Efficient simple structure red phosphorescent organic light emitting devices with narrow band-gap fluorescent host

Abstract

Using a narrow band-gap fluorescent host material, bis(10-hydroxybenzo[h] quinolinato)beryllium complex, efficient red phosphorescent organic light emitting diodes (PHOLEDs) comprising two layers have been reported. Significantly low driving voltage of $4.5\mathrm{V}$ to reach a luminance of $1000\mathrm{cd}∕{\mathrm{m}}^2$ is reported in this simple structure PHOLEDs. The current and power efficiencies of bilayered red PHOLED are $9.66\mathrm{cd}∕\mathrm{A}$ and $6.90\mathrm{lm}∕\mathrm{W}$ , respectively, promising for low power display and lighting applications.