Device structure of the top-emitting OLEDs studied. MeO-TPD is used as organic capping layer.
Current efficiency vs luminance of the top-emitting OLEDs with capping layer thicknesses of 0, 27, 58, 75, 90, 103, 124, 151, and , respectively.
Calculated transmittance , reflectance , and absorptance of the top contact stack (shown in the inset) at a wavelength of depending on the capping layer thickness using a transfer matrix method. The thickness of the organic layer is assumed to be infinite and the refractive index of both the organic layer and the organic capping layer at the wavelength of is determined by a method described in Ref. 16. The scattered solid dots represent current efficiency at of the top-emitting OLEDs studied.
Normalized EL spectra of devices with different capping layer thicknesses. The PL spectrum of is shown as a reference.
EL intensity (radiation) vs the observation angle for top-emitting OLEDs with capping layer thicknesses of 0, 27, 75, 97, 103, 124, and , measured at .
EL spectra at various viewing angles depending on the capping layer thicknesses: 0 (a), 75 (b), 103 (c), and (d). EL intensity data are normalized to the case of forward direction.
Performance data of the devices with selected capping layer thickness.
Article metrics loading...
Full text loading...