吳忠幟臺灣大學：電子工程學研究所洪蘊華Hong, Yun-HuaYun-HuaHong2007-11-272018-07-102007-11-272018-07-102006http://ntur.lib.ntu.edu.tw//handle/246246/57392在本篇論文中，藉由量子化學計算來重建不同取代基之寡聚芴衍生物，如帶有甲苯基、乙烷基、螺旋芴基等的能階密度來研究這些衍生物的電子結構。這些寡聚物的模擬能階密度與實驗所量測的結果相比，有很高的一致性。我們藉由能階密度的計算結果與分子軌域相對照，研究不同取代基對分子特性的影響。 此外，量子化學計算方法亦被用在研究不同連接法，如3-3’連接法與3-9’連接法之寡聚咔唑衍生物的光物理特性。這兩種不同的連接法導致了不同的三重態分佈，並影響了不同的三重態-三重態耦合值。3-9’ 寡聚咔唑衍生物的三重態的局域性是由於其三重態-三重態耦合值十分小所造成The quantum chemical calculation is used to study electronic structures of oligofluorenes with pure alkyl substituents, diaryl substituents and spiro-linked substituents by reproducing the density of state (DOS) of each molecule. It shows good consistence between the calculated results with the measured ultraviolet photoemission spectroscopy (UPS) results. By comparing the calculated DOS and frontier molecular orbitals, we investigated the influence of different substituents. The calculation methods are also performed to understand the photophysical properties of oligocarbazole derivatives with various linking topologies, such as 3-6’ and 3-9’ linking systems. The two linking topologies result in the different distribution of triplet state and therefore influence the triplet-triplet (TT) couplings. The localization of the spin population of 3-9’ oligocarbazoles is attributed to the weak TT coupling.Content Chapter 1 Introduction 1.1 Overview of Organic Semiconductors……………………………………….1 1.2 The Role of Quantum Chemical Calculation in the Organic Semiconductors………………………………………………………………3 1.3 Thesis Organization…………………………………………………………..4 Chapter 2 Basic Concepts in Quantum Chemical Calculation 2.1 Introduction…………………………………………………………………..5 2.2 Born-Oppenheimer Approximation………………………………………….6 2.3 Hartree-Fock Approximation and Self-consistent Field Calculation………...8 2.4 Semi-empirical Method……………………………………………………..16 2.5 Configuration Interaction…………………………………………………...20 2.6 Density Functional Theory………………………………………………….22 2.7 Time-Dependent Density Functional Theory……………………………….24 Chapter 3 Influences of Substitution on Electronic Structures of Oligofluorenes 3.1 Introduction…………………………………………………………………27 3.2 Principles of UPS…………………………………………………………...28 3.3 Electronic Structures of Organic Semiconductors………………………….29 3.4 Calculations of DOS of Organic Semiconductors………………………….30 3.5 Results and Discussions………………………………………………….…33 3.5.1 Experimental Results………………………………………………...33 3.5.2 Calculation Results…………………………………………………..33 3.5.3 Discussions…………………………………………………………..34 3.6 Summary…....……………………………………………………………....38 Chapter 4 Investigation of Photophysical Properties of Oligocarbazoles 4.1 Introduction…………………………………………………………………48 4.2 Optical Absorption and Emission in Molecular Systems..............................49 4.2.1 Absorption Process.............................................................................49 4.2.2 Fluorescence Emission Process..........................................................52 4.2.3 Phosphorescence Emission Process....................................................53 4.3 Theoretical Approaches for Analyses.............................................................55 4.3.1 Detachment/Attachment Density.........................................................55 4.3.2 Singlet-Singlet/Triplet-Triplet Coupling.............................................57 4.4 Results and Discussions.................................................................................60 4.4.1 Experimental Results...........................................................................60 4.4.2 Calculation Results..............................................................................60 4.4.3 Discussions..........................................................................................61 4.5 Summary.........................................................................................................64 Chapter 5 Summary and Future Works 5.1 Summary.........................................................................................................77 5.2 Future Works..................................................................................................78 Reference...............................................................................................................792408243 bytesapplication/pdfen-US有機半導體量子化學量子化學計算電子結構organic semiconductorquantum chemistryquantum chemical calculationelectronic structurethesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/57392/1/ntu-95-R93943059-1.pdf