4 results on '"Guntu, Ravi Kumar"'
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2. Spectroscopic and TL properties of Sm2O3 doped lead silicate glasses containing alumina and antimony oxides.
- Author
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Ashok, Padala, Guntu, Ravi Kumar, Devi, S. Shashi, Ramesh, Ch., and Rama Krishna Chand, N.
- Subjects
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SAMARIUM , *CRYSTAL glass , *ALUMINUM silicates , *LASER pumping , *ACTIVE medium , *GLASS transition temperature , *ANTIMONY , *PHOSPHATE glass - Abstract
The present investigation, aimed to prepare lead silicate glasses doped with samarium ions and to study it's structure, elastic, spectroscopic and thermoluminiscence properties with Al(10−x)Sbx composite influence. The objective of the investigation is to develop TL sustained good laser active resource by means of studying photo and thermoluminiscence properties. In this direction, we have prepared the glass series of Al(10−x)SbxSm0.1Pb30Si59.9 materials (where, 0 ≤ x ≤ 10, with steps of 0, 2, 4, 6, 8 and 10 mol%) after that planned for structural (XRD, FT-IR, DTA, EDS & SEM), Optical (UV & PL) and thermoluminescence characterization. The XRD and SEM studies reveal the glassy behavior of test samples. The EDX analysis signifies the chemical constitutes with atomic weight %. The physical properties such as density and molar volume of glasses were evaluated. The DTA studies of glasses reveal the glass transition and crystallization temperature points. The values of thermal stabilities of glasses found to be purely function of Sb3+ ions. Various structural vibrations of test glass conformed using FT-IR studies. Using ultrasonic velocities of the test glasses, the glasses' micro-hardness was evaluated. From the absorption spectra, the Judd–Ofelt intensity parameters (Ω2, Ω4, Ω6) have been calculated. The PL spectra under stimulation at 402 nm show a prominent reddish–orange emission at 602 nm. The experimental lifetimes (τr) of the 4G5/2 → 6H7/2 (602 nm) luminescence transition were measured using the decay spectral profiles of this transition. The evaluated emission cross-sections (σse), branching ratios (βr), and quantum efficiency (η) allow us to speculate that the lead silicate glasses doped with Sm3+ ions are ideally suitable as potential gain mediums for visible reddish orange lasers pumped directly by readily available 405 nm laser diodes. Quantum efficiencies of the produced glasses are obtained using a decay curve analysis. The emission spectra used to establish the developed glasses' reddish orange emission are used to compute the CIE chromaticity coordinates. It is evident from the stated fluorescent properties that the developed glasses are suited for reddish–orange laser applications, particularly in opto-electronic devices. From all of the values obtained, it can be observed that SAS6 glass code is ideally suited for reddish–orange laser applications. The TL properties are studied at 30 kGy gamma irradiation dose range. The frequency factor and A.E. of glasses were evaluated. This reveals that the TL behavior of glasses is a purely function of Sb3+ ions. Overall, the Al(10−x)SbxSm0.1Pb30Si59.9 glasses prepared are mechanical hard, TL effective, and optically useful resources. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Optical behavior, TL defect center analysis and photocatalytic characterization of Ag2O doped ZnO nano crystals.
- Author
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Guntu, Ravi Kumar, Devi, S. Shashi, Ashok, Padala, Bhikshamaiah, G., Chand, N. Rama Krishna, Sripadha, Suresh, Prasad, P. Syam, and Rao, Ch. Srinivasa
- Subjects
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ZINC oxide films , *ZINC oxide , *BAND gaps , *CRYSTALS , *DEGRADATION of textiles , *SOL-gel processes , *SILVER ions - Abstract
The objective of the study is to prepare Ag+-doped ZnO nano crystals and to assess their structure, optical behavior, TL analysis, photocatalytic activity. Using sol–gel technique the Ag+-doped ZnO nano crystals prepared. Using the FT-IR, XRD, BET surface area, SEM, EDX characterization techniques, we have examined the structure of the developed samples. The TL analysis of samples was done under a dose of 25 kGy gamma irradiation. Trap depth parameters of the samples evaluated. Which suggested the ZnO nano crystals doped with Ag+ ions are purely TL active. The optical studies such optical absorption, photoluminescence of samples reveal their optical behavior. The optical band gap of the samples also evaluated. Which is increasing with increase in concentration of Ag+ ions in ZnO nano crystals. Using the MV (10 ppm) and CR (10 ppm) dyes, under visible light the photocatalytic activity of the samples reported. At a reaction period of 90 min, the nano powder containing 1.0 mol% Ag+-doped ZnO nano crystals and a band gap energy of 2.75 eV demonstrated the best photocatalytic efficiency (∼91 %) in both colors. The evaluation was done on the impact of radical scavenger research and catalyst dosage on degrading efficiency. The rate of reaction in the presence of 1.0 mol% Ag+-doped ZnO nano crystals was four times higher than the ZnO catalyst's rate constants, and the degradation reaction follows pseudo-first-order kinetics. The degrading process shows pseudo-first-order kinetics, and the reaction rate was four times higher than the ZnO catalyst in the presence of 1.0 mol% Ag+-doped ZnO nano crystals. It took three cycle runs for the degrading efficiency to drop by 1 %. Thus, 1.0 mol% Ag+-doped ZnO nano crystals was employed as a promising photocatalyst with strong reusability potential for the degradation of textile colors, which will be very beneficial. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Photocatalysis and irradiative TL defect center analysis studies of Cu2+ ionic ZnO nano lattice.
- Author
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Guntu, Ravi Kumar
- Subjects
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BAND gaps , *ZINC oxide , *GAMMA rays , *PHOTOCATALYSIS , *REFLECTANCE spectroscopy , *DYES & dyeing , *PHOTODEGRADATION - Abstract
The objective of the study is to create a series of ZnO nano powders doped with CuO using sol–gel technology in order to look into their photocatalytic activity for the photodegradation and cleaning process. XRD, BET surface area, surface morphology, chemical analysis, and FT-IR measurements have all been used to look at the nano powders' structure from this point of view. The results suggest that the materials were made at the nanoscale level, and their hexagonal shape makes them good as catalytic nano resources. Photoluminescence and UV–visible diffusion reflection spectroscopy were also used to test the nano powders. The results show that the nano powders that were made are visually active. To find out how photocatalytic the nanoparticles are, they were used to break down CR (10 ppm) and MV (10 ppm) dyes when exposed to light. The nano powder with 1.0 mol% of CuO doped ZnO nanoparticles had the highest photocatalytic efficiency (86 %). It had a band gap energy of 3.15 eV and reacted with both dyes for 90 min. Researchers looked at radical scavengers and the effect of catalyst dose on how well they broke down substances. The reaction that broke down had pseudo-first-order kinetics, and the rate of the reaction was four times faster when 1.0 mol% Cu was added to the ZnO catalyst. The degradation efficiency only dropped by 1 % after three rounds of the process. Because of this, the 1.0 mol% Cu-ZnO was used as a photocatalyst that broke down textile dyes well and had a lot of promise to be used again. The samples were also checked for thermoluminescence while they were exposed to 25 kGy of gamma radiation. Samples were tested for their trap depth characteristics, indicating the test samples' potential for TL activity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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