CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

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(Fig.6 (b)) have been observed on excitation at 253 nm. Strong near infrared (NIR) emission (1535 nm) has also been observed from the Er 3+ doped CaWO 4 nanoparticles. Intensity (arb.units) BaWO 4 SrWO 4 CaWO 4 20 nm 10 nm 7 nm Intensity (arb.units) CaWO 4 :2%Eu CaWO 4 :2%Sm CaWO 4 :2%Dy CaWO 4 :2%Tb CaWO 4 10 20 30 40 50 60 70 2θ /° 400 500 600 700 Wavelength (nm) (a) (b) Figure 6. (a) XRD patterns of different tungstate nanoparticles and (b) Emission spectrum from lanthanide ions doped CaWO 4 nanoparticles. Samples were excited at 250 nm. Chapter 7 gives the summary of the results on the luminescence and structural aspects of nanomaterials of the present study together with the future scope of this work. Possible reasons for the tunability of emission observed from different type of nanomaterials has been discussed mainly based on the different experimental parameters involved in their synthesis and in their structural aspects. Future scope and main interest involved in the development of such materials lies with their applications as active materials in display and electro-luminescent devices. Factors that are relevant for employing the above materials for such applications have also been discussed in this chapter. References: 1. C. Burda, X. Chen, R. Narayanan, M. A. El-Sayed, Chem. Rev., 105 (2005) 1025. 2. T. Vossmeyer, L. Katsikas, M. Giersig, I. G. Popovic, K. Diesner, A.Chemseddine, A. Eychmuller, H. Weller, J. Phys. Chem., 98 (1994) 7665. xxii
3. N. M. Dimitrijevic, Z. V. Saponjic, B. M. Rabatic, O. G. Poluektov, T. Rajh, J. Phys. Chem. C, 111 (2007) 14597. 4. C. N. R. Rao, P.J. Thomas, G.U. Kulkarni, Nanocrystals: Synthesis, Properties and Applications, Springer-Verlag Berlin, Heidelberg, 2007 5. V. Sudarsan, S. Sivakumar, F. C. J. M. van Veggel, Chem. Mater., 17 (2005) 4736. 6. T. Justel, H. Nikol, C. Ronda, Angew. Chem., Int. Ed., 37 (1998) 3085. 7. D. B. Barber, C. R. Pollock, L. L. Beecroft, C. K. Ober, Opt. Lett., 22 (1997) 1247. 8. V. I. Klimov, A. A. Mikhailovsky, S. Xu, A. Malko, J. A. Hollingsworth, C. A. Leatherdale, H. J. Eisler, M. G. Bawendi, Science, 290 (2000) 314. 9. G. A. Hebbink, J. W. Stouwdam, D. N. Reinhoudt, F. C. J. M. van Veggel, Adv. Mater., 14 (2002) 1147. xxiii
Page 1 and 2: SYNTHESIS AND CHARACTERIZATION OF L
Page 3 and 4: STATEMENT BY AUTHOR This dissertati
Page 5 and 6: Dedicated to ……… My beloved b
Page 7 and 8: also thankful to all the members of
Page 9 and 10: 2.3 Synthesis of binary oxide nanom
Page 11 and 12: CHAPTER 5: Zinc Gallate ...........
Page 13 and 14: imaging, scintillators, lasers, etc
Page 15 and 16: morphology by heating at 500 and 90
Page 17 and 18: nanoparticles having hexagonal stru
Page 19 and 20: 100°C and 185°C, respectively in
Page 21: into poly methyl methacryllate (PMM
Page 25 and 26: Fig.13: Fig.14: (a) Simplified ray
Page 27 and 28: Eu 3+ ions after heat treatment at
Page 29 and 30: 615 nm Fig.50: FT-IR patterns (a) a
Page 31 and 32: area electron diffraction pattern a
Page 33 and 34: different amounts of Eu 3+ . Fig.86
Page 35 and 36: and 545 nm, respectively. Fig.106:
Page 37 and 38: List of Tables: Table 1: Variation
Page 39 and 40: CHAPTER 1: Introduction 1.1 Histori
Page 41 and 42: Rods, cylinders, wires and tubes ar
Page 43 and 44: must be supersaturated either by di
Page 45 and 46: - + - + charge stabilized nanoparti
Page 47 and 48: exothermic reaction between the met
Page 49 and 50: constant, ħ is h/2π, e is the ele
Page 51 and 52: these platinum complexes have been
Page 53 and 54: (IR), visible and ultra-violet (UV)
Page 55 and 56: in Ce 3+ , Pr 3+ , Tb 3+ and CT abs
Page 57 and 58: assisted by lattice phonons of appr
Page 59 and 60: decay-time reduction is much easier
Page 61 and 62: nanocrystals is shown in Fig.10 [58
Page 63 and 64: depends strongly on the nature of t
Page 65 and 66: corresponding emission and excitati
Page 67 and 68: doped nanomaterials of the above me
Page 69 and 70: will be formed and subsequently it
Page 71 and 72: 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
Page 91 and 92:
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
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espectively. Value of this integral
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ethylene glycol moiety (stabilizing
Page 175 and 176:
Room temperature and 100°C synthes
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heavier metal ion as compared to La
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Similar studies were also carried o
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3+ 3+ faster decay component is ass
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the other hand the Eu 3+ lifetime h
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3+ 4.4.8 Luminescence studies on Sm
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CHAPTER 5: Zinc gallate (ZnGa 2 O 4
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In pure EG an amorphous product is
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water content in the reaction mediu
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nucleation, thereby leading to incr
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particles. Thus the TEM studies als
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value. The lattice parameters calcu
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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
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 222:
and Dy 3+ doped CaWO 4 nanoparticle
Page 223 and 224:
REFERENCES 1. D. J. Barber, I. C. F
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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