Hygroelectric-photovoltaic coupling generator using self-assembled bio-nano hybrids

The ubiquitous ambient moisture and sunlight are clean energy sources that have attracted increasing research interest for developing sustainable power technology. However, it is a great challenge to harvest energy from a single source to generate continuous electricity for practical use, due to temporal and geographical limitations. Herein, we report the first hygroelectric-photovoltaic coupling generator (HPG) using self-assembled Geobacter sulfurreducens-carbon nitride polymer (G.s-CNx) bio-nano hybrids for simultaneously harvesting hydro and solar energy. The HPG functions with hygroelectric-photovoltaic coupling effect during the day and hygroelectric effect at night, thus resulting in a sustainable power generator. The heterojunction constructed from the combination of G.s and CNx nanoparticles facilitates the separation of photogenerated carriers on light illumination which is then synergistically enhanced by moisture exposure. Thus, the coupling of hygroelectric and photoelectric effects on the bio-nano hybrids yielded an output power density of 122.9 mW/m2, higher than that of previously reported hygroelectric generators. The HPG was able to continuously generate power for 10 days with negligible attenuation, showing outstanding stability. The output performance of the hybrid generator could easily be scaled up and used to directly drive commercial electronic devices. This work provides significant guidance for the design of uninterrupted power generators by harvesting multiple natural energy sources.