Intriguing Two-Dimensional BeO-Based Tribo-Piezoelectric Nanogenerator

The remarkable piezoelectric characteristics manifested by two-dimensional (2D) materials render them immensely coveted candidates for deployment in nanoscale energy harvesting tools. In this study, we demonstrate the generation of nanoenergy from the tribo-piezoelectric effect in a 2D BeO bilayer system by employing first-principles density functional theory calculations. We find that compression and sliding motions between two BeO layers produce a substantial tribo-piezoelectric effect. Lateral sliding of the upper BeO layer while the bottom BeO layer remains fixed engenders tribological energy from the vertical resistance force. Through tribological energy conversion, we show how BeO bilayers may overcome the interfacial sliding barrier and generate tribo-piezoelectricity. We obtain maximum energy corrugation in the range of 101–301 meV and shear strength in the range of 0.4–2.38 GPa during vertical compression. The highest out-of-plane piezoelectricity is obtained when the bilayers are in the A–A stacking configuration by lateral sliding. A maximum induced voltage of ∼0.22 V is attained through the vertical compressive sliding of the upper layer. These findings offer potential opportunities for harvesting nanoenergy from the tribo-piezoelectric effect of BeO systems, paving the way for advancing the field of self-powered sensors, wireless electronics, and wearable devices.