An insight into optical properties of Pb:CdS system (a theoretical study)

In current work, we explored optical properties of Pb doped CdS system by employing PBE-GGA approximation. To accomplish computational work, we supposed various supercell configurations and in these supercells, Cd atoms were substituted by Pb atoms. It was found that by varying supercell configurations, optical properties of Pb doped CdS system were changed. The study was performed using Wien2K code by employing density functional theory. Calculated data for optical absorption in the case of 1.56% Pb concentration (similar to 2 x 2 x 2 supercell) showed redshift as compared to pure CdS while for 6.25% (similar to 1 x 1 x 2 supercell) and 3.12% (similar to 1 x 2 x 2 supercell) Pb concentrations, it showed a blueshift. Moreover, optical absorption increases in visible region but traces oscillatory behavior in the UV region. However, it was noticed that doping Pb into host CdS lattice enhanced opto-electrical properties and hence CdS:Pb system behaves as an ideal material for QDs based solar cells, photo-detector and photosensitive applications.