Two-dimensional penta-Sn3H2 monolayer for nanoelectronics and photocatalytic water splitting: a first-principles study

Exploring two-dimensional materials with novel properties is becoming particularly important due to their potential applications in future electronics and optoelectronics. In the current work, the electronic and optical properties of penta-Sn3H2 are investigated by density-functional theory. By assessing the phonon spectrum, we find that penta-Sn3H2 monolayer is energetically more favorable compared with pristine penta-stanene due to hydrogenation transforming the sp2-sp3 hybrid orbitals into sp3 hybridization. Our calculations revealed that penta-Sn3H2 is a semiconductor with indirect band gaps of 1.48 eV according to the GGA functional (2.44 eV according to the HSE06 functional). Moreover, the electronic structures of penta-Sn3H2 can be effectively modulated by biaxial tensile strain. Meanwhile, our calculations reveal that the indirect to direct band gap transition can be achieved in this monolayer sheet by >4% biaxial strain. On the other hand, the well-located band edge and visible light absorption make penta-Sn3H2 a potentially promising optoelectronic material for photocatalytic water splitting.