Top-gate type, ambipolar, phosphorescent light-emitting transistors utilizing liquid-crystalline semiconducting polymers by the thermal diffusion method

In order to obtain phosphorescent emission from organic field-effect transistors, thermal diffusion of a phosphorescent dye at the interface between the active layer and gate insulator was controlled by utilizing the fact that liquid-crystalline semiconducting polymers self-organize due to reorientation of the molecules and increase in the size of the crystalline regions during thermal annealing. For top-gate type devices using poly(alkylfluorene) doped with a red emissive phosphorescent material, ambipolar characteristics and red emission from the phosphorescent material were clearly observed. We demonstrate the possibility of producing phosphorescent organic light-emitting transistors using a liquid-crystalline semiconducting polymer doped with phosphorescent emissive dopants by the thermal diffusion method.

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► Transistors based on liquid-crystalline semiconducting polymers.
► Semiconducting polymer doped with emissive dopants by the thermal diffusion method.
► A top-gate structure was employed for organic light-emitting transistors.
► Ambipolar characteristics and red emission from the phosphorescent material were achieved.