Structural and optical properties of zinc-blende CdSe/CdS core/shell nanocrystals: Atomistic tight-binding theory

The tight-binding theory of the structural and optical properties in CdSe/CdS core/shell nanocrystals of experimentally applicable sizes is studied with the aim to analyze the impact of the CdS growth shell. Presented in this paper are the single-particle spectra, band gaps, excitonic gaps, carrier overlaps, radiative lifetimes, atomistic character, and oscillation strengths with several growth shell thicknesses. The detailed calculations extensively emphasize the sensitivity of shell on the electronic behaviors of CdSe/CdS core/shell nanocrystals. The significant improvements of device performance in the presence of shell are mainly observed. The sensitivity of the spin–orbit coupling on the resulting data is principally realized. In addition, the simulations using a tight-binding theory successfully show a good consistency with experimental data. Finally, the theoretical knowledge of CdS shell configuration on the structural and optical properties of CdSe core will be informative in the fabrication of various optoelectronic devices.