Aqueous Photovoltaics and Integrated Portable Devices: Novel Trends in the Solar Cells Scenario

Photovoltaic (PV) technology has evolved rapidly in the past few decades and now encompasses a large variety of materials and device structures. A key aspect to be taken into account in any PV technology is the operational durability under real outdoor conditions, as well as the sustainability of materials/components and the facile integration with energy storage systems. In the last five years, dye-sensitized solar cells (DSSCs) with water-based electrolytes are considered as one of the possible breakthroughs towards DSSCs large-scale diffusion. If opportunely developed and optimized, aqueous solar cells can be truly considered a zero-impact photovoltaic device with no toxic components. Moreover, the possibility of gellyfing the electrolyte into a solid matrix can reduce the leakage outside the device, thus increasing the long-term stability. In this respect, we present bio-derived polymers as promising candidates for electrolyte stabilization, being renewable and easy available at low cost. At the same time, the increasing energy request in off-grid conditions is forcing the scientific and industrial community to explore the feasibility of integrated PV-based harvesting storage devices. To this purpose, DSSCs and electrical double layer capacitors (EDLCs) combinations are reaching wide attention, also thanks to the simple configuration, long cycle life and high power density of the latter. Here we present different platforms applied for the fabrication of innovative self-powered devices integrating energy harvesting and storage sections.