Silafluorene moieties as promising building blocks for constructing wide-energy-gap host materials of blue phosphorescent organic light-emitting devices
作者:Dongdong Wang、Qingqing Liu、Yue Yu、Yong Wu、Xinwen Zhang、Hua Dong、Lin Ma、Guijiang Zhou、Bo Jiao、Zhaoxin Wu、Runfeng Chen
DOI:10.1007/s11426-015-5329-6
日期:2015.6
In this article, we reported the synthesis and characterization of a novel silafluorene-based host material, 1,3-bis(5-methyl-5H-dibenzo[b,d]silol-5-yl)benzene (Me-DBSiB), for blue phosphorescent organic light-emitting devices (PHOLEDs). The Me-DBSiB was constructed by linking 9-methyl-9-silafluorene units to the phenyl framework through the sp3-hybridized silica atom to maintain high singlet and triplet energy, as well as to enhance thermal and photo-stability. The calculated result shows that the phenyl core does not contribute to both the highest occupied molecular orbital and lowest unoccupied molecular orbital. Wide optical energy gap of 4.1 eV was achieved. When the Me-DBSiB was used as the host and iridium (III) bis[(4,6-difluorophenyl)pyridinato-N,C2′]picolate (Firpic) as the guest, a maximum current efficiency was 14.8 cd/A, lower than the counterpart of 1,3-bis(9-carbazolyl)benzene (28 cd/A). The unbalanced barrier for electron and hole injection to host layer may be responsible for low efficiency. Even so, our results show that silafluorene moieties are promising building blocks for constructing wide-energy-gap host materials.
在这篇文章中,我们报道了一种新型硅芴基主材料--1,3-双(5-甲基-5H-二苯并[b,d]硅醇-5-基)苯(Me-DBSiB)的合成和表征,该材料可用于蓝色磷光有机发光器件(PHOLED)。Me-DBSiB 是通过sp3杂化硅原子将 9-甲基-9-硅芴单元连接到苯基框架上而构建的,以保持较高的单线和三线能量,并提高热稳定性和光稳定性。计算结果表明,苯基核心对最高占有分子轨道和最低未占有分子轨道均无贡献。实现了 4.1 eV 的宽光学能隙。以 Me-DBSiB 为宿主,双[(4,6-二氟苯基)吡啶-N,C2′]吡啶铱(Firpic)为客体时,最大电流效率为 14.8 cd/A,低于 1,3-双(9-咔唑基)苯(28 cd/A)。电子和空穴注入寄主层的势垒不平衡可能是效率低的原因。尽管如此,我们的研究结果表明,硅芴分子是构建宽能隙宿主材料的有前途的构件。