Development of high-performance flexible and stretchable sensor based on secondary doped PEDOT–PSS:TiO2 nanocomposite for room-temperature detection of nitric oxide

The development of smart sensors towards monitoring health and environmental has been receiving growing attention in the recent past. In particular, development of wearable, flexible, stretchable, and semitransparent sensors are desirable for modern technological applications. In this work, we present a simple strategy towards preparation of highly flexible and stretchable composite sensors based on poly (3,4-ethylenedioxythiophene: poly(styrene sulfonic acid)) (p-PEDOT–PSS) and titanium dioxide (n-TiO2) treated with diethylene Glycol (DEG) using a simple bar coating technique. The surface morphology, distribution of TiO2 nanoparticles, thermal stability, and various functional groups present in the composite were characterized by SEM, TEM, TGA, and FT-IR techniques. Presence of TiO2 and DEG treatment in PEDOT–PSS enhances the electrical conductivity (2 S/cm to 515 S/cm) and mechanical stability of the composite films. This ultra-sensitive, highly flexible, and stretchable thin layer of PEDOT–PSS:TiO2 treated with (DEG) was employed as a resistive sensor for the detection of Nitric Oxide (NO) (1–250 ppm) at room temperature. These ultra-sensitive nanocomposite films exhibit a sensitivity of 96% (@ 250 ppm) with excellent sensitivity retention under mechanical deformations such as bending and stretching. For the first time, this report presents the simultaneous determination of conductivity and NO-sensing performance of rolled and stretched sensing films based on conductive PEDOT–PSS composites. Owing to its low-cost fabrication, excellent conductivity, high sensitivity under mechanical deformations and long-term stability, the composite films studied in this work could potentially be used as a wearable and flexible gas sensor in organic electronics towards detection of NO gas.