Emerson University, Multan, formerly known as the Government Emerson College Multan is located in the city of Multan in the Punjab province of Pakistan. It is also called Govt. College Multan, GC Multan, or Govt. Bosan Road College Multan. It is the largest college in Multan city located on Bosan Road.[citation needed] The prestigious and historic school is affiliated with Bahauddin Zakariya University, Multan, Pakistan.
This study investigates the nonlinear optical (NLO) properties of YCrO4 (YC), YCrO4:Zn (9 mol%) (YCZ), YCrO4:Ni (9 mol%) (YCN), YCrO4:Eu (9 mol%) (YCE), and YCrO4:Tb (9 mol%) (YCT) NPs. These NPs are synthesized by Aloe vera gel extract mediated solution combustion method. The X-ray diffraction patterns of YCrO4 confirm the formation of tetragonal phase with the space group I 141/amd. No other impurity related peaks were observed even after doping with transition/rare earth metal ions except the variation in intensity. Lattice distortion in the host lattice due to the addition of dopants leads to slight shifting of Bragg peaks towards lower angle side. The direct optical band gap of YC, YCZ, YCN, YCE and YCT were tuned to 3.08, 3.05, 2.96, 2.86 and 2.75 eV respectively. The nonlinear absorption coefficient and optical limiting behavior were analyzed using the Z-scan technique under high-intensity laser irradiation. The results reveal significant variations in the nonlinear absorption coefficient among the samples, indicating the influence of dopants on the material's NLO performance. Among them, YCN exhibited the highest nonlinear absorption coefficient (14 m/W), demonstrating its strong reverse saturable absorption (RSA) characteristics. The optical limiting thresholds were also evaluated, showing that YCN had the lowest threshold (2.02 W/m2), making it a promising candidate for laser protection applications. These findings suggest that doping YCrO4 with specific elements such as Ni2+ enhances its nonlinear optical response, making it suitable for advanced photonic and optoelectronic applications.
Europium-doped cerium oxide nanoparticles (CeO2:Eu3+, 1-11 mol%) were successfully synthesized via an Aloe vera-mediated green solution combustion method. X-ray diffraction confirmed a single-phase cubic fluorite structure with crystallite sizes decreasing from 23.5 to 14.3 nm with an increase in Eu doping, accompanied by enhanced lattice strain and defect density. UV-Vis analysis revealed a band gap narrowing from 3.06 eV when compared to undoped CeO2 to 3.00 eV at 11 mol% Eu, attributed to defect-assisted band structure modification. Photoluminescence studies demonstrated intense red emission centered at 618 nm ascribed to 5D0 -> 7F2 transition of Eu3+, with maximum emission efficiency observed at 5 mol% doping before concentration quenching dominated. The calculated Judd-Ofelt parameter Omega 2 reached 497.18 x 10-20 cm2 at 5 mol%, confirming enhanced local asymmetry around Eu3+ ions. Electrochemical measurements indicated a dual charge storage mechanism (b = 0.69), combining electric double-layer capacitance and pseudocapacitance from Ce3+/Ce4+ and Eu3+ redox couples. Specific capacitance increased steadily with doping, from 92 F g-1 for 1 mol% to 128 F g-1 for 11 mol% at 10 mV s-1. The optimized electrode of 11 mol% Eu delivered an energy density of 17 Wh kg-1 and a power density of 37 kW kg-1, while retaining 88% of its initial capacitance after 5000 cycles with nearly 100% coulombic efficiency. These findings establish Aloe vera-assisted Eu-doped CeO2 nanoparticles as eco-friendly multifunctional materials for both photonic in red emission and high-performance supercapacitor applications.
Terbium-doped zinc gallate (ZnGa2O4) nanoparticles (NPs) with a cubic spinel structure were successfully synthesized via the solution combustion method employing Aloe vera gel extract as an environmentally friendly fuel. The combustion-derived powders were subsequently calcined at 600 degrees C for 3 h to enhance crystallinity. Powder X-ray diffraction (PXRD) confirmed the formation of a single-phase cubic spinel, with systematic peak shifts toward lower diffraction angles upon Tb3+ incorporation, indicating lattice strain and local distortion due to ionic size mismatch. Transmission electron microscopy (TEM) analysis shows agglomerated clusters composed of nearly spherical NPs with an average size of 13.47 nm. The optical energy band gap, estimated from diffuse reflectance spectra, decreased from 3.02 eV (undoped) to 2.94 eV (highest Tb3+ concentration), evidencing band-structure modification. Photoluminescence excitation at 310 nm yielded emission peaks at 437, 513, and 647 nm, corresponding to the 5D4-7F4, 5D4-7F5 and 5D4-7F3 transitions of Tb3+, respectively. The calculated CIE chromaticity coordinates lie within the white-light region, and the average correlated color temperature (CCT) of 8145 K suggests suitability for warm ambient illumination in residential, commercial, and decorative lighting. Electrochemical analyses in a three-electrode configuration revealed enhanced redox activity, improved electrode kinetics, and superior ionic transport with increasing Tb3+ content, achieving specific capacitances between 106.03 and 177.09 F/g at low scan rates. These results demonstrate that ZnGa2O4:Tb3+ nanoparticles possess synergistic optical and electrochemical functionalities, positioning them as promising candidates for integrated applications in solid-state lighting, display devices, and high-performance energy storage systems.
In the present communication, Bi2O3/Al2O3 nanocomposites (NCs) are synthesized by Aloe vera gel extract mediated combustion method. Bragg reflections confirms the formation of both monoclinic Bi2O3 and orthorhombic Al2O3 nanoparticles. No other impurity related peaks were observed. The surface morphology consists small irregular shaped Bi2O3 NCs and flake like structured Al2O3 NCs. The optical energy band gap was tuned to 3.02 eV. The photoluminescence emission spectra was recorded at two excitation wavelengths 220 and 250 nm. The emission spectra recorded at Tex = 220 nm consists peaks in blue and red region whereas at Tex = 250 nm peaks located in blue, green and red region. As the excitation wavelength changes from 220 nm to 250 nm, the chromaticity coordinates shift slightly from the blue-green region to a more prominent blue region. The color correlated temperature was found to be more than 5000 K. Thus, the synthesized nanophosphor might exhibit cooler appearance and finds an application in street lights, display etc. The electrochemical performance of Bi2O3/Al2O3 nanocomposites was evaluated for supercapacitor applications. Cyclic voltammetry (CV) over 0-1000 mV at scan rates of 10-50 mV/s exhibited quasi-rectangular curves, indicating a primarily capacitive charge storage mechanism. The specific capacitance ranged from 17.49 F/g at 10 mV/s to 13.66 F/g at 50 mV/s, reflecting the diffusion-controlled ion transport. Electrochemical impedance spectroscopy (EIS) revealed low charge transfer resistance (small semicircle diameter) and diffusion-dominated behavior, while GCD curves confirmed stable, reversible charge storage. These results highlight the material's potential for energy storage, balancing energy and power density, with scope for optimization.
In this study, Bismuth Copper Tungsten (Bi–Cu–W) nanocomposite was synthesized using an eco-friendly combustion method with Aloe vera gel as a green surfactant and reducing agent. The synthesized nanocomposite was thoroughly characterized using PXRD, Morphological analysis, FTIR, UV-visible spectroscopy, and photoluminescence techniques to assess its structural, morphological, optical, and emission properties. PXRD results confirmed the formation of Bi4O7 (triclinic), CuO2 (orthorhombic), and W5O14 (tetragonal) phases with an average crystallite size of 40.7 nm. Morphological analysis revealed agglomerated nanoparticles with irregular morphology, while EDS confirmed the elemental purity of Bi, Cu, W, and O. The optical bandgap was estimated to be 3.06 eV, making the material suitable for UV optoelectronic applications. FTIR spectra verified the presence of metal–oxygen vibrations associated with Bi–O, W–O, and Cu–O bonds. Radiation shielding analysis indicated that the Bi–Cu–W nanocomposite demonstrates high radiation protection efficiency (RPE), particularly at low photon energies, rivaling that of lead. Additionally, photoluminescence studies revealed a strong emission peak at 499 nm upon 272 nm excitation, with the calculated CIE coordinates placing the emission in the blue–green region. The composite’s neutron shielding parameters were also superior to conventional materials such as concrete. These results suggest that the Bi–Cu–W nanocomposite holds great potential for dual applications in radiation shielding and photonic devices.
