A first-principles prediction of the structural, electronic, transport and photocatalytic properties of GaGeX 3 (X = S, Se, Te) monolayers.

The discovery of new 2D materials with superior properties motivates scientists to make breakthroughs in various applications. In this study, using calculations based on density functional theory (DFT), we have comprehensively investigated the geometrical characteristics and stability of GaGeX 3 monolayers (X = S, Se, or Te), determining their electronic and transport properties, and some essential optical and photocatalytic properties. AIMD simulations show that these materials are highly structurally and thermodynamically stable. Notably, the GaGeSe 3 monolayer is a semiconductor with a band gap of 1.9 eV and has a high photon absorption coefficient of up to 1.1 × 10 5 cm -1 in the visible region. The calculated solar-to-hydrogen conversion efficiency of the GaGeSe 3 monolayer is 11.33%, which is relatively high compared to some published 2D materials. Furthermore, the electronic conductivity of the GaGeSe 3 monolayer is 790.65 cm 2 V -1 s -1 . Our findings suggest that the GaGeSe 3 monolayer is a new promising catalyst for the solar water-splitting reaction to give hydrogen and a potential new 2D material for electrical devices with high electron mobility.