vii
TABLE OF CONTENT
CHAPTER
1
2
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENT
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENT
vii
LIST OF TABLES
x
LIST OF FIGURES
xii
LIST OF SYMBOLS
xvi
LIST OF APPENDICES
xviii
INTRODUCTION
1.1
General Introduction
1
1.2
Statement of Problem
3
1.3
Glass System Chosen
4
1.4
Objectives of the Study
5
1.5
Scope of the Study
6
1.6
Significance of the Study
7
LITERATURE REVIEW
2.1
Introduction
8
2.2
Definition of Glass
8
2.3
Melt Quenching Technique
9
viii
2.4
Phosphate Glass
11
2.5
X-Ray Diffraction (XRD)
12
2.5.1 Introduction
12
2.5.2 Effect of Rare Earth and Nanoparticles
14
Fourier Transform Infrared (FTIR) Spectroscopy
16
2.6.1 Introduction
16
2.6.2 Effect of Rare Earth and Nanopaticles
19
Thermal Analysis
21
2.7.1 Introduction
21
2.7.2 Effect of Rare Earth and Nanoparticles
24
Ultraviolet-Visible (UV-Vis) Spectroscopy
24
2.8.1 Introduction
24
2.6
2.7
2.8
2.8.2 Interband Absorption: Direct and Indirect
Band Gaps
28
2.8.3 Absorption Coefficient, Optical Energy Band
Gap and Urbach Energy
2.9
3
31
2.8.4 Effect of Rare Earth and Nanoparticles
32
Luminescence
34
2.9.1 Photoluminescence (PL)
35
2.9.2 Effect of Rare Earth and Nanoparticles
36
RESEARCH METHODOLOGY
3.1
Introduction
38
3.2
Sample Preparation
39
3.3
Sample Characterization
41
3.3.1 X-Ray Diffraction (XRD)
41
3.3.2 Fourier Transform Infrared (FTIR)
Spectroscopy
4
43
3.3.3 Thermal Analysis
45
3.3.4 Ultraviolet-Visible (UV-Vis) Spectroscopy
47
3.3.5 Photoluminescence (PL)
48
RESULTS AND DISCUSSION
4.1
Introduction
49
ix
4.2
Glass Preparation
49
4.3
XRD Spectra
51
4.4
Infrared Spectra
55
4.5
DTA Traces
58
4.6
Absorption Spectra
61
4.6.1 Absorption Coefficient (α)
63
4.6.2 Optical Band Gap Energy, Eg
67
4.6.3 Urbach Energy, ∆E
69
Luminescence Spectra
72
4.7
5
CONCLUSION AND FURTHER OUTLOOK
5.1
Introduction
76
5.2
Conclusions
76
5.3
Further Outlook
78
REFERENCES
79
Appendices A - B
87
x
LIST OF TABLES
TABLE NO.
TITLE
2.1
Optical properties of alkali chlorophosphate glasses
3.1
The nominal composition of NPs embedded erbium doped
phosphate glass system
4.1
PAGE
33
40
Composition of successfully prepared
P2O5–ZnO–Li2O–Er2O3 glass system containing ZnO NPs
50
4.2
The NPs size calculated from Scherrer’s equation
54
4.3
Peak frequencies (cm-1) observed in the IR spectra of the
glass system (with 0 ≤ x ≤ 1.2 mol%)
4.4
DTA characteristics for glass system as a function
of NPs concentration
4.5
59
Absorption bands wavelength for glass systems and
absorption band energy levels of the Er3+ ions
4.6
57
63
ZnO NPs concentration and the values of optical energy band
gap, Eg
68
xi
4.7
The value of Urbach energy, ∆E for the glass systems with
different ZnO NPs concentration
70
xii
LIST OF FIGURES
FIGURE NO.
TITLE
PAGE
2.1
The structure of crystal and glass
2.2
Relationship between volume, enthalpy and temperature
.
9
of the amorphous state in comparison to a crystal
10
2.3
The structure of tetrahedral phosphate
11
2.4
The structure of phosphate glass
11
2.5
The illustration of Bragg diffraction
12
2.6
The illustration of Full Width Half Maximum
14
2.7
XRD pattern obtained for (Gd0.95Eu0.05)2O3 NPs, pure
Zinc metaphosphate, Eu2O3 doped zinc metaphosphate
and (Gd0.95Eu0.05)2O3 nanoparticles doped zinc metaphosphate
glasses
2.8
The vibrational stretching mode (i) Symmetric and
(ii) Asymmetric
2.9
15
The vibrational bending mode: (i) In-plane rocking,
(ii) In-plane scissoring, (iii) Out-plane wagging, and
18
xiii
(iv) Out-plane twisting
2.10
19
IR spectra of erbium doped sodium phosphate glasses at various
Er2O3 content: (a) 1.0 mol%, (b) 2.0 mol%, (c) 4 mol% and
(d) 6.0 mol%
2.11
20
IR spectra of Ag2O NPs in phosphate glass with various of Ag2O
NPs content: x= 0, 0.05, 0.18 and 0.25 mol%
21
2.12
Typical of DTA spectra for glass sample
23
2.13
Interband optical absorption between an initial state of energy
Ei in an occupied lower band and a final state at energy Ef in an
empty upper band
2.14
29
Interband transition in solids: (a) Direct band gap (b) Indirect
band gap. The vertical arrow represents the photon absorption
process, while the wiggly arrow in part (b) represents the
absorption or emission of a phonon, q
2.15
Absorption spectra of 1 wt% Er3+ doped alkali chlorophosphate
glasses
2.16
36
Luminescence spectra of Er3+doped phosphate glass
containing silver NPs
3.1
34
Visible and near IR PL excited with 532 nm for highly Er3+
doped sodium aluminium phosphate glass
2.18
33
Effect of AgCl concentration on the fluorescence bands
(green and red) due to Er3+ ion in phosphate glass
2.17
31
37
Flow chart of the glass preparation process by melt quenching
technique
40
xiv
3.2
The optical path of the X-ray diffraction
3.3
Schematic of Michelson interferometer setup in FTIR
42
spectroscopy
44
3.4
Schematic of differential thermal analyser
46
3.5
Schematics of UV-Vis sphectrophotometer
47
4.1
P2O5–ZnO–Li2O–Er2O3 glass samples with different ZnO
NPs concentration. a) 0 mol% ZnO NPs, b) 0.2 mol% ZnO NPs,
c) 0.4 mol% ZnO NPs, d) 0.6 mol% ZnO NPs, e) 0.8 mol%
ZnO NPs, f) 1.0 mol% ZnO NPs and g) 1.2 mol% ZnO NPs
4.2
50
X-ray diffraction patterns of the glass system for different
concentration of ZnO NPs
52
4.3
Smoothed XRD patterns for x = 1.2 mol%
53
4.4
IR spectra of phosphate glasses for different composition
56
4.5
DTA patterns for glass system. Peaks are exothermic and
dips are endothermic
4.6
58
The dependences of Tg, Tc and Tm on the ZnO NPs
concentration
59
4.7
The thermal stability versus the ZnO NPs concentration
61
4.8
Absorption spectra of glass systems for different ZnO NPs
concentration as indicated
4.9
62
Spectral absorption band for glass systems in the region of
300 nm to 350 nm
64
xv
4.10
Absorption coefficient against photon energy for the
glass system
66
4.11
(αћω)1/2 against photon energy (ћω) glass system
67
4.12
The variation of energy gap, Eg versus ZnO NPs concentration
69
4.13
A plot of ln α against photon energy, ћω
70
4.14
A plot of Urbach energy, ∆E against ZnO NPs concentration
(mol%)
4.15
71
Luminescence spectra in range of 400 – 800 nm, excited at
357 nm
73
4.16
Up conversion intensity for glass systems
74
4.17
Simplified Er3+energy level scheme with indication of the
transitions
75
xvi
LIST OF SYMBOLS
A
-
Absorbance
B2O3
-
Boron trioxide
BCE
-
Before the Common Era
BO
-
Bridging Oxygen
d
-
Distance between each adjacent crystal planes
D
-
Nanocrystal diameter
d2
-
Thickness sample
DTA
-
Differential Thermal Analyzer
e
-
Electron charge
E
-
Energy
Ef
-
Energy upper band
Ec
-
Conduction band energy
Eg
-
Energy band gap
Ei
-
Energy lower band
Eopt
-
Optical energy gap
Ev
-
Valence band energy
Er2O3
-
Erbium oxide
Er3+
-
Trivalent erbium ion
eV
-
Electron Volt
FTIR
-
Fourier Transform Infrared
IR
-
Infrared
k
-
Force constant of the bond
Li2O3
-
Lithium oxide
m
-
Mass of atom
n
-
Integer
xvii
NBO
-
Non-bridging Oxygen
NIR
-
Near-infrared
NPs
-
Nanoparticles
OT
-
Terminal oxygen
P
-
Poise
P=O
-
Double bond
P2O5
-
Phosphorus pentoxide
P4O10
-
Tetraphosphorusdecaoxide
PL
-
Photoluminescence
PO4
-
Phosphate
RE
-
Rare earth
SiO2
-
Silicon dioxide
Tc
-
Crystallization temperature
Tg
-
Glass formation temperature
Tm
-
Melting temperature
UV-Vis
-
Ultraviolet Visible
v-P2O5
-
vitreous phosphoric oxide
XRD
-
X-Ray Diffraction
ZnO
-
Zinc oxide
α
-
Absorption coefficient
β
-
Full width half at maximum (FHWM)
ΔE
-
Urbach energy
θ
-
Bragg angle
λ
-
Wavelength of incident X-ray beam
μ
-
Reduced mass
σ -bonds
-
Sigma bond (strongest covalent bond)
υ
-
Vibrational frequency
ω
-
Frequency
ћω
-
Photon energy
xviii
LIST OF APPENDICES
APPENDIX
TITLE
PAGE
A
Calculation of Glass Composition
90
B
Calculation of Nanoparticles Size
92