Electronic, Optical, piezoelectric properties and photocatalytic water splitting performance of Two-dimensional group IV-V compounds

Using first-principles calculations, we predicted the physical properties and property-guided potential applications of group IV-V compound MX2 (M = Si, Ge, Sn; X = N, P, As) and its Janus structure MXY (X ≠ Y), which are isostructural to the synthesized compound SiP2. We demonstrated that 8 out of 18 monolayers are stable in thermodynamics, dynamics, and mechanics. Electronic calculations showed that these monolayers are semiconducting with optimal bandgaps ranging from 0.99 to 2.33 eV. The calculated piezoelectric coefficients d11 for the MX2 and MXY monolayers are in the range from 8.0 to 26.9 pm/V. Moreover, our results showed that these 2D materials have suitable band edge positions, excellent solar absorption, moderate exciton binding energies, and fair light conversion rates, rendering them potential application in photocatalytic water splitting. Our results may be instructive for the design, synthesis, and applications of group IV-V compounds for the future electronic, optoelectronic devices, and hydrogen producing materials.