New blue emitters based on anthracene through charge transfer control

Abstract

We designed new moieties with varying electron-donating effects and sizes based on diphenylamine and introduced them into anthracene to synthesize three types of emitting materials. All three materials exhibited high thermal stability with glass transition temperatures above 175°C, confirming their potential as OLED emitters. Devices doped with N9,N9,N10,N10-tetraphenylanthracene-9,10-diamine (TAD), where diphenyl amine is substituted on both sides, and N9,N10-di([1,1′-biphenyl]-4-yl)-N9,N10-bis(dibenzo[b,d]furan-2-yl)anthracene-9,10 diamine (ABFA), with a fused side group of diphenyl amine and dibenzofuran, showed EQEs of 1.28 % and 3.57 % respectively. Due to the intramolecular charge transfer (ICT), they exhibited ELmax values at 517 nm and 538 nm. On the other hand, the device doped with N,N′-(anthracene-9,10-diylbis(4,1-phenylene))bis(N-([1,1′-biphenyl]-4-yl)dibenzo[b,d]furan-2-amine) (APBFA), which has optimized side groups that suppress ICT and intermolecular packing, achieved a relatively high EQE of 4.48 % and showed blue emission with CIE coordinates of (0.146, 0.142).