PbBi2Se4 monolayer: A new 2D material with outstanding electronic, photocatalytic, and optical properties

Two-dimensional layered PbBi2Se4 nanosheets were recently successfully produced [Chatterjee et al., Phys. Chem. Chem. Phys., 2014,16, 14,635-14639]. Inspired by these promising experimental findings, herein we examine the electronic and photocatalytic properties of the PbBi2Se4 monolayer by density functional calculations. The phonon dispersion of the designed monolayer validated that the PbBi2Se4 is dynamically and thermally stable. Our results showed that the PbBi2Se4 has a bandgap of 1.211/1.650 eV according to the PBE/HSE06 hybrid functional. In addition, the optoelectronic properties are altered by the application of electric field and strain, but the band gap is more significantly modified by strain than by electric field, which reduces the energy gap. Interestingly, the results of photocatalytic properties revealed that PbBi2Se4 is an effective photocatalyst for hydrogen production. Under the application of a biaxial strain of -8%, the superior absorption coefficient of PbBi2Se4 is 20.1 x 104 cm -1, consequently, the application of strain resulted in an improvement in the absorption of light in the visible and ultraviolet ranges. Furthermore, the greatest value of the conductivity is due to the compressive strain, which is about 8.14 x 1015 at 3.23 eV for -8%. These results suggest that the PbBi2Se4 monolayer has potential uses in the development of sensors, solar cells, and photocatalysts.