• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 223
  • 37
  • 20
  • 13
  • 8
  • 7
  • 5
  • 4
  • 2
  • 1
  • 1
  • Tagged with
  • 407
  • 407
  • 407
  • 109
  • 50
  • 44
  • 35
  • 34
  • 34
  • 31
  • 31
  • 31
  • 29
  • 28
  • 28
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Device Engineering for Enhanced Efficiency from Platinum(II) Phosphorescent OLEDs

Li, Minghang 08 1900 (has links)
Phosphorescent organic light emitting diodes (PHOLEDs) based on efficient electrophosphorescent dopant, platinum(II)-pyridyltriazolate complex, bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II) (Pt(ptp)2) have been studied and improved with respect to power efficiency, external efficiency, chromacity and efficiency roll-off. By studying the electrical and optical behavior of the doped devices and functionality of the various constituent layers, devices with a maximum EQE of 20.8±0.2 % and power efficiency of 45.1±0.9 lm/W (77lm/W with luminaries) have been engineered. This improvement compares to devices whose emission initially could only be detected by a photomultiplier tube in a darkened environment. These devices consisted of a 65 % bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]platinum(II) (Pt(ptp)2) doped into 4,4'-bis(carbazol-9-yl)triphenylamine (CBP) an EML layer, a hole transporting layer/electron blocker of 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), an electron transport layer of 1,3,5-tris(phenyl-2-benzimidazolyl)-benzene (TPBI), and a LiF/Al cathode. These devices show the acceptable range for warm white light quadrants and qualify to be called "warm white" even w/o adding another emissive layer. Dual EML devices composed of neat Pt(ptp)2 films emitting orange and CBP: Pt(ptp)2 film emitting blue-green produced a color rendering index (CRI) of 59 and color coordinates (CIE) of (0.47,0.49) at 1000Cd/m² with power efficiency of 12.6±0.2 lm/W and EQE of 10.8±0.2 %. Devices with two blue fluorescent emission layers as singlet filters and one broad yellow emission layer from CBP: Pt(ptp)2 displayed a CRI of 78 and CIE of (0.28,0.31) at 100Cd/m² with maximum power efficiency of 6.7±0.3 lm/W and EQE of 5.7±0.2 %.
122

An investigation into novel red emitting phosphors and their applications

Stone, Roni January 2011 (has links)
New red emitting phosphors, based on the double tungstate/molybdates, were discovered. Some were able to retain their luminous efficacy after substituting Y3+ for Eu3+, reducing the cost of the phosphor. This substitution was attempted for existing commercial red emitting phosphors and proved unsuccessful. Another set of phosphors based on these lattices were discovered and the emitted luminous efficacy was 140% greater than other reported Eu3+ phosphors. The best of these was Na2WO4MoO4Eu0.44Al1.34Sm0.011. The integration of phosphors to the lighting application was also studied, including improvements in light extraction for existing phosphors. ACEL panels are currently applied to many applications and were briefly examined. The more recent OLED technology was investigated and comparisons can be drawn with the ACEL panels. LEDs were also a focus of the work with a new method developed for remote application of phosphors to LEDs, based on a dome shaped encapsulant, and this was adopted commercially by a high brightness LED manufacturer. The studies on the phosphors reported herein were aimed at integrating these into commercial applications. Although this was not achieved as brightness and particles size were problematic, if it is demonstrated that further development of the synthetic methods produce phosphors with suitable attributes, this may lead to the integration in applications.
123

Topics in many-particle quantum systems. / 多體量子系統問題 / Topics in many-particle quantum systems. / Duo ti liang zi xi tong wen ti

January 2007 (has links)
Li, Kwan Ho = 多體量子系統問題 / 李君豪. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves [243]-246). / Text in English; abstracts in English and Chinese. / Li, Kwan Ho = Duo ti liang zi xi tong wen ti / Li Junhao. / Abstract --- p.i / Acknowledgment --- p.iv / Chapter I --- Computational Quantum Mechanics and Its Applications --- p.1 / Chapter 1 --- Theoretical Methodology of Electronic Structures --- p.2 / Chapter 1.1 --- The Schrodinger Equation --- p.3 / Chapter 1.2 --- Molecular Hamiltonian and Born-Oppenheimer Approximation --- p.4 / Chapter 1.3 --- The Variational Method --- p.7 / Chapter 1.3.1 --- Rayleigh-Ritz Variation Principle --- p.7 / Chapter 1.3.2 --- Linear Variation --- p.8 / Chapter 1.4 --- Many-Electron Wavfunction --- p.9 / Chapter 1.4.1 --- Hartree-product Wavefunction --- p.9 / Chapter 1.4.2 --- Slater Determinant and the Pauli Exclusion Principle --- p.11 / Chapter 1.5 --- The Expectation Value of Total Electronic Energy --- p.13 / Chapter 1.6 --- Derivation of the Hartree-Fock Equations --- p.16 / Chapter 1.7 --- Orbital Energies and the SCF Total Electronic Energy --- p.19 / Chapter 1.8 --- Koopmans' Theorem --- p.20 / Chapter 1.9 --- The LCAO expansion and Self-Consistent Field Calculation --- p.22 / Chapter 1.10 --- AO Basis Sets --- p.23 / Chapter 1.10.1 --- Slater-Type Orbitals --- p.24 / Chapter 1.10.2 --- Gaussian Functions --- p.24 / Chapter 1.11 --- Hartree-Fock Limit --- p.25 / Chapter 1.12 --- Electron Correlation --- p.26 / Chapter 1.12.1 --- Weakness in the Single Determinantal Wavefunction --- p.26 / Chapter 1.12.2 --- Configuration Interaction --- p.26 / Chapter 1.13 --- Density Functional Theory --- p.27 / Chapter 1.13.1 --- Early approximations --- p.28 / Chapter 1.13.2 --- Hohenberg-Kohn Theorems --- p.31 / Chapter 1.13.3 --- Kohn-Sham (KS) Method --- p.33 / Chapter 1.13.4 --- Exchange-Correlation Energy Functional and B3LYP --- p.36 / Chapter 2 --- Theoretical Investigation of Oxadiazole-Triphenylamine Based Compounds --- p.40 / Chapter 2.1 --- Organic Light Emitting Diode and Oxadiazole-Triphenylamine Based Com- pounds --- p.40 / Chapter 2.2 --- Methodology --- p.42 / Chapter 2.2.1 --- Theoretical Methodology --- p.42 / Chapter 2.2.2 --- Computational Methodology --- p.46 / Chapter 2.3 --- Computational Results --- p.47 / Chapter 2.3.1 --- Molecular Structure --- p.47 / Chapter 2.3.2 --- Electronic Structure --- p.79 / Chapter 2.4 --- Absorption and Emission Energy --- p.94 / Chapter 2.5 --- Reorganization Energy and Mobility --- p.95 / Chapter 2.6 --- Summary --- p.99 / Chapter 3 --- The Transport Properties of Oligoacenes --- p.102 / Chapter 3.1 --- Introduction --- p.102 / Chapter 3.2 --- Computational Details --- p.103 / Chapter 3.3 --- Results and Discussions --- p.103 / Chapter 3.3.1 --- Molecular Configuration --- p.103 / Chapter 3.3.2 --- Reorganization Energy --- p.106 / Chapter 3.3.3 --- Coupling Matrix Element --- p.107 / Chapter 3.4 --- Conclusion --- p.133 / Chapter 4 --- The Transport Properties in Rubrene Thin Film and Crystal --- p.135 / Chapter 4.1 --- Introduction --- p.135 / Chapter 4.2 --- Computational Details --- p.137 / Chapter 4.3 --- Results and Discussions --- p.137 / Chapter 4.3.1 --- Molecular Structure --- p.137 / Chapter 4.3.2 --- Frontier Orbitals --- p.144 / Chapter 4.3.3 --- Reorganization Energy --- p.147 / Chapter 4.3.4 --- Coupling Matrix Element and Mobility --- p.147 / Chapter 4.4 --- Conclusion --- p.175 / Chapter II --- Analytical Studies of Anisotropic Spin-1/2 Heisenberg Anti-ferromagnetic Linear Chains --- p.177 / Chapter 5 --- Coupled-Cluster Approximation for Two Anisotropic Spin-1/2 Heisenberg Antiferromagnetic Linear Chains with Inter-chain Anisotropic Ferromagnetic Interaction --- p.178 / Chapter 5.1 --- Introduction --- p.178 / Chapter 5.2 --- Approximation in the Coupled-Cluster Method --- p.179 / Chapter 5.3 --- Anisotropic spin-1/2 Heisenberg Antiferromagnetic Model in One Dimension --- p.183 / Chapter 5.3.1 --- The Zeroth Level --- p.185 / Chapter 5.3.2 --- The First Level --- p.186 / Chapter 5.3.3 --- The Second Level --- p.189 / Chapter 5.4 --- Two Anisotropic Spin-1/2 Heisenberg Antiferromagnetic Linear Chains with Inter-chain Anisotropic Ferromagnetic Interaction --- p.198 / Chapter 5.4.1 --- The Zeroth Level --- p.199 / Chapter 5.4.2 --- The First Level --- p.201 / Chapter 5.4.3 --- The Second Level --- p.206 / Chapter 5.5 --- Conclusion --- p.242 / Bibliography --- p.243
124

Why did video screens get slimmer? : a study of the role of Intellectual Property in the commercial development of organic light-emitting diodes

Sewagudde, Deborah Nabbosa Miriam January 2017 (has links)
This research project consists of a critical analysis of the role of intellectual property amongst other factors in the successful commercial development at the Cavendish Laboratory of optoelectronic light emitting diode display devices based on novel organic semiconductor materials. It begins by giving the background to the quantum mechanical properties upon which the technology is based, followed by a discussion of the path of innovation, describing the interaction between the different socioeconomic factors that influence this path. It then draws an analogy with the development of an analogous technology - inorganic semiconductors - to signpost the factors that may affect the developmental history of the technology. This is followed by an analysis of a chronology derived initially from patents downloaded from the World Patents Database of the European Patent Office to showcase the technology's development steps, and to study the patenting strategy of Cambridge Display Technology (CDT) - the company that was set up to commercialise the novel technology - through a patent trends analysis. From that, the major socioeconomic factors critical to the technology's development are analysed, followed by a test and extension of an existing Black Box mathematical model for studying the dynamics of innovation that is based on the interaction of those factors. Finally, through a patent citation analysis, CDT's commercial strategy for the technology is shown as being based on its patents portfolio to build an extensive licensing programme that pooled major academic, industry and commercial partners for the furtherance of the technology. This later evolved into a new ecosystem for the innovation, of which CDT occupied a central and indispensable position.
125

Tuning metal oxides for solar cells and light emitting diodes

Hoye, Robert Lianqi Zhao January 2015 (has links)
No description available.
126

A solar PV-LED lighting system with bidirectional grid ballasting

Deng, Wenpeng January 2015 (has links)
No description available.
127

Cause, effect and remedy of indium diffusion in Poly(3,4-ethylene dioxythiophene):poly(styrene sulphonate)--based polymer light emitting device. / 以PEDOT:PSS為本的高份子發光器件中銦的擴散之研究 / Cause, effect and remedy of indium diffusion in Poly(3,4-ethylene dioxythiophene):poly(styrene sulphonate)--based polymer light emitting device. / Yi PEDOT:PSS wei ben de gao fen zi fa guang qi jian zhong yin de kuo san zhi yan jiu

January 2003 (has links)
Yip Hin-lap = 以PEDOT:PSS為本的高份子發光器件中銦的擴散之研究 / 葉軒立. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 113). / Text in English; abstracts in English and Chinese. / Yip Hin-lap = Yi PEDOT:PSS wei ben de gao fen zi fa guang qi jian zhong yin de kuo san zhi yan jiu / Ye Xuanli. / Abstract --- p.ii / 論文摘要 --- p.iv / Acknowledgements --- p.v / Table of Contents --- p.vi / List of Figures --- p.x / List of Tables --- p.xii / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Overview --- p.1 / Chapter 1.2 --- Conjugated Polymer --- p.3 / Chapter 1.2.1 --- Electronic and Geometric Configuration --- p.3 / Chapter 1.2.2 --- Charge Carriers --- p.7 / Chapter 1.2.3 --- Concept of Doping --- p.9 / Chapter 1.2.4 --- Electrical Conductivity and Charge Transport Mechanisms --- p.15 / Chapter 1.3 --- "Poly(3,4-ethylenedioxythiophene) [PEDOT]" --- p.16 / Chapter 1.4 --- Polymer Light Emitting Diodes --- p.20 / Chapter 1.4.1 --- Device Fabrication --- p.21 / Chapter 1.4.2 --- Material Design and Properties --- p.23 / Chapter 1.4.3 --- Interface and surface of PLED --- p.25 / Chapter 1.5 --- """Chemistry"" and Diffusion at Interface" --- p.27 / Chapter 1.6 --- Surface/Interface Modification with Self-Assembled Monolayers --- p.30 / Chapter 1.7 --- Aims of This Thesis --- p.33 / References --- p.34 / Chapter CHAPTER 2 --- INSTRUMENTATION --- p.38 / Chapter 2.1 --- X-ray Photoelectron Spectroscopy --- p.38 / Chapter 2.1.1 --- Fundamental Theory of XPS --- p.39 / Chapter 2.1.2 --- Qualitative Analysis using XPS --- p.43 / Chapter 2.1.2.1 --- Chemical Shifts --- p.43 / Chapter 2.1.2.2 --- Shake-up satellites --- p.45 / Chapter 2.1.2.3 --- Valence band structure --- p.45 / Chapter 2.1.3 --- Quantitative Analysis Using XPS --- p.46 / Chapter 2.1.4 --- Depth Profiling --- p.47 / Chapter 2.1.4.1 --- Non-Destructive Method Using Angled-Resolved XPS --- p.47 / Chapter 2.1.4.2 --- Destructive Method Using Ion Sputtering --- p.49 / Chapter 2.1.5 --- Instrumental Setup of XPS --- p.49 / Chapter 2.2 --- PLED Fabrication and Characterization System --- p.51 / Chapter 2.3 --- Current-Voltage-Luminescence (I-V-L) Measurement --- p.53 / Chapter 2.4 --- Electrical Measurement --- p.54 / Chapter 2.5 --- Kelvin Probe Measurement --- p.55 / Chapter 2.6 --- pH Measurement --- p.56 / Chapter 2.7 --- Film Thickness Measurement --- p.56 / Chapter 2.8 --- Contact Angle Measurement --- p.57 / References --- p.60 / Chapter CHAPTER 3 --- STABILITY OF PEDOT:PSS/ITO INTERFACE --- p.61 / Chapter 3.1 --- Introduction --- p.61 / Chapter 3.2 --- Sample Preparation --- p.62 / Chapter 3.3 --- Results and Discussion --- p.63 / Chapter 3.3.1 --- XPS of Core levels in PEDOT:PSS --- p.63 / Chapter 3.3.1.1 --- XPS of S 2p Core Level --- p.64 / Chapter 3.3.1.2 --- XPS of O Is Core Level --- p.66 / Chapter 3.3.1.3 --- XPS of C Is Core Level --- p.68 / Chapter 3.3.2 --- Composition Analysis of PEDOT:PSS Films --- p.71 / References --- p.80 / Chapter CHAPTER 4 --- ELECTRICAL AND ELECTRONIC PROPERTIES OF PEDOT:PSS WITH DISSOLUTED INDIUM --- p.81 / Chapter 4.1 --- Introduction --- p.81 / Chapter 4.2 --- Sample Preparation --- p.81 / Chapter 4.2.1 --- Four-Point Probe Measurement --- p.82 / Chapter 4.2.2 --- Current-Voltage Measurement --- p.82 / Chapter 4.2.3 --- Work Function Measurement --- p.83 / Chapter 4.2.4 --- XPS Experiment --- p.83 / Chapter 4.3 --- Results and Discussion --- p.85 / Chapter 4.3.1 --- Electrical Properties of PEDOT:PSS --- p.86 / Chapter 4.3.2 --- Electronic Properties of PEDOT:PSS --- p.89 / References --- p.97 / Chapter CHAPTER 5 --- BLOCKING REACTIONS BETWEEN ITO AND PEDOT:PSS WITH A SELF-ASSEMBLY MONOLAYER --- p.98 / Chapter 5.1 --- Introduction --- p.98 / Chapter 5.2 --- Sample Preparation --- p.99 / Chapter 5.3 --- Result and Discussion --- p.103 / Chapter 5.3.1 --- In Diffusion Blocking Effect by SAM --- p.103 / Chapter 5.3.2 --- PLED Devices Performance --- p.107 / References --- p.113 / Chapter CHAPTER 6 --- CONCLUSION --- p.114 / Chapter CHAPTER 7 --- FURTHER WORKS --- p.116
128

Study of interfacial interactions in a novel polymer light emitting device. / 新的有機發光器件的界面研究 / Study of interfacial interactions in a novel polymer light emitting device. / Xin de you ji fa guang qi jian de jie mian yan jiu

January 2005 (has links)
Ho Ming Kei = 新的有機發光器件的界面研究 / 何銘基. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Ho Ming Kei = Xin de you ji fa guang qi jian de jie mian yan jiu / He Mingji. / Abstract --- p.i / 论文摘要 --- p.iii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.viii / List of Tables --- p.xiii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview --- p.1 / Chapter 1.2 --- Conjugated Polymers --- p.2 / Chapter 1.2.1 --- Electronic and geometric Configuration --- p.2 / Chapter 1.2.2 --- Charge Carries of conjugated polymers --- p.4 / Chapter 1.2.3 --- Polymer Light Emitting Diodes --- p.11 / Chapter 1.2.4 --- Device Fabrication --- p.12 / Chapter 1.2.5 --- Polymeric Luminescent Material Development --- p.18 / Chapter 1.2.6 --- Interface and Surface of PLED --- p.21 / Chapter 1.3 --- Aims of this thesis --- p.22 / References --- p.24 / Chapter Chapter 2 --- Instrumentation --- p.26 / Chapter 2.1 --- X-ray Photoelectron Spectroscopy --- p.26 / Chapter 2.1.1 --- Introduction --- p.26 / Chapter 2.1.2 --- Basic Principles and Theory --- p.28 / Chapter 2.1.3 --- Qualitative Analysis Using XPS --- p.29 / Chapter 2.1.4 --- Angular Effect on XPS --- p.29 / Chapter 2.1.5 --- Chemical Shifts --- p.30 / Chapter 2.1.6 --- Quantitative Analysis using XPS --- p.31 / Chapter 2.1.6.1 --- Survey spectrum --- p.32 / Chapter 2.1.6.2 --- Core level spectrum --- p.32 / Chapter 2.1.6.3 --- Valence band spectrum --- p.33 / Chapter 2.1.7 --- Instrumental Setup for XPS --- p.33 / Chapter 2.2 --- HV physical vapor deposition system with nitrogen glove box --- p.36 / Chapter 2.2.1 --- Nitrogen grove box --- p.38 / Chapter 2.2.2 --- HV physical vapor deposition system --- p.38 / Chapter 2.3 --- L-V-I measurement system --- p.41 / Chapter 2.3.1 --- Keithley 236 source-measure unit --- p.41 / Chapter 2.3.2 --- Photo Research PR-650 photo meter --- p.43 / Chapter 2.3.3 --- Test Environment Chamber --- p.43 / Chapter 2.4 --- a-Step Profilometer --- p.44 / References --- p.45 / Chapter Chapter 3 --- Interface study between MEHPPV: PEG and Aluminum --- p.46 / Chapter 3.1 --- Introduction --- p.46 / Chapter 3.2 --- Sample Preparations --- p.47 / Chapter 3.2.1 --- Si(lll) substrate preparation --- p.47 / Chapter 3.2.2 --- Au sputtering on the clean Si Surface --- p.48 / Chapter 3.2.3 --- Polymer film formation --- p.48 / Chapter 3.3 --- Results and Discussion --- p.49 / Chapter 3.3.1 --- XPS Survey scan ofMEHPPV --- p.51 / Chapter 3.3.2 --- XPS of Cls Core level ofMEHPPV --- p.51 / Chapter 3.3.3 --- XPS ofOls Core level ofMEHPPV --- p.55 / Chapter 3.3.4 --- XPS of A12p Core level ofMEHPPV --- p.59 / Chapter 3.3.5 --- XPS Survey scan of PEG --- p.64 / Chapter 3.3.6 --- XPS of Cls Core level of PEG --- p.64 / Chapter 3.3.7 --- XPS of Ols Core level of PEG --- p.67 / Chapter 3.3.8 --- XPS of A12p Core level of PEG --- p.70 / Chapter 3.3.9 --- XPS survey scan of MEHPPV:PEG(10wt% PEG) --- p.73 / Chapter 3.3.10 --- XPS Cls core level of MEHPPV:PEG(10wt% PEG) --- p.73 / Chapter 3.3.11 --- XPS Ols core level of MEHPPV:PEG(10wt% PEG) --- p.76 / Chapter 3.3.12 --- XPS A1 2p core level of MEHPPV: PEG --- p.80 / Chapter 3.3.13 --- Surface migration of bulk absorbed oxygen --- p.84 / Chapter 3.4 --- Conclusions --- p.84 / Reference --- p.87 / Chapter Chapter 4 --- Efficiency enhancement in polymer light emitting diodes using Crown ether 18-C6 and aluminum cathode --- p.89 / Chapter 4.1 --- Introduction --- p.89 / Chapter 4.2 --- Sample preparation --- p.91 / Chapter 4.2.1 --- The Cleaning of substrate --- p.91 / Chapter 4.2.2 --- PEDOT: PSS film formation --- p.93 / Chapter 4.2.3 --- Emissive polymer layer formation --- p.94 / Chapter 4.2.4 --- Deposition of metal cathode --- p.94 / Chapter 4.2.5 --- Epoxy Encapsulation --- p.95 / Chapter 4.3 --- Results and Discussion --- p.95 / References --- p.101 / Chapter Chapter 5 --- Concluding Remarks and Future Work --- p.102 / Chapter 5.1 --- Concluding Remarks --- p.102 / Chapter 5.2 --- Future Work --- p.103
129

New luminescent organometallic complexes of platinum (II), iridium (III), copper (I) and gold (III) and their optoelectronic applications

Xie, Zheng 01 January 2013 (has links)
No description available.
130

Conjugated metal-organic phosphorescent materials and polymers containing fluorene and carbazole units

Ho, Cheuk Lam 01 January 2007 (has links)
No description available.

Page generated in 0.281 seconds