Blue Organic Electrophosphorescence Diodes using Diarylamino-substituted Heterocyclic Compounds as Host Material

摘要

Diarylamino-substituted heterocyclic compounds(DHCs),2,6-dicarbazolo-l,5-pyridine(PYD2)and 2,4,6-tricarbazolo-l,3,5-pyrimidine(PYM3),possess a high triplet energy level(T_1)of T_1= 2.93 eV(PYD2)and T_1= 2.89 eV(PYM3),respectively,in their solid state films.6wt%-Iridium(III)bis[(4,6-di-fluorophenyl)-pyridinato-N,C~2]picolinate(FIrpic):PYD2-and 6wt%-FIrpic:PYM3-doped films showed high photoluminescence(PL)efficiencies of PHI_(PL)= 88±2 % and PHI_(PL)= 80 ± 1 %,indicating near perfect confinement of FIrpic triplet excitons.By increasing the FIrpic concentration in DHC hosts,lower driving voltage and higher external electroluminescence(EL)quantum efficiencies(eta~(EL))were observed,indicating enhancement of electron injection and transport(electron current)in these emitting layers.