A Theoretical Study on Band-Gap Engineering of CsCaI3 by Si Doping for Photo Voltaic Applications

Density functional theory based First Principles calculations were used to study the effect of Silicon (Si) doping on the structural, electronic and optical properties of CsCaI3. From our calculations, we predict that CsCaI3 can form stable perovskite structure. It is also observed that after substitutional doping of Si in CsCaI3, the material still can stay in perovskite form. Band structure studies showed that with Si doping, the band gap can be varied from 4.76eV for un-doped CsCaI3 to 0.639eV for 75 percent Si doped CsCaI3. The optical absorption spectra of the materials showed that Si doping can induce light absorption in the visible region in CsCaI3. Electron Localization Function (ELF) and effective mass calculations show that Si doping can improve the electronic conduction in this material to meet the requirements of photo Voltaic applications.