| Sumario: | Systematic density functional theory studies and model analyses have been used to show that the band gap of iron pyrite (FeS) can be increased from ~1.0 to 1.2-1.3 eV by replacing ~10% of the sulfur atoms with oxygen atoms (i.e., ~10% O impurities). O formation is exothermic, and the oxygen atoms tend to avoid O-O dimerization, which favors the structural stability of homogeneous FeSO alloys and frustrates phase separation into FeS and iron oxides. With an ideal band gap, absence of O-induced gap states, high optical absorptivity, and low electron effective mass, FeSO alloys are promising for the development of pyrite-based heterojunction solar cells that feature large photovoltages and high device efficiencies.
|
|---|