Graduation date: 1995

Graduation date: 1993

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references. Also available in electronic version.

The structural design, synthesis and characterization of luminogens with aggregation-induced emission (AIE) properties are studied in this thesis. The remarkable emission properties, thermal stability and biocompatibility of the AIE-active materials demonstrate the promising applications in bioimaging and organic light-emitting diodes (OLEDs).;Chapter 1 introduces the existence of aggregation-caused quenching (ACQ) effect in most conventional organic dyes as well as phosphorescent transitional metal complexes. Discovery of AIE and its mechanical study allow further exploration of usage in organic luminescent materials. This chapter also gives some examples and the applications these AIE-active compounds.;In Chapter 2, a series of cyanostilbenes with simple electron donor (D)-p-electron acceptor (A) structure are presented and synthesized. They exhibit remarkable AIE effect as well as deep red emission peak in 95 % water fraction in THF. These results indicate that attachment of these electron acceptors provides alternative strategy for designing highly emissive AIE-active materials.;In Chapter 3, strongly emissive cyanostilbenes with phenothiazine unit are designed and synthesized. This chapter also investigates the effect of substituents in phenothiazine and terminal cyanostilbene on the photophysical properties and AIE effect. The results suggest that they are AIE-active with different sizes in nano-aggregates. Furthermore, these dyes exhibit clear and strong fluorescence in live cell imaging with excellent biocompatibility.;In Chapter 4, a series of AIE-active phosphorescent Pt(II) complexes made up of C^N^C tridentate ligands are designed and synthesized. They exhibit different morphologies and emission properties upon aggregation in 90 % water in acetonitrile although similar tridentate ligands are applied. One of the complexes in this chapter show nano-rod formation with the highest quantum efficiency in aggregated state, suggesting that rapid self-assembly process occurs to prevent non-radiative decay and oxygen quenching.;In Chapter 5, a series of bis-cyanostyryl fluorophores are designed and synthesized. They are emissive in solid state with colour range from orange to NIR region. Furthermore, they are AIE-active and some of them may contain hybridized local and charge transfer (HLCT) excited state to achieve highly efficient emission upon solvatochromic investigation. Some bis-cyanostyryl thiophenes are fabricated in OLED devices show deep-red to NIR emission, indicative of a promising way to design solid-state NIR-emissive compounds using bis-cyanostyryl derivatives.;Finally, Chapter 6 and 7 present the concluding remarks and the experimental details of the work in Chapters 2 to 5, respectively.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

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

Graduation date: 1998

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available in print.