Highly efficient white light with sharp red–green–blue emissions from iridium complexes doped carbazole-grafted poly(para-phenylene)

We demonstrated a high-efficiency white polymer light-emitting diode (WPLED) based on carbazole-grafted poly(para-phenylene) (CzPPP) doped with green- and red-emitting Ir complexes as the emitting layer. The device exhibits pure white light yet with stable sharp blue (430 nm), green (512 nm), and red (613 nm) emissions and has the maximum current and external quantum efficiencies of 16.8 cd/A and 8.65%, respectively. The overall performance is resulted from the excellent shielding effect of CzPPP host to prevent back transfer of triplet energy especially from the green phosphor.