OFET based explosive sensors using diketopyrrolopyrrole and metal organic framework composite active channel material

Detection of explosives using organic compounds poses many challenges, primarily because of the stability of the organic compound at nominal operating conditions. This paper addresses the aforementioned challenge by reporting a new organic material composite, whose stability is suitable for practical applications. Additionally, the reported organic composite is also capable of detecting vapors of Nitro based explosive compounds such as 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX). An alternating copolymer of thiophene flanked diketopyrrolopyrrole with thienylene-vinylene-thienylene (PDPP-TVT) was used as a solution processable and spin coatable organic semiconductor active channel material for the organic field effect transistor (OFET) sensor. A composite of PDPP-TVT and metal organic framework (MOF) was used as a receptor and pre-concentrator sites for sensing of the explosive analytes. The sensor devices were characterized and the receptor sites were confirmed by the Fourier Transform Infrared Spectroscopy (FTIR) and atomic force microscopy (AFM). The detection of viable analytes is recognized by the percentage change in the saturated drain current (%ΔIDsat) obtained by the current (I)–voltage (V) characteristics with and without the analyte. The corresponding %ΔIDsat recorded for nitrobenzene (NB), dinitrobenzene (DNB), nitromethane (NM), TNT and RDX are −7%, 2%, 24%, 81% and 50%, respectively.