New -MTDATA skeleton-based hole transporting materials for multi-resonant TADF OLEDs

• Published in: Physical chemistry chemical physics : PCCP 2022-11, Vol.24 (45), p.27847-27855
• Main Authors: Bucinskas, A, Bezvikonnyi, O, Durgaryan, R, Volyniuk, D, Tomkeviciene, A, Grazulevicius, J. V
• Format: Article
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d2cp03811k

Six new hole transporting materials based on the commercially available m -MTDATA core were synthesized by introducing different electron donating groups, such as methoxy, ethoxy and dimethylamino groups. To achieve the target compounds simple two-step synthesis was used by employing the Buchwald-Hartwig reaction. New derivatives were investigated experimentally and their thermal, optical, photoelectrical, and charge transporting properties were compared with the respective results of their commercial counterpart ( m -MTDATA). In solid-state and DCM solutions, target compounds and commercial m -MTDATA showed comparable ionization potential values. The compound with methoxy groups at the meta position showed a hole mobility of 1.06 × 10 −3 cm 2 V −1 s −1 at an electric field of 4.62 × 10 5 V cm −1 . These values exceed those reported for m -MTDATA. The synthesized derivatives were employed for the preparation of hole transporting layers in multi-resonant TADF OLEDs. Excellent colour purity and high maximum external quantum efficiency reaching 13.8% were achieved for OLEDs employing the synthesized hole-transporting material and the deep-blue MR-TADF emitter t -DABNA. Investigation of the impact of different types of electron donating groups on the thermal, electrochemical, charge transporting, and optoelectrical properties of new hole transporting m -MTDATA skeleton-based materials.