New generation of europium and terbium activated phosphors : from syntheses to applications

458 Pages·2011·12.484 MB·English

by  Mihail Nazarov, Do Young Noh

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New Generation of
Europium and Terbium
Activated Phosphors
from syntheses to applications
CRC Press
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Version Date: 20111012
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Contents
Preface
1. Phosphors and Luminescence 1
xi
Types of Excitation
1.1 Luminescence Classification 1
Fluorescence and Phosphorescence
1.1.1 2
1.1.2 4
Quantum Numbers, Term Symbols and
1.2 Luminescence Terminology 5
L-S Coupling
1.2.1
Selection Rules
6
1.2.2 10
The Past and Present of Phosphors
1.3 Luminescent Materials 11
Major Applications of Phosphors
1.3.1 11
1.3.2 14
Radiative and Non-radiative Transitions
1.4 Rare Earth Activation 15
Peculiarities of Eu and Tb Activation
1.4.1 15
2. Synthesis of Phoshors 25
1.4.2 21

2.1 General Requirements of Phosphors 25
Solid State Reaction
2.2 Solid State Methods 27
2.2.1 27
2.2.2.1 Preliminary powder preparation 28
2.2.2.2 Firing and calcinations 29
Microwave Synthesis Method
2.2.2.3 Post-treatment 31
2.2.2 32
Co-Precipitation
2.3 Wet-Chemical Methods 35
Sol–Gel Techniques
2.3.1 36
Hydrothermal
2.3.2 36
2.3.3 39
vi Contents
Solvothermal
Colloidochemical
2.3.4 42
Spray–Pyrolysis
2.3.5 44
Combustion Method
2.3.6 47
3. Phoshor Characterization 55
2.3.7 51
3.1 Morphology Analysis with Scanning Electron
Electron Beam Interaction with Solid Matter
Microscopy 55
SEM Images of Phosphors in Back-Scattered
3.1.1 56
Electrons
3.1.2
58
Monochromatic Cathodoluminescence
3.2 Cathodoluminescence Characterization 60
Panchromatic or Color Cathodoluminescence
3.2.1 62
Composite Cathodoluminescent and
3.2.2 63
Back-Scattering Electron Contrast in SEM
3.2.3
64
Electron Probe Micro-Analyzer
3.3 Microanalysis 66
Energy-Dispersive X-Ray Spectroscopy
3.3.1 66
Wavelength-Dispersive X-Ray Spectroscopy
3.3.2 68
Example of Microanalysis Application
3.3.3 69
3.3.4 72
Methods of Particle Analysis
3.4 Particle Size Analysis 72
Laser Diffraction
3.4.1 72
Cumulative and Density Distribution
3.4.2 74
3.4.3 75
X-Ray Generation and Properties
3.5 X-Ray Diffraction Measurements 76
Lattice Planes and Bragg’s Law
3.5.1 76
Powder Diffraction
3.5.2 77
Example of XRD Application
3.5.3 79
3.5.4 80
3.6 Spectroscopic Methods in Structural, Morphology
 Spectroscopy Classification 
and Luminescence Characterization 81
Photoluminescence Spectroscopy
3.6.1 81
3.6.2 83
3.6.2.1 Photoluminescence excitation
spectroscopy 84
3.6.2.2 Measurements in the vacuum-ultraviolet
region 85
Contents vii
X-Ray Generated Luminescence
Cathodoluminescence Spectroscopy
3.6.3 86
Fourier Transform Infrared Spectroscopy
3.6.4 88
Raman Spectroscopy
3.6.5 89
Terahertz Spectroscopy
3.6.6 93
3.6.7 100
Ab initio Calculations
3.7 Computational Materials Science 104
Monte Carlo Calculations
3.7.1 104
Hartree–Fock Algorithm
3.7.2 109
Density Functional Theory
3.7.3 110
4. Pho3sp.7h.4ors for Different Applications 111151
Introductory Remarks
4
4.1 Europium and Terbium Activated CaWO 115
Phosphor Preparation
4.1.1 115
Luminescence of Eu3+ and Tb3+ Activated
4.1.2 117
CaWO Phosphors
4.1.3
Analysis of Optical Lines
4
117
Polarization Selection Rules
4.1.4 126
Ab initio Calculations
4.1.5 132
Concluding Remarks
4.1.6 137
4
4.1.7 142
3+ Introductory Remarks
4.2 RE Activated Y(Ta,Nb)O -Based Phosphors 143
Self-Activated Y(Ta,Nb)O Phosphors
4.2.1 143
Terbium Activated Y(Ta,Nb)O Phosphors
4
4.2.2 146
4
4.2.3 158
4.2.3.1 Effect of flux materials 160
4.2.3.2 Effect of flux concentration 168
4.2.3.3 Effect of terbium concentration 173
Europium Activated Y(Ta,Nb)O Phosphors
4.2.3.4 Effect of niobium addition 176
4
4.2.4 182
4.2.4.1 Photoluminescence properties 184
4.2.4.2 Crystalline structure 188
4.2.4.3 Morphology and particle size 191
Double Activated Y(Ta,Nb)O :Eu ,Tb
4.2.4.4 Vibrational spectra 191
3+ 3+
4
4.2.5 202

4.2.5.1 Sample preparation 202
4.2.5.2 Particle morphology and sizes 202
4.2.5.3 X-ray diffraction measurement 203
viii Contents
4.2.5.4 X-ray luminescent measurement 204
4.2.5.5 X-ray diffraction characterization 205
4.2.5.6 Cathodoluminescence 208
4.2.5.7 VUV excitation 213
4.2.5.8 X-ray luminescence characterization 214
4.2.5.9 Luminescence mechanism in double
Stark Levels and Selection Rules 3+ 3+
4
activated Y(Ta,Nb)O :Eu Tb 217

4.2.6 223
4.2.6.1 Stark levels and selection rules for the
3+ 3+ 8
transitions in Tb and Eu (4f shell) 223
4.2.6.2 Experimental measurements 226
4.2.6.3 VUV excitation 228
4.2.6.4 X-ray excitation 231
First-Principles Electronic Structure Calculations
4.2.6.5 Low-temperature PL measurements 232
4.2.7 235
4.2.7.1 Samples preparation 236
4.2.7.2 Densities of states calculations 236
4.2.7.3 Experimental results 239
Red Emission Properties of (Y,M)NbO :Eu
4.2.7.4 DOS and luminescence 240
(M:Al,Ga) 3+
4
4.2.8
246
4.2.8.1 nUV excitation 248
 Configurational Coordinate Diagram and Energy 
4.2.8.2 X-ray excitation 255
Transfer Model
4.2.9
Terahertz Spectroscopy in Study Y(Ta,Nb)O -

263
Based Phosphors
4
4.2.10
Concluding Remarks
264
4.2.11 268
4.3 Phosphors Based on Europium Doped Oxides and
Introductory Remarks
Oxysulfides 270
Eu Activated Y O
4.3.1 270
3+
2 3
4.3.2 271
4.3.2.1 Synthesis of europium doped yttrium
oxide phosphors 271
4.3.2.2 Structural and luminescent
Eu Doped Y O –La O –Gd O
characterization 271
3+
2 2 2 2 2 2
4.3.3 280
Contents ix
4.3.3.1 Synthesis of europium doped yttrium–
gadolinium–lanthanum oxide phosphors 280
4.3.3.2 Structural and luminescent
Eu Doped Y O S–La O S–Gd O S.
characterization 280
3+
2 2 2 2 2 2
4.3.4 282
4.3.4.1 Synthesis of europium doped
yttrium–gadolinium–lanthanum
oxysulfide phosphors 282
4.3.4.2 Structural and luminescent
Phosphors Based on YVO :Eu and (Y,Gd)VO :Eu
characterization 283
Gd 3+ 3+
4 4
4.3.5 285
3+
X 1-X 4
4.3.5.1 Synthesis of (Y , )VO :Eu phosphor
by co-precipitation and solid state
reaction route 285
4.3.5.2 Structural and luminescent
Concluding Remarks
characterization 286
4.3.6 293
4.4 Yttrium and Terbium Aluminate Phosphors
Introductory 3R+ emarks
Co-activated by Eu 294
Physico-chemical Aspects Related with
4.4.1 294
the Synthesis of YAG-Based Phosphors
4.4.2
Luminescence Properties of Tb Al O Ce Eu
296
3+ 3+
3 5 12
4.4.3 : 300
4.4.3.1 Preparation of the phosphors 300
4.4.3.2 Measurements 300
Luminescence Mechanism and Energy-Level
4.4.3.3 Luminescence properties 301
Diagram
4.4.4
 Quantum Efficiency of YAG and TAG 
305
Phosphors
4.4.5
308
Introductory Remarks
4.5 Thiogallate Luminescent Materials 315
Structural and Luminescent Properties of Calcium,
4.5.1 315
Strontium, and Barium Thiogallates
4.5.2
 New Efficient Multiphase Green Phosphor 
319
[SrGa S + MgGa O ]:Eu 335
4.5.3
2+
2 4 2 4