Gas Sensing with Solar Cells: The Case of NH₃ Detection through Nanocarbon/Silicon Hybrid Heterojunctions

• Main Authors: Giovanni Drera, Sonia Freddi, Tiziano Freddi, Andrea De Poli, Stefania Pagliara, Maurizio De Crescenzi, Paola Castrucci, Luigi Sangaletti
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Nanomaterials
• Subjects: carbon nanotubes; PV cells; CNT/Si heterojunctions; gas sensing; NH₃
• Online Access: https://www.mdpi.com/2079-4991/10/11/2303

Photovoltaic (PV) cells based on single-walled carbon nanotube (SWCNT)/silicon (Si) and multiwalled carbon nanotube (MWCNT)/Si junctions were tested under exposure to NH₃ in the 0–21 ppm concentration range. The PV cell parameters remarkably changed upon NH₃ exposure, suggesting that these junctions, while being operated as PV cells, can react to changes in the environment, thereby acting as NH₃ gas sensors. Indeed, by choosing the open-circuit voltage, V_OC, parameter as read-out, it was found that these cells behaved as gas sensors, operating at room temperature with a response higher than chemiresistors developed on the same layers. The sensitivity was further increased when the whole current–voltage (I–V) curve was collected and the maximum power values were tracked upon NH₃ exposure.