Figure 1a shows a schematic of the fabricated
hybrid energy cell. All of the materials used for the
fabrication are flexible. The bottom pyroelectric/
piezoelectric NG consists of two Ag electrodes and
PVDF film. The optical images of the fabricated PVDF
film-based pyroelectric/piezoelectric NG are shown
in Figure S1 of the Supporting Information, indicating
that the NG can be bent and the surface area is
about 600 mm2. A cross-section SEM image of the
PVDF film in Figure S2 shows that the thickness is
about 110 μm. The micrometer size PVDF film was
chosen for easy manipulation and just as a model
system in the hybrid energy cell for this study.