Effective thermally activated delayed fluorescence emitter and its performance in OLED device

Ideal Molecular Design of Blue Thermally Activated Delayed Fluorescent Emitter for High Efficiency, Small Singlet–Triplet Energy Splitting, Low Efficiency Roll-Off, and Long Lifetime

“…High QE is preferred in the OLEDs for low power consumption and low driving voltage. Therefore, the development of high QE OLEDs such as phosphorescent OLEDs − or thermally activated delayed fluorescent (TADF) OLEDs − is a hot issue. In particular, the TADF OLEDs are promising as high efficiency blue OLEDs for practical application because the TADF emitters have only chemically stable sp 2 type chemical bonds instead of unstable IrC and IrN bonds of blue phosphorescent emitters possessing a phenylimidazole type ligand according to molecular calculation results. − …”

“…It is true that TADF emitters have potential as high efficiency blue emitters, but only a few design methods have been reported to develop blue TADF emitters. The most popular method was to couple donor and acceptor moieties using moderate acceptors like triazine, − benzophenone , and diphenylsulfone, − and strong donors like acridine , and carbazolylcarbazole ,,, using a phenyl linker. The donor and acceptor moieties were properly chosen for blue emission, and they were typically interconnected through the para- position of the phenyl linker to obtain high photoluminescence quantum yield (PLQY), although the origin of the high PLQY is not yet clear.…”

2,7(3,6)-Diaryl(arylamino)-substituted Carbazoles as Components of OLEDs: A Review of the Last Decade

“…The compounds 27DBrCr, 36DBr9ArCr, or 36DI9ArCr were firstly obtained as starting materials for the synthesis, as shown in Scheme 1. The target compounds E21 [100,101] and E23 [102] were obtained during the Buchwald-Hartwig amination reaction, and the materials E22 [79], E24 [103], and E25 [104] were obtained during the Ullmann reaction of the starting derivatives.…”

Recent progress of green thermally activated delayed fluorescent emitters

“…The EQE of the devices, however, was less than 10% in the two devices. 5-(9 H-[9,3 :6 ,9 -tercarbazol]-9 -yl)isophthalonitrile (DCN3) was also an emitter with the 3,5-dicyanobenzene acceptor and the 3,6-dicarbazolylcarbazole donor [30]. In spite of the small E ST of 0.13 eV, the low PLQY of 0.39 resulted in a moderate EQE of 13.3%.…”