Eco-Friendly Disposable WS2 Paper Sensor for Sub-ppm NO2 Detection at Room Temperature

We developed inexpensive and disposable gas sensors with a low environmental footprint. This approach is based on a biodegradable substrate, paper, and features safe and nontoxic electronic materials. We show that abrasion-induced deposited WS2 nanoplatelets on paper can be employed as a successful sensing layer to develop high-sensitivity and selective sensors, which operate even at room temperature. Its performance is investigated, at room temperature, against NO2 exposure, finding that the electrical resistance of the device drops dramatically upon NO2 adsorption, decreasing by similar to 42% (similar to 31% half a year later) for 0.8 ppm concentration, and establishing a detection limit around similar to 2 ppb (similar to 3 ppb half a year later). The sensor is highly selective towards NO2 gas with respect to the interferents NH3 and CO, whose responses were only 1.8% (obtained for 30 ppm) and 1.5% (obtained for 8 ppm), respectively. Interestingly, an improved response of the developed sensor under humid conditions was observed (tested for 25% relative humidity at 23 degrees C). The high-performance, in conjunction with its small dimensions, low cost, operation at room temperature, and the possibility of using it as a portable system, makes this sensor a promising candidate for continuous monitoring of NO2 on-site.

Automated summary

We developed low-cost and disposable gas sensors with a low environmental impact. These sensors are based on biodegradable paper substrate and use safe electronic materials. The sensors utilize WS2 nanoplatelets deposited on paper through abrasion as a sensing layer, demonstrating high sensitivity and selectivity even at room temperature. The sensors exhibit a significant drop in electrical resistance upon NO2 adsorption, making them promising candidates for on-site continuous monitoring of NO2.