Since 2012, UK-based Power Roll has been working on a way to print low-cost solar film to generate clean energy from sunlight. It's now one crucial step closer to manufacturing its lightweight, apply-anywhere film, with a new design for its perovskite solar cells that should make make production cheap and scalable.

Power Roll has been focusing on embossing 'microgroove structures' into a plastic substrate, similar to a "hologram" on a credit card. A single square meter has 500,000 microgroove structures, and these are coated with conductive materials and photo-active ink. Layers of encapsulation film keep the printed rolls stable and enhance their durability.