Asymmetric XMoGeY 2 (X = S, Se, Te; Y = N, P, As) monolayers as potential flexible materials for nano piezoelectric devices and nanomedical sensors.

Highly efficient nano piezoelectric devices and nanomedical sensors are in great demand for high-performance piezoelectric materials. In this work, we propose new asymmetric XMoGeY 2 (X = S, Se, Te; Y = N, P, As) monolayers with excellent piezoelectric properties, dynamic stability and flexible elastic properties. The piezoelectric coefficients ( d 11 ) of XMoGeY 2 monolayers range from 2.92 to 8.19 pm V -1 . Among them, TeMoGeAs 2 exhibits the highest piezoelectric coefficient ( d 11 = 8.19 pm V -1 ), which is 2.2 times higher than that of common 2D piezoelectric materials such as 2H-MoS 2 ( d 11 = 3.73 pm V -1 ). Furthermore, all XMoGeY 2 monolayers demonstrate flexible elastic properties ranging from 96.23 to 253.70 N m -1 . Notably, TeMoGeAs 2 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 XMoGeY 2 monolayers can be attributed to their asymmetric structures and flexible elastic properties. This study provides valuable insights into the potential applications of XMoGeY 2 monolayers in nano piezoelectric devices and nanomedical sensors.