Air-Stable Highly Sensitive Self-Assembled P3HT/GQD Nanocomposite-Based Organic Thin-Film Transistor for Multiparametric HS Real-Time Detection at Room Temperature<sub/>
Ankit Verma, V. N. Mishra, Rajiv Prakash
Abstract
This article demonstrates the highly selective and responsive room temperature (RT = 25 °C) operated hydrogen sulfide ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{H}_{{2}}\text{S}$ </tex-math></inline-formula> ) 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 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${S}/{V}$ </tex-math></inline-formula> ) ratio of the sensing surface, which incorporates quick and highly responsive <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{H}_{{2}}\text{S}$ </tex-math></inline-formula> sensing. The sensing film has been developed on a SiO2-coated <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{p}^{++}$ </tex-math></inline-formula> Si substrate by solution-processed floating-film transfer (FTM) method, and the multiparameters of the fabricated sensor have been investigated with varying <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{H}_{{2}}\text{S}$ </tex-math></inline-formula> 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.