Small Molecular White Organic Light Emitting Devices with Single Emission Zone

Abstract

An organic white-light-emitting device has been demonstrated by mixing two colors from a single emissive layer. The device structure included indium tin oxide glass (ITO) substrate/30 nm 4,4',4''-tris{N,-(3-methylphenyl)-N-phenylamino}triphenylamine (m-MTDATA) as hole injection layer/10 nm N,N-diphenyl-N,N-bis1-naphthy l-1,1-biphenyl-4,4-diamine (NPB) as hole transparent layer/30 nm bis [2-(2-hydroxyphenyl)-pyridine]beryllium (Bepp2) doped with 0.2% rubrene as emitting layer/40 nm tris-8-hydroxyquinoline aluminum (Alq3) as electron transport layer/0.8 nm LiF/aluminum (Al). A stable white emission Commission Internationale de 1'Eclairage (CIE) chromaticity coordinate range from (0.38, 0.36) to (0.31, 0.31) for forward bias voltage which changing from 6 to 17 V has been achieved. Its maximum luminance was 29000 cd/m2 at 15v, and the maximum power and current efficiencies were 3.0 lm/W at 5 V and 6.3 cd/A at 7 V, respectively.