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8586333 
Journal Article 
High-efficiency blue-fluorescence N-BDAVBi-based organic light-emitting device with double emission layers 
Wang, J; Wang, FJ; Zhang, B; Wang, S; Chang, X; Ding, GY; Jiang, WL 
2013 
24 
3 
445-450 
Chinese 
High-efficiency blue fluorescent organic light emitting devices (OLEDs) with double emission layers (DELs) have been demonstrated with structure of ITO/4, 4', 4″-Tris (N-3-methylphenyl-N-phenyl-amino) triphenylamine (m-MTDATA)(40 nm)/N, N'-Bis(naphthalen-1-yl)-N, N'-bis(phenyl)benzidine(NPB)/(10 nm)/9, 10-Di(naphth-2-yl) anthracene(ADN): N-(4-((E))-2-(6-((E)-4-(diphenyl-amino)styryl)naphthalen-2-yl) vinyl) phenyl)-N-phenylbenzenamine(N-BDAVBi) (15 nm)/4, 4'-Bis(2, 2-diphenyl-ethen-l-yl) biphenyl(DPVBi):N-BDAVBi(15 nm)/2, 2', 2″-(1, 3, 5-Benzinetriyl)-tris(1-phe-nyl-1-H-benzimidazole(TPBI)(30 nm)/LiF(0.6 nm)/Al. N-BDAVBi as blue emitting dopant is doped into ADN host and DPVBi host simultaneously to form DELs. The DEL devices show significant improved efficiency compared with the conventional devices with a single emitting layer (SEL). The maximum current efficiency of 8.13 cd/A with a Commission International deL'Eclairage (CIE) coordinate of (0.178, 0.302) at current density of 18.81 mA/cm2 is obtained in DEL device, which is about 140% and 80% greater than that of the devices with ADN:N-BDAVBi and DPVBi:N-BDAVBi as emission layer, respectively. The improvement of the current efficiency is attributed to the reduced accumulation of charge carriers at the interfaces, the expansion of the exciton generation region, and the efficient energy transfer from host to dopant. The maximum luminance of 20620 cd/m2 has been achieved at 14 V in DEL device. The CIE chromaticity coordinate of DEL device changes only from (0.181, 0.308) to (0.172, 0.292) as the luminance increases from 1000 cd/m2 to 5000 cd/m2. 
Blue light; Double emitting layers; Electroluminescence (EL); Fluorescence