1 Device Architecture Fig. 6a) shows a detailed scheme of the device architecture. On top of the glass substrate, an ITO electrode is located. Then two pin-OLEDs are stacked on top, separated by a wetting layer electrode of only 10 nm metal. Doped layers are given with the corresponding doping ratio. In the case of BPhen:Cs the doping ratio is chosen to achieve a conductivity of 10 − 5 S/cm. Additionally, the electrical connections are indicated in Fig. 6a). Figure 6 | Stack Architecture Detailed scheme of the device architecture. Long names of the materials can be found in the materials section of the main article. Top-electrode Bottom-electrode 1 2 3 4 5 6 7 8 9 10 11 12 13 100nm BPhen:Cs 320nm 1:1 BPhen 10nm NPB: Ir(MDQ)$_{2}$(acac) 20nm 10wt% NPB Spiro-TTB: F6-TCNNQ 40nm 4wt% Ag 2nm Au 8nm 230nm 1:1 NPB:Ir(piq)$_{3}$ 10wt% 20nm 4wt% Al BPhen:Cs BPhen NPB Spiro-TTB: F6-TCNNQ 10nm 10nm 10nm 20nm ITO/Glass a b Solving Maxwell’s equations for the stratified device, one obtains a distribution of the intensity of the electric field. 1, 2 In the simulation used in this contribution the field is, of course, taken into account. The visualization of the location of the emissive layer within this field helps to interpret the out-coupled spectra. As shown in Fig. 6b), the emission layer for side emission is located close to a field minimum at 0 $^{◦}$. By increasing the viewing angle, a local maximum is shifted to the position of the emission layer. Note that for simplicity here the emission zone is assumed to be infinitesimal thin. The emission zone in the forward emission unit faces a local maximum at 0 $^{◦}$, which increases in intensity with increasing viewing angle up to 35 ◦ and only then starts to drop. 2