Photovoltaics are a low-cost and effective green energy solution but their popularity amongst building developers and owners has been held back by the perception that they are an eye sore. Moreover, if Germany is to achieve its Energy Transition targets – a further 2,500 square kilometres of solar panels need to be built by 2050 – the facades of buildings must also be utilised as well as rooves.

The Fraunhofer Institute for Solar Energy Systems (ISE) has therefore developed an aesthetically appealing solar technology called MorphoColour, named after the bright blue Morpho butterfly native to the south and central American rainforests. “The brainwave behind this development was not to colour the protective glass with pigments, but to imitate the physical effect of butterfly wings,” says Dr Thomas Kroyer, head of the coating technologies and systems group, in a press release.

The butterfly wings have an ultra-fine surface texture, which reflect a narrow range of wavelengths, creating the impression of colour. The Freiburg experts applied a similar texture to the back of the protective glass of the modules using a vacuum technique and used a special surface coating. As a result, MorphoColour panels can absorb 93 percent of the sun’s rays while reflecting back just 7 percent, which still allows for a wide spectrum of colour.

The technology gives solar modules a sleek, homogenous appearance and can either be used to create bright cladding or can be made to blend in with the shade of an existing façade or roof. And the researchers went a step further, developing an assembly method for the conductive strips that mimics roof shingles and designing strip photovoltaics that go around edges and irregular surfaces.

The shingled modules were exhibited at the BAU trade fair on 13 to 15 January, which took place online this year.