Studying the Reactions of CdTe Nanostructures and Thin CdTe Films with Ag+ and AuCl4-.


Danieli T, Gaponik N, Eychmuller A, Mandler D. Studying the Reactions of CdTe Nanostructures and Thin CdTe Films with Ag+ and AuCl4-. J. Phys. Chem. CJournal of Physical Chemistry C. 2008;112 (24) :8881 - 8889.

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The reactions between Ag+ and AuCl4- ions with 3 different CdTe systems, i.e., thermally evapd. thin CdTe films, CdTe nanoparticles (NPs) stabilized by thioglycolic acid (TGA), and 20 layers of these CdTe NPs embedded in poly(diallyldimethylammonium) chloride (CdTe-20lbl), were studied. AuCl4- oxidized the CdTe, in all studied systems, to form metallic Au. However, the kinetics of the reaction was substantially sluggish for the thin CdTe films than with the CdTe NPs systems. However, the reaction with Ag+ was rather complex, and the findings alluded to different reaction for each system. Although it is possible that a Ag-SR bond was formed between Ag+ and the thiol group of the TGA-stabilized NPs, cation exchange between Ag+ and Cd2+ is evidenced when these CdTe NPs were embedded in a polymer (CdTe-20lbl). Also, Ag+ reacted with thin CdTe films to form a ppt. consisting of Ag. The authors studied the reactions between locally generated Ag+ and AuCl4- and CdTe surfaces using scanning electrochem. microscopy (SECM). A flux of Ag and Au chloride ions was electrochem. generated from their resp. microelectrodes upon applying a pos. potential close to thin CdTe films and CdTe-20lbl. The flux of AuCl4- resulted in the local formation of Au NPs on the CdTe surface, whereas local quenching of CdTe-20lbl was achieved by the flux of Ag+ ions. Finally, the current transients recorded during the SECM expts. provided invaluable information regarding the reactions at the CdTe surface below the microelectrodes. [on SciFinder(R)]


CAPLUS AN 2008:628442(Journal)