CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

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peaks are found to decrease with increase in ethylene glycol content in the reaction medium. Table 7 shows the variation in average crystallite size as a function of relative amounts of ethylene glycol and glycerol in the reaction medium. From these results, it is inferred that the average crystallite size can be tuned by varying the relative amounts of ethylene glycol and glycerol in the reaction medium. The observed variation in the crystallite size with change in the relative concentration of the solvent has been explained based on the increase in viscosity of the medium with increase in the relative concentration of glycerol and associated increase in growth rate. XRD patterns are least square fitted to determine the lattice parameters. The values for un-doped SbPO 4 samples are a = 5.099(1) Å, b = 6.767(2) Å, c = 4.749(1) Å with β = 94.73. Corresponding values for the 5% Tb 3+ doped nanoparticles are a = 5.093(1) Å, b = 6.769(2) Å, c = 4.733(1) Å with β = 94.69. There is no significant change in the values of lattice parameters for both doped and un-doped samples. This can be attributed to the comparable ionic radii of Sb 3+ and Tb 3+ under a coordination number of four. In order to check the nature of amorphous product obtained when pure ethylene glycol is used as the solvent, IR patterns were recorded for the amorphous product and it is compared with the patterns obtained from crystalline SbPO 4 sample. Figure 62 shows IR spectra of as prepared SbPO 4 sample obtained by using pure ethylene glycol, pure glycerol and a mixture of glycerol and ethylene glycol (10 ml each). Table.7. Effect of variation volume of solvents on the average crystallite size of SbPO 4 nanomaterials. Volume of glycerol (ml) Volume of ethylene glycol (ml) Average crystallite size (nm) 20 0 46 10 10 28 8 12 12 0 20 - 114
(001) (110) (011) (101) (020) (101) (111) (200) (121) (002) (201) (112) (130) (a) (022) (131) Intensity (arb.units) (b) (c) (d) 20 30 40 50 2θ /° Fig.61. XRD Patterns of SbPO :Tb 3+ 4 nanomaterials synthesized from (a) 20 ml glycerol, (b) 10 ml ethylene glycol and 10 ml glycerol, (c) 12 ml ethylene glycol and 8 ml glycerol and (d) 20 ml ethylene glycol. % Transmittance (arb. units) 590 640 958 600 900 1200 wavenumber (cm -1 ) (a) (b) 1135 (c) 1040 Fig.62. FT-IR Spectra of SbPO :Tb 3+ 4 samples obtained in (a) ethylene glycol medium, (b) glycerol medium and (c) mixture of ethylene glycol and glycerol medium (10 ml each). 115
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SYNTHESIS AND CHARACTERIZATION OF L
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STATEMENT BY AUTHOR This dissertati
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Dedicated to ……… My beloved b
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also thankful to all the members of
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2.3 Synthesis of binary oxide nanom
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CHAPTER 5: Zinc Gallate ...........
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imaging, scintillators, lasers, etc
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morphology by heating at 500 and 90
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nanoparticles having hexagonal stru
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100°C and 185°C, respectively in
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into poly methyl methacryllate (PMM
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3. N. M. Dimitrijevic, Z. V. Saponj
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Fig.13: Fig.14: (a) Simplified ray
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Eu 3+ ions after heat treatment at
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615 nm Fig.50: FT-IR patterns (a) a
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area electron diffraction pattern a
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different amounts of Eu 3+ . Fig.86
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and 545 nm, respectively. Fig.106:
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List of Tables: Table 1: Variation
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CHAPTER 1: Introduction 1.1 Histori
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Rods, cylinders, wires and tubes ar
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must be supersaturated either by di
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- + - + charge stabilized nanoparti
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exothermic reaction between the met
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constant, ħ is h/2π, e is the ele
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these platinum complexes have been
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(IR), visible and ultra-violet (UV)
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in Ce 3+ , Pr 3+ , Tb 3+ and CT abs
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assisted by lattice phonons of appr
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decay-time reduction is much easier
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nanocrystals is shown in Fig.10 [58
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depends strongly on the nature of t
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corresponding emission and excitati
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doped nanomaterials of the above me
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will be formed and subsequently it
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Eu 3+ ions were also subjected to s
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transferred into a two-necked RB fl
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Where λ is the wavelength of X-ray
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Micro-structural characterization b
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electrons (i.e. diffraction mode).
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diffraction spots. By tilting a cry
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surface. The contact mode can obtai
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three types lines in the scattered
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solids tend to be broadened because
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sample fluoresce. The fluorescent l
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pulse frequency) as excitation sour
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Lanthanide ions doped Ga 2 O 3 nano
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atoms at three corners and the lone
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Figure 19 (a-d) shows SEM images of
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Based on these results, it can be i
Page 101 and 102: almost normal to the equatorial pla
Page 103 and 104: Table 2. Summary of important modes
Page 105 and 106: systematic disappearance of these t
Page 107 and 108: comparison, Eu 3+ ions alone in wat
Page 109 and 110: the samples, suggesting that Eu 3+
Page 111 and 112: These inferences are further substa
Page 113 and 114: Similar DTA peaks have been reporte
Page 115 and 116: GaOOH samples doped with different
Page 117 and 118: The cell parameters increases with
Page 119 and 120: strong emission compared to corresp
Page 121 and 122: curves are shown in Fig.39. Lifetim
Page 123 and 124: Similar results are also observed f
Page 125 and 126: intensity of XRD peaks correspond t
Page 127 and 128: compared to the bulk material and a
Page 129 and 130: is almost 1½ times that of peak B1
Page 131 and 132: 3.8 Interaction of Eu 3+ ions with
Page 133 and 134: The spectrum shows strong emission
Page 135 and 136: The decay curves are found to be bi
Page 137 and 138: As prepared undoped Sb 2 O 3 sample
Page 139 and 140: Intensity(arb.units) 1.0 0.8 0.6 0.
Page 141 and 142: 3+ having surface lanthanide ions.
Page 143 and 144: diffraction patterns from the GaPO
Page 145 and 146: 5 D 0 7 F 2 level to 7 F 7 7 1 , F
Page 147 and 148: The second possibility is the excha
Page 149 and 150: chemical shift anisotropy is much h
Page 151: not have strong interaction with th
Page 155 and 156: growth centre compared to higher vi
Page 157 and 158: observed after excitation at 250 an
Page 159 and 160: 3+ 3+ concentration quenching. Tb l
Page 161 and 162: Compared to the selected area elect
Page 163 and 164: lattice. Lanthanide ions occupying
Page 165 and 166: obtained after 275 nm excitation is
Page 167 and 168: The luminescence dynamics associate
Page 169 and 170: that the broad peak can be resolved
Page 171 and 172: espectively. Value of this integral
Page 173 and 174: ethylene glycol moiety (stabilizing
Page 175 and 176: Room temperature and 100°C synthes
Page 177 and 178: heavier metal ion as compared to La
Page 179 and 180: Similar studies were also carried o
Page 181 and 182: 3+ 3+ faster decay component is ass
Page 183 and 184: the other hand the Eu 3+ lifetime h
Page 185 and 186: 3+ 4.4.8 Luminescence studies on Sm
Page 187 and 188: CHAPTER 5: Zinc gallate (ZnGa 2 O 4
Page 189 and 190: In pure EG an amorphous product is
Page 191 and 192: water content in the reaction mediu
Page 193 and 194: nucleation, thereby leading to incr
Page 195 and 196: particles. Thus the TEM studies als
Page 197 and 198: value. The lattice parameters calcu
Page 199 and 200: Quantum yield of the blue emission
Page 201 and 202: 5.5.2. Eu 3+ doped ZnGa 1.5 In 0.5
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CHAPTER 6: Tungstates [MWO 4 (M = C
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ionic radius of the metal cation ca
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lattice. Asymmetric ratio is ~ 12 f
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700 Intensity (arb.units) 600 λ ex
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Intensity (arb.units) 25000 20000 1
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Strong green emission has been obse
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consists of strong band at 255 nm a
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peak can be attributed to the cryst
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nm) is observed from Er 3+ doped Ga
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and Dy 3+ doped CaWO 4 nanoparticle
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REFERENCES 1. D. J. Barber, I. C. F
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32. K. A. Gschneidner, Jr., L. Eyri
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65. Z. Deng, F. Tang, D. Chen, X. M
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100. A. Rouanel, J. J. Serra, K. Al
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130. F. Li, W. Jianhuai, L. Jiongti
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166. L. Fu, Z. Liu, Y. Liu, B. Han,
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205. R. Sasikala, V. Sudarsan, C. S
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238. E. Oldfield, R. A. Kinsey, K.
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271. B. G. Hyde, S. Andersson, ”I
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B. S. Naidu, B. Vishwanadh, V. Suda
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9. Room temperature synthesis of mu
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CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

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