Solar energy is one of the most promising renewable energy sources, yet increasing solar cell production raises concerns about end-of-life recycling. Currently, solar panel recycling remains challenging due to the difficulty to separate valuable materials from glass and encapsulants, making device redesign essential. This thesis explores cellulose as a substrate that supports the fabrication of perovskite solar cells.

The research assessed cellulose films in terms of their compatibility with perovskite solar cells, mainly their optics, surface morphology, mechanical properties. After optimizing the transparency, surface roughness, and tensile strength of unmodified cellulose nanofibrils films, different nanocellulose grades were tested alongside, yet, they were deemed too rough to be used as substrates. Cellulose nanocrystal films reached surface roughness comparable to conventional substrates, though with reduced flexibility. Combining nanocrystals with nanofibrils improved flexibility and moisture resistance, but increased surface roughness. Additionally, while highly transparent at normal incidence, nanocellulose films exhibited increased reflectivity at angles above 45° due to light scattering by cellulose fibrils.

In the traditional perovskite solar cell fabrication route, the bottom electrode is deposited on the substrate, then etched and patterned for electrically isolated sections (i.e., pixels). To accommodate cellulose substrates, a customizable measuring apparatus was developed to circumvent this step. This tool helped to prove that devices made on non-patterned unetched substrates devices work as well as those made on etched ones, enabling early-stage characterization on cellulose films. This work concludes with the creation of a methodology for the fabrication of more sustainable solar cells through the combination of robust cellulose substrates and alternative perovskite solar cell fabrication methods. These findings contribute to the development of truly renewable energy sources.