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Enhancement of hydrogen sulfide gas sensing of PbS colloidal quantum dots by remote doping through ligand exchange.
- Source :
-
Sensors & Actuators B: Chemical . Jun2015, Vol. 212, p434-439. 6p. - Publication Year :
- 2015
-
Abstract
- Colloidal quantum dots (CQDs) are solution-synthesized semiconductor nanocrystals with size typically below 10 nm. Their large surface-to-volume ratio and abundant active surface sites, combined with the grain size effect and solution-processability make CQDs promising building blocks for low-cost and high-performance gas sensors. Here we employed the ligand exchange strategy to develop low-power and highly sensitive H 2 S gas sensors based on PbS CQDs. Following the layer-by-layer spin-coating of PbS CQDs capped with long-chain oleic acid ligands from synthesis, a surface treatment using different inorganic salts was conducted for ligand exchange in air ambient at room temperature. Upon exposure to 50 ppm of H 2 S at 135 °C, the resistance of all those sensors decreased shown as the response and the Pb(NO 3 ) 2 treatment yielded highest response (4218 at 135 °C) with shortest response/recovery time. We tentatively proposed a H 2 S-induced and temperature-promoted p-to-n transition of PbS CQDs as the sensing mechanism and the role of Pb(NO 3 ) 2 treatment was attributed to an n-type remote doping effect realized by the ligand exchange, which was further supported by the energy dispersive spectrometry (EDS) and ultraviolet photoelectron spectroscopy (UPS) analysis. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09254005
- Volume :
- 212
- Database :
- Academic Search Index
- Journal :
- Sensors & Actuators B: Chemical
- Publication Type :
- Academic Journal
- Accession number :
- 101941268
- Full Text :
- https://doi.org/10.1016/j.snb.2015.02.047