Bipolar Host Materials Based on 1,3,5-Triazine Derivative for Green Phosphorescent Organic Light-emitting Diode

Abstract

We designed and synthesized new bipolar host materials 2-4, through microwave-assisted Suzuki-coupling reaction with 1,3,5-triazine unit and carbazole/fluorene group. The photophysical and thermal properties of the synthesized 1,3,5-triazine derivatives 2-4 were investigated by ultraviolet-visible (UV-vis) spectrometer, spectrofluorometer, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The 1,3,5-triazine derivatives 2-4 have suitable energy bandgap (E-g = 3.15-3.35 eV) and high triplet energy level (E-T, 2.63-2.87 eV) for phosphorescent green host. Device performance of 2-4 materials shows that maximum luminescence efficiency (LE) and external quantum efficiency (EQE) of green device A-C were 29.25, 49.67, and 48.74 cd/A and 8.68, 14.52, and 14.30%, respectively.