Asymmetric XMoGeY2 (X = S, Se, Te; Y = N, P, As) monolayers as potential flexible materials for nano piezoelectric devices and nanomedical sensors

Abstract

Highly efficient nano piezoelectric devices and nanomedical sensors are in great demand for high-performance piezoelectric materials. In this work, we propose new asymmetric XMoGeY₂ (X = S, Se, Te; Y = N, P, As) monolayers with excellent piezoelectric properties, dynamic stability and flexible elastic properties. The piezoelectric coefficients (d₁₁) of XMoGeY₂ monolayers range from 2.92 to 8.19 pm V⁻¹. Among them, TeMoGeAs₂ exhibits the highest piezoelectric coefficient (d₁₁ = 8.19 pm V⁻¹), which is 2.2 times higher than that of common 2D piezoelectric materials such as 2H-MoS₂ (d₁₁ = 3.73 pm V⁻¹). Furthermore, all XMoGeY₂ monolayers demonstrate flexible elastic properties ranging from 96.23 to 253.70 N m⁻¹. Notably, TeMoGeAs₂ has a Young's modulus of 96.23 N m⁻¹, which is only one-third of that of graphene (336 N m⁻¹). The significant piezoelectric coefficients of XMoGeY₂ monolayers can be attributed to their asymmetric structures and flexible elastic properties. This study provides valuable insights into the potential applications of XMoGeY₂ monolayers in nano piezoelectric devices and nanomedical sensors.