Synthesis of CdS nanoparticles within thermally evaporated aerosol OT thin films

Abstract

In this paper, we discuss the synthesis of cadmium sulfide (CdS) quantum dots within thermally evaporated sodium bis(2-ethylhexyl)sulfosuccinate (AOT) thin films. This procedure uses electrostatic interactions to entrap positively charged cadmium ions into thin films of the anionic surfactant AOT by a simple immersion of the film in electrolyte solution. Thereafter, the composite film is treated with H₂S gas/Na₂S solution resulting in the in-situ formation of CdS nanoparticles in the quantum size regime. It is believed that the ability of AOT molecules in the thermally evaporated thin films to form reverse micelles is responsible for the CdS nanoparticle size control observed. Investigation of the entrapment of cadmium ions in the AOT film and subsequent quantum dot synthesis was carried out by quartz crystal microgravimetry (QCM), UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) measurements.