Resonant photoactivation of cadmium sulfide and its effect on the surface chemical activity

Year: 2014

Authors: Giberti A., Fabbri B., Gaiardo A., Guidi V., Malagu C.

Autors Affiliation: MIST ER Scrl, I-40129 Bologna, Italy; Dept Phys & Earth Sci, I-44124 Ferrara, Italy; CNR, INO, I-50124 Florence, Italy

Abstract: Photo-enhanced surface chemical activity of cadmium sulfide gives rise to a wide class of surface-dependent phenomena, such as heterogeneous photocatalysis, chemoresistivity, and chemiluminescence, which have several technological and scientific applications. In this work, the photochemical properties of nanostructured cadmium sulfide films are investigated by means of electrical conductance measurements in controlled atmosphere, while irradiated by light of wavelengths ranging from 400 to 645 nm. Chemisorption of benzene, carbon monoxide, methane, ethanol, and hydrogen sulfide onto CdS surface has been analyzed as a function of the wavelength, in a gas concentration range of the order of parts per million. It resulted that the increase of photoconductance with gas adsorption is resonant with the bandgap energy. It turns out that this resonant enhancement of the surface chemical activity can be of advantage for all the optical and chemical mechanisms that depend upon it. An interpretation of these results, in terms of electronic optical transitions and Fermi level shift induced by light, is proposed. (C) 2014 AIP Publishing LLC.


Volume: 104 (22)      Pages from: 222102  to: 222102

More Information: This work was supported by Programma Operativo FESR 2007-2013, Regione Emilia-Romagna-Attivita I.1.1.
DOI: 10.1063/1.4881179

Citations: 14
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