High colour rendering index non-doped-type white organic light-emitting devices with a RGB-stacked multilayer structure

A non-doped-type white organic light-emitting device with high colour rendering index has been reported. The structure of the device is ITO/NPB (50 nm)/TPBI (3 nm)/Alq 3 (d nm)/DCM2 (0.1 nm)/TPBI (40 − d nm)/ Alq 3 (10 nm)/LiF/Al, where NPB is N, N-bis-(1-naphthyl)-N, N-diphenyl-1, 1-biph-enyl-4, 4-diamine, TPBI is 2, 2 , 2-(1, 3, 5-phenylene) tris(1-phenyl-1H-benzimidazole), Alq 3 is tris (8-hydroxyquinoline) aluminium, DCM2 is [2-methyl-6-[2-(2, 3, 6, 7-tetrahydro-1H, 5H-benzo[ij] quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene] propane-dinitrile. Through the optimization of d, pure white emission with CIE coordinates of (0.3198, 0.3400) at 9 V was obtained, at which the colour temperature and colour rendering index were 6080 K and 97, respectively. The CIE coordinates of the device change from (0.4552, 0.3867) at 4 V to (0.2864, 0.2865) at 19 V that are well in the white region. Its maximum luminance was 10 855 cd m −2 at 19 V and maximum power efficiency was 1.31 lm W −1 at 5 V.