Breaking the mould

One can recognise a solar panel set up from miles due to its signature black and grey hues. But if you look up to the latest invention by two IIT-B innovators, you will know that these panels can also be produced in distinct tints of purple, red, blue and green as well. But why would one want coloured solar panels, we wonder?

IIT Bombay inventors, professor Dr Aldrin Antony and Ph.D student Anishkumar Soman of Energy Science Department of the institute, are the brains behind the invention. Dr Aldrin explains, “We have found a promising method through which we can use any conventional solar cell technology to integrate into buildings as architectural glass for building fenestrations like windows, facades, roof shingles etc. We have succeeded in mixing nanophotonic coatings to generate a different colour appearance for solar modules.” 

Building Integrated Photovoltaics is at a very nascent stage, where researchers across the globe are trying to find new ways to integrate solar cells to building material, Aldrin emphasises. “At present, more than 90 per cent of the solar market consists of silicon solar cells, which are used as roof top or stand-alone systems. Though there are new technologies like perovskite cells, which are capable of giving colour, they suffer from stability issues due to which they are not yet commercialised,” he explains.

The team has been working on the model since 2015, and had to face their share of challenges too, “The main factor which limited the production of coloured solar cells was giving a colour to the cells which results in very high reflection losses, causing the solar cell beneath to not work. However, this invention reflects only a selected wavelength of light to give it a coloured effect whereas the cell below works with nearly 60 to 80 per cent relative efficiency,” he says.

The inventors believe that with increasing urbanisation, this technology can help utilise the vertical area for energy production and thereby support zero energy buildings. “Currently solar panels are only installed on roof tops and are big bulky systems which consume a lot of space and are unaesthetic due to their blue or black colour. However, if this technology gets commercialised it could revolutionise the way we use solar energy. Not only will it help people to customise the colour of the solar modules but also use the vertical area of buildings as against the horizontal area,” Aldrin says.  The team plans to patent their invention and have applied for it.