Researchers at Fraunhofer Institute for Solar Energy Systems (ISE) in Freiburg have developed a light-sensitive film that can be applied to photovoltaic modules and laser-etched to mimic tile, masonry and other building materials. The colour is created by 3D photonic structures rather than pigments — the same physical principle as Morpho butterflies. Adding the film costs only a few percentage points of efficiency, leaving modules at about 95% — comparable to standard PV. Fraunhofer ISE separately introduced a solar cell last month that cuts silver use by 10x.