High‐Efficiency Area‐Emissive White Organic Light‐Emitting Transistor for Full‐Color Display

The construction of high‐performance white organic light‐emitting transistor (OLET) with uniform area emission is crucial for smart display technologies but remains greatly challenging. Herein, high‐efficiency uniform area‐emissive OLETs based on a unique lateral‐integrated device configuration which incorporates efficient energy transfer of phosphorescent and fluorescent guests, enabling color‐tunable and white emission, are demonstrated. Through precisely regulating the energy transfer between host and guests, high external quantum efficiency of 13.9% for white‐emission OLETs is achieved due to the improved high exciton utilization and light outcoupling efficiency which is the highest value reported so far for OLETs and prevents exciton‐charge annihilation and electrode photon losses. Moreover, good loop stability is also achieved, along with effective gate tunability and ultralow driving voltage of below 5 V. Finally, a 4 × 6 white‐emission OLET array for full‐color display is demonstrated for the first time, suggesting its great potential applications for advanced display technologies. Uniform area‐emissive white OLET device with an efficiency of 13.9% is realized by incorporating phosphorescent blue emissive and fluorescent yellow emissive guests in the active layer based on a unique lateral‐integrated device configuration, which is the highest value in the field and demonstrates great potential for full‐color display as backlight source for the first time.