Highly efficient and high colour rendering index white organic light-emitting devices using bis(2-(2-fluorphenyl)- 1,3-benzothiozolato-N,C~(2')) iridium (acetylacetonate) as yellow emitter

摘要

Multiple emissive layer (MEML) white organic light-emitting devices (OLEDs) are fabricated. In the MEML, the yellow phosphorescent emitter bis(2-(2-fluorphenyl)-1,3-benzothiozolato-N,C~(2')) iridium(acetylacetonate) [(F-BT)_2Ir(acac)] is introduced to codope with the red one bis(2,4-diphenyl-quinoline) iridium acetylacetonate [Ir(piq)_2acac] into 4,4'-N,N'-dicarbazole-biphenyl (CBP), fac tris(2-phenylpyridine) iridium [Ir(ppy)_3]-doped CBP is used for green emitting and N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB) is used for both hole transporting and blue emitting. By adjusting the devices' structure, we get the OLED which has the maximum luminance of 50 030 cd m~(-2), maximum efficiencies of 21.6 cd A~(-1) (at 7 V), 10.3 lm W~(-1) (at 5 V) and 8.4% (at 7 V) and colour rendering index (CRI) of 85. In addition, its Commission International de L'Eclairage (CIE) coordinates slightly change from (0.3867, 0.4075) to (0.3638, 0.4070) when the drive voltage shifts from 7 V (1862 cd m~(-2)) to 13 V (39 270 cd m~(-2)).