Ordinary ink absorbs light, creating heat. Specially developed photovoltaic ink, however, is able to harness that heat and convert part of it to electricity. Researchers Janne Halme, Ghufran Hashmi, Alpi Rimppi, and Merve Özkan worked together at Aalto University to create the special ink and the semi-transparent solar cell on which to print. The team used their own portraits to test the technology. The initial printed solar cell also includes a QR code which, when scanned, links to the team’s research paper.