aDevice configuration: ITO/MoO3 (10 nm)/X/LiF (1 nm)/Al. For devices A-C: X = NPB (60 nm)/mCP (15 nm)/emitter (30 nm)/TPBi (30 nm). For devices D-F: X = emitter (60 nm)/TPBi (30 nm). For devices G-I: X = NPB (60 nm)/mCP (10 nm)/emitter:PO-01 (20 nm, 10 wt%)/Bphen (40 nm). bAbbreviations: = turn-on voltage at 1 cd m-2; = maximum luminance; , , and = maximum power, current, and external quantum efficiencies, respectively; CIE = Commission International de l’Éclairage coordinates. cDevices J-M: literature results for comparison.