Achieving a Good Life Time in a Vertical-Organic-Diode Gas Sensor

Sensors

Ming-Zhi Dai¹  Yen-Ho Chen¹  Ming-Yen Chuang²  Hsiao-Wen Zan² 

[1] Institute of Physics, National Chiao Tung University, Hsinchu 300, Taiwan; E-Mails:;Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 300, Taiwan; E-Mail:

关键词: ammonia;    gas sensor;    polythiophene;    solid-state sensors;   

DOI  :  10.3390/s140916287

来源: mdpi

【 摘 要 】

In this study, we investigate the keys to obtain a sensitive ammonia sensor with high air stability by using a low-cost polythiophene diode with a vertical channel and a porous top electrode. Poly(3-hexylthiophene) (P3HT) and air-stable poly(5,5′-bis(3-dodecyl-2-thienyl)-2,2′-bithiophene) (PQT-12) are both evaluated as the active sensing layer. Two-dimensional current simulation reveals that the proposed device exhibits numerous connected vertical nanometer junctions (VNJ). Due to the de-doping reaction between ammonia molecules and the bulk current flowing through the vertical channel, both PQT-12 and P3HT VNJ-diodes exhibit detection limits of 50-ppb ammonia. The P3HT VNJ-diode, however, becomes unstable after being stored in air for two days. On the contrary, the PQT-12 VNJ-diode keeps an almost unchanged response to 50-ppb ammonia after being stored in air for 25 days. The improved storage lifetime of an organic-semiconductor-based gas sensor in air is successfully demonstrated.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.