Researchers from LORDIN, in collaboratioon with researchers from Korea's Dankook University, Gachon University and Hongik University, have reported on a highly efficient and stable ultra-pure blue phosphorescent OLED emitter, based on Lordin's Tetradentate Pt(II) material Complex with a vibration suppression effect.
The researchers say that the new emitter offers a lifetime of 451 hours (LT50 at 1,000 cd/m2), and an EQE of 25.1%. The emission spectrum is extremely narrow - full width at half a maximum of 22 nm. The researchers further developed a tandem OLED device based on this new emitter, which achieves an EQE of 50.3% and a lifetime of 589 hours (LT 70).
The new blue material is a modified tetradentate Pt(II) emitter with a spirofluorene onto the carbazole unit. The researchers say that this modification minimizes the vibration modes, corresponding to the structural relaxation during the de-excitation (the vibration suppression effect). This modification reduces the intensity of the second peak in the spectrum and Shockley–Read–Hall recombination by blocking direct hole injection into the emitter while enhancing Förster resonance energy transfer.
