色安定與色溫可調變白色有機發光元件研製

Fabrication Study of Color-Stable and Color-Temperature-Tunable White Organic Light-Emitting Devices

吳明軒(Ｍing-Hsuan Wu)

指導教授 ： 周卓煇

國立清華大學/工學院/材料科學工程學系/博士(2010年)

摘要

本研究從元件結構設計的角度，探討如何製備高色安定性及色溫可調變白色有機發光二極體；在研究中，以一高自發光性之螢光藍光有機發光材料2-(N,N-diphenyl-amino)-6-[4-N,N-diphenylamino)styryl]naphthalene (DPASN)作為主體，搭配其他光色的染料；配合及單一發光層，或是多發光層之元件結構設計，分別製備高色安定性螢光白光有機發光二極體，以及色溫可調變有機發光二極體。
第一部份中，先使用DPASN，製備高效率螢光藍光有機發光二極體，元件在亮度100 cd/m2下之能量效率可達6 lm/W，CIE色座標為(0.16, 0.17)；隨後，以DPASN為主體，搭配一橘黃光染料5,6,11,12-tetra-phenylnaphthacene，製備出高效率高色安定性之白光有機發光二極體，在亮度100 cd/m2時，發光效率可達9.5 lm/W，且在亮度由100增加至10,000 cd/m2時，其光色座標由(0.321, 0.357)改變至(0.315, 0.344)，色偏僅有(0.006, 0.013)；此白光OLED元件結構的設計，使得電子、電洞能有效被侷限在單一發光層中，載子再結合區域不易因電壓變化而產生偏移，使元件光色呈現高色安定性；同時，其發光層結構設計，亦避免激子在客體分子上產生淬熄，而減輕了在高電壓下，因激子淬熄而導致的光色藍位移現象。
第二部份中，以DPASN作為主體，搭配綠光發光染料bis[(p-isopropylohenyl)(p-tolyl)amino]-10-10’-phenanthracene，紅光發光染料4-(dicyanomethylene)-2-tertbutyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl-4H-pryan，製備一色溫可調變有機發光二極體；元件在不同電壓下，可發出2,300至8,200K之光色，完全涵蓋日光在不同時間及地區下之色溫變化；與色安定性元件的發光層結構設計相反，此元件採用多發光層結構，以及一薄層載子調制層的設計，可使載子再結合區域隨著電壓的變化，在藍、綠、紅光發光層中產生偏移，即再結合區域可從低電壓時靠近陰極處，高電壓時在移動到較靠近陽極的位置，如此一來，便能使得元件光色隨電壓不同而產生寬廣的色溫變化。

關鍵字

有機發光二極體 ； 色安定 ； 色溫可調變

並列摘要

In this study, fabrications of highly color-stable and color-temperature tunable organic light-emitting diodes (OLEDs) are investigated from the viewpoint of device architecture. A highly electroluminescent blue fluorescent emitter 2-(N,N-diphenyl-amino)-6-[4-N,N-diphenyl-amino)styryl]naphthalene (DPASN) is employed as the host and doped with other emitters to fabricate highly color-stable fluorescent white OLED or color-temperature tunable OLED in single-emissive-layer or multi-emissive-layers device architecture.
In the first part, the high-efficiency fluorescent blue OLED using DPASN exhibits a power efficiency of 6 lm/W at 100 cd/m2, with CIE coordinates of (0.16, 0.17). Using DPASN as the host and doping an orange emitter of 5,6,11,12-tetra-phenylnaphthacene, a highly efficient and highly color-stable white OLED is fabricated with an efficiency of 9.5 lm/W at 100 cd/m2. The CIE coordinates of which deviate from (0.321, 0.357) to (0.315, 0.344) as the luminance increasing from 100 to 10,000 cd/m2, showing a slight chromaticity deviation of (0.006, 0.013). The device architecture in this white OLED confines electrons and holes effectively within the single emissive layer, preventing recombination zone shift caused by voltage variation and consequently having the emission to be highly color-stable. In addition, the emissive-layer architecture design may prevent excessive exciton quenching on guest, reducing exciton-quench-causing blue shift phenomenon at high voltages.
In the second part, DPASN is employed as the host, doped with green emitter of bis[(p-isopropylphenyl)(p-tolyl)amino]-10-10’-phenanthracene and red emitter of 4-(dicyanomethylene)-2-tertbutyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl-4H-pyran to fabricate color-temperature tunable OLED. The device is capable of yielding an illumination with color-temperature ranging between 2300 and 8200 K, fully covering those of the entire daylight at different times and regions. Opposite to the emissive architecture design of the color-stable device, the color-temperature tunable device employs multi-emissive layers and a thin carrier-modulation layer architecture to have the recombination zone shift along the blue, green and red emissive layers with voltage variation. The recombination core is capable to shift from the cathode side at low voltage to the anode side at high voltage, consequently to have the device yield a relatively wide color-temperature span.

並列關鍵字

organic light-emitting diode ； color-stable ； color-temperature tunable

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