Improved performances in a top-emitting green organic light-emitting device with light magnification

Abstract

A top-emitting organic light-emitting device (TOLED) with an architecture of Si/SiO 2/Ag (100 nm)/Ag 2O (UV ozone treatment for 30 s)/ 4′,4ʺ-tris(3-methylphenylphenylamino)triphenylamine (45 nm)/4,4′-bis [ N-(1-naphthyl-1-)- N-phenyl-amino]-biphenyl (5 nm)/tris-(8-hydroxyquinoline) aluminum (Alq 3):10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1 H,5 H,11 H-benzo[ l]-pyrano[6,7,8- ij]quinolizin-11-one (C545T) (1: 0.5 weight %, 20 nm)/Alq 3 (30 nm)/LiF(1 nm)/Al (0.5 nm)/Ag(30 nm) is designed with a resonance wavelength in the TOLED corresponding to the peak wavelength of C545T. With this enhanced cavity structure, light magnification with a coefficient of ∼ 19 (forward direction) is observed, leading to significantly improved performances with brightness of 80215 cd/m 2 at 9 V, luminous efficiency of 32.7 cd/A at 6 V, external quantum efficiency of 8.9% at 7.5 V, and low turn-on voltage of 2.5 V.