High performance of solution-processed green phosphorescent light emitting-diodes based on a new Pt(II)-complex

Abstract

New Pt(II)-complex named as AT8809 was used as dopant to prepare green phosphorescent light emitting diodes (PhOLEDs) by solution -processed method. According to the research results, the device with the structure of ITO/PEDOT: PSS/PVK/CBP: AT8809/TPBi/LiF/Al achieved the highest performance, such as 10561 cd/m2 of the luminance, 41.7 cd/A of the current efficiency with the peak around 518 nm. The spectra of devices with different dopant ratio or thickness of ETL red shifted, even there was a second peak, which should be caused by the interaction between excitons and the aggregation luminescence of AT8809. The PL and TRPL were tested to discuss the reason of wavelength red shift by changing the doping ratio of AT8809. In PL spectra, the peak red shifts gradually as the doping ratio increasing, even in pure AT8809 film, the PL shows a red peak at 660 nm rather than green peak at 520 nm, which corresponds to the aggregation luminescence and traditional luminescence of AT8809 respectively. The film with a high doping ratio shows a fast PL decay, which means that the increasing concentration of dopant leads to a severe intermolecular reaction.