Achieving a good life time in a vertical-organic-diode gas sensor.
Sensors (Basel)
; 14(9): 16287-95, 2014 Sep 02.
Article
in En
| MEDLINE
| ID: mdl-25184492
ABSTRACT
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.
Full text:
1
Database:
MEDLINE
Main subject:
Semiconductors
/
Thiophenes
/
Organoselenium Compounds
/
Conductometry
/
Gases
/
Ammonia
Language:
En
Year:
2014
Type:
Article