Reduced efficiency roll-off in electrophosphorescent devices by a short-living rhenium emitter with well-matched energy levels

摘要

We demonstrated reduced efficiency roll-off in electrophosphorescent devices based on a rheniumnu0004Reu0002Iu0003u0005 complex, u00069, 9-Di-u00049u0002-u00024u0003-phenoxybutylu0003-9u0002H-carbazylu0005-9-H-4,5-Diazafluorene Reu0002COu00033Bru0007nu0002Re-PCDFu0003. The devices based on Re-PCDF exhibited the peak luminance of 7888 cd/m2nand thenmaximum efficiency of 7.41 cd/A, respectively. Remarkably, the devices exhibited very smallnefficiency roll-off with only ca. 28%, which is much better than the reported Reu0002Iu0003 complexes basedndevices. Such excellent performances could be ascribed to the short luminescent lifetime ofnRe-PCDF and well-matched energy levels between the singlet host and the triplet emitter. Thendetailed mechanisms of such small efficiency roll-off were also investigated. © 2010 AmericannInstitute of Physics. u0004doi:10.1063/1.3531576