Micro-patterned BaTiO3@Ecoflex nanocomposite-assisted self-powered and wearable triboelectric nanogenerator with improved charge retention by 2D MoTe2/PVDF nanofibrous layer

Abstract

With applications in robotic technology, human-machine interfaces and healthcare unit, the self-powered wearable triboelectric nanogenerator has the ability to detect different physical parameters. These aspects continue to be incredibly exciting for the researchers. Herein, a self-powered, skin-attachable and flexible triboelectric nanogenerator (EPMTNG) is designed with a charge generating layer using micro-patterned BaTiO₃@Ecoflex (EBTO) nanocomposite, nanofibrous trapping layer with 2D MoTe₂ and carbon tape as a charge collecting layer. Furthermore, charge recombination becomes the significant issue, which not only reduces the surface potential but also diminishes the output performance of TENG. For this, a 2D transition metal dichalcogenide (MoTe₂) incorporated PVDF nanofibrous (PM5) layer is introduced as a charge trapping layer to prevent the charge recombination and improve the output performance of the device. Additionally, the incorporation of 2D MoTe₂ nanoparticles reinforces the polarization effect by gathering more charge carriers and improves the dielectric property and conductivity of the device. To establish our concept of inclusion of an intermediate trapping layer in EPMTNG, a theoretical simulation model has been prepared confirming the rise of surface potential and output voltage in the presence of the trapping layer. Along with this, a surface modification technique has been resorted to create surface roughness and improve the output performance of EPMTNG. Thus, the intermediate trapping layer and micro-patterned nanocompositebased EPMTNG device generate a colossal output voltage of 319 V and an instantaneous power density of 2.9 W m⁻² under an axial pressure of 12 N. Also, the high sensitivity (32.5 V kPa⁻¹) of the device at low-pressure region assists in successfully detection of robotic gestures, including artificial finger bending and objects gripping. Moreover, the flexibility and skin attachable properties encourage the EPMTNG device in tracking human physiological signals coming from blood flow, glottis movement, neck up down, wrist bending, etc., and monitor the wireless transmission of these signals. Therefore, the self-powered flexible device may be useful in health monitoring units and soft robotics applications.