Fig. 4: Examples of self-powered sensors.
From: Wearable and flexible electrochemical sensors for sweat analysis: a review
a Form factor and system-level block diagram of a self-powered photovoltaic cell-based smartwatch for continuous sweat glucose detection87. Copyright 2019, ACS. b Working principle of a self-powered wearable sweat sensor based on a biofuel cell19. Copyright 2016, RSC. c Schematic of a battery-free, biofuel-powered e-skin that efficiently harvests energy from the human body128. Copyright 2020, AAAS. d Schematic diagram of a triboelectric nanogenerator-based motion-driven wearable sweat sensor130. Copyright 2020, AAAS. e System diagram of the energy microgrid system, consisting of the TEG, BFC, and SC modules, and the wearable applications20. Copyright 2021, Springer Nature
