Wide energy gap materials dispiro[fluorene-9,9′-anthracene-10′,9″-fluorene] (SAS) and dispiro[xanthene-9,9′-anthracene-10′,9″-xanthene] (XAX) containing double spiro–carbons, are introduced as hosts for blue phosphorescent organic light-emitting diodes (PHOLEDs). Both SAS and XAX are free of heteroatomic exocyclic bonds, which are implicated in limiting the stability of blue PHOLEDs. The materials are synthesized in gram-scale quantities through short and efficient paths. They have large energy gaps (≥5.0 eV) between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and correspondingly have high triplet energies in solid state (ET ≈ 3.0 eV). Analysis of devices using SAS and XAX as host materials with the blue phosphorescent dopant fac-tris(N,N-di-p-tolyl-pyrizinoimidazol-2-yl)iridium(III) (Ir(tpz)3), shows that charges are transported and trapped by the dopant, which subsequently forms excitons directly on the phosphor. As a result, luminescence quenching pathways are suppressed which leads to blue phosphorescent devices with high (≈18%) external quantum efficiency. Thus, SAS and XAX serve as promising host materials, with high triplet energies suitable for blue PHOLEDs.
|Journal||Advanced Optical Materials|
|Publication status||Published - 2022 Jan 18|
Bibliographical noteFunding Information:
This work was supported by the Universal Display Corporation. Also, S.R.F. acknowledges the US Air Force Office of Scientific Research, Grant No. 17RT0908 for partial support of this work. The authors thank Dr. Joanna M. Guerrero for help with the TGA measurements.
© 2021 Wiley-VCH GmbH
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics