Figure 1: Schematic illustrations of iPLED devices.
From: Highly efficient inverted polymer light-emitting diodes using surface modifications of ZnO layer

The insets illustrate the chemical structures of the emissive layer, F8BT, and the interfacial layer, 2-ME+EA, as well as the detailed surface structure of ZnO-R. (a,b) Device architectures of iPLEDs with (a) ZnO-F and (b) ZnO-R.