CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

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3+ Fig.59. Schematic diagram of Eu species present on the surface of the GaPO nanoparticles. 4 For understanding the nature of interaction of ligands (glycerol molecule) with the surface Ga 3+ /Eu 3+ species present in GaPO 4 nanoparticles, FT-IR spectra were recorded for both GaPO 4 nanoparticles and GaPO nanoparticles containing 2.5 at % Eu 3+ 4 ions and are shown in Fig.60. Both the patterns are identical with peak positions around 3403, 2948, 2117, 2356 and 1654 cm -1 as can be seen from Fig.60. In fact, the spectra for the 5 and 10 atom % Eu 3+ containing samples are also same as that of undoped GaPO 4 nanoparticles. The peaks centered around 3403 and 1654 cm -1 correspond to stretching and bending vibrations respectively of O-H groups present on the surface of the nanoparticles as well as from glycerol molecule [240]. The less intense peak ~ 2948 cm -1 is assigned to asymmetric and symmetric stretching vibrations of C-H linkages of the stabilizing glycerol molecules. The weak peaks around 2117 and 2356 cm -1 can be considered as the overtones of the δ(OH) bending vibrations [241]. There is no change in the line shape and peak positions of the peaks corresponding to the different vibrational modes of the ligand molecules present with both undoped and 2.5 at % Eu 3+ containing GaPO nanoparticles. This suggests that Eu 3+ ions do 4 112
not have strong interaction with the ligand molecules. Hence from the luminescence, FT-IR and 31 3+ P MAS NMR spectrum, it is confirmed that up to 2.5 at % Eu containing GaPO 4 nanoparticles, Eu 3+ replaces protons of the Ga-OH linkages, forming Ga-O-Eu type of linkages and beyond which separate EuPO phase is formed. 4 80 % Transmittance 60 40 1654 2117 2356 GaPO 4 GaPO 4 :Eu 2948 3403 1500 2000 2500 3000 3500 4000 Wavenumber (cm -1 ) Fig.60. FT-IR spectrum of GaPO nanoparticles containing 0 % and 2.5 at % Eu 3+ 4 4.3. Studies on Antimony phosphate nanomaterials: Antimony phosphate nanomaterials were prepared at 130°C by precipitating Sb 3+ using ammonium dihydrogen phosphate in ethylene glycol, glycerol and mixture of them. 4.3.1. Effect of ethylene glycol to glycerol ratio on size and shape of SbPO 4 :Ln nanomaterials: Figure 61 shows XRD patterns of as prepared SbPO 4 sample, obtained by using pure glycerol, mixtures of glycerol and ethylene glycol and pure ethylene glycol. For samples prepared in glycerol as well as mixture of glycerol and ethylene glycol, crystalline SbPO 4 with monoclinic structure has been observed. It should be noted here that for samples prepared in pure ethylene glycol, no sharp peak characteristic of crystalline material is observed revealing that reaction in pure ethylene glycol leads to the formation of an amorphous product. Average crystallite sizes as calculated from the line width of the XRD 113
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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
Page 99 and 100: 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: chemical shift anisotropy is much h
Page 153 and 154: (001) (110) (011) (101) (020) (101)
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
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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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