Abstract

A new process for modifying a polymeric material for use as a hole injection transport layer in organic light-emitting diodes has been studied, which is through 2π + 2π photodimerization of a DNA-mimetic π-conjugated poly(triphenylamine-carbazole) presenting pendent uracil groups (PTC-U) under 1 h of UV irradiation. Multilayer florescence OLED (Organic light-emitting diodes) device with the PTC-U-1hr as a hole injection/transport layer (ITO (Indium tin oxide)/HITL (hole-injection/transport layer) (15 nm)/N,N'-di(1-naphthyl)- N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB) (15 nm)/Tris-(8-hydroxyquinoline) aluminum (Alq₃) (60 nm)/LiF (1 nm)/Al (100 nm)) is fabricated, a remarkable improvement in performance (Q_max (external quantum efficiency) = 2.65%, B_max (maximum brightness) = 56,704 cd/m², and LE (luminance efficiency)_max = 8.9 cd/A) relative to the control PTC-U (Q_max = 2.40%, B_max = 40,490 cd/m², and LE_max = 8.0 cd/A). Multilayer phosphorescence OLED device with the PTC-U-1hr as a hole injection/transport layer (ITO/HITL (15 nm)/Ir(ppy)₃:PVK (40 nm)/BCP (10nm)/Alq₃ (40 nm)/LiF (1 nm)/Al (100 nm)) is fabricated by successive spin-coating processes, a remarkable improvement in performance (Q_max = 9.68%, B_max = 41,466 cd/m², and LE_max = 36.6 cd/A) relative to the control PTC-U (Q_max = 8.35%, B_max = 34,978 cd/m², and LE_max = 30.8 cd/A) and the commercial product (poly(3,4-ethylenedioxythiophene):polystyrenesulfonate) PEDOT:PSS (Q_max = 4.29%, B_max = 15,678 cd/m², and LE_max = 16.2 cd/A) has been achieved. View Full-Text