Abstract
With its excellent mechanical flexibility, low-cost and low-temperature processing, the solution processed organic field-effect transistor (OFET) is a promising platform technology for developing ubiquitous sensor applications in digital health, environment monitoring and Internet of Things. However, a contradiction between achieving low voltage operation and having stable performance severely hinder the technology to become commercially viable. This work shows that, by reducing the sub-gap density of states (DOS) at the channel for low operation voltage and using a proper low-k non-polar polymer dielectric layer, such an issue can be addressed. Stable electrical properties after either being placed for weeks or continuously prolonged bias stressing for hours in ambient air are achieved for all solution processed unencapsulated OFETs with the channel being exposed to the ambient air for analyte detection. The fabricated device presents a steep subthreshold swing less than 100 mV/decade, and an ON/OFF ratio of 106 at a voltage swing of 3 V. The low voltage and stable operation allows the sensor made of the OFET to be incorporated into a battery-powered electronic system for continuously reliable sensing of ammonia vapor in ambient air with very small power consumption of about 50 nW.
Highlights
In the last decades, remarkable progresses have been made on development of high mobility soluble organic semiconductors[16,17], and solution or printing based fabrication techniques to develop a commercially competitive manufacturing approach for OFETs18–20
For organic field-effect transistor (OFET) in an unencapsulated structure, the channel layer is exposed to the ambient air
This work shows that, based on this material system to reduce the operation voltage, the contradiction between achieving low voltage operation and having stable device performance can be addressed for all solution processed OFETs by selecting a low-k non-polar polymer dielectric layer
Summary
Linrun Feng*, Wei Tang*, Jiaqing Zhao, Ruozhang Yang, Wei Hu, Qiaofeng Li, Ruolin Wang & Xiaojun Guo. A contradiction between achieving low voltage operation, and having stable device performance severely hinder solution processed OFETs to become commercially viable for the targeted ubiquitous sensor applications. Our previous study reveals that, it is feasible to reduce the effective sub-gap DOS at the channel through blended solution of small molecule organic semiconductor and insulating polymer binder, and OFETs of steeper S can be realized for low voltage operation with less strict requirements on the capacitance of gate dielectric layer[39,40,41,42]. This work shows that, based on this material system to reduce the operation voltage, the contradiction between achieving low voltage operation and having stable device performance can be addressed for all solution processed OFETs by selecting a low-k non-polar polymer dielectric layer. The power consumption of the OFET sensor tag is as low as 50 nW
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
