Improving Blue Organic Light Emitting Diode Efficiency and Reliability using Purcell Effect-enhanced Tandem Emitters

In recent years, organic light emitting diodes (OLEDs) have become ubiquitous, particularly in mobile display applications, such as smart watches and phones. While OLEDs have many desirable properties, including high color-rendering, high luminous efficacy, and flexibility, the presence of high energy triples in blue phosphorescent emitters can be detrimental to the operational lifetime of the device. Recently, experimental evidence has emerged to support the theory that using the Purcell effect to decrease the radiative lifetime of high energy triplets can improve the device operational lifetime by more than a factor 4. In this work, we use optical design to integrate a tandem blue OLED structure into a Purcell effect-enhanced cavity structure. With the increased luminance provided by the tandem structure and the lifetime enhancement provided by the Purcell effect, we demonstrate approximately a factor of three enhancement, compared to a Purcell effect-enhanced device with a single emissive layer, without sacrificing deep blue color quality.