Electronic and photochemical properties of hybrid binary silicon and germanium derived Janus monolayers. Issue 32 (6th August 2021)

• Record Type: Journal Article
• Authors: Li, Xiuyuan; Zhang, Kaining; Zeng, Xin; Li, Nan; Wang, Jichang
• Is Part Of: Physical chemistry chemical physics. Volume 23:Issue 32(2021)
• Page Start: 17502
• Page End: 17511
• Publication Date: 2021-08-06
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d1cp01507a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : A series of novel 2D Janus M2 XY monolayers (M = Si, Ge; X, Y = N, P, As; X ≠ Y) have been proposed. Their elastic, electronic and photochemical properties have been predicted. Janus Si2 PAs, Ge2 NP and Ge2 PAs are promising candidates for photocatalysis. Abstract : The electronic structures and optical properties of a novel class of hybrid binary Janus materials derived from IV–V groups were investigated using first principles calculations. The computational results demonstrated that, except for Ge2 NAs, all the other five structures of M2 XY monolayers (M = Si, Ge; X, Y = N, P, As; X ≠ Y) have excellent thermal and dynamical stabilities. Janus Si2 NP, Si2 NAs, Si2 PAs and Ge2 NP are semiconductors with direct band gaps spanning the range between 0.82 and 2.49 eV. Notably, the hybrid M2 XY materials exhibit highly efficient absorption within the visible light region, which are greatly higher than their pristine MX structures. Janus Si2 PAs and Ge2 PAs possess appropriate band edge alignments that straddle the water redox potentials in the pH range from 0 to 14, making them promising photocatalysts for water splitting under visible light. Our calculations further demonstrate that the catalytic selectivity for the water splitting reaction could be achieved through the hybrid Janus M2 XY, where, for instance, Ge2 NP appears to facilitate only the oxidation, but not the reduction of water under certain conditions. This outcome provides a new route for the design of novel photocatalysts with improved efficiency and selectivity.