Govt First College was established on October 15, 1750 in Ankola, India. The college's name was changed to Poojageri. The college is a public institution in the Uttara Kannada District. The Principal is S.V. Nayak. The college offers B.A, B.Com, B.Sc, B.B.A, and M.A in economics courses. GFGC Ankola comes under the Kud Department. It has about 600 students.
Zn2V2O7:Sm (1-9 mol %) Nanoparticles (NPs), denoted as ZV:Sm, are synthesized for the first time using a solution combustion method mediated by Menthaspicata leaves extract. The doping of Sm3+ induces a shift in the hkl planes, indicating alignment with the monoclinic crystal structure and the C2/c(2/m) space group characteristic of the ZV host matrix. Additionally, a transition in surface morphology is noted, transitioning from irregularly shaped nanoparticles to hexagonal ones as the dopant concentration varies. The crystallite size, determined via Scherrer's method, concurs closely with transmission electron microscopy analysis. Moreover, analysis of the UV-Visible absorption spectra using Tauc's plot illustrates a modulation of the optical band gap, shifting from 3.03 to 2.94 eV with increasing dopant concentration. Upon excitation at 300 nm, Sm3+-doped ZV NPs exhibit characteristic spectra which arises due to 4G5/2-6H5/2 and 4G5/2-6H7/2 transition. Through experimentation, the optimal doping content is determined to be 3 mol%, which arises due to dipole dipole transition between the dopant ions and host matrix. CIE coordinates fall well within the orange-red region with increasing dopant concentration, while the average color-coordinated temperature of 3131 K suggests a warmer appearance which finds applications in photography, decorative lighting, public spaces, stage lighting, museums, galleries, etc. Electrochemical studies and Galvanostatic Charge-Discharge (GCD) analysis showed super capacitance values between 93.73 to 150.59 F/g at a scan rate of 10 mV/s, with an increasing dopant concentration, underscoring the material's potential for use in energy storage and display technologies.
A range of un-doped and Pr3+ doped CaAl12O19 (1-6 mol%) (CAO:Pr3+) phosphors are prepared through combustion synthesis method. Comprehensive characterization through X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence spectroscopy analysis demonstrated its outstanding performance. Photoluminescence (PL) studies revealed two prominent emission peaks centered at 610 nm and 652 nm under 445 nm excitation, corresponding to characteristic transitions of Pr3+ ions. A concentration quenching effect is observed beyond 3 mol% Pr3+ doping, primarily attributed to non-radiative energy transfer mechanisms, particularly dipole-dipole (d-d) interactions. The optimized CAO:3Pr(3+) phosphor demonstrated CIE chromaticity coordinates of (0.5901, 0.3753), correlated color temperature (CCT) of 1392 K, and excellent color purity (CP) of 89.7 %, indicating its suitability for warm reddish-orange emission. The prepared phosphors demonstrated significant temperature sensitivity over the range of 300-480 K and retained temperature stability of 86.60 % at 420 K. The CAO:3Pr(3+) is accompanied by an impressive internal quantum efficiency (IQE) of 79.6 % and an activation energy (Ea) of 0.319 eV. A maximum relative sensor sensitivity is 3.32 % K-1 at 300 K indicating excellent potential for non-contact thermometry applications. A white light- emitting diode (wLED) constructed with this phosphor exhibited a CCT of 5187 K and a color rendering index (CRI, Ra) value of 87. The phosphor demonstrates latent fingerprints (LFPs) and lip print (LPs) visualization capabilities, particularly in resolving Level I-III ridge details of fingerprints (FP) on diverse substrates and type I-V characteristics of LPs. Additionally, when incorporated into a polyvinyl alcohol (PVA) matrix, the phosphor exhibits intense red fluorescence under 365 nm excitation, highlighting its potential for use in anti-counterfeit ink applications. Based on the above findings, CAO: Pr3+ phosphors hold considerable potential for applications in w-LEDs and advanced forensic technology.
This research presents the development of a multifunctional composites synthesized through a green approach. Carbon dots (CDs) were derived from Zingiber officinale extract, while Sr2Ga2GeO7 :Eu3+ (SGGO:Eu3+) phosphors were prepared via combustion synthesis using Aloe vera (A.V.) gel as a natural fuel. The integration of CDs with SGGO:Eu3+ formed a hybrid composite material, whose successful formation is confirmed using XRD, SEM, TEM, Raman, and FTIR analyses. Optical investigations revealed efficient Forster Resonance Energy Transfer (FRET) from CDs to Eu3+ ions, resulting in enhanced photoluminescence (PL). The composites displayed dual emissions arising from both CDs and Eu3+ ions, making it suitable as a Ratiometric fluorescent probe for detecting tetracycline (TC). The sensing process is attributed to a static quenching of CD emission via the inner filter effect (IFE), coupled with Eu3+ luminescence enhancement facilitated by the antenna effect upon interaction with TC. The probe demonstrated high specificity and sensitivity, achieving a low detection limit of 4.55 nM with a linear response range from 0 to 80 mu M. Real-sample analyses in milk and honey demonstrated recovery rates between 97% and 117.4%, with relative standard deviations (RSD) under 2.06%, validating its practical reliability. Furthermore, the dual-emission behaviour (blue and red) was utilized to construct a plant growth LEDs (LED-1, LED- 2, LED-3) using a 395 nm UV chip. Among the fabricated devices, LED-2 based on CDs (5 wt%)@SGGO: Eu3+ (4 mol%) exhibited a balanced emission spectrum that effectively supported tomato seedling growth by enhancing both photosynthetic efficiency and morphological traits. This study offers a sustainable strategy for creating dual-purpose materials applicable in both environmental sensing and intelligent agricultural lighting systems.
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.
