Polarization Electric Field in 2D Polar Monolayer Silicon Monochalcogenides SiX (X = S, Se) as Potential Photocatalysts for Water Splitting

The polarization electric field generated by the dipole moment can swiftly separate photogenerated carriers. Herein, the first-principles calculations to study the structural, electronic, polarization electric field, optical, and photocatalytic properties of 2D polar monolayer silicon monochalcogenide SiX (X = S, Se) are studied. The polarization electric field induced by a noncentrosymmetric structure is a direction from the X (X = S, Se) atomic surface to the Si atomic surface. The polar monolayer SiS (SiSe) is an indirect semiconductor with a bandgap of 2.997 eV (2.903 eV). The absorption coefficients of the polar monolayer SiX (X = S, Se) reach the order of 10(5) cm(-1), and the absorption onset can be extended to the visible light region. The band alignment of the 2D polar monolayer SiX (X = S, Se) is suitable for photocatalytic water splitting. The obtained results show that the 2D polar monolayer SiX (X = S, Se) with a polarization electric field is a potential catalyst for photocatalytic water splitting.

Automated summary

The structural, electronic, polarization electric field, optical, and photocatalytic properties of 2D polar monolayer silicon monochalcogenide SiX (X = S, Se) are studied using first-principles calculations. The results show that the polarization electric field induced by a noncentrosymmetric structure can effectively separate photogenerated carriers. The 2D polar monolayer SiX (X = S, Se) with high absorption coefficients and suitable band alignment is a potential catalyst for photocatalytic water splitting.