A comparison study of the structural, electronic and mechanical properties of the pure pyrite FeS2 and oxygen doped pyrite FeO0.25S1.75 under pressure range from 0 to 25 GPa

• Published in: Physica. B, Condensed matter Condensed matter, 2022-05, Vol.633, p.413710, Article 413710
• Main Authors: Zhang, Jian-Min, Liu, Tian-Lun, Huang, Yu-Hong, Wei, Xiu-Mei
• Format: Article
• Language: English
• Subjects: Absorptivity; Band gap; Electronic property; Energy gap; FeO0.25S1.75; First principles; Mechanical properties; Mechanical stability; Oxygen; Photoelectricity; Photovoltaic cells; Pyrite; Semiconductors; Stability criteria; Structural property
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2022.413710

Despite pure pyrite FeS2 has a very high optical absorption coefficient about 105cm−1, its smaller band gap about 0.95eV leads to a lower than 3% photoelectric conversion efficiency and thus limits its semiconductor photovoltaic applications. In this paper, we make a comparison study of the structural, electronic and mechanical properties of the pure pyrite FeS2 and oxygen doped pyrite FeO0.25S1.75 under pressure range of 0–25 GPa by first-principles calculations within GGA + U method. With increasing the pressure from 0 to 25 GPa, the band gap of the pure pyrite FeS2 oscillation decreases from 0.936eV at zero pressure to 0.682eV at 25 GPa and thus is not suitable for semiconductor photovoltaic application. Fortunately, the band gap of the oxygen doped FeO0.25S1.75 increases firstly from 1.080eV at zero pressure to the maximum value of 1.290eV at 13 GPa and then decreases slightly but is still larger than that of the pure pyrite FeS2. Especially, this maximum band gap value of 1.290eV at 13 GPa closes to the value of 1.340eV of Shockley-Queisser limit for semiconductor photovoltaic applications. Furthermore, the oxygen doped FeO0.25S1.75 is mechanical stable under pressure range of 0–25 GPa based on Born stability criteria. Our study shows that it is feasible to further increase the band gap of the oxygen doped pyrite FeO0.25S1.75 by applying a suitable pressure. •Band gap of pure FeS2 oscillation decreases from 0.936eV at 0GPa to 0.682eV at 25GPa.•Band gaps of O-doped FeO0.25S1.75 are all larger than those of pure FeS2 under 0 to 25GPa.•O-doped FeO0.25S1.75 is mechanical stable under pressure range of 0 to 25GPa.•The states of O-doped FeO0.25S1.75 at Γ-point contributed by S-3p shift down with increasing pressure.•The states of O-doped FeO0.25S1.75 at R-point contributed by Fe-eg shift up with increasing pressure.