China makes new progress in the research of organic field-effect transistors

OFETs are the most important unit devices in the future of organic electronics. Because of their simple preparation process, low cost, and flexibility, they have broad prospects in applications such as smart cards, electronic trademarks, electronic paper, memory, sensors, and active matrix displays. . At present, the research of organic-based semiconductor material-pentacene field-effect transistor has made great progress. Its main technical indicators, mobility and switching ratio have basically reached the application requirements. However, there are also disadvantages such as high pinch-off voltage and difficulty in controlling the threshold voltage.

Polyvinyl carbazole (PVK) is a commonly used polymer host material in organic optoelectronic devices, with excellent film formation, good carrier storage capacity, and wide band gap. In this study, 20 nm thick PVK films were used as buffer layers to modify the pentacene-SiO2 interface to prepare pentacene OFETs. The results show that the addition of PVK buffer layer significantly improves the device mobility and switching ratio (mobility is about 0.5cm2/V s, and the switching ratio is about 107); at the same time, the pinch-off voltage of the device (the pinch-off voltage of the device) is significantly reduced. The absolute value is less than 20V). It has also been found that the start gate voltage can change the number of carriers stored in the PVK buffer layer, thereby realizing the regulation of the threshold voltage of the device by the start gate voltage in a single device.