We demonstrate high efficiency red organic light-emitting diodes
(OLEDs) based on a planar microcavity comprised of a dielectric mirror
and a metal mirror. The microcavity devices emitted red light at a peak
wavelength of 610 nm with a full width at half maximum (FWHM) of 25 nm
in the forward direction, and an enhancement of about 1.3 factor in
electroluminescent (EL) efficiency has been experimentally achieved
with respect to the conventional noncavity devices. For microcavity
devices with the structure of distributed Bragg reflectors
(DBR)/indium-tin-oxide(ITO)/V2O5/N,N' -di(naphthalene-1-yl)-N,N' -diphenyl-benzidine(NPB)/4-(dicy-anome-thylene)-2-t-butyl-6(1,1,7,7-tetrame-thyljulolidyl-9-enyl) -4H-pyran(DCJTB):tris(8-hydroxyquinoline)aluminium(Alq3)/Alq3/LiF/Al, the maximum brightness arrived at
37000 cd/m2 at a current density of 460.0 mA/cm2, and the
current efficiency and power efficiency reach 13.7 cd/A at a current
density of 0.23 mA/cm2 and 13.3 lm/W at a current density of
0.04 mA/cm2, respectively.