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Researchers from University of Genoa Report New Studies and Findings in the Area of Chalcogens (Oxygen Sensitivity of Atomically Passivated CdS...

August 5, 2014

Researchers from University of Genoa Report New Studies and Findings in the Area of Chalcogens (Oxygen Sensitivity of Atomically Passivated CdS Nanocrystal Films)

By a News Reporter-Staff News Editor at Life Science Weekly -- A new study on Chalcogens is now available. According to news originating from Genoa, Italy, by NewsRx correspondents, research stated, "CdS nanocrystals (NCs) synthesized by colloidal chemistry methods have been intensively studied for various applications. However, little attention has been paid to the interaction between the oxygen molecules present in air and the NC surface, which has a strong influence on the electrical properties of NC films."

Our news journalists obtained a quote from the research from the University of Genoa, "Here, we discuss the effect of oxygen adsorption at the NC surface on the photoconductivity of CdS NC films that were treated by propyltrichlorosilane, which is known to replace the native ligands at the NC surface with chloride ions. The photocurrent voltage (Ply) characteristics of NC@Cl films recorded under oxygen atmosphere reveal a significant reduction in the photocurrent, as compared to those recorded under argon or vacuum. We demonstrate that this reduction can be related to adsorbed oxygen ions that effectively passivate the NC surface. This passivation reduces the free electron concentration and thereby reduces the photocurrent. Furthermore, we have investigated the light intensity dependence of the photocurrent dynamics of our devices in argon and in oxygen. These measurements confirm that the adsorption of oxygen is a photo-assisted process. Eventually, the potential of using our devices as oxygen sensors is assessed. A remarkable sensitivity of 35 is obtained at room temperature for 10% (concentration) oxygen flow, which is at least one order of magnitude higher than the results reported in the literature."

According to the news editors, the research concluded: "Our work clarifies the mechanism of the photoconductivity reduction in CdS NC films upon oxygen adsorption and opens up opportunities of exploring such devices for gas sensing applications."

For more information on this research see: Oxygen Sensitivity of Atomically Passivated CdS Nanocrystal Films. ACS Applied Materials & Interfaces, 2014;6(12):9517-9523. ACS Applied Materials & Interfaces can be contacted at: Amer Chemical Soc, 1155 16TH St, NW, Washington, DC 20036, USA. (American Chemical Society -; ACS Applied Materials & Interfaces -

The news correspondents report that additional information may be obtained from L. Maserati, University of Genoa, Dept. of Phys, I-16146 Genoa, Italy. Additional authors for this research include I. Moreels, M. Prato, R. Krahne, L. Manna and Y. Zhang (see also Chalcogens).

Keywords for this news article include: Genoa, Italy, Europe, Chalcogens

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Source: Life Science Weekly

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