From the Solarpunk Aesthetic tumblr:
Biotechnologist Marin Sawa and her University of London research group have created a proof-of-concept for printing solar cells onto paper using carbon nanotubes and cyanobacteria.
This technology is "[...] capable of generating a sustained electrical current both in the dark (as a ‘solar bio-battery’) and in response to light (as a ‘bio-solar-panel’) with potential applications in low-power devices."