## 3 Calculation Results
This out-of-phase difference of maximum and minimum intensities between horizontally and vertically oriented dipoles is ascribed to the combined effects of the phase difference induced by the Ag metal anode and the initial phase relation of the emitted electric fields [39]. On the other hand, the TM-polarized relative radiative power coupled to the SP modes steadily increases as the dipole emitter moves from the middle of the EML (\(z_{\textit{ex}}\) = 125 nm) to the bottom (\(z_{\textit{ex}}\) = 0 nm) or top (\(z_{\textit{ex}}\) = 250 nm) EML/Ag interface in both horizontal and vertical dipole orientations. In Figure 5a,b, the relative radiative power coupled to the NF absorption is extremely small at the middle of the EML (\(z_{\textit{ex}}\) = 125 nm). As the dipole emitter shifts toward the EML/Ag interfaces, the relative radiative power coupled to the NF absorption dramatically increases. When the distance between the dipole emitter and the EML/Ag interface is less than 10 nm, the relative radiative power coupled to the NF absorption becomes predominant over the other optical modes and the relative radiative power coupled to the NF absorption converges to the total relative radiative power. These calculation results indicate that the contribution of the NF absorption should be considered in the analysis of the exciton power dissipation when the dipole position is close to the dielectric/metal interface. In addition, we find that the relative radiative power coupled to the NF absorption becomes minimized at the middle of two organic/metal interfaces in the top-emitting OLED, which is different from the previous result that the relative radiative power coupled to the NF absorption keeps decreasing as the dipole emitter moves away from a single organic/metal interface [18]. On the other hand, it is noticeable that the relative radiative power coupled to the NF absorption is symmetric in reference to the middle of two organic/metal interfaces, as shown in Figure 5. This is ascribed to the fact that the 250-nm Alq\({}_{3}\) EML is sandwiched between the same metallic materials of the 100-nm Ag bottom anode and the 37-nm Ag semi-transparent top cathode, although their respective thicknesses are different in the device structure of the top-emitting OLED in \[F_{\parallel,\text{WG}}^{\text{TE}}=\int_{u_{crit}}^{\infty}K_{\parallel}^{\text{TE} }(u)du^{2}=\int_{u_{crit}}^{\infty}K_{\parallel}^{\text{TE}}(u)udu, \tag{34}\]0 However, this symmetric relative radiative power pattern of the NF absorption cannot be observed if the refractive indices of the materials sandwiching the EML are different. Randomly patterned nanostructured metallic electrodes have been applied to OLEDs with the micro-cavity effect alleviated, which enables the broadband and angle-independent out-coupling enhancement of the WG mode with minimized surface plasmonic loss [40, 41]. As our theoretical model of the NF absorption is applicable to and intended for OLEDs with planar metallic electrodes, it will not be directly applied to OLEDs with randomly patterned metallic electrodes. Similarly to solar cells with a randomly patterned metallic nanostructure [42], the localized SP mode will be excited in OLEDs with randomly patterned metallic electrodes, of which the theoretical calculation will be able to be performed through numerical simulations such as the finite-difference time domain. In the case of transparent OLEDs with thin metallic electrodes [43], the excitation intensity of the SP mode will decrease because a part of the light will pass through the other electrode without strong light reflection and move back to the thin metallic electrode. According to the calculation results in Figure 5, the relative radiative power coupled to the NF absorption is proportional to that coupled to the SP modes. Thus, the total relative radiative power of the NF absorption and its influence will decrease in the case of transparent OLEDs.