Dimers with thermally activated delayed fluorescence (TADF) emission in non-doped device

Abstract

Two novel TADF molecules, with donor#1–σ–donor#2–π–acceptor (D1–σ–D2–π–A) conformation, were designed and synthesized through-bond charge transfer (TBCT) and through-space charge transfer (TSCT). These two materials differ only in the D1 groups with triphenylamine for SFCCN and 10-phenyl-10H-phenoxazine for SFCCNO. Due to the unconjugated linkage, both materials showed very similar emission to that from D2–π–A TBCT effect in dilute solution. SFCCNO can form dimers at the aggregation state and exhibit intermolecular D1/A TSCT emission because of the planar D1 conformation. Therefore, a non-doped device based on SFCCNO exhibited efficiencies of 12.9% at 100 cd m⁻² and 10.4% at 1000 cd m⁻², which are much higher than the SFCCN based device.