Prediction of a ternary two-dimensional pentagonal Zn2C2P2 monolayer for photocatalytic water splitting with high carriers mobility

Abstract Using first-principle calculations, a noble ternary pentagonal two-dimensional compound (penta-Zn2C2P2) is proved to be thermally and mechanically stable among 15 structures with a stoichiometry of Zn2A2B2 (A/B= N, B, S, C, P and Si, A≠B). The orientation-dependent Young’s modulus (35.5 ∼ 61.1 GPa·nm) and Poisson’s ratio (0.12 ∼ 0.34) indicate that penta-Zn2C2P2 is a very soft material with highly anisotropic mechanical properties. Electronic structure calculations showed that penta-Zn2C2P2 is a semiconductor with a direct bands gap of 1.16 eV which can be efficiently engineered by biaxial strain. Also, it exhibits ultrahigh carrier mobility up to 0.62×105 cm2V-1s-1 for electrons and 0.99×105 cm2V-1s-1 for holes respectively. In addition, penta-Zn2C2P2 have good infrared and visible light absorption and can serve as single photocatalyst for photocatalytic water splitting with total energy conversion efficiency (STH) up to 17.1%. The exotic properties make penta-Zn2C2P2 a versatile and promising 2D material for applications in photocatalyst and nanoelectronics.