Solution-processing has the potential to reduce the cost and energy requirements in the fabrication of organic light-emitting diode (OLED) devices. In non-doped emissive layers, polymers are commonly used but often suffer from batch-to-batch variation. Oligomers, which have precise molecular structures, avoid this problem but maintain the favourable film-forming properties that polymers possess. We present three benzothiadiazole-containing fluorene-based oligomers, BT-F3 2 , BT-F4 2 and BT-F5 2 , which have terfluorene, quaterfluorene and pentafluorene arms, respectively, attached to a benzothiadiazole core. The materials show very high photoluminescence quantum yields, with BT-F4 2 exhibiting the highest PLQY of 0.96 in the thin film. Although there is little change in the electroluminescence spectra, the oligomer size influences device performance. BT-F3 2 had an external quantum efficiency of 1.9 % and high luminance whilst BT-F4 2 reached an external quantum efficiency of 2.3 %. Furthermore, the stability of the OLED devices was evaluated and showed that the device lifetime decays with increasing molecular length.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.