Improving the Performance of Red Organic Light-Emitting Transistors by Utilizing a High-k Organic/Inorganic Bilayer Dielectric

Integration of electrical switching and light emission in a single unit makes organic light-emitting transistors (OLETs) highly promising multifunctional devices for next-generation active-matrix flat-panel displays and related applications. Here, high-performance red OLETs are fabricated in a multilayer configuration that incorporates a zirconia (ZrOx)/cross-linked poly(vinyl alcohol) (C-PVA) bilayer as a dielectric. The developed organic/inorganic bilayer dielectric renders high dielectric constant as well as improved dielectric/semiconductor interface quality, contributing to enhanced carrier mobility and high current density. In addition, an efficient red phosphorescent organic emitter doped in a bihost system is employed as the emitting layer for an effective exciton formation and light generation. Consequently, our optimized red OLETs displayed a high brightness of 16 470 cd m(-2) and a peak external quantum efficiency of 11.9% under a low gate and source-drain voltage of -24 V. To further boost the device performance, an electron-blocking layer is introduced for ameliorated charge-carrier balance and hence suppressed exciton-charge quenching, which resulted in an improved maximum brightness of 20 030 cd m-2. We anticipate that the new device optimization approaches proposed in this work would spur further development of efficient OLETs with high brightness and curtailed efficiency roll-off.

Automated summary

The integration of electrical switching and light emission in organic light-emitting transistors (OLETs) makes them highly promising for next-generation active-matrix flat-panel displays and related applications. This study focuses on fabricating high-performance red OLETs with a multilayer configuration and a bilayer dielectric that provides a high dielectric constant and improved interface quality. The use of an efficient red phosphorescent organic emitter as the emitting layer enhances exciton formation and light generation. The optimized OLETs exhibited high brightness and peak external quantum efficiency.