title: Shape tailored green synthesis of CeO₂:Ho³⁺ nanopowders, its structural, photoluminescence and gamma radiation sensing properties.
abstract: CeO2:Ho(3+) (1-9 mol%) nanopowders have been prepared by efficient and environmental friendly green combustion method using Aloe vera gel as fuel for the first time. The final products are well characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), fourier transform infrared (FTIR). Bell, urchin, core shell and flower like morphologies are observed with different concentrations of the A. vera gel. It is apparent that by adjusting the concentration of the gel, considerable changes in the formation of CeO2:Ho(3+) nano structures can be achieved. Photoluminescence (PL) studies show green (543, 548 nm) and red (645, 732 nm) emissions upon excited at 400 nm wavelength. The emission peaks at ∼526, 548, 655 and 732 nm are associated with the transitions of (5)F3→(5)I8, (5)S2→(5)I8, (5)F5→(5)I8 and (5)S2→(5)I7, respectively. Three TL glow peaks are observed at 118, 267 and 204°C for all the γ irradiated samples which specify the surface and deeper traps. Linear TL response in the range 0.1-2kGy shows that phosphor is fairly useful as γ radiation dosimeter. Kinetic parameters associated with the glow peaks are estimated using Chen's half width method. The CIE coordinate values show that phosphor is quite useful for the possible applications in WLEDs as orange red phosphor.
authors.affiliation: Department of Physics, University College of Science, Tumkur University, Tumkur 572 103, India.
authors.forename: J
authors.initials: J
authors.lastname: Malleshappa
authors.affiliation: Prof. C.N.R. Rao Centre for Advanced Materials Research, Tumkur University, Tumkur 572 103, India. Electronic address: bhushanvlc@gmail.com.
authors.forename: H
authors.initials: H
authors.lastname: Nagabhushana
authors.affiliation: Department of Physics, Channabasaveshwara Institute of Technology, Gubbi 572 216, India.
authors.forename: D
authors.initials: D
authors.lastname: Kavyashree
authors.affiliation: Research Center, Department of Physics, East West Institute of Technology, Bengaluru 560 091, India. Electronic address: scphysics@gmail.com.
authors.forename: S C
authors.initials: SC
authors.lastname: Prashantha
authors.affiliation: Vice Chancellor, Chattisgarh Swami Vivekananda Technical University, Bhilai (CG) 493 441, India.
authors.forename: S C
authors.initials: SC
authors.lastname: Sharma
authors.affiliation: Department of Physics, Acharya Institute of Technology, Bengaluru 560 107, India.
authors.forename: H B
authors.initials: HB
authors.lastname: Premkumar
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560 012, India.
authors.forename: C
authors.initials: C
authors.lastname: Shivakumara
mesh_terms: D000504:Aloe / Q000737:chemistry; D002563:Cerium / Q000737:chemistry*; D003460:Crystallization; D004583:Electrons; D005720:Gamma Rays; D055772:Green Chemistry Technology / Q000379:methods*; D006695:Holmium / Q000737:chemistry*; D007700:Kinetics; D049449:Luminescence; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D011208:Powders; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014961:X-Ray Diffraction
chemical_list: D011208:Powders; D002563:Cerium; C030583:ceric oxide; D006695:Holmium
keywords: Green synthesis; Kinetic parameters; Luminescence; Morphology; Phosphor