以天藍光染料製作高效率紫藍光有機發光二極體

Fabrication of Efficient Purplish-blue OLEDs from a Sky-blue Emitter

陳昱霖(Yu-Lin Chen)

指導教授 ： 周卓煇

國立清華大學/工學院/材料科學工程學系/碩士(2012年)

https://doi.org/10.6843/NTHU.2012.00350

摘要

本研究以天藍色染料，製備出紫藍色有機發光二極體。將位於CIExy (0.190, 0.241) 之天藍色染料1-((9,9-diethyl-9H-fluoren-2-yl)ethynyl)
pyrene摻雜於主體4,4’-bis(9-carbazolyl)-biphenyl時，能放出CIExy (0.155, 0.063) 的紫藍光色，並將色飽和度提昇至100%以上；效率表現上，在亮度為 100 cd/m2 時，外部量子效率為3.5%，能量效率為 1.2 lm/W。
顯著的深藍位移可歸因為： ㄧ、低的摻雜濃度可以避免因染料過度聚集而產生的紅位移；二、搭配一與客體極性相匹配的主體可進一步分散染料；三、好的主客體能階搭配可以使激子在主體上產生，進而驅動高能量的放光；四、選擇有能力放出短波長，驅動更高能量激子的主體。
獲得高效率的原因為：ㄧ、低的摻雜濃度可避免染料聚集，因能量焠息(quenching)所導致的效率滾降(roll-off)；二、好的能階結構搭配，使激子在主體上產生，讓主至客體間效率有效地傳遞；三、具有良好主-客體間能量傳遞特性之主體。
更值得注意的是，此方法同時適用於不具有立體空間障礙的淡藍光染料，可以調整其光色使更飽和。

關鍵字

溼式製作 ； 有機發光二極體 ； 深藍光

並列摘要

We reveal in this communication a new finding regarding the use of a sky-blue emitter to generate purplish-blue emission from organic light emitting diodes (OLEDs) with a polarity matching and high-energy exciton generating host. The resulting device exhibits CIExy coordinates of (0.155, 0.063) and a 3.5% external quantum efficiency with a 1.2 lm/W power efficiency at 100 cd/m2 as a sky-blue emitter, 1-((9,9-diethyl-9H-fluoren-2-yl)ethynyl)pyrene, with CIExy of (0.19, 0.24) is doped into a host of 4,4’-bis(9-carbazolyl)-biphenyl for example. The resulting purplish-blue emission enables a greater than 100% color saturation. The extraordinarily marked blue-shift may be resulted from a low doping concentration to prevent bathochromic shift due to emitter segregation, a polarity matching host to further disperse the emitter, and a proper host and guest energy level paring that enables exciton to generate on host to trigger short wavelength emission. Furthermore, the host is capable of generating excitons with higher energy to facilitate triggering emission with a shorter wavelength. The high efficiency may be attributed to the low doping concentration preventing concentration-quenching caused efficiency roll-off, the exciton generated on host facilitating the occurrence of the efficiency effective host-to-guest energy transfer, and the employed host possessing an effective host-to-guest energy transfer effect. Notably, the new approach also works for other light-blue emitters in yielding a highly desirable deep-blue light provided whose molecular structure is free of steric hindrance.

並列關鍵字

dry-processed ； OLED ； deep-blue

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