Abstract
In this work, we have investigated the visible light assisted gas sensing properties of multiwalled carbon nanotubes (MWCNTs) functionalized with two organic molecules namely pyrene tetratopic ligands (PTL), and 1-pyrene acetic acid (PAA). Structural, optical and electrical properties have been examined on pure and functionalized samples using FESEM, Raman spectroscopy, UV–Visible spectroscopy, Photoluminescence (PL) spectroscopy, and current -voltage (I–V) characteristics. Sensor devices have been fabricated and tested in a gas sensor setup by passing saturated vapours of different VOCs like ethanol, n-hexane and triethylamine under dark and visible light conditions. Scanning Kelvin probe (SKP) studies have demonstrated that pyrene-MWCNTs hybrids significantly alter the contact potential difference upon interaction with volatile organic compounds (VOCs) and the response depends on the functional groups. The PTL+MWCNTs (sensitivity = 9.99 × 10−4 ppm−1) hybrid has outperformed when compared to PAA functionalized counterparts (sensitivity = 2.27 × 10−5 ppm−1) with triethylamine exposure. The presence of additional –COOH groups in PTL furnishes strong intermolecular hydrogen bonding through donor-acceptor interactions with the VOCs. Overall, our results suggests that the MWCNTs coated with pyrene molecules bearing suitable functional groups can be efficient sensors for detection of VOCs
