Synthesis And Optoelectronic Properties Of Phosphorescnet Host Materials And Blue Thermally Activated Delayed Fluorescence Emitters

OLEDs based on the phosphorescent materials and TADF materials which have achieved ηint values of almost 100% are gaining more and more attention in the past two decades. Here, we have synthesized a series of TADF materials and Host materials for phorescent emitters, respectively.By incorporating the acridinone moiety and aromatic amine moiety into one molecule, we have synthesized two bipolar Host materials: APCz and APDPA. All of them have obtained a high triplet energy level due to the large dihedral angle between the acridinone and its connected phenyl ring, which have interrupted the π-conjugation of the host materials. PHOLEDs were fabricated by doping Ir(ppy)3 into the these developed materials and CBP, and PHOLEDs based on APCz and APDPA all exhibited a low turn on voltage. The device based on APCz exhited higher device efficiency and reduced efficiency roll-off with an EQEs of 13.65% at 100 cd m-2 and 13.61% at 100 cd m-2.By combinge the 9,9-dimethyl-10-phenyl-9,10-dihydroacridine donor unit with different acceptor units of carbonyl, benzophone and 2,6-diphenyl-1,3,5-triazine, we have synthesized a series blue TADF emitters. By moderately adjusting the dihedral angle between the donor and acceptor moiety, we tuned the CT characteristic of the D-A molecules and obtained blue TADF emitters with a weakened CT state. OLEDs based on PhDMAc-C, PhDMAc-TRZ and PhDMAc-C have achieved maximal EQE of 11.48%, 10.86% and 8.65%, respectively, with a CIE coordinate of(0.16, 0.11),(0.15, 0.11) and(0.14, 0.17), which is close to that of the National Television Standards Committee standard blue of(0.14, 0.08).