Atomic-thick 2D MoS2/insulator interjection structures for enhancing nanogenerator output

Abstract

Ultra-small size and large electric output are highly desirable for piezoelectric nanogenerators for powering nanodevices. However, ultra-small size usually leads to low output. Here, we simulated the output performance of MoS₂ nanogenerators based on atomic-thick 2D MoS₂/insulator interjection structures and their rational integration. We showed that the output performance is greatly increased by selecting SiO₂ as the insulator material, decreasing the thickness of insulator layers and increasing the side length of MoS₂ unit layers. When mechanically resonant with external pressure at a frequency of 215 MHz, the output generated from our rationally designed nanogenerator (70 μm × 70 μm × 5.2 μm) reaches 36 mW (corresponding to an average power density of 735 W cm⁻²) and this output was able to directly power some nanodevices that usually need several milliwatts. Such a high power-density positions our rationally designed nanogenerator as a first-class high-efficiency nanogenerator. In addition, a significantly high instantaneous conversion efficiency of 71% from mechanical energy to electrical energy can be achieved. Our work may give some suggestions for the rational design and experimental realization of ultra-small and high-output nanogenerators.