Enhancing the Performance of Ink-Jet Printed Phosphorescent Green OLEDs via Post-Synthetic Vacuum-Assisted Annealing
발표자
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초록
내용
Inkjet printing (IJP) is widely used technique for organic light-emitting diode (OLED) fabrication because it allows production in ambient atmosphere as compared to conventional vacuum-based methods. However, the high boiling point of inkjet solvent often leads to solvent trapping, producing film with poor morphology affecting OLED device performance. Herein, we developed an efficient vacuum-assisted annealing (VAA) treatment to improve the printing quality of Ir(mppy)3 based emissive layer (EML) for phosphorescent green OLEDs. Surface characterization reveals that VAA treatment removes trapped solvent in the film, creating a more textured morphology for better interfacial charge injection. The external quantum efficiency of the OLED device improved from ~3.6% (pristine) to ~6.3% (VAA treated). There are no changes in the EL and PL peak positions (~510 nm) even after VAA-treatment. These results show that VAA treatment reduces non-radiative recombination increasing efficiency.