Numerical study on optoelectronic properties of alkaline-earth metal doped g-C3N4

Highlights: • The electric and optical properties of doped g-C₃N₄ structures have been studied. • We investigated band structure, density of states under different doping elements. • We detected the change on band structure and density of states of doped g-C₃N₄. • It implies Ca doped g-C₃N₄ has potential application for photovoltaic devices. Different models such as pure and alkaline-earth metal (Mg, Ca, Sr and Ba) doped graphitic carbon nitrides (g-C₃N₄) were constructed on the basis of first principle for studying its photoelectric properties, the numerical investigations reveal that Fermi level of alkaline-earth metal doped g-C₃N₄ all move to valence band maximum, which means they are beneficial to p-type semiconductor. The gap and population analysis show Ca doped g-C₃N₄ exhibits stronger ionic bonding and has more stable structure. The dielectric function of Ca doped g-C₃N₄ moves to the lower energy direction (red shift), the conductivity of which is higher in the range of 510 ~ 1100 nm, and it has better absorption with wavelength more than 530 nm; however, the optical properties of Ca doped g-C₃N₄ are excellent compared to others. The results show that the Ca doped g-C₃N₄ is an outstanding tailorable material for photocatalysis-driven application related to visible and near infrared region.