Chemo-Resistive Gas Sensors Based on PbS Colloidal Quantum Dots

In this paper, we investigate the sensitivity and selectivity of lead sulphide colloidal quantum dots (CQDs) gas sensor. The benefits of CQDs, compared to commercial bulk sensor gas, are a large surface/volume ratio, a lower operating temperature, an easy deposition process and a precise control of dimensions to increase sensor sensitivity. The sensor is based on a chemo-resistive device with an active layer composed by PbS CQDs deposited on interdigitated metal contacts with a ligand exchange treatment. The sensor performance are validated on different gas pollutants (NO
₂
, NO, CO
₂
and CO) for increasing gas concentrations and times. The sensor shows high selectivity towards NO and NO
₂
against CO and CO
₂
at room temperature.