Efficient small molecular and polymer organic devices using bis[2-(4- tert-butylphenyl)benzothiazolato-N,C 2′] iridium (III) (acetylacetonate) dye as emitter

Abstract

Small molecular organic light-emitting diodes (MOLED) and polymer organic light-emitting diodes (POLED) were fabricated with yellow light emission phosphorescent dye bis[2-(4- tert-butylphenyl)benzothiazolato-N,C 2′] iridium (III) (acetylacetonate) doped in different hosts. The electroluminescent (EL) spectra of both devices shown two peaks generated from iridium dye but the position of main peak changed and became broader for POLED. The maximum luminance of 10,500 cd/m 2 achieved at 12.5 V for MOLED is higher than maximum luminance of 9996 cd/m 2 at 20 V for POLED. The maximum power efficiency of small molecular device is 6.4 lm/W, which is higher than 2.3 lm/W of polymer device, but the efficiency of both devices will roll off at large current density.