Co/Zn bimetal organic framework elliptical nanosheets on flexible conductive fabric for energy harvesting and environmental monitoring via triboelectricity

Abstract

Flexible and portable power sources are imperative chunks of wearable electronic devices. Fabric-based triboelectric nanogenerators (TENGs) have become most promising energy sources for wearable electronic devices as they can generate electrical energy from biomechanical movements with great flexibility. In this study, a highly flexible Co/Zn bimetal organic framework based TENG (BMOF TENG) is fabricated. Facilely prepared Co/Zn BMOF nanosheets are coated on flexible conductive fabric (BMOF/FCF) and utilized as the tribo-positive material against PTFE/Al based tribo-negative material for the fabrication of the BMOF TENG. The content of Zn is varied from 0% to 50% to achieve superior electrical output and observed that the 15% of Zn is appropriate for superior electrical output. The open circuit voltage, the short circuit current, and the charge density of the BMOF TENG are increased from 11 V to 47 V, from 1.06 µA to 7 µA, and from 4 nC/cm 2 to ~17 nC/cm 2 , respectively when the Zn content is increased from 0% to 15%. Thus, the optimized content of Zn in Co/Zn BMOF helped to enhance the electrical output of the BMOF TENG by nearly 450%. The output power of the BMOF TENG is found to be 1.1 mW/m 2 at a load resistance of 2 MΩ. As the phenomenon of gas sensing is largely associated to the surface of the material, the advantage of unique surface features of the BMOF/FCF is utilized in sensing hazardous gases. The device has shown variations in its electrical output in the presence of air and targeted gas and the good selectivity towards ammonia at room temperature. Ultimately, the BMOF TENG proposed in this study can convert mechanical energy into electrical energy and can be employed as an ammonia sensor in environmental monitoring and food quality assessment. • For the first time, Co/Zn bimetal organic framework (BMOF) nanosheet coated fabric is used for TENG. • At the optimized content of Zn (15%) in Co/Zn BMOF, the BMOF TENG is generated enhanced electrical output. • Fabric based flexible BMOF TENG is successfully employed as a room temperature ammonia sensor. • The unique surface morphology of BMOF has helped to evince good sensing behavior of the device. • Proposed BMOF TENG is able to serve as an energy harvesting as well as environmental monitoring device.