Lead sulphide colloidal quantum dots for room temperature NO2 gas sensors

Federica Mitri; Andrea De Iacovo; Massimiliano De Luca; Alessandro Pecora; Lorenzo Colace

doi:10.1038/s41598-020-69478-x

Lead sulphide colloidal quantum dots for room temperature NO₂ gas sensors

Sci Rep. 2020 Jul 28;10(1):12556. doi: 10.1038/s41598-020-69478-x.

Authors

Federica Mitri¹, Andrea De Iacovo², Massimiliano De Luca³, Alessandro Pecora⁴, Lorenzo Colace¹

Affiliations

¹ Department of Engineering, University Roma Tre, Via Vito Volterra 62, 00146, Rome, Italy.
² Department of Engineering, University Roma Tre, Via Vito Volterra 62, 00146, Rome, Italy. andrea.deiacovo@uniroma3.it.
³ Institute of Marine Engineering (INM), CNR, Via Fosso del Cavaliere 100, 00133, Rome, Italy.
⁴ Institute for Microelectronics and Microsystems (IMM), CNR, Via Fosso del Cavaliere 100, 00133, Rome, Italy.

Abstract

Colloidal quantum dots (CQDs) have been recently investigated as promising building blocks for low-cost and high-performance gas sensors due to their large effective surface-to-volume ratio and their suitability for versatile functionalization through surface chemistry. In this work we report on lead sulphide CQDs based sensors for room temperature NO₂ detection. The sensor response has been measured for different pollutant gases including NO₂, CH₄, CO and CO₂ and for different concentrations in the 2.8-100 ppm range. For the first time, the influence of the QDs film thickness on the sensor response has been investigated and optimized. Upon 30 ppm NO₂ release, the best room temperature gas response is about 14 Ω/Ω, with response and recovery time of 12 s and 26 min, respectively. A detection limit of about 0.15 ppb was estimated from the slope of the sensor response and its electric noise. The gas sensors exhibit high sensitivity to NO₂, remarkable selectivity, repeatability and full recovery after exposure.