藍光有機發光元件及混和層發光層之研究

Blue Organic Light-Emitting Device and the Study of the Mixed-Host Emitting Layer

林典群(Tien-Chun Lin)

指導教授 ： 李君浩

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.01012

摘要

在本篇論文中，我們製造出藍光有機電激發光元件。在此元件中，我們選用了9,10-di(2-naphthyl)anthracene (AND) 作為此元件的發光層主體材料，4,4'-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl (DPAVBi) 則作為摻入發光層主體的藍光染料。效率的提升可歸因於我們選用了高電子載子遷移率的 bis(10-hydroxybenzo[h]qinolinato) beryllium (Bebq2) 作為電子傳輸層材料，如此可使元件中的載子傳播更加平衡，進而增進元件藍光的發光效率。此外，藉由暫態電激發光 (transient electroluminescence) 訊號的量測，我們可以知道 DPAVBi 作為染料摻入主體材料 ADN 時並不會對元件的電性造成太大的影響。由實驗的量測可知，當摻染濃度約 2% 到 4% 時效率最好，此時的效率為 16.4 cd/A ，驅動電壓為 4.9 V。
在混合層的研究方面，我們製造了異質接面元件和不同混合比例的混合層 (NPB:Alq3) 元件，NPB全名是 N,N-Bis(naphthalen-1-yl)-N,N-bis(phenyl)benzidine而 Alq3 是 tris(8-hydroxyquinoline) aluminum藉由比較他們頻譜的變化，我們可以決定不同比例的混合層元件中發光區的位置。此外，我們採用光學模擬程式來模擬其光學特性。當混合層比例為 NPB: Alq3=1:3，1:1，3:1 時，發光區的位置分別是在距離 ITO 陽極500，600，700 A 的位置。

關鍵字

有機電激發光元件 ； 藍光 ； 混合層

並列摘要

In this thesis, we report a blue organic light emitting diode (OLED) whose emitting layer is 9,10-di(2-naphthyl)anthracene (ADN) doped with 4,4'-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl (DPAVBi). The efficiency improvement of this device compared with others is attributed to the use of high electron mobility material bis(10-hydroxybenzo[h]qinolinato) beryllium (Bebq2) as the electron transport layer such that a better carrier balance can be achieved. From transient electroluminescence (TREL) measurements of the blue devices, we also confirmed that the DPAVBi dopant in the ADN blue emitting host does not affect the electrical property too much. When the dopant concentration is changed from 2% to 4%, a highest current efficiency of 16.4 cd/A is measured under the condition of a current density of 20 mA/cm2 at a driving voltage of 4.9 V.
In the study of mixed layer (NPB:Alq3) OLED, heterojunction and mixed layer devices were fabricated, where NPB represents N,N -Bis(naphthalen-1-yl)- N,N-bis(phenyl)benzidine and Alq3 represents tris(8-hydroxyquinoline) aluminum. By comparing the spectral shift of electroluminescence between heterojunction and mixed host OLEDs, the recombination zone positions with different mixing concentrations have been determined. The results show that the recombination zone shifts from the anode to the cathode side with increasing the mixed ratio of NPB. An optical simulation program was used to model its optical characteristics. We found that when the NPB:Alq3 mixed ratio is equal to 1:3, 1:1, and 3:1, the major recombination position is at 500, 600, 700 A away from the ITO anode, respectively..

並列關鍵字

organic light-emitting device ； OLED ； mixed layer ； blue

參考文獻

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