Innovative Approach to Photo-Chemiresistive Sensing Technology: Surface-Fluorinated SnO₂ for VOC Detection

Abstract

Transparent electronics continues to revolutionize the way we perceive futuristic devices to be. In this work, we propose a technologically advanced volatile organic compound (VOC) sensor in the form of a thin-film transparent display fabricated using fluorinated SnO 2 films. A solution-processed method for surface fluorination of SnO 2 films using Selectfluor as a fluorinating agent has been developed. The doped fluorine was optimized to be <1%, resulting in a significant increase in conductivity and reduction in persistent photoconductivity accompanied by a faster decay of the photogenerated charge carriers. A combination of these modified properties, together with the intrinsic sensing ability of SnO 2 , was exploited in designing a transparent display sensor for ppm-level detection of VOCs at an operating temperature of merely 150 °C. Even a transparent metal mesh heater is integrated with the sensor for ease of operation, portability, and less power usage. A sensor reset method is developed while shortening the UV exposure time, enabling complete sensor recovery at low operating temperatures. The sensor is tested toward a variety of polar and nonpolar VOCs (amines, alcohols, carbonyls, alkanes, halo-alkanes, and esters), and it exhibits an easily differentiable response with sensitivity in line with the electrondonating tendency of the functional group present. This work opens up the door for multiplexed sensor arrays with the ability to detect and analyze multiple VOCs with specificity.

Scalable Fabrication of Scratch-Proof Transparent Al/F–SnO2 Hybrid Electrodes with Unusual Thermal and Environmental Stability

“…Such films with minimal sensitivity toward different organic compounds and moisture are highly advantageous in fabricating the multi-layered optoelectronic devices, as they will not change the inherent properties during the layer coatings. Additionally, our previous work shows that fluorine doping reduces the oxygen vacancies in SnO 2 and increases the trap states. This may result in effective charge separation, which is important for an optoelectronic device.…”

“…For SnO 2 fluorination, the film was placed in a Selectfluor (F-TEDA) solution (0.01 M in acetonitrile) at 60 °C for an hour, followed by washing in acetonitrile and heating at 150 °C for 15 min.…”

2D materials: increscent quantum flatland with immense potential for applications

“…In Fig. 6 d, Bahuguna et al fabricated a thin-film F-SnO 2 -based sensor for VOC detection [ 101 ]. In Fig.…”

“…c Response of the Ti 3 C 2 T x MXene/PANI/BC composite aerogel-based gas sensor to NH 3 gas for varied concentration ranges. [ 98 ] d Sensor current response profile with the UV-on of F-SnO 2 sensor [ 101 ] e fabrication process and design of the 2H-WSe 2 nanosheet sensor. f Dynamic response of 2H-WSe 2 (2D), 2H-WSe 2 (8D), and 2H-WSe 2 (12D) sensors at RT.…”

Chemical insights into electrophilic fluorination of SnO2for photoelectrochemical applications

“…In previous reports, by using F-TEDA as an electrophilic uorine precursor, we have developed a recipe for uorination of various nanomaterials, including SnO 2 for the fabrication of gas sensors and energy storage devices. 43,44 However, a clear understanding of the uorination mechanism and its inuence on the band structure is still missing in the literature. Herein, an in-depth study is carried out for understanding the uorination process using XPS depth proling and its inuence on electrical properties, surface oxygen defects, trap states, and electronic energy levels by impedance and UPS spectroscopic studies.…”