1. Name and full correspondence address : Dr. Ch. Srinivasa Rao
Lecturer in PHYSICS
Andhra Loyola College (Autonomous)
Vijayawada 520008
Andhra Pradesh, India
2. Email(s) and contact number(s) : drchsr1971@
+919490608071
3. Institution : Andhra Loyola College (Autonomous)
Vijayawada 520008
4. Date of Birth: 14-07-1971
5. Gender (M/F/T) : Male
Influence of Ni2+ ions on the physical, structural, elastic, optical, and thermal aspects of oxy fluoro borate glasses mixed with sesquioxide ions (Al3+/Y3+/Sb3+) B.K. Sudhakar, N. Rama Krishna Chand, T. Vennela, P.V.S. Sairam, G. Ravi Kumar, G. Srinivasa Rao, Ch. Srinivasa Rao Results in Optics, 2024 Oxy Fluoro Borate (OFB) Glasses mixed with Sesquioxide ions (Al3+/Y3+/Sb3+) were synthesized using the traditional melt quenching technique. The properties of the structure of the glasses prepared are investigated by SEM, EDS and XRD methods. Variations in properties like density in glasses allow Nickel/Aluminium/Antimony/Yttrium ions to go through the borate glass matrix with an increase in respective dopant mole fraction. The decrease in the values of different elastic constants with B-O-Ni/Al/Sb/Y bonds and alsoby the function of NiO/Al2O3/Sb2O3/Y2O3 as a modifier and converting a portion of BO3 tetrahedral units into BO4octahedral units indicates the depolymerization in the glass matrix. The I.R. spectra and FTIR spectra show an increment in the occupation of cations Ni2+, Y3+, Sb3+ and Al3+ ions in the octahedral positions of the glass matrix with an enhancement in their molefraction. Creation of NBOs owing to the transformation of BO3 to BO4 units is greater in Al3+ and the smallest in Y3+ with an increment in the sesquioxide concentration at a 1.00 mol% NiO concentration. The dominance of the nickel ions octahedral occupancy in the glasses prepared is revealed by the optical absorption spectra, which may be because of the ligand fields produced by various ions of sesquioxides present within the glass matrix creating NBO and many trapped electrons at the donor centers. Photoluminescence spectra of the prepared glasses show the octahedral occupation of the Ni2+ ions that is indicated by the transitions 3A2g(F) ↔ 3T1g(P) and 3T1g(P) → 3T2g(F). The synthesized glasses exhibit effective luminescence by Nickel ions, and the AlNi and NiAl glass series exhibit superior luminescence properties owing to their highest emission cross-sections compared with the other series of prepared glasses.
The physical, structural, elastic, optical and thermal studies on sesquioxides (Al2O3, Y2O3, Sb2O3) doped Oxy Fluoro Cobalt Borate Glasses B K Sudhakar, N Rama Krishna Chand, Vennela Tirupati, Sairam PVS, G Ravi Kumar, G Srinivasa Rao, Ch Srinivasa Rao Physica Scripta, 2023 Sesquioxides (Al2O3, Y2O3, Sb2O3) doped Oxy fluoro Cobalt borate novel luminescent series of glasses are prepared by melt quenching method. The structural characteristics of these glasses were studied by XRD, SEM and EDS techniques. The change in physical parameters such as density of all the series of glasses prepared gives a pathway for cobalt/Alumina/Antimony/Yttrium ions to enter in to borate glass network with the enhancement in the concentration of corresponding dopants. The depolymerization of the borate glass network is evident by the decline in various elastic parameters with B-O-Co/Y/Sb/Al bonds and by the modifier role of CoO/Y2O3/Sb2O3/Al2O3 transforming a fraction of tetrahedral BO3 units into BO4 units. Both FTIR and IR spectra indicate an increase in octahedral occupancy of cations Co2+, Y3+, Sb3+and Al3+ ions in the glass network with the increase of their concentration. The conversion rate of tetrahedral BO3 units to octahedral BO4 units leading to the formation of NBOs is more in Al3+ and least in Y3+ with the increase of concentration of sesquioxides at 0.05 mol% concentration of CoO. The optical absorption spectra of all series of glasses prepared reveal that octahedral occupancy of cobalt ions is dominant due to the ligand fields created by different sesquioxide ions in the glass network produce NBOs and number of electrons trapped at the donor centers. The PL spectra of all the series of these glasses reveal the octahedral occupancy of Co2+ ions, which is evident from the two emission transitions 2T1g(H) →4T1g(F) (531–556 nm) and 2Eg→5T2g (699–718 nm).The prepared series of glasses show efficient luminescence of Cobalt ions, and Al2O3 series of glasses are better candidates for luminescence as their emission Cross-sections are highest when compared with the remaining series of glasses.
Influence of manganese ions on elastic and spectroscopic properties of ZnO doped novel calcium fluorophosphate bio active glasses N Rama Krishna Chand, B K Sudhakar, G Ravikumar, G Srinivasa Rao, Ch Srinivasa Rao Physica Scripta, 2021 The glass system 20CaF2-20ZnO-(60-x)P2O5:xMnO with 0 ≤ x ≤ 5.0 was prepared and investigated. The structural changes induced by the addition of MnO in the glass network were explained by using physical, elastic, thermal, chemical durability and spectroscopic studies. Results indicate that with the increase of concentration of MnO content from 1 to 5 mol% the parameters like density, pH of the immersion liquid, elastic moduli and glass characteristic temperatures increases. While the dissociation rate, the Poisson’s ratio and volume per mol decreases and signifying the increased mechanical strength of the prepared glasses. FTIR spectral analysis predicts that all the specific vibrational bands of phosphate bonds like bridging oxygen with phosphorous action, linkages like P-O-P, O-P-O and the crossed linkages like P-O-Mn & P-O-Zn are affected by the incorporation of MnO in the glass matrix. The changes observed in peak positions and intensities of all vibrational bands of IR spectra and optical absorption spectra confirm that manganese ions behaves as a glass former and also as a glass modifier depending on the concentration of MnO. The analysis of the optical absorption spectra of the glasses in particular the crystal field and interelectronic repulsion parameters shows that manganese ions are predominantly occur in the divalent state and occupy tetrahedral sites in the glass matrix when the concentration of MnO in the CaF2-ZnO-P2O5 glasses exceeds 1.0 mol%.
ZrxCa30-xP70 thermoluminescent bio glass, structure and elasticity G. Anil Kumar, Y. Rambabu, Ravi Kumar Guntu, K. Sivaram, M. Sreenath Reddy, Ch. Srinivasa Rao, V. Venkatramu, V. Ravi Kumar, N. Ch. Sriman Narayana Iyengar Journal of the Mechanical Behavior of Biomedical Materials, 2021
Prediction and analysis of sentiments on twitter data using hybrid naive bayes approach International Journal of Innovative Technology and Exploring Engineering, 2019
Spectroscopic studies on alumino alkali zirconia silicate glasses mixed with tiatanium ions for optoelectronic device application International Journal of Chemtech Research, 2015
Spectroscopic studies on Li2O-Nb2O5-SiO2:V2O5 glass ceramics embeded with nano ferroelectric crystals International Journal of Chemtech Research, 2014
Non linear optical effects in nano-crystallized lithium silicate glass ceramics mixed with small concentrations of CuO International Journal of Chemtech Research, 2014
Optical absorption studies on lithium aluminosilicate glasses doped with low concentrations of WO3 International Journal of Chemtech Research, 2014
