Air-Stable Highly Sensitive Self-Assembled P3HT/GQD Nanocomposite-Based Organic Thin-Film Transistor for Multiparametric HS Real-Time Detection at Room Temperature

This article demonstrates the highly selective and responsive room temperature (RT = 25 °C) operated hydrogen sulfide (
$\text{H}_{{2}}\text{S}$
) gas sensor based on poly(3-hexylthiophene-2,5-diyl) (P3HT)/graphene quantum dot (GQD) nanocomposite as a sensing surface. The GQD has an average size of ~2 nm that is randomly distributed over the P3HT film and enhances the charge transfer mechanism and the surface area/volume (
${S}/{V}$
) ratio of the sensing surface, which incorporates quick and highly responsive
$\text{H}_{{2}}\text{S}$
sensing. The sensing film has been developed on a SiO2-coated
$\text{p}^{++}$
Si substrate by solution-processed floating-film transfer (FTM) method, and the multiparameters of the fabricated sensor have been investigated with varying
$\text{H}_{{2}}\text{S}$
gas concentrations in the range of 0–25 ppm. To investigate the effect of the GQD in the polymer matrix, the sensing performance of the pristine P3HT-based organic thin-film transistor (OTFT) has been compared to P3HT/GQD nanocomposite-based OTFT. The P3HT/GQD-based OTFT has better sensing responses of ~91% at 25 ppm over pristine P3HT-based OTFT 30% at 25 ppm. The enhanced sensing performance of the nanocomposite matrix (P3HT/GQD) is attributed to an improved charge carrier transfer mechanism due to GQD over the pristine P3HT-based OTFT.