Development of an electronic nose based on thin film organic transistors (OTFTs) for the detection of 2-methylisoborneol (MIB) and geosmin (geo)

Abstract

The electronic nose is a non-specific multisensory system complementary to the liquid phase system. The literature describes results with chemical sensors for MIBs based on MIPs with gas phase measurements, but the performance of such devices can be compromised by the low concentrations of MIB and GEO that must be detected in the air. In this context, Organic Thin-Film Transistors (OTFTs), although not yet applied to the MIB and GEO sensing, are characterized by a potential increase in the detection limit when compared to the sensors chemicals. Its sensory potential has been demonstrated for volatile organic solvents such as alkanes, alcohols, esters, ketones and nitriles, as well as gases such as moisture, ammonia and carbon dioxide. The main difference in relation to the chemical sensor is in the gate electrode, responsible for the accumulation of charges in the region of the electric conduction channel formed between the source and drain electrodes, and consequently the control of the resistance of the same. The active layer of these devices can be obtained from polymers used in chemical sensors, in addition to semiconductors already established for application in OTFTs, such as derivatives of poly (para-phenylene vinylene) (PPV), polythiophene (PT), oligothiophenes and benzenes .