentration of isolated SeO32- pyramidal groups. Overall, the rise of SeO2 content in Yb3+ doped PbO–B2O3–SeO2 glass system facilitated the increase of PL emission of Yb3+ ions largely.
P2O5–MgO–Na2O glasses with varied concentrations of (RE) Dy3+ ions (Dy2O3: 0.5, 1.0, 1.5, and 2.0 mol percent) were prepared by melt quenching technique. The prepared glass samples have been ...characterized using XRD and SEM techniques and the amorphous nature of the samples was ensured. Optical absorption and photoluminescence spectra and also decay characteristics were recorded. Using absorbance spectra, the J-O parameters Ω2, Ω4, and Ω6 were calculated for the glass doped with 1.0 mol % of Dy2O3. Several radiative parameters such as radiative probability, AR, radiative lifetime τR, branching ratio, βR, emission cross-section, σEP for Dy2O3 doped glasses were evaluated and reported using the emission spectra. The quantum efficiency of 1.0 mol% Dy2O3 doped glass was determined to be 86%, which is observed to be the largest when compared to that of all other glasses. The color chromaticity co-ordinates were observed to move towards white region as the concentration of Dy2O3 is increased. The quantitative analysis of these data in commination with results of infrared spectral investigations, revealed that the 1.0 mol % of Dy3+ ions is optimal concentration for achieving the highest luminescence efficiency.
Excitation spectra of P2O5–MgO–Na2O glasses mixed with the concentrations of Dy2O3. Display omitted
The glasses of the composition 30PbO–60B
2
O
3
–5.5SiO
2
–(4.5 −
x
) Al
2
O
3
–
x
Ho
2
O
3
(with
x
varied from 0 and 2 mol%) were prepared. Density (
ρ
), refractive index (
n
), and average ...molecular weight (
M
) were calculated from experimental measurements of these glasses. The spectra of optical absorption besides the photoluminescence were recorded at room temperature in the wavelength range of 300–2200 nm and 450–2200 nm, respectively. Using the optical absorption spectra the oscillator strengths were estimated and found to be in good agreement with the theoretical values evaluated using optical absorption spectra. Glasses doped with 0.5 mol% holmium had the highest bonding parameter, while those doped with 2.0 mol% holmium had the lowest. From this observation, it was concluded that holmium ions are in a more covalent environment in H
20
glasses. The overall analysis of the luminescence spectral results indicated maximal luminescence efficiency of the glasses with 0.5 mol%.
•Sb2O3‒Li2O‒MO (M=Mg, Ca & Sr): Eu2O3 glasses were prepared.•Optical absorption and PL spectra were recorded.•R/O intensity ratio is the highest for SrO mixed glasses.•Reasons for enhancement are ...enlightened on the basis of structural variations.
In this study, role of three modifier oxides (viz., MgO, CaO and SrO) on red luminescence efficiency of Eu3+ ions in Sb2O3‒Li2O glass system was investigated. The absorption spectra of these glasses exhibited the bands due to 7F0→ 5D4,3,2,1,0,5G4,2,5L6 and 7F0, 1→7F6 transitions in the visible and NIR regions, respectively. Emission spectra recorded at λexc=394 nm exhibited the bands due to 5D0→7FJ (J = 0 to 4) transitions. Out of these, the band due to5D0→7F2 (red emission ) was found to be more intense. J-O parameters, Ω2 and Ω4 were evaluated using integral R/O ratio of emission spectra. Radiative parameters viz., AR, βR and σEP for Eu3+ions were calculated using J-O parameters, These parameters were observed to be the maximal for SrO mixed glasses. Variations of local symmetry and covalency in the vicinity of Eu3+ ions were found to be responsible for such larger values of these parameters and for intense red emission for SrO mixed glasses.
The Indian Government is providing grains to those in need at affordable prices through a process known as the Public Distribution System. However, the current distribution methods employed in the ...public distribution system rely on manual processes, which may lead to errors, be time-consuming, and foster corruption. To address these issues, the proposed work employs Advanced Interdisciplinary Techniques such as RFID cards and readers to authenticate ration cardholders and ensure precise ration dispensing, significantly reducing inaccuracies and fraudulent activities. Furthermore, it incorporates a GSM-based mechanism with OTP authentication, adding an extra layer of security and efficiency. The GSM module sends a one-time password (OTP) to the user’s registered mobile number before dispensing rations, ensuring that only authorized individuals receive their entitled goods. Customers can select the goods they need from the allocation provided by the Government, and the amount will be automatically deducted from their RFID card based on the goods selected. A microcontroller manages the motor and relay to dispense items, while an alarm system alerts in cases of incorrect OTP entries, effectively deterring unauthorized access to rations. This system promises to make the ration distribution process more efficient, transparent, and accountable. Incorporating Advanced Interdisciplinary Techniques for Revolutionized Government Ration Dispensing System Using IoT.
