Bright electrophosphorescent devices based on sterically hindered spacer-containing Cu(I) complex

A Cu(I) complex, [Cu(Dppp)(DPEphos)]BF4 (Dppp=2,3-diphenyl-pyrazino[2,3-f][1,10]phenanthroline, DPEphos=Bis[2-(diphenylphosphino)phenyl]ether), is synthesized and used as the dopant in bright electrophosphorescent devices with the general structure ITO/m-MTDATA (30 nm)/NPB (20 nm)/CBP: ×wt% [Cu(Dppp)(DPEphos)]BF4 (30 nm)/Bphen (20 nm)/Alq3 (20 nm)/LiF (0.8 nm)/ Al (200 nm). These devices exhibit a maximum brightness of 4483 cd/m2 and a peak efficiency of 3.4 cd/A. Compared with previously reported similar devices based on Cu(I) complexes, the brightness of the devices presented in this article is the best. Meanwhile, 2% [Cu(Dppp)(DPEphos)]BF4-based devices exhibit white light-emitting properties with CIE coordinates of (0.32. 0.35) at 10 V.