Electroluminescence and Electrical Properties of White-OLEDs Studied by Dc and Ac Measurements. (2015)

• Record Type: Journal Article
• Authors: Costa, J.; Pereira, L.
• Is Part Of: Materials today. Volume 2:Number 1(2015)
• Page Start: 20
• Page End: 25
• Publication Date: 2015
• Subjects: White-OLED -- Electroluminescence -- Electrical properties -- doping; Materials science -- Congresses -- Periodicals; 620.1
• DOI: 10.1016/j.matpr.2015.04.003
• Languages: English
• ISSNs: 2214-7853

Abstract

Abstract: White-OLEDs were made by thermal evaporation using NPB (N, N'-Bis (naphthalen-1-yl)-N, N'-bis (phenyl) benzidine) doped with DCM1 (4 - (Dicyanomethylene) – 2 – methyl – 6 - (4 -dimethylaminostyryl)-4H-pyran) in a single layer with two emitters. The electroluminescent emission has a CIE (x, y) color coordinates of (0.32, 0.37) with a brightness around 350 cd/m 2 and a maximum luminous efficiency of 0.5 cd / A in normal view direction. Under dc conditions the electroluminescence changes almost linearly with the applied voltage with no noticeable change in color coordinates. The ac electrical measurements show the relaxation frequencies in order of a hundred of kH and can be correlated with the parallel RC models associated to the emissive organic layer. The simulated electrical behavior shows a good balanced contribution for the two active layer emitters.