LAUSR

Abstract Two novel 2,4-difluorenylquinoline derivatives with different length of alkyl chain at fluorene unit (Q-F1 with methyl and Q-F2 with octyl chain) of donor-acceptor (D-A) type were synthesized and comprehensively characterized. The compounds exhibited bright emission in the blue spectral region at 400 nm and high fluorescence efficiency of 63–97% in solution. The EL measurements of OLEDs with Q-F1, and for comparison 2,4-dicarbazolylquinoline (Q-C1) were performed to determine any correlations between the device performance and the different D units at quinoline core. These fluorenyl and carbazolyl substituted quinolines (Q-F1 and Q-C1) were found to display good thermal stability with a decomposition temperature of 301 and 416 °C, respectively. A molecule with carbazole units (Q-C1) dispersed in a host matrix exhibited higher PL quantum yield (15%) compared to Q-F1 (11%). The devices with structure ITO/PDOT:PSS/PVK:PBD:compound/Al with 15 (Q-F1) and 2 (Q-C1) wt. % of compound content in a blend were constructed. The diode based on Q-C1 emitted green light with EL maximum at 550 nm under an applied external voltage. Furthermore, by incorporation of a layer of plasmonically active silver nanowires into the device based on Q-C1 (ITO/PEDOT:PSS + AgNWs/PVK:PBD:Q-C1 (2 wt%)/Al) the noticeably more intense EL signal was detected. These results show that these compounds are promising candidates and may be used in organic light emitting devices.