Novel organic dyes for photovoltaics with indoor applications

The exponential spreading of portable electronics and devices for wireless sensor networks is part of the Internet of Things (IoT) revolution that will lead the next future. In this scenario, industry and society demand new, more sustainable, and efficient energy sources. Dye-Sensitized Solar Cells (DSSCs) present all the key characteristics to be the favorite candidate for indoor IoT applications: they are inexpensive, tuneable, aesthetically appealing, have no toxicity issues, and have already shown impressive efficiencies under indoor light illumination. DSSCs are photovoltaic devices composed of a photoanode that absorbs the light through a photosensitizer; the excited electrons are injected into a layer of TiO2, then into the external circuit and they are eventually collected at the cathode. The two electrodes are connected through an electrolyte that regenerates the oxidized dye. Each component of the cell must be carefully optimized in order to maximize the overall efficiency of the device. Herein we present a series of novel dyes designed and synthesized to achieve good performances under both solar and low-light conditions. Several DSSC setups have been tested tuning cathode construction and electrolyte nature in order to maximize performances. Photovoltaic measurements have been carefully optimized in order to pursue reproducibility and reliability into the hazy field of indoor illumination characterization.