Modulation of interfacial properties for low-voltage operated organic thin-film transistors

ShengKuang Peng^1*, WeiYang Chou¹

¹Department of Photonics, National Cheng Kung University, Tainan, Taiwan

* Presenter:ShengKuang Peng, email:L78041169@mail.ncku.edu.tw

The properties of interface within OTFTs are highly correlated with the electrical performance of devices. In this study, we proposed an effective method to modulate interfacial properties between dielectric and active layers to manipulate electrical performance of organic thin-film transistors (OTFTs). The OTFTs were composed of N,N’-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13H27) as the semiconducting layer and aluminum oxide as the dielectric layer. Various solid contents of polyimide (PI) solutions (1.6%, 3.2%, 4.7%, and 6.3%) were spin-coated onto the aluminum oxide to act as the modification layer. The OTFT devices with the PI layer from 6.3% solution have fewer trap states and their drain current increases dramatically during continuous operation. Under continuous operation, the PI layer formed from high solid content solution could generate a strong gate- field-induced dipole moment. Thus, few trap states and strong dipole moment facilitated charge accumulation to increase the drain current of the devices. Accordingly, the performances of OTFTs can be controlled by the solid content of PI solution in PI modification layer. This simple and effective method shows a great potential for controlling device performances and applying in other organic devices.

Keywords: polyimide, organic thin-film transistor, solid content, trap states, dipole moment