CdS/TiO2 nanocomposite film and its enhanced photoelectric responses to dry air and formaldehyde induced by visible light at room temperature.

Photoelectric responses of pure TiO 2 and CdS/TiO 2 nanocomposite devices to dry air and formaldehyde under visible light irradiation at room temperature were investigated in this work. The pure TiO 2 film was firstly prepared by screen printing and CdS/TiO 2 nanocomposite film by the subsequent SILAR process. XRD, FE-SEM, HR-TEM and UV–vis DRS analysis were employed to examine the fundamental characteristics of as-prepared samples. Photoelectric responses of pure TiO 2 device displayed that no obvious photocurrent was observed upon turning the visible light on either in dry air or in formaldehyde. But in contrary to pure TiO 2 device, the photoelectric response of CdS/TiO 2 nanocomposite device has been obviously enhanced. It is the adding of CdS, which works as a sensitizer, that accounts for the enhanced response and makes the CdS/TiO 2 device sensitive to the visible light. Moreover, the CdS/TiO 2 nanocomposite device exhibits excellent stability to formaldehyde. The present work does not only shed light on the photoelectric gas sensing properties of TiO 2 and CdS/TiO 2 , but also suggests that the CdS/TiO 2 nanocomposite may be a promising material for fabricating visible-light-induced photoelectric gas sensors working at room temperature. [ABSTRACT FROM AUTHOR]