CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

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exchange properties of the nanomaterials. For example Dong, et al. [279] have demonstrated that when GdF 3 nanoparticles dispersed in water are exposed to excess of La 3+ ions, rapid ion exchange of Gd 3+ from GdF 3 lattice by La 3+ ions in aqueous solution takes place, resulting in the formation of LaF 3 nanoparticles and aqueous solution of Gd 3+ ions. It is observed that lanthanide ions in the left of the periodic table (for example La 3+ ) can replace the ones from the right (for example Gd 3+ ) present in a lattice. In a recent study [280] it is also observed that rapid cation exchange takes place between Ce 3+ ions in CePO 4 host and Eu 3+ and Y 3+ ions in solution. Hence, in order to understand the potential of nanomaterials for separation applications, it is proposed to carry out detailed ion exchange studies on phosphate based nanomaterials synthesized in the present study. It is also proposed to carry out work on electro-luminescence properties of the nanomaterials like ZnGa 2 O 4 , CaWO 4 , Sb 2 O 3 , etc., after incorporating them in suitable polymers. This will be helpful for the development of polymer based display devices. The general approach used for electroluminescence devices is given in the Fig.118. It consists of anode (generally ITO coated glass), hole injector, emissive layer and cathode. Electrons will be injected from cathode while holes will be injected from anode. They will recombine in the emissive layer which is nanoparticles incorporated polymer film. Fig. 118. Schematic diagram of an electro-luminescent device. 184
REFERENCES 1. D. J. Barber, I. C. Freestone, Archaeometry, 32 (1990) 33. 2. J. Yacaman, L. Rendon, J. Arenas, M. C. S. Puche, Science, 273 (1996) 223. 3. http://www.britishmuseum.org/explore/highlights/highlight_objects/pe_mla/t/the_lycu rgus_cup.aspx 4. http://aveburybooks.com/faraday/catalog.html 5. M. Faraday, Philos. Trans. R. Soc., London, 147 (1857) 145. 6. G. Bredig, Z. Angew. Chem., 11 (1898) 951. 7. J. Donau, Monatsh, 25 (1905) 525. 8. R. Zsigmondy, Z. Phys. Chem., 56 (1906) 65. 9. R. Feynman, lecture entitled “There's Plenty of Room at the Bottom” given at American Physical Society meeting at Caltech on December 29, 1959. 10. E. Drexler, “Nanosystems: Molecular Machinery, Manufacturing and Coputation”, Wiley, 1991, Newyork. 11. X. Peng, L. Manna, W. Yang, J. Wickham, E. Scher, A. Kadavanich, A. P. Alivisatos, Nature, 404 (2000) 59. 12. Y. Jun, J. Choi, J. Cheon, Angew. Chem. Int. Ed., 45 (2006) 3414. 13. C. Burda, X. Chen, R. Narayanan, M. A. El-Sayed, Chem. Rev., 105 (2005) 1025. 14. C. N. R. Rao, A. Muller, A. K. Cheetham, “Nanomaterials Chemistry: Recent Developments and New Directions”, WILEY-VCH Verlag GmbH & Co. KGaA, 2007, Weinheim. 15. C. N. R. Rao G. U. Kulkarni, P. J. Thomas, “Nanocrystals: Synthesis, Properties and Applications”, Springer Berlin Heidelberg, 2007, New York. 16. B. L. Cushing, V. L. Kolesnichenko, C. J. O’Connor, Chem. Rev., 104 (2004) 3893. 17. J. McKittrick, L. E. Shea, C. F. Bacalski, E. J. Bosze, Displays, 19 (1999) 169. 185
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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
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almost normal to the equatorial pla
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Table 2. Summary of important modes
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systematic disappearance of these t
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comparison, Eu 3+ ions alone in wat
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the samples, suggesting that Eu 3+
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These inferences are further substa
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Similar DTA peaks have been reporte
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GaOOH samples doped with different
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The cell parameters increases with
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strong emission compared to corresp
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curves are shown in Fig.39. Lifetim
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Similar results are also observed f
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intensity of XRD peaks correspond t
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compared to the bulk material and a
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is almost 1½ times that of peak B1
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3.8 Interaction of Eu 3+ ions with
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The spectrum shows strong emission
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The decay curves are found to be bi
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As prepared undoped Sb 2 O 3 sample
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Intensity(arb.units) 1.0 0.8 0.6 0.
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3+ having surface lanthanide ions.
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diffraction patterns from the GaPO
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5 D 0 7 F 2 level to 7 F 7 7 1 , F
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The second possibility is the excha
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chemical shift anisotropy is much h
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not have strong interaction with th
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(001) (110) (011) (101) (020) (101)
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growth centre compared to higher vi
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observed after excitation at 250 an
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3+ 3+ concentration quenching. Tb l
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Compared to the selected area elect
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lattice. Lanthanide ions occupying
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obtained after 275 nm excitation is
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The luminescence dynamics associate
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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
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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
Page 203 and 204: CHAPTER 6: Tungstates [MWO 4 (M = C
Page 205 and 206: ionic radius of the metal cation ca
Page 207 and 208: lattice. Asymmetric ratio is ~ 12 f
Page 209 and 210: 700 Intensity (arb.units) 600 λ ex
Page 211 and 212: Intensity (arb.units) 25000 20000 1
Page 213 and 214: Strong green emission has been obse
Page 215 and 216: consists of strong band at 255 nm a
Page 217 and 218: peak can be attributed to the cryst
Page 219 and 220: nm) is observed from Er 3+ doped Ga
Page 221: and Dy 3+ doped CaWO 4 nanoparticle
Page 225 and 226: 32. K. A. Gschneidner, Jr., L. Eyri
Page 227 and 228: 65. Z. Deng, F. Tang, D. Chen, X. M
Page 229 and 230: 100. A. Rouanel, J. J. Serra, K. Al
Page 231 and 232: 130. F. Li, W. Jianhuai, L. Jiongti
Page 233 and 234: 166. L. Fu, Z. Liu, Y. Liu, B. Han,
Page 235 and 236: 205. R. Sasikala, V. Sudarsan, C. S
Page 237 and 238: 238. E. Oldfield, R. A. Kinsey, K.
Page 239 and 240: 271. B. G. Hyde, S. Andersson, ”I
Page 241 and 242: B. S. Naidu, B. Vishwanadh, V. Suda
Page 243: 9. Room temperature synthesis of mu
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