Harvesting Triplet Excitons in High Mobility Emissive Organic Semiconductor for Efficiency Enhancement of Light-emitting Transistors.

Organic light-emitting transistors (OLETs), a kind of highly integrated and minimized optoelectronic devices, demonstrate great potential applications in various fields. The construction of high performance OLETs requires the integration of high charge carrier mobility, strong emission, and high triplet exciton utilization efficiency in the active layer. However, it remains a significant long-term challenge, especially for single component active layer OLETs. Herein, we demonstrate the successful harvesting of triplet excitons in a high mobility emissive molecule, 2,6-diphenylanthracene (DPA), through triplet-triplet annihilation (TTA) process. By incorporating a highly emissive guest into DPA host system, an obvious increase of photoluminescence efficiency along with exciton utilization efficiency results in an obvious enhancement of external quantum efficiency with 7.2 times for OLETs compared to the non-doped devices. Moreover, well-tunable multi-color electroluminescence, especially white emission with CIE of (0.31, 0.35), from OLETs are also achieved by modulating the doping concentration with controlled energy transfer process. This work opens a new avenue for integrating strong emission and efficient exciton utilization in high mobility organic semiconductors for high performance OLETs and advancing their related functional device applications. This article is protected by copyright. All rights reserved.