Postsynthesis Crystallinity Improvement of Colloidal CdTe Nanoparticles Using Rapid Thermal Annealing

Abstract

Rapid thermal annealing has been applied to poly(acrylic acid)-capped CdTe nanoparticles. This annealing process has shown to provide some control over the semiconductor core properties, while preserving the capping ligand intact. The photoluminescence and absorption properties of the nanoparticles remain nominally unchanged up to annealing temperatures of 400 °C and annealing durations of 30 s. This process was found to be an effective postsynthesis means of improving the crystallinity of the semiconductor core. The crystallinity enhancement is identified by solution-based Raman spectroscopy using a hollow-core photonic crystal fiber. This novel method of detecting a crystalline change in nanoparticles is corroborated by powder X-ray diffraction measurements and X-ray photoelectron spectroscopy.