Phosphorescent Polymer Light-Emitting Devices Doped with Red Iridium (III) Bis(2-phenyl-Isoquinoine)(2-acetyl-cyclohexane) Complex

Abstract

Devices with a configuration of ITO/PEDOT/Ir-PIQCH (10 wt%) in Polymer/BAlq (30 nm)/Alq3(20 nm)/LiF (1 nm)/Al (120 nm) were fabricated. In the emitting layer, three different polymers, poly(N-(2-ethyhexyl)-3,6-dibromocarbazole-alt-aniline) (P(3,6-EHCZ-alt-Al)) ( 1 ), poly(bis[6-bromo-N-(2-ethylhexyl)-carbazole-3-yl-alt-aniline] (P(Bis-EHCZ-alt-Al)) ( 2 ) and poly(N-(2-ethyhexyl)-2,7-dibromocarbazole-alt-aniline) (P(2,7-EHCZ-alt-Al)) ( 3 ) were used as a host material, respectively, and new cyclometalated red phosphorescent iridium complex with phenyl-isoquinoline and 2-acetyl-cyclohexanone ligands (Ir-PIQCH) was employed as a guest material. Surface morphology of thin emitting films fabricated by spin-coating from the dilute solution was studied by using 3D optical analyzer. The average roughness of the surface was measured in the range of 1-2 nm to show the films uniformly formed. From the electroluminescent measurement, a red electrophosphorescence was observed with emission peak at approximately 620 nm, 624 nm or 632 nm for Ir-PIQCH doped P(3,6-EHCZ-alt-Al) ( 1 ), Ir-PIQCH doped P(Bis-EHCZ-alt-Al) ( 2 ) or Ir-PIQCH doped P(2,7-EHCZ-alt-Al) ( 3 ) device.