PTB7 Decorated ZnO-Nanorod-Based Room-Temperature Ammonia Gas Sensor

We demonstrate a poly ([4,8-bis[(2-ethylhexyl) oxy]benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl][3-fluoro-2-[(2-et- hylhexyl)carbonyl]thieno[3,4-b] thiophenediyl]) (PTB7) decorated zinc oxide (ZnO) nanorod-based interdigitated metal–semiconductor–metal (MSM) device as ammonia (NH3) sensor at room temperature. The gas sensor response is 66.92% at 20 ppm and 2 V of bias at ambient temperature (~25 °C). The average roughness and the root-mean-square roughness of the hydrothermally synthesized ZnO nanorods (ZnO NRs) were measured as 0.140 and
$0.175 ~\mu \text{m}$
, respectively. The device was found sensitive at gas concentration as low as ~2 ppm with a response of 7.12%. At a gas flow rate of 20 ppm and a bias of 2 V, the response and recovery times of the as-fabricated device were measured to be 5 and 30 s, respectively.