Stack design of OLEDs with high performance and simplified device structures

The increasingly complex layer structure of commercial Organic Light Emitting Devices (OLEDs) leads to higher manufacturing costs. In this paper, we demonstrate a simplified device structure with only two layers between the anode and the emissive layer, compared with the usual three or four layers in state‐of‐the‐art devices. The stack is designed so as to ensure efficient hole injection and transport. As a result, the devices achieve longer lifetime and higher efficiency, than the more complex structure, while maintaining equivalent chromaticity and a comparable operating voltage. Such a performance trend is observed in all three RGB colors, in both bottom and top emission devices, as well as in tandem devices. Fewer layers help cost‐effective mass production, and we demonstrate that such simplified device structure has a great potential in both OLED display and lighting applications. Simplified OLED device structures, with longer lifetime and higher efficiency while maintaining equivalent chromaticity and a comparable operating voltage, have been explored here. The excellent performance with the simplified OLED device is achieved with a combination of a deep highest occupied molecular orbital (HOMO) hole‐transport material and a novel deep lowest unoccupied molecular orbital (LUMO) p‐dopant.