Color-stable, reduced efficiency roll-off hybrid white organic light emitting diodes with ultra high brightness

摘要

High-brightness and color-stable two-wavelength hybrid white organic light emitting diodes (HWOLEDs)with the configuration of indium tin oxide (ITO)/ N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (MeOTPD):tetrafluoro-tetracyanoqino dimethane (F4-TCNQ)/N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB)/4,4-N,N-dicarbazolebiphenyl (CBP):iridium (Ⅲ) diazine complexes (MPPZ)2Ir(acac)/NPB/2-methyl-9,10-di(2(-)naphthyl)anthracene (MADN):p-bis(p-N,N-di-phenyl-aminostyryl)benzene (DSA-ph)/ bis(10-hydroxybenzo[h] quinolinato)beryllium complex (Bebq2)/LiF/Al have been fabricated and characterized.The optimal brightness of the device is 69932 cd/m2 at a voltage of 13 V,and the Commission Internationale de l'Eclairage (CIE) chromaticity coordinates are almost constant during a large voltage change of 6-12 V.Furthermore,a current efficiency of 15.3 cd/A at an illumination-relevant brightness of 1000 cd/m2 is obtained,which rolls off slightly to 13.0 cd/A at an ultra high brightness of 50000 cd/m2.We attribute this great performance to wisely selecting an appropriate spacer together with effectively utilizing the combinations of exciton-harvested orange-phosphorescence/blue-fluorescence in the device.Undoubtedly,this is one of the most exciting results in two-wavelength HWOLEDs up to now.