Dr. Suresh Kukkamalla
@gcrjy.ac.in
Lecturer in Physics
Government College (A), Rajahmundry
EDUCATION
M.Sc., Ph.D.,
RESEARCH INTERESTS
Luminescence (Display materials, LEDs, Glass materials)
Material Science
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Kishore Kumar Aitha, D. Dinakar, Payal P. Pradhan, K. Yadagiri, K. Suresh, Naresh Degda, K.V.R. Murthy, and D. Haranath
Informa UK Limited
Mocharla Purna Durga Parimala, M. C. Rao, K. Suresh, Ch. Vijay Anil Dai, K. V. R. Murthy, and Vikas Dubey
Wiley
AbstractIn this paper, we present new aspects of Sm3+‐doped pure Li2CaSiO4 as a suitable candidate for white light emitting diode (WLED) applications. The samples were mainly prepared using a conventional modified solid‐state synthesis technique. The structural studies were done using X‐ray diffraction and Rietveld refinement. Instruments such as a scanning electron microscope (SEM) were used to obtain information about the morphology of the as‐prepared samples. Photoluminescence (PL) analysis of phosphor samples for variable concentrations of doping ions with variable excitations were presented. When doped with Sm3+ in host Li2CaSiO4 it emitted intense blue, green and red emissions and a more intense red emission peak (605 nm) under 408 nm excitation (near‐UV–blue). Our study shows that the as‐prepared phosphor may be useful for optical devices and mainly for WLEDs. The corresponding transitions of doping ions and concentration quenching effect were studied in detail. The 1931 Commission Internationale de l'Eclairage (x, y) chromaticity coordinates showed the distribution of spectral regions calculated from PL emission spectra and this was found (0.63, 0.36) in the red region, so the phosphor may be useful for near‐UV–blue excited WLED applications.
J. Kishore Babu, Mandava Sridhar, A.S. Sai Prasad, Gratian Patrick, and K. Suresh
Elsevier BV
Karanukar Shakampally, Y. Aparna, K. Suresh, and K. V. R. Murthy
Author(s)
J. Kishore Babu, B. Subba Rao, K. Suresh, Mandava Sridhar, and K. V. R. Murthy
Author(s)
Ch. Vijay Anil Dai, K. Suresh, T. Niranjan Kumar, Ch. Srinivasu, and K. V. R. Murthy
Author(s)
Binary Glass system with the composition 40Sb2O3-(60-x) B2O3: xCr2O3 for x = 0.1, 0.3 and 0.5 mol % were prepared by the melt-quenching technique. The prepared glass samples were characterized by XRD, FTIR, EPR, PL and Optical absorption spectra. The physical properties were also studied. From the XRD studies the glass samples were amorphous in nature. From the FTIR spectra it is observed that the % of transmittance decreased with the increase of dopant concentration. From the EPR spectra of pure and Cr3+ doped antimony borate glasses, two principal resonance lines are observed. The first is a broad asymmetric band at low magnetic field with an effective g value of 4.2281 and the second is a broad asymmetric line at high magnetic field with an effective g value of 1.9716. No EPR signal was detected for the pure glass, which indicates that the pure glass is free of paramagnetic impurities. Optical absorption and luminescence spectra of all the glasses were recorded at room temperature. From the observed absorption edges optical band gap, the Urbach energies were calculated. The optical band gap is found to decrease with the concentration of Cr2O3. The luminescence spectra exhibited conventional near infra-red emission bands at around 789, 845 nm under 420 and 460 nm excitation wavelength.Binary Glass system with the composition 40Sb2O3-(60-x) B2O3: xCr2O3 for x = 0.1, 0.3 and 0.5 mol % were prepared by the melt-quenching technique. The prepared glass samples were characterized by XRD, FTIR, EPR, PL and Optical absorption spectra. The physical properties were also studied. From the XRD studies the glass samples were amorphous in nature. From the FTIR spectra it is observed that the % of transmittance decreased with the increase of dopant concentration. From the EPR spectra of pure and Cr3+ doped antimony borate glasses, two principal resonance lines are observed. The first is a broad asymmetric band at low magnetic field with an effective g value of 4.2281 and the second is a broad asymmetric line at high magnetic field with an effective g value of 1.9716. No EPR signal was detected for the pure glass, which indicates that the pure glass is free of paramagnetic impurities. Optical absorption and luminescence spectra of all the glasses were recorded at room temperature. From the observed ab...
J. Kishore Babu, B. Subba Rao, K. Suresh, Mandava Sridhar, and KVR Murthy
Elsevier BV
K. Suresh, Nannapaneni V. Poornachandra Rao, and K. V. R. Murthy
Wiley
AbstractCaS:Ce3+ is an efficient green‐emitting (535 nm) phosphor, excitable with blue light (450–470 nm) and was synthesized via a solid‐state reaction method by heating under a reducing atmosphere. The luminescent properties, photoluminescent (PL) excitation and emission of the phosphor were analyzed by spectrofluorophotometry. The excitation and emission peaks of the CaS:Ce3+ phosphor lay in the visible region, which made them relevant for light‐emitting diode (LED) application for the generation of white light. Judd‐Oflet parameters were calculated and revealed that green light emitted upon blue illumination. The prepared phosphor had strong blue absorption at 470 nm and a broad green emission band range from 490–590 nm with the peak at 537 nm. The characteristics of the CaS:Ce3+ phosphor make it suitable for use as a wavelength tunable green emitting phosphor for three band white LEDs pumped by a blue LED (470 nm). The Commission International de l'Eclairage co‐ordinates were calculated by a spectrophotometric method using the spectral energy distribution (0.304, 0.526) and confirm the green emission. The potential application of this phosphor is as a phosphor‐converted white light‐emitting diode. Copyright © 2015 John Wiley & Sons, Ltd.
K. Suresh, N. V. Poornachandra Rao, and K. V. R. Murthy
Springer Science and Business Media LLC
K. Suresh, K.V.R. Murthy, Ch. Atchyutha Rao, N.V. Poornachandra Rao, and B. Subba Rao
Elsevier BV
K.V.R. Murthy, B.Nageswara Rao, B.N. Rajasekhar, B. Walter Ratna Kumar, K. Suresh, and B. Subba Rao
Elsevier BV
K.V.R. Murthy, Ch. Atchyutha Rao, K. Suresh, N.V. Poornachandra Rao, B. Subba Rao, B. Walter Ratna Kumar, B.N. Rajasekhar, and Bellam N. Rao
Institute of Combustion Problems
<p>Phosphors the ceramic materials should able to work in tough environment surrounded and bombarded by high energy Vacuum Ultra Violet (VUV), UV or electron beam radiations in any discharge tube. The plasma display panel (PDP) is increasingly gaining attention over conventional cathode ray tube (CRT)- based TVs as a medium of large format (60+”) television (TV), particularly high definition TVs (HDTVs). Improvements have been made not only in size but also in other areas such as resolution, luminescence efficiency, brightness, contrast ratio, power consumption, and cost reduction. The formation of a phosphor host and doping process by solid solution is critical and is highly dependent on the reaction temperature and conditions. Since the purity of starting chemicals is very important to the synthesis of phosphors, the starting chemicals are typically 99.9%, 99.999% in purity. Required amounts of starting ingredients are mixed in the presence of an appropriate flux (if necessary) and fired at high temperatures (1200 °C) in air or in a controlled atmosphere (N<sub>2</sub>, C, CO, or N<sub>2</sub> with 2-5% of H<sub>2</sub>). The present paper reports the synthesis and luminescence characteristics of different ceramic materials (phosphors) for display applications.</p>
K.V.R. Murthy, K. Suresh, B. Nageswara Rao, B. Walter Ratna Kumar, Ch. Atchyutha Rao, B.N. Rajasekhar, B. Subba Rao, and N.V. Poornachandra Rao
Institute of Combustion Problems
<p>The present paper reports the Photoluminescence (PL) of the Sr<sub>2</sub>CeO<sub>4</sub> phosphor, singly doped with Erbium rare-earth ion with different concentrations (0.01, 0.1, 0.2, 0.5 and 1%).The phosphor samples were synthesized using the standard solid state reaction technique. The effect of Er dopant on the structural, morphological, and Photoluminescent properties of the samples are studied with X-ray diffraction (XRD), PL and SEM analysis. The PL emission of undoped Sr<sub>2</sub>CeO<sub>4</sub> phosphor was observed at 470 nm with high intensity followed by the primary Er emissions with good intensity at 525, 530, 549, 557 and 565 nm.</p>
Kattimuttathu I. Suresh, Jaki R. Tamboli, Butti S. Rao, Suraj Verma, and G. Unnikrishnan
Wiley
AbstractIn this paper, the influence of molecular structure variations on the mesophase behavior, photocurability, and film properties of polymerizable mesogenic diacrylates is reported. The effect of methoxy or chloro substituent on the mesophase behavior of the monomers, present at the 2‐position of the phenylene core, in comparison to the unsubstituted core, has been studied using thermal and photo‐DSC techniques. These monomers were used in combination with a chiral dopant to form cholesteric mesophases, which was subsequently crosslinked through photopolymerization. Optical microscopy and polarized optical microscopy (POM) were used to study the morphology of monomers as well as the photopolymerized films. Optical images show the influence of chiral dopant on the texture present in the films, both before and after the crosslinking. POM images show the mesophase present in the monomers and the free films. Evaluation of viscoelastic properties of the photocured films demonstrates the influence of mesogenic core substituents on the network transition temperature, modulus, and damping characteristics. Copyright © 2008 John Wiley & Sons, Ltd.
K. I. Suresh, K. Saji Thomas, B. S. Rao., and C. P. Reghunadhan Nair
Wiley
AbstractA study on the thermo‐oxidative stabilization (cyclization) of polyacrylonitrile (PAN) terpolymers using dynamic mechanical thermal analysis (DMTA) is reported in this article. When the changes in viscoelastic properties were monitored in a rectangular tension mode, besides the tan δ peak characteristic of the glass transition observed below 200°C, the copolymer and the terpolymer displayed a second peak above 200°C due to the cyclization leading to the formation of ladder structures. The initiation temperature of the cyclization process as well as the peak temperature is found to depend on the acid value and the composition of the precursor polymer. The results presented show that monitoring the changes in viscoelastic properties during cyclization provides insight into the material properties as a result of the chemical changes that are taking place. These observations were confirmed by structural characterization using IR spectroscopy, and the observed chemical changes agree with the literature studies, as due to the thermal cyclization process. Copyright © 2008 John Wiley & Sons, Ltd.
Kattimuttathu I. Suresh, Andrei Veniaminov, and Eckhard Bartsch
Wiley
AbstractThis article reports the application of the Photo‐Induced Grating Relaxation technique (also known as Forced Rayleigh Scattering) to investigate the dynamics of films prepared from structured core–shell latex particles via the transport property of the photochromic tracer molecule Aberchrome 540®. The core–shell particles were prepared with a fluoropolymer core (immiscible and impenetrable to the tracer) and a poly(butyl methacrylate) shell. The incompletely dried films (with residual water) manifest their spatial heterogeneity via non‐Fickian behavior (spatial scale‐ dependent apparent diffusion coefficient). The diffusion data was interpreted using the two‐state diffusion model, previously developed to describe the tracer diffusion in latex films without any core–shell structure. In contrast to dry latex films made from homogeneous particles, where one observes Fickian diffusion indicative of a homogeneous polymer film, we find that the lattice of fluoropolymer cores leads to a length scale dependent diffusion coefficient for the tracer. This effect can be interpreted as microscopic evidence for a strain hardening effect due to the presence of a hardened layer of matrix polymer (= shell) surrounding the core, which act as nanofillers. This strain hardening effect could be quantified within the two‐state diffusion model in terms of tracer diffusion coefficients and root mean squared displacements. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2823–2834, 2007