本論文探討硬桿式高分子sPBI製作成單層發光二極體(PLED)及研討其螢光放射效應，其發光起始電壓是4.5 V，俱有發綠光(530 nm)的電致光功能；由sPBI吸收光譜的紅位移(red shift)可知，在苯環接上SO3H懸垂基能提供更佳之電子非區域性(delocalization)，因而降低能階差，俱有增進電子共振的有效共軛鏈長。從分子改質部分，化學合成水溶性硬桿式聚電解質sPBI-PS(Li+)，來探討鋰鹽LiCF3SO3 (LiTf) 或者LiN(CF3SO2)2 (LiTfSI)混摻到sPBI-PS(Li+)發光層製作成單層電致光電池(PLEC)，並研究其發光亮度、發光光譜和薄膜導電度的效應。研究發現sPBI-PS(Li+)薄膜的光致光效應沒有隨著鋰鹽LiTf 或LiTfSI的摻雜而改變。sPBI-PS(Li+)電致光電池(PLEC)為發綠色光(514 nm)元件，在正電壓驅動時，當LiTfSI混摻比例為0.41 wt. %可達最高亮度，其發光起始電壓是3.0 V；在負電壓驅動時，當LiTfSI混摻比例為1.01 wt. %可達最高亮度，其發光起始電壓是-4.6 V。此外，隨著發光層的離子導電度增加並沒有同步觀察到電致光電池(PLEC)元件發光亮度隨著提高的現象。

In this research, we investigated a novel rigid-rod polymer sPBI for mono-layer polymer light emitting diode (PLED) fabrication and luminescence emission. sPBI could be a luminescent polymer with a low threshold voltage of 4.5 V and green light electroluminescence emission (530 nm). Its SO3H pendant attached to the p-phenyl ring improved electronic delocalization along the backbone resulted in a red shift of the absorption spectrum. By attaching propanesulfonated pendants to the heterocyclic moiety of intractable fully conjugated sPBI, water-soluble rigid-rod polyelectrolyte sPBI-PS(Li+) was synthesized to promote its processibility in water or common organic solvent. This water-soluble rigid-rod polyelectrolyte sPBI-PS(Li+) was fabricated for polymer light-emitting electrochemical cells (PLECs) with LiCF3SO3 (LiTf) or LiN(CF3SO2)2 (LiTfSI) dopants for investigating the influence of propanesulfonated pendants as well as dopants on the opto-electronic emission and the room-temperature DC conductivity. The effect of lithium salts (LiTf or LiTfSI) on photoluminescence color of doped sPBI-PS(Li+) films was negligible. sPBI-PS(Li+) PLECs doped with 0.41 and 1.01 wt. % of LiTfSI showed higher green light electroluminescence emission (514 nm) with a lower threshold voltage of 3.0 V and -4.6 V, respectively. Emission brightness of the sPBI-PS(Li+) PLEC did not raise upon increasing the ionic conductivity of the luminescent layer.

TABLE OF CONTENTS
LIST OF FIGURES……………………………………………………III
LIST OF TABLES………………………………………………………VI

CHAPTER 1 INTRODUCTION……………………………………………1
1.1 History of Light Emitting Diodes…………………………2
1.2 Conjugated Rigid-rod Polymer………………………………5
1.3 Research Objective……………………………………………6

CHAPTER 2 FUNDAMENTALS OF EXPERIMENTS…………………………8
2.1 Energy Band Theory……………………………………………8
2.2 Luminescence Theory…………………………………………11
2.3 Principle of Light Emitting Diodes……………………12
2.4 Principle of Light-emitting Electrochemical Cells…13
2.4.1 PLECs of Conjugated Polymer and PEO Blends………14
2.4.2 PLECs of Single Component Luminescent Polymers……15
2.4.3 PLECs of Solid Polyelectrolytes.………………………16
2.4.4 Theoretical Models of PLECs.……………………………16
2.5 Comparison between PLED and PLEC………………………17

CHAPTER 3 EXPERIMENTS AND INSTRUMENTS………………………19
3.1 Instruments……………………………………………………20
3.1.1 UV-Vis Spectrophotometer………………………………20
3.1.2 Photoluminescence (PL) Emission………………………21
3.1.3 Spin Coater…………………………………………………22
3.1.4 Vacuum Thermal Evaporator………………………………23
3.1.5 Current-voltage (I-V) Response………………………24
3.1.6 Electroluminescence (EL) Emission……………………24
3.1.7 Thermogravimetric Analyzer……………………………25
3.1.8 Electrical Conductivity…………………………………25
3.2 Luminescent Polymers and Lithium Salt Dopants………26
3.3 Thin Film Fabrication………………………………………27
3.4 Thin-film Optical Characterization……………………27
3.4.1 UV-Vis Absorption Spectrum……………………………27
3.4.2 PL Emission Spectrum……………………………………28
3.5 PLED and PLEC Devices Fabrication………………………28
3.5.1 Preparation of Rigid-rod Polymer Solution…………28
3.5.2 Cleaning of ITO Substrate………………………………28
3.5.3 Spin-coating of Polymer Solution……………………30
3.5.4 Thermal Deposition of Cathode…………………………30
3.6 PLED and PLEC Devices Characterization………………31
3.6.1 Current-voltage (I-V) Curve……………………………31
3.6.2 Electroluminescence Emission Spectrum………………31

CHAPTER 4 RESULTS AND DISCUSSION……………………………33
4.1 Conjugated Rigid-rod Polymer sPBI………………………33
4.1.1 sPBI Thin-film and Mono-layer PLEDs…………………34
4.1.2 UV-Vis Absorption and PL Emission……………………34
4.1.3 Current-voltage (I-V) Curve……………………………37
4.1.4 Electroluminescence Emission…………………………38
4.2 Conjugated Rigid-rod Polymer sPBI-PS(Li+)……………40
4.2.1 DC Conductivity of Rigid-rod Polymer sPBI-PS(Li+).41
4.2.2 sPBI-PS(Li+) Thin-film and Mono-layer PLECs………43
4.2.3 UV-Vis Absorption and PL Emission……………………44
4.2.4 I-V-L Characteristics……………………………………47
4.2.5 Electroluminescence Emission…………………………49

CHAPTER 5 CONCLUSIONS……………………………………………53

REFERENCES……………………………………………………………54

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