A novel
cross-linkable electron
transport material, 1,3,5-tris(5-(4-vinylphenyl)pyridin-3-yl)benzene
(TV-TmPY), for solution-processing as well as a small molecule, 1,3,5-tris(5-phenylpyridin-3-yl)benzene
(TmPY), for vacuum deposition were designed and synthesized for OLEDs.
TV-TmPY and TmPY with identical core structures are fully characterized
to systematically investigate the impact of solution processing and
vacuum deposition on the performance of phosphorescent OLEDs. Over
90% EQE (external quantum efficiency) was achieved for the solution-processed
TV-TmPY-based device compared to that of the vacuum-deposited TmPY
at a luminance of 1000 cd m<sup>–2</sup>. An EQE deviation
of 0.7% was observed ranging from 100 to 1000 cd m<sup>–2</sup> with TV-TmPY, which is the smallest value to date for solution-processed
OLEDs, and over 12% EQEs were achieved for the trilayered solution-processed
green and blue phosphorescent OLEDs
