13‐4: Closing the Reliability Gap between Blue and Green Phosphorescent Organic Light‐emitting Devices using the Double‐sided Polaritonenhanced Purcell Effect

Short operational lifetime of blue phosphorescent organic lightemitting diodes (PHOLEDs) is one of the greatest challenges in organic electronics. The polariton‐enhanced Purcell (PEP) effect has recently been introduced to extend the lifetime of blue PHOLEDs. Here, we introduce the polariton‐enhanced Purcell effect from both the anode and cathode contacts to achieve the 10X absolute device lifetime enhancement in tandem blue PEPPHOLEDs. With color saturation due to microcavity effects, we show that tandem blue PEP‐PHOLEDs achieve a lifetime of 1800 ± 100h, effectively closing the gap between the lifetime of efficient green and deep‐blue PHOLEDs.