| Summary: | 博士 === 國立交通大學 === 材料科學與工程系所 === 94 === The synthesis, optical, thermal, electrical and electroluminescent properties of some novel organic electroluminescent materials are reported in this thesis. These functional materials were divided into four classes. Class 1. Quinoxalines incprporating arylamine (QuPy): These dipolar compounds possess high thermal decomposition temperature (Td > 400 °C). The emission color of these materials varies from green to orange red. Two types of organic light-emitting diodes (LED) were fabricated. : (I) ITO/QuPy/Alq3/Mg:Ag; (II) ITO/QuPy/TPBI/Mg:Ag. The recombination zone in most of those devices was confined in quinoxaline segments which emits green to orange colors and corresponds well with the film PL of the material used. Class 2. Dibenzothiophene incprporating arylamine (S1-S6): These dibenzothiophene derivatives are amorphous and their Tgs range from 86 to 190 oC. They are fluorescent and emit in the blue to bluish green region. Two types of devices were fabricated. (I) ITO/S1-S6/TPBI/LiF/Al ; (II) ITO/S1-S6/Alq3/LiF/Al. Several type I devices emit pure blue light, and most of the devices II have very promising performance. The relation between the energy levels of the materials and the performance of the light-emitting diodes is discussed. Class 3. Dibenzothiophene-S,S-dioxide incprporating arylamine (SO): These dipolar compounds emit light in blue to green region. They readily form glass with glass transition temperatures ranging from 102 to 138 oC. High performance single-layer green-emitting device was fabricated: ITO/SO2/LiF/Al. The hole and electron mobility measured by TOF method were comparable (μ~10-4 cm2/(V•s)). Class 4. Dibenzothiophene/oxide- incprporating quinoxaline/pyrazine (DQ): These new materials are amorphous with a glass transition temperature ranging from 132 to 194 oC. The TOF measurement indicated that these compounds are electron transporting (mobility = 2-5 x 10-4 cm2/(V•s)). Two types of double-layer devices fabricated, (I) ITO/Qn/DQ/LiF/Al ; (II) ITO/Qn/DQ/LiF/Al (Qn = 2,3-bis[4-(N-phenyl-9-ethyl-3- carbazolyl-amino)phenyl]-quinoxaline), were found to exhibit good performance.
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