A Low Voltage, Self-Oriented Organic Polymer Nanocomposite-Based Flexible TFT for Ammonia Gas Sensing at Room Temperature

This study includes the fabrication and characterization of a novel, low-voltage, flexible organic thin film transistor (OTFT) for ammonia sensing at room temperature (RT 25 degrees C). The device fabrication process uses a hybrid (inorganic oxide/polymer) dielectric layer as a gate oxide and a polymer/2-D nanocomposite as an active layer. The UV-cured synthesized hybrid dielectric layer of ZrOx/poly(methyl methacrylate) (PMMA)/poly melamine co-formaldehyde (PMCF) passes with a very smooth film (rms roughness-0.388 nm) (thickness-55 +/- 4 nm), the high areal capacitance of 310 nF/cm(2), a dielectric constant of similar to 20, low leakage current density of similar to 10(-9) A/cm(2) at -2 V, and a high band gap of 5.27 eV. A uniform thickness of 35 +/- 4 nm polymer nanocomposite layer, deposited by the solution-casted floating film transfer (FTM) technique, has been used to investigate the electrical characteristics of the flexible sensor in terms of I/V plot, subthreshold swing (SS), mobility, etc. The bending test of the device has been performed over the curved holder and shows a reliable performance with solution-processed hybrid dielectric and polymer nanocomposite film. Using polymer/2-D nanocomposite material as a sensing layer offers a low detection limit of 500 ppb, a sensing response of 69%, and a fast response/recovery time of 4 +/- 0.5/36 +/- 4 s over 20 ppm ammonia gas. The fabricated flexible device, therefore, has a potential application in the area of low voltage operated OTFT for ammonia sensing application.

Automated summary

This study focuses on the fabrication and characterization of a low-voltage, flexible organic thin film transistor (OTFT) for ammonia sensing. The device utilizes a hybrid dielectric layer and a polymer/2-D nanocomposite as the gate oxide and active layer respectively. The results show that the fabricated device has good electrical characteristics and can detect ammonia gas at low concentrations.