Abstract
By combining visible transparency and solar energy conversion, transparent photovoltaics (TPV) prompted the interest to fill the gap of applications in which the conventional opaque solar cells are not feasible. In pioneering TPV adoption in practical application, aesthetics is equally important as photovoltaic performances. In this context, average visible transmittance (AVT), color rendering index (CRI), correlated color temperature (CCT), and chromaticity coordinates, along with other colorimetric evaluations, gain a crucial role in the TPV domain. Dye Sensitized Solar Cells (DSSC) have been deemed an interesting technology to achieve efficient energy conversion and the required visual comfort by being wavelength selective to the NIR. The peculiarity of being highly transparent and color-neutral can be achieved by consolidating the capability of harvesting selectively the NIR part of the solar spectrum with a fully colorless electrolyte. The results of this thesis work are divided into three main sections. In the first section, we report the first attempt towards NIR-DSSC through symmetrical cyanine dye coded VG20. This cyanine VG20 dye achieved a power conversion efficiency (PCE) of 3.1% while rendering highly transparent devices with an AVT value of 76%, a 93.6 CRI, and a CCT of 4297 K. The main limitation of higher performances was identified to be the energy transfer from monomer to aggregates. In the second section, the identified limitations were tackled by dye engineering, resulting in novel pyrrolopyrrole cyanine dyes (PPcy). The PPcy dyes showed remarkable performances with PCE > 4% and AVT values > 75%. Finally, the third section investigates different colorless and transparent electrolytes, leading to achieving color-neutral NIR-DSSC with a high CRI of 96 and AVT value of 78%. This thesis work provides future directions to enhance the performances of this non-intrusive NIR-DSSC technology