Green power now comes in green (and maybe other colours)

It might perhaps be construed as almost the definition of a First World Problem, but some householders, it seems, decide against installing roof-top solar panels because they don’t like the colour.

A team led by Verena Neder, a researcher at AMOLF, a facility operated by the Dutch Foundation for Fundamental Research on Matter, in Amsterdam, has developed a way of adding colour-changing silicone nano-particles to existing solar panels.

The added particles scatter green light giving the panels a green appearance from most angles. Unfortunately, the application also reduces panel efficiency by roughly 10%, but Neder and her colleagues reason the decrease might be worthwhile if the changed colour induces more people to invest in the technology.

“Some people say ‘why would you make solar cells less efficient?’ But we can make solar cells beautiful without losing too much efficiency,” she says.

“The new method to change the color of the panels is not only easy to apply but also attractive as an architectural design element and has the potential to widen their use.”

Her team’s coloured panels are certainly not the first to hit the market, but existing models rely on dyes and coatings, reducing efficiency by much greater margins.

The new method – reported in the journal Applied Physics Letters – uses an application technique called soft-print lithography, imprinting an array of nano-cylinders onto the surface of each panel.

The cylinders, which are about 100 nanometres wide, scatter a particular light wavelength. Their shape and orientation can be fine-tuned to achieve the desired result.

“The structure we made is not very sensitive to the angle of observation, so even if you look at it from a wide angle, it still appears green,” says Neder.

The next step, she adds, is to refine the process to make solar panels appear red and blue.

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