Boosting the Output Performance of the MoS 2 Monolayer-Based Piezoelectric Nanogenerator by Artificial Dual Strain Concentration.

Piezoelectric nanogenerators (PENGs) with molybdenum disulfide (MoS ₂ ) monolayers have been intensively studied owing to their superior mechanical durability and stability. However, the limited output performance resulting from a small active area and low strain levels continues to pose a significant challenge that should be overcome. Herein, we report a novel strategy for the epoch-making output performance of a PENG with a MoS ₂ monolayer by adopting the additive strain concentration concept. The simulation study indicates that strain in the MoS ₂ monolayer can be initially augmented by the wavy structure resulting from the prestretched poly(dimethylsiloxane) (PDMS) and is further increased through flexural deformation (i.e., bending). Based on these studies, we have developed concentrated strain-applied PENGs with MoS ₂ monolayers. The wavy structures effectively applied strain to the MoS ₂ monolayer and generated a piezoelectric output voltage and current of around 580 mV and 47.5 nA, respectively. Our innovative approach to enhancing the performance of PENGs with MoS ₂ monolayers through the artificial dual strain concept has led to groundbreaking results, achieving the highest recorded output voltage and current for PENGs based on two-dimensional (2D) materials, which provides unique opportunities for the 2D-based energy harvesting field and structural insight into how to improve the net strain on 2D materials.