Abstract
During the recent years, it has been widely recognized that the use of semiconductor nanoparticles for the fabrication of chemical gas sensors by screen-printing technology definitely improves the sensor performance. In this paper, we review the possibilities offered by Fourier transform infrared (FTIR) spectroscopy for the study of semiconductor nanoparticles. Thanks to FTIR spectroscopy, it is possible to identify the surface chemical groups, to characterize the surface reactivity, to monitor the surface functionalization, to investigate the surface reactions at the origin of the gas detection, and to evaluate the gas sensing potentiality of the nanoparticles before the device fabrication. All these steps are critical for the optimization of nanoparticle-based gas sensors because they ensure i) the reproducibility of the surface chemical composition and of the surface chemistry, ii) the control of the surface modifications to decrease cross-sensitivity, particularly to humidity, iii) the investigation of the gas detection mechanism to properly tailor the surface structure, iv) the selection of the best nanoparticles batches for further processing. Examples of tin oxide and titanium oxide nanoparticles are discussed with regards to CO and NOx detection.
