Improving the performance of phosphorescent polymer light-emitting diodes using morphology-stable carbazole-based iridium complexes
作者:Kai Zhang、Zhao Chen、Chuluo Yang、Xiaowei Zhang、Youtian Tao、Lian Duan、Liang Chen、Linna Zhu、Jingui Qin、Yong Cao
DOI:10.1039/b705342h
日期:——
A series of morphology-stable carbazole-based iridium(III) complexes with green to red emission have been prepared and characterized by elemental analysis, nuclear magnetic resonance, and mass spectroscopy. Their thermal, electrochemical, electronic absorption, and photoluminescent properties have been studied. Highly efficient polymer light-emitting devices by using these complexes as dopant emitters, both non-conjugated polymer (PVK) and conjugated polymer, polyhedral oligomeric silsesquioxane-terminated poly(9,9-dioctylfluorene) [PFO(poss)], as the host materials, have been achieved. With the device structure of ITO/PEDOT/(PFO(poss) + 30% PBD)–2 wt.% 1/Ba/Al, a maximum external quantum efficiency of 6.4% and a maximum luminous efficiency of 6.00 cd A−1 with red emission at 608 nm were obtained. With the device configuration of ITO/PEDOT/(PFO(poss) + 30% PBD)–4 wt.% 4/Ba/Al, a maximum external quantum efficiency of 9.9% and a maximum luminous efficiency of 22.4 cd A−1 with yellow–green emission at 544 nm were realized. The increased morphology stability of 1 and 2 imparted by the N-decyl long chains at the N atom of carbazole results in significantly better device performance than their short chain analogues 1a and 2a under identical device configurations.
我们制备了一系列形态稳定的咔唑基铱(III)配合物,这些配合物具有绿色至红色发射,并通过元素分析、核磁共振和质谱对其进行了表征。研究了它们的热学、电化学、电子吸收和光致发光特性。利用这些复合物作为掺杂发射体,以非共轭聚合物(PVK)和共轭聚合物--多面体低聚硅倍半氧烷端聚(9,9-二辛基芴)[PFO(poss)]为宿主材料,实现了高效的聚合物发光器件。采用 ITO/PEDOT/(PFO(poss) + 30% PBD)-2 wt.% 1/Ba/Al 的器件结构,获得了 6.4% 的最大外部量子效率和 6.00 cd A-1 的最大发光效率,并在 608 nm 处发出红色光。在 ITO/PEDOT/(PFO(poss) + 30% PBD)-4 wt.% 4/Ba/Al 的器件配置下,最大外部量子效率为 9.9%,最大发光效率为 22.4 cd A-1,在 544 纳米波长处发出黄绿色光。咔唑 N 原子上的 N-癸基长链提高了 1 和 2 的形态稳定性,因此在相同的器件配置下,其器件性能明显优于短链类似物 1a 和 2a。