New Amorphous Hole Blocking Materials for High Efficiency OLEDs

Abstract

Two new amorphous molecular materials, 2,5-bis(2',5'-dimethyl-4-triphenylsilyl-phenyl)-[1,3,4]oxadiazole (BDTSO) and 2,5-bis(2',5'-dimethyl-4-triphenylsilyl-phenyl)-[1,3,4]thiadiazole (BDTST) were synthesized and investigated as hole blocking materials (HBM) for organic light-emitting diodes. The efficiency of electroluminescent device was improved by using BDTSO instead of BAlq. The current and power efficiency of the device using BDTSO as HBM is 39.6 cd/A and 13.1 lm/W at 10 mA/cm2, respectively, which is higher compared to the same values for devices using BDTST and BAq which are typically used as HBM.

Ultrahigh-efficiency solution-processed simplified small-molecule organic light-emitting diodes using universal host materials

“…The tetrahedral configurations with two meta-pyridine substituents give it good morphological stability and solubility ( 27 , 28 ). In addition, 3d-π interaction between the central Si atom and the phenyl or pyridyl phenyl group without disconnection of conjugation at the Si atom yields a wide band gap and high T1 state for a blue phosphorescent host.…”

“…To fulfill these requirements, we designed new tetrahedral siliconbased hosts, which are composed of a central Si atom with a 3d orbital, and a phenyl or m-pyridyl phenyl moiety. The tetrahedral configurations with two meta-pyridine substituents give it good morphological stability and solubility (27,28). In addition, 3d-p interaction between the central Si atom and the phenyl or pyridyl phenyl group without disconnection of conjugation at the Si atom yields a wide band gap and high T1 state for a blue phosphorescent host.…”