Liu Bin, Yuan Yi, He Dan, Huang De-Yue, Luo Cheng-Yuan, Zhu Ze-Lin, Lu Feng, Tong Qing-Xiao, Lee Chun-Sing
Department of Chemistry and Key laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Guangdong, 515063, P. R. China.
Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong SAR, P. R. China.
Chemistry. 2016 Aug 16;22(34):12130-7. doi: 10.1002/chem.201602122. Epub 2016 Jul 14.
Donor-acceptor (D-A) molecular architecture has been shown to be an effective strategy for obtaining high-performance electroluminescent materials. In this work, two D-A molecules, Ph-BPA-BPI and Py-BPA-BPI, have been synthesized by attaching highly fluorescent phenanthrene or pyrene groups to the C6- and C9-positions of a locally excited-state emitting phenylamine-phenanthroimidazole moiety. Equipped with good physical and hybridized local and charge-transfer properties, both molecules show high performances as blue emitters in nondoped organic light-emitting devices (OLEDs). An OLED using Ph-BPA-BPI as the emitting layer exhibits deep-blue emission with CIE coordinates of (0.15, 0.08), and a maximum external quantum efficiency (EQE), current efficiency (CE), and power efficiency (PE) of 4.56 %, 3.60 cd A(-1) , and 3.66 lm W(-1) , respectively. On the other hand, a Py-BPA-BPI-based, sky-blue OLED delivers the best results among nondoped OLEDs with CIEy values of < 0.3 reported so far, for which a very low turn-on voltage of 2.15 V, CIE coordinates of (0.17, 0.29), and maximum CE, PE, and EQE values of 10.9 cd A(-1) , 10.5 lm W(-1) , and 5.64 %, were achieved, respectively. More importantly, both devices show little or even no efficiency roll-off and high singlet exciton-utilizing efficiencies of 36.2 % for Ph-BPA-BPI and 39.2 % for Py-BPA-BPI.
供体-受体（D-A）分子结构已被证明是获得高性能电致发光材料的有效策略。在这项工作中，通过将高荧光性的菲或芘基团连接到局域激发态发射的苯胺-菲并咪唑部分的C6和C9位置，合成了两种D-A分子，即Ph-BPA-BPI和Py-BPA-BPI。这两种分子具有良好的物理性质以及局域和电荷转移杂化特性，在非掺杂有机发光二极管（OLED）中作为蓝色发射体均表现出高性能。以Ph-BPA-BPI作为发光层的OLED呈现出深蓝色发射，其CIE坐标为（0.15, 0.08），最大外量子效率（EQE）、电流效率（CE）和功率效率（PE）分别为4.56%、3.60 cd A⁻¹和3.66 lm W⁻¹。另一方面，基于Py-BPA-BPI的天蓝色OLED在迄今报道的CIEy值< 0.3的非掺杂OLED中取得了最佳结果，其开启电压低至2.15 V，CIE坐标为（0.17, 0.29），最大CE、PE和EQE值分别为10.9 cd A⁻¹、10.5 lm W⁻¹和5.64%。更重要的是，这两种器件几乎没有效率滚降，Ph-BPA-BPI的单重态激子利用效率高达36.2%，Py-BPA-BPI的为39.2%。
