Selective Ammonia-Sensing Platforms Based on a Solution-Processed Film of Poly(3-Hexylthiophene) and p-Doping Tris(Pentafluorophenyl)Borane.

Alem Araya Meresa,Felix Sunjoo Kim

doi:10.3390/polym12010128

Abstract

Here, we fabricate ammonia sensors based on organic transistors by using poly(3-hexylthiophene) (P3HT) blended with tris(pentafluorophenyl)borane (TPFB) as an active layer. As TPFB is an efficient p-type dopant for P3HT, the current level of the blend films can be easily modulated by controlling the blend ratio. The devices exhibit significantly increased on-state and off-state current levels owing to the ohmic current originated from the large number of charge carriers when the active polymer layer contains TPFB with concentrations up to 20 wt % (P3HT:TPFB = 8:2). The current is decreased at 40 wt % of TPFB (P3HT:TPFB = 6:4). The P3HT:TPFB blend with a weight ratio of 9:1 exhibits the highest sensing performances for various concentrations of ammonia. The device exhibits an increased percentage current response compared to that of a pristine P3HT device. The current response of the P3HT:TPFB (9:1) device at 100 ppm of ammonia is as high as 65.8%, 3.2 times that of the pristine P3HT (20.3%). Furthermore, the sensor based on the blend exhibits a remarkable selectivity to ammonia with respect to acetone, methanol, and dichloromethane, owing to the strong interaction between the Lewis acid (TPFB) and Lewis base (ammonia).

Highlights

The fabrication of chemical detectors has attracted considerable attention owing to their applications in health and environmental monitoring [1,2,3,4,5,6]
In terms of sensing capability, chemical sensors based on organic field-effect transistors (OFETs) are a very promising platform [1,2,3,4,5,6]
As both components are well soluble in common organic solvents, e.g., chloroform, a thin film of the P3HT:TPFB blend can be deposited onto a substrate, which enables the use of the

Summary

Introduction

The fabrication of chemical detectors has attracted considerable attention owing to their applications in health and environmental monitoring [1,2,3,4,5,6]. In terms of sensing capability, chemical sensors based on organic field-effect transistors (OFETs) are a very promising platform [1,2,3,4,5,6]. They directly transduce the chemical signal into an electrical signal, unlike other types [8,9,10,11,12,13,14,15]. Owing to the gate-induced signal amplification, OFET-based sensors are more scalable and sensitive than their resistor-based counterparts [16,17,18,19]

Methods

Results

Conclusion