Electrochemical Synthesis of CdSe Nanoparticles Using a Se-modified RVC Electrode and Mercaptoacetic Acid as a Stabilizer

Abstract

Semiconductor nanoparticles (NPs) are of fundamental and practical interest due to unique quantum size effects which result in strongly size dependent electronic, optical and electrochemical properties. Among them, CdSe nanoparticles are of much interest because of applications in solar photovoltaic cells, sensors and optoelectronic devices. CdSe NPs have been extensively studied following the development of chemical preparation procedures using hot trioctylphosphine oxide (TOPO) as a capping agent. Unlike the original method which employed toxic dimethyl cadmium as a cadmium source, other researchers have developed a “green synthesis” route and they synthesized CdSe NPs using CdO as a precursor. While hot TOPO-based approaches require rather severe experimental conditions such as toxic chemicals and high temperatures, electrochemical methods can provide much more “green” environments. Recently, CdTe NPs have been electrochemically synthesized using a Te disc electrode. In this method, a Te disc electrode was cathodically polarized in the electrolyte containing Cd and mercaptoacetic acid (MAA), which served as a stabilizer. We have developed a two-step method for the electrochemical synthesis of semiconductor films or particles. This approach is based on initial electrochemical modification of the substrate with the chalcogen. Subsequent electrochemical reduction of chalcogen in an aqueous electrolyte solution dosed with the desired metal generates compound semiconductor films on the substrate surface or particles in bulk solution with stirring. This approach has been successfully used for the synthesis of semiconductor NPs such as CdTe and films such as FeS2, In2S3, CdS, CdSe, CdTe, and ZnTe. Here we report the first example of electrochemical synthesis of CdSe NPs, in which particle size can be tuned by controlling heating time. In this study a RVC electrode was employed for the first time to synthesize CdSe NPs and this approach can be used for the synthesis of NPs in large quantities. Optical properties of NPs with different heating times were studied by absorption and photoluminescence spectroscopy.