All-Day Thermogalvanic Cells for Environmental Thermal Energy Harvesting
Characterizations of the polypyrrole- (PPy-) modified graphite sheet. (a) Schematic of multiple scattering of radiation in the nano-/microstructure of PPy. (b) Photographs and SEM images of pristine graphite sheet (graphite) and PPy-modified graphite sheet (PPy/graphite). (c) Cross-sectional SEM of PPy/graphite. The average thickness of PPy on the graphite sheet is approximately 20 μm. (d) FTIR spectrum of PPy/graphite, pristine PPy, and graphite. (e) Measured absorptivity/emissivity spectrum of PPy/graphite and graphite in both the solar (0.3 to 2.5 μm) and infrared (2.5 to 25 μm) regions, with the standard AM1.5 solar spectrum (shaded orange) and atmospheric transmittance (shaded blue) plotted for reference .