BaZnF₄/Polydimethylsiloxane Composite Film-Based Nanogenerators for Energy Harvesting and Human-Machine Interface Applications

Automated motorized systems are very popular in the modern world of technology and consume a considerable amount of electricity because they are continuously in standby mode. This has driven the need for alternative sustainable energy sources and self-sustainable technologies. Hybrid nanogenerators (HNGs), known as enhanced versions of triboelectric nanogenerators, can be used as a highly efficient mechanical energy harvesting technology with impressive sensing capabilities. In this report, an HNG keypad-based human-machine interface system employing a highly efficient barium zinc fluoride (BaZnF₄, (BZF))/polydimethylsiloxane (PDMS) composite film (CF)-based HNG is proposed. BZF with a ferroelectricity/high dielectric constant was synthesized, and different concentrations were loaded inside PDMS. HNGs consisting of BZF/PDMS CFs and paper as the negative and positive triboelectric layers, respectively were fabricated and operated in contact-separation mode. The electrical output from the HNGs was investigated to determine the optimal BZF concentration in the CFs. The optimized HNG with a highly efficient and stable electrical output was implemented to power light-emitting diodes and a liquid-crystal display (LCD) timer. The conversion of abundantly available biomechanical energy into electricity was demonstrated by mounting an HNG onto the human body. A unique HNG keypad was fabricated by integrating 12 similar HNGs in a single 3D-printed structure, which was connected to an Arduino mega board combined with a stepper motor and LCD indicator. The entire system was tested as a security door that was locked when the desired combination of HNGs (equivalent numbers) was sequentially tapped.