Government First Grade College, Vijayanagar

In this study, Dysprosium-doped Zinc chromite nanoparticles (NPs) were synthesized via Exothermic Combustion Synthesis using Aloevera extract as a green fuel. The calcined samples (500 degrees C, 3 h) were thoroughly characterized. X-ray diffraction confirmed a pure cubic spinel structure with crystallite size decreasing from 14.42 nm to 11.18 nm as Dy content increased. Morphological analysis revealed randomly shaped nanoparticles and nanorods. The optical band gap narrowed from 3.12 eV to 3.03 eV. Photoluminescence spectra (lambda(ex) = 275 nm) exhibited a strong emission at 567 nm, with concentration quenching beyond 5 mol%. Chromaticity and correlated color temperature analyses verified yellowish-green emission from Dy3+ ions, suitable for indoor lighting. Electrochemical studies, including cyclic voltammetry, elucidated the redox behavior and electrode kinetics. The specific capacitance varied from 79.28 F/g to 114.34 F/g, depending on dopant concentration. These findings highlight Dy3+-doped ZnCr2O4 as a promising material for energy storage and display applications.

The effect of Tb3+ dopant concentration on photoluminescence and electrochemical properties of Bi2Cr4O15 nanoparticles is studied for the first time. Bi2Cr4O15:Tb (1-9 mol%) NPs are synthesized via Aloe vera gel extract mediated green combustion route. Bragg reflections confirmed the formation of the triclinic Bi2Cr4O15 structure with no secondary phases up to 5 mol% dopant concentration. At 7 and 9 mol%, minor peak corresponding to alpha phases of Bi2O3 are observed. The crystallite size was found to decrease from 22 to 10 nm and optical energy band gap decreases from 3.06 to 3.02 eV with increase in dopant concentration. The surface morphology consists aggregated irregular, cubic, rod and plate like structures are observed with variation in dopant concentration. The photoluminescence emission spectrum exhibits multiple peaks at 284, 381, 474, and 712 nm at 242 nm excitation wavelength. The 474 nm peak corresponds to the 5D4 -> 7F6 transition of Tb3+. The red emission at 712 nm band tentatively ascribed to defect-related recombination in the host lattice. Other peaks at 284 nm and 381 nm may arise from additional host emissions or inter-band transitions. The CIE coordinates lies well within the blue region with cooler appearance. Thus, the synthesized sample might finds an application in display technology as a blue nanophosphor material. The supercapacitive behavior of Tb3+-doped Bi2Cr4O15 nanoparticles was investigated across doping concentrations ranging from 1 to 9 mol%. A significant enhancement in specific capacitance was observed, increasing from 30.03 F/g at 1 mol% to 69.3 F/g at 9 mol%, with near-linear improvement up to 7 mol% and marginal saturation thereafter. The improvement is attributed to increased oxygen vacancy concentration, enhanced electron transport, and the substitution of Tb3+ at Bi3+ lattice sites, facilitating efficient redox activity. The 9 mol% doped sample demonstrated superior electrochemical performance, with the largest CV area, longest GCD discharge time, and highest specific capacitance. Electrochemical impedance spectroscopy and Warburg analysis confirmed reduced charge transfer resistance and enhanced ionic diffusion, with a high Warburg coefficient (sigma = 1184.0 Omegas1/2). These findings establish 9 mol% Tb3+ as the optimal doping concentration for maximizing the electrochemical performance of Bi2Cr4O15-based electrodes in supercapacitor applications.

Let B_k,ℓ(n) count the number of (k,ℓ ) -regular bipartitions of n. In this paper, we establish infinite families of congruences modulo powers of 5 for B_5^2k-1, 5^2k(n) , for k ≥ 1 . In particular, for any integers n ≥ 0 , β≥ 0 and k ≥ 1 , we prove that B_5^2k-1, 5^2k( 5^2k+2β -1 n + 2 · 5^2k+β - 3 · 5^2k-1 + 112) ≡ 0 5^k+β, by deriving the exact generating functions of specific arithmetic progressions in B_5^2k-1, 5^2k(n) . This result substantially extends the earlier findings of Tang (Quaestiones Mathematicae 2020, 43(2): 169-183).

This study used an Aloe vera-mediated solution combustion approach to create spinel cubic ZnSnO3:Sm3+ (1-9 mol%) nanoparticles, which were then calcined at 600 degrees C for three hours. As the quantity of dopant rose, the size of the crystallite was observed to drop from 18 nm to 10 nm. When the surface morphology was investigated with field emission scanning electron microscopy, it became clear that there were distinct agglomerations of unevenly sized and shaped nanoparticles. When the concentration of the dopant rose, it was noticed that the optical energy band gap, as calculated from Tauc's figure, increased from 3.073 eV to 3.079 eV. The photoluminescence emission spectra recorded under 310 nm excitation consists characteristic peaks of Sm3+ at (4)G(5/2)-> H-6(5/2) ->(552, 576 nm) transition, (4)G (5/2)-> H-6(7/2) (618 nm) and (4)G(5/2)-> H-6(9/2 )(665 nm) within the host matrix. The concentration quenching is observed at 5 mol %. Principle mechanism for concentration quenching in Sm3+ within the host matrix is dipole-dipole interaction. The CIE coordinates fell within the white region with an average CCT 7222K showing a cooler appearance. This study investigates the electrochemical performance of samarium-doped zinc stannate (ZnSnO3:Sm3+ ) nanoparticles as potential supercapacitor materials. The doping concentrations range from 1 mol% to 9 mol%, with specific capacitance values spanning from 40.50 F/g to 92.18 F/g at lower scan rates. Results indicate that higher concentrations of samarium significantly enhance the redox reactions, electrode kinetics, ionic transport, and overall supercapacitive performance of ZnSnO3. From all these results, the synthesized material might be a promising nano phoshor material in cool white light emitting diodes as well as in high energy storage devices such as supercapacitors.

For the first time, Eu3+-doped Zn2V2O7 nanoparticles (NPs) were successfully synthesized via an eco-friendly solution combustion route using Menthaspicata leaf extract. X-ray diffraction con- firmed the monoclinic crystal structure (C2/c(2/m) space group), with crystallite sizes of 25–35 nm, consistent with TEM analysis. A morphological transition from irregular to hexagonal-shaped NPs was observed upon Eu3+ doping. Optical studies revealed a systematic reduction in the band gap from 3.03 to 2.94 eV with increasing dopant concentration. Photoluminescence analysis showed strong red emission under 300 nm excitation, with the electric dipole transition dominating and optimal intensity achieved at 5 mol