Electrochemical Preparation of Cadmium Selenide Nanoparticles by the Use of Molecular Templates

We report the electrochemical preparation of cadmium selenide nanoparticles at gold electrodes modified with molecular templates. The molecular templates were obtained by properly arranging thiolated β-cyclodextrin self-assembled monolayers (SAMs) on gold electrodes. Selenium was first deposited on a SAM-modified gold electrode at an appropriate potential, followed by reduction to HSe in a solution containing Cd 2+ , leading to the deposition of CdSe. The Cd codeposited at the time of CdSe deposition was removed by anodic dissolution at a potential where it was oxidized. Scanning electron microscopic pictures showed that Se 0 and cadmium selenide particles of smaller than 60 and 150 nm diam, respectively, were deposited on the SAM-modified gold electrodes. Selenium particles of as small as 1-2 nm diam and ∼0.2 nm height were observed by in situ electrochemical scanning tunneling microscopy experiments during the early stages of electrochemical deposition.