Fig. 3: Output performance of Ag₂Se network-based FTEG.

The simulated internal temperature distribution of the full filled (a), 10% filled (b) bulk FTEGs and the network-based FTEG (c) at an ambient temperature of 290 K. Further simulation details are provided in the supplementary materials. d, e, The simulated single leg voltage and power density in an ambient temperature range from 273 K to 305 K. f The infrared image and optical photograph (inset) of a network-based FTEG dressed on a human wrist. The top electrode was removed to avoid the effect caused by its low emissivity. g, h The measured voltage and power density at an ambient temperature of 290 K and 297 K. Inset shows a device under test. i Summary of the FTEG’s power generation at different ambient temperatures. All the measurements were performed on human skin without heat sinks. Red line and red circles respectively represent the simulated and measured values of the Ag₂Se network-based FTEG. Source data are provided as a Source Data file.