芳香取代吡咯螢光分子之光物理性質及有機電激發光元件特性

Photophysical Properties and Organic Light-Emitting Diode Characteristics of Aryl-Substituted Pyrrole Fluorophores

劉季侃(Chi-Kan Liu)

指導教授 ： 詹立行

國立暨南國際大學/科技學院/應用材料及光電工程學系/碩士(2015年)

https://doi.org/10.6837/NCNU.2015.00142

摘要

本研究係探討2na-DMF(P型)與2Cz系列材料(D-A型)五個螢光分子材料之光物理性質與有機電激發光元件特性。此五種材料係由?咯核心與不同芳香取代基所建構而成。P型螢光分子材料2na-DMF為?咯核心接上推電子基所合成；而D-A型雙極螢光分子2Cz系列材料則為?咯核心接上推電子基與不同拉電子基所合成。
2na-DMF先前已有應用於非摻雜有機電激發光元件的研究。本研究利用能隙大之特點，將2na-DMF材料應用於紅色磷光元件主體材料的發展。透過調整元件電子傳輸層能階匹配、載子平衡與客體摻雜濃度，可得到元件之最佳表現。當電子傳輸層以TPBi取代BCP/Alq3時，元件表現出最佳的發光效率，其效率分別為啟動電壓2.7 V、最大亮度27649 cd/m2、電流效率25.2 cd/A、功率效率27.6 lm/W與最大外部量子效率14.6%。
2Cz系列材料發展為非摻雜型元件之發光層時，會由於發光層內分子堆疊而導致電致發光光譜明顯紅移，因此朝向主客體發光系統發展。所製作出之OLED元件最大亮度介於1352-2879 cd/m2，最大電流效率為0.7-1.0 cd/A，最大功率效率為0.3-0.6 lm/W，最大外部量子效率為2.3-2.6%，元件電致發光光譜介於403-408 nm之間，接近紫外光範圍。與過去相關文獻相比，此研究結果對於紫外光有機發光二極體的發展具有相當良好的潛力。

關鍵字

?咯 ； 非摻雜 ； 主客體系統 ； 磷光 ； 紫外光 ； 有機發光二極體

並列摘要

In this work, we have studied the photophysical properties and OLED characteristics of five fluorescent materials, named 2na-DMF (P-type) and 2Cz-based materials (D-A type). These five materials were constructed by changing various aryl-substituents linking to the pyrrole central core. For P-type fluorescent material, 2na-DMF, was the electron-donating units linking to the pyrrole central core. The D-A type bipolar fluorescent materials, 2Cz-based materials, were electron-donating along with different electron-withdrawing units attaching to the pyrrole core.
2na-DMF has been studied in non-doped organic light-emitting diodes, previously. Due to the wide energy bandgap, 2na-DMF was developed as the host material for phosphorescent OLED herein. The highest performances of the device were obtained by tuning the energy level matching between the electron transport layers and the emission layer, charge balance, and doping concentration of guest material. The best device was achieved when the electron transporting layer was TPBi instead of BCP/Alq3, with the turn-on voltage of 2.7V, maximum luminance of 27649 cd/m2, current efficiency of 25.2 cd/A, power efficiency of 27.6 lm/W and external quantum efficiency of 14.6%, respectively.
2Cz-based materials were firstly fabricated as the emissive layer of non-doped organic light-emitting diodes. However, these devices showed significantly red-shifted in electroluminescence spectra which were induced by molecular aggregation. Consequently, 2Cz-based materials were developed for host-guest system OLEDs application. As a result, the devices showed the maximum luminance in the range of 1352-2879 cd/m2, current efficiency of 0.7-1.0 cd/A, power efficiency of 0.3-0.6 lm/W, and external quantum efficiency of 2.3-2.6%. Moreover, EL spectra peak of these devices in the range of 403-408 nm, which were near ultraviolet region. Compared with the UV organic light-emitting diode in literatures, the performance of these devices in this work showed promising potential for UV OLED applications.

並列關鍵字

pyrrole ； non-doped ； host-guest system ； phosphorescent ； UV ； organic light-emitting diode

參考文獻

1. Tao, S. L.; Zhou, Y. C.; Lee, C. S.; Zhang, X. H.; Lee, S. T., High-Efficiency Nondoped Deep-Blue-Emitting Organic Electroluminescent Device, Chem. Mater. 2010, 22, 2138.

2. Pope, M.; Kallmann, H. P.; Magnante, P., Electroluminescence in Organic Crystals, J. Chem. Phys. 1963, 38, 2042.

3. Tang, C. W.; VanSlyke, S. A., Organic Electroluminescent diodes, Appl. Phys. Lett. 1989, 51, 913.

4. Barth, S.; Müller, P.; Riel H.; Seidler, P. H.; Riess, W.; Vestweber, H; Bassler, H., Electron mobility in tris(8-hydroxy-quinoline)aluminum thin films determined via transient electroluminescence from single- and multilayer organic light-emitting diodes, J.Appl. Phys.2001, 89, 3711.

5. Adachi, C.; Tsutsui, T.; Saito, S., Organic electroluminescent device having a hole conductor as an emitting layer, Appl. Phys. Lett. 1989, 55, 1489.