title: Calotropis procera mediated combustion synthesis of ZnAl2O4:Cr(3+) nanophosphors: structural and luminescence studies.
abstract: ZnAl2O4:Cr(3+) nanophosphors were synthesized for the first time by a simple and environment friendly route using Calotropis procera milk latex as fuel. The structural and surface morphological studies were carried out using powder X-ray diffraction (PXRD), scanning electron microscopy and transmission electron microscopy techniques. The photoluminescence (PL) properties of ZnAl2O4:Cr(3+) as a function of dopant concentration and calcination temperature was studied in detail. The PXRD patterns and Rietveld confinement confirmed the cubic crystal system with space group Fd-3m. The crystallite size estimated from Scherrer's and W-H plots was found to be in the range of 16-26 nm. The PL spectrum shows an intense peak at ∼688 and ∼699 nm assigned to spin-forbidden (2)Eg→(4)A2g transition of Cr(3+) ions. The PL measurements for two excitations (∼410 and 527 nm) and with respect to calcination temperature indicated no significant change in the shape and position of emission peak except PL intensity. The CIE chromaticity coordinates lies well within the white region. Thermoluminescence (TL) studies revealed well resolved glow peak at ∼212°C with a small shoulder at 188 and 233°C. The glow peak intensity at ∼212°C increases linearly with γ-dose which suggest ZnAl2O4:Cr(3+) is suitable candidate for radiation dosimetric applications. The activation energy (E in eV), order of kinetics (b) and Frequency factor (s) were estimated using glow peak shape method.
authors.affiliation: C.N.R. Rao Centre for Advanced Materials, Tumkur University, Tumkur 572 103, India.
authors.forename: B S
authors.initials: BS
authors.lastname: Ravikumar
authors.affiliation: C.N.R. Rao Centre for Advanced Materials, Tumkur University, Tumkur 572 103, India. Electronic address: bhushanvlc@gmail.com.
authors.forename: H
authors.initials: H
authors.lastname: Nagabhushana
authors.affiliation: Chhattisgarh Swami Vivekananda Technical University, North Park Avenue, Sector-8, Bhilai, Chhattisgarh 490 009, India.
authors.forename: S C
authors.initials: SC
authors.lastname: Sharma
authors.affiliation: Department of Physics, LBSGFGC, Bangalore 560 032, India.
authors.forename: Y S
authors.initials: YS
authors.lastname: Vidya
authors.affiliation: Research Center, Department of Chemistry, East West Institute of Technology, Bangalore 560 091, India.
authors.forename: K S
authors.initials: KS
authors.lastname: Anantharaju
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D031107:Calotropis / Q000737:chemistry*; D003460:Crystallization; D007700:Kinetics; D049449:Luminescence; D008163:Luminescent Measurements; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D010087:Oxides / Q000737:chemistry*; D011208:Powders; D013696:Temperature; D014961:X-Ray Diffraction; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D017607:Aluminum Compounds; D010087:Oxides; D011208:Powders; D017967:Zinc Compounds
keywords: Calotropis procera; Photoluminescence; Thermoluminescence; ZnAl(2)O(4):Cr(3+) nanophosphors