| Summary: | 博士 === 國立交通大學 === 應用化學系碩博士班 === 101 === In this study, we focus on three major subjects which based on supramolecular
electroluminescent and hole injection materials
1. A New Supramolecular POSS Electroluminescent Material.
A new polyhedral oligomeric silsesquioxane (POSS) core star-like supramolecular blue-light electroluminescent material, 4-uracilbutyl-1-methylpyrene ether (U-PY) / octakis[dimethyl(N-(6-acetamidopyridin-2 yl))siloxy] silsesquioxane (ODAP-POSS) has been synthesized. This U-PY/ODAP-POSS contains eight pyrene chromophore arms formed through complementary uracil-diamidopyridine (U-DAP) pairs and exhibits high quantum efficiencies and good solution processing properties. The photoluminescence spectra of U-PY/ODAP-POSS (50/50) reveal that the color is stable after heating the sample at 150℃ for 1h, in contrast, the pyrene/ ODAP-POSS (50/50) shows significant thermal quenching. An electroluminescence (EL) device based on U-PY/ODAP-POSS exhibits higher maximum brightness and higher luminance efficiency relative to that of the U-PY. In addition, U-PY/ODAP-POSS also behaves as an effective dopant that enhances energy transfer from itself to MEH-PPV. The U-PY/ODAP-POSS-doped MEH-PPV blends exhibit high luminance efficiency, 1.45 times greater than MEH-PPV.
2. A New Supramolecular Hole Injection/Transport Material on Conducting Polymer for Application in Light-Emitting Diodes.
A new concept to modify and enhance properties of existed functional polymers through supramolecular interaction has been exploited. In this paper, a new suparmolecular π-conjugated polymer poly(triphenylamine-carbazole) (PTC-S) has been prepared which exhibits high thermal stability, non-corrosion, excellent hole injection and electron-blocking abilities in the solid state owing to the uracil induced physical cross-linking. When the PTC-S is utilized as a hole injection /transport layer (HITL) in a bilayer OLED device, a remarkable improvement in performance relative to the control PTC under similar experimental conditions has been achieved. Further comparison with a control device using a conventional PEDOT:PSS, a trilayer device with PTC-S is approximately 1.6 times higher than that of PEDOT:PSS-based devices. Thus, these results illustrate the opportunity to further imrove the performance of OLEDs and optoelectronic devices.
3. A New Hole Injection/Transport Materials formed through Hydrogen Bonding Interactions for Application in Light-Emitting Diodes.
A new concept to modify and enhance properties of existed functional polymers through hydrogen bonding interaction has been exploited. In this paper, A new supramolecular π-conjugated polymer poly(triphenylamine-carbazole) (PTC-H) have been prepared. In comparison with PTC-S, PTC-H exhibit higher thermal stability, higher electrochemical stability, better solvent-resistance ability and more excellent hole injection/transport properties due to the more stable physically cross-linking structure formed by adenine-adenine interactions. When the PTC-H is utilized as a hole injection/transport layer (HITL) in a trilayer OLED device, a remarkable improvement in performance relative to the control PTC and PTC-S under similar experimental conditions has been achieved. Further comparison with a control device using a conventional PEDOT-PSS, solution-processed OLED device using iridium-based triplet emitting layers and physically cross-linked PTC-H films as a HITL show significantly improved performance including higher luminance, higher external quantum efficiency, and higher luminance efficiency, as compared to the control device prepared with PEDOT-PSS. Thus, these results illustrate the opportunity to further improve the performance of OLEDs and optoelectronic devices.
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