BioEST project develops novel multifunctional biomaterials for flexible emerging solar cells. Biomaterials such as cellulose are cheap, abundant, and environmentally friendly options that could be used as a basis of roll-to-roll manufacturable flexible solar cells. In BioEST, we incorporate the newest developments in the field of advanced biomaterials to battle a major lifetime limiting factor in emerging solar devices: the penetration of moisture to the cell. Furthermore, besides the new materials approaches, BioEST combines device level modeling to the experimental aging research - an approach that will leapfrog the lifetime analysis to a complete new level enabling new features such as prediction of the device lifetime.