Organic Semiconductor Material Featuring 4-Ethylbenzoyl-3-(4-ethynylbenzonitrile-phenyl)-thiourea (CYT-1) of Donor-π-acceptor for Chemiresistive Carbon Dioxide (CO2) Sensing

In this work, a new member of acetylide-thiourea namely 4-ethylbenzoyl3-(4-ethynylbenzonitrile-phenyl)-thiourea (CYT-1) was successfully designed, synthesised, and characterised by nuclear magnetic resonance (NMR) analysis. In turn, CYT-1 acting as sensor was fabricated onto interdigitated electrodes (IDEs) by drop-casting method. The performance of CYT-1 on reaction response and sensitivity characteristics towards carbon dioxide (CO2) as chosen gas was measured at different CO2 concentration (10-1000 ppm) for 30 min of time exposure. The investigation was carried out at room temperature via studying the changes in resistivity measurement before and upon CO2 exposure. The unique molecular characteristic of CYT-1 is due to the presence of two potential active sites of -NH-C=O and acetylide -C=C- for H-bonding and π-π interaction to take place between molecule and CO2 analyte.