Synergistic contribution of flexoelectricity and piezoelectricity towards a stretchable robust nanogenerator for wearable electronics

• Published in: Nano energy Vol. 91; p. 106691
• Main Authors: Yoon, Chongsei, Ippili, Swathi, Jella, Venkatraju, Thomas, Alphi Maria, Jung, Jang-Su, Han, Yire, Yang, Tae-Youl, Yoon, Soon-Gil, Yoon, Giwan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2022
• Subjects: F-PENG; LDH–ZnO heterostructure; Piezoelectricity; Stretchability; ZnAl:LDH Ns; Piezoelectricity; Stretchability; LDH–ZnO heterostructure; ZnAl:LDH Ns; F-PENG
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2021.106691

The fabrication of a high-performance piezoelectric nanogenerator (PENG) with high stretchability and durability is desirable for the next-generation of stretchable and wearable electronics. Herein, an eco-friendly and stretchable flexoelectricity-enhanced piezoelectric nanogenerator (F-PENG) based on zinc-aluminum layered double hydroxide nanosheets (ZnAl:LDH Ns)-ZnO heterostructure is demonstrated on stretchable polydimethylsiloxane (PDMS) substrates. The vertically-oriented eco-friendly ZnAl:LDH Ns are facilely synthesized by dipping the 10 wt% aluminum-doped zinc oxide (AZO) thin films in deionized (DI) water at room temperature. The enhanced output performance of the F-PENG is demonstrated under tapping, bending, and stretching modes, and is attributed to the synergistic flexoelectric and piezoelectric effects. The achieved maximum output power density of F-PENG under tapping is ~2.7 µW/cm2. The pressure-sensing capability of the F-PENG is demonstrated by the generated outputs under the three applied modes. In addition, the biomechanical energy harvesting capability of the F-PENG is demonstrated by subjecting it to various biomechanical motions. The F-PENG exhibits an excellent mechanical durability in all three modes of operation. The present study not only paves the way towards the facile fabrication of stretchable and high-performance F-PENGs with combined flexoelectric and piezoelectric effects, but also validates a wide range of applications in the next generation of stretchable and wearable electronics. An eco-friendly and stretchable flexoelectricity-enhanced piezoelectric nanogenerator (F-PENG) is demonstrated by ZnAl:LDH Ns-ZnO heterostructure fabricated on stretchable PDMS substrates. The energy harvesting of the F-PENG is demonstrated under three applied modes of strains including tapping, bending, and stretching. Further, biomechanical energy harvesting and pressure sensing ability of the F-PENG is confirmed. [Display omitted] •A facilely synthesized ZnAl:LDH-ZnO heterostructured F-PENG as a high-performance piezoelectric nanogenerator.•Synergistic enhancements by the flexoelectric and piezoelectric effects of the F-PENG.•High-performance, stretchable, and durable F-PENG fabricated on pre-stretched PDMS substrate.•Predominant biomechanical energy harvesting capability of stretchable F-PENG.