52.4: Highly Efficient Single‐Unit White OLED Device with Emission from Both Singlet and Triplet Excitons

We succeeded in developing a single-unit hybrid organic light-emitting diode (OLED) device with efficient light emission from both a phosphorescent layer and a fluorescent layer. The single-unit hybrid OLED achieved power efficiency higher than that of a two-unit hybrid tandem OLED with a phosphorescent and fluorescent layers.