Institute of Optoelectronic Sciences, National Taiwan Ocean University , Keelung 202, Taiwan.
Department of Chemistry, National Taiwan University , Taipei 106, Taiwan.
ACS Appl Mater Interfaces. 2017 Mar 1;9(8):7355-7361. doi: 10.1021/acsami.6b16083. Epub 2017 Feb 14.
This work reports a new strategy of introducing remote steric effect onto the electron donor for giving the better performance of the exciplex-based organic light-emitting device (OLED). The bulky triphenylsilyl group (SiPh) was introduced onto the fluorene bridge of 4,4'-(9H-fluorene-9,9-diyl)bis(N,N-di-p-tolylaniline) (DTAF) to create remote steric interactions for increasing the possibility of effective contacts between electron-donating chromophores and acceptor molecules, rendering the resulting exciplex to have a higher photoluminescence quantum yield (PLQY). The green exciplex device based on DSDTAF:3N-T2T (1:1) as an emitting layer exhibits a low turn-on voltage of 2.0 V, high maximum efficiencies (13.2%, 42.9 cd A, 45.5 lm W), which are higher than the device employed DTAF (without SiPh groups) (11.6%, 35.3 cd A, 41.3 lm W) as donor under the same device structure. This strategy was further examined for blue exciplex, where the EQE was enhanced from 9.5% to 12.5% as the electron acceptor PO-T2T mixed with a tert-butyl group substituted carbazole-based donor (CPTBF) as the emitting exciplex in device. This strategy is simple and useful for developing high performance exciplex OLEDs.
这项工作报道了一种在给体中引入远程空间位阻的新策略，以提高基于激基复合物的有机发光器件（OLED）的性能。将体积庞大的三苯基硅基（SiPh）引入 4,4'-(9H-芴-9,9-二基)双(N,N-二对甲苯基苯胺)（DTAF）的芴桥，以产生远程空间位阻相互作用，增加供电子发色团和受体分子之间有效接触的可能性，从而使所得激基复合物具有更高的光致发光量子产率（PLQY）。基于 DSDTAF:3N-T2T（1:1）作为发射层的绿色激基复合物器件表现出低的开启电压为 2.0 V，高效率（13.2%，42.9 cd A，45.5 lm W），高于采用 DTAF（无 SiPh 基团）作为供体的器件（11.6%，35.3 cd A，41.3 lm W）在相同的器件结构下。该策略进一步应用于蓝色激基复合物，其中随着电子受体 PO-T2T 与具有叔丁基取代的咔唑基供体（CPTBF）混合作为发射激基复合物的器件，EQE 从 9.5%增强到 12.5%。该策略简单且有助于开发高性能激基复合物 OLED。
