Feasibility of band gap engineering of iron pyrite (FeS2) by codoping Os, Ru or Zn together with O

Abstract For increasing the band gap of iron pyrite (FeS2) to make it more suitable for photovoltaic applications, we calculated the structural, electronic and optical properties of pure FeS2 and doped systems M0.25Fe0.75O0.25S1.75 (M = Zn, Ru or Os) by first-principle within the GGA + U method. The results show that doping with Zn and O simultaneously decreases the band gap of the iron pyrite and thus makes Zn0.25Fe0.75O0.25S1.75 unusable for photovoltaic applications. Fortunately, doping with either Ru and O or Os and O simultaneously increases obviously the band gap of the iron pyrite and thus makes Ru0.25Fe0.75O0.25S1.75 and Os0.25Fe0.75O0.25S1.75 useable for photovoltaic applications. The optical properties of the iron pyrite are also improved by doping with either Ru and O or Os and O simultaneously, the red shift phenomena also make both Ru0.25Fe0.75O0.25S1.75 and Os0.25Fe0.75O0.25S1.75 promising for photovoltaic applications with large photovoltage and high device efficiency.