Nanoampere‐Level Piezoelectric Energy Harvesting Performance of Lithography‐Free Centimeter‐Scale MoS₂ Monolayer Film Generators

Abstract 2D transition‐metal dichalcogenides have been reported to possess piezoelectricity due to their lack of inversion symmetry; thus, they are potentially applicable as electromechanical energy harvesters. Herein, the authors propose a lithography‐free piezoelectric energy harvester composed of centimeter‐scale MoS₂ monolayer films with an interdigitated electrode pattern that is enabled only by the large scale of the film. High‐quality large‐scale synthesis of the monolayer films is conducted by low‐pressure chemical vapor deposition with the assistance of an unprecedented Na₂S promoter. The extra sulfur supplied by Na₂S critically passivates the sulfur vacancies. The energy harvester having a large active area of ≈18.3 mm² demonstrates an unexpectedly high piezoelectric energy harvesting performance of ≈400.4 mV and ≈40.7 nA under a bending strain of 0.57%, with the careful adjustment of side electrodes along the zigzag atomic arrays in the two dominant domain structure. Nanoampere‐level harvesting has not yet been reported with any 2D material‐based harvester.