If you have ever wanted to wear a shirt made of solar cells or hang plastic solar cell curtains on your windows to power your house, a group of Hong Kong researchers have brought your dream one step closer to reality. Semi-transparent perovskite solar cells, developed by a team of Polytechnic University scientists, are thinner and more flexible than previous versions that were previously only able to absorb about half the energy of photovoltaic panels. Using electrodes made from graphene, a form of carbon, the PolyU researchers created solar cells which are both semi-transparent and able to convert about 12 per cent of the sunlight they absorb into electricity. Previously, perovskite solar cells had a conversion rate of about 7 per cent. Photovoltaic panels have a typical conversion rate of around 20 per cent. PolyU Department of Applied Physics associate professor Dr Yan Feng said the development was a breakthrough and would allow for solar panels to be placed on windows, bus shelters, the sides of skyscrapers and even worn as clothing. “[The cells] have many functions – they can generate electricity, but say if we used these solar panels on a building, it can provide sound protection, thermal control, weather proofing and control of shade and light, as well,” he said. Yan said the new cells also produced electricity at a cheaper rate and were made from less expensive materials than existing solar cells. But Yan said the new technology was not ready for commercialisation yet, as the team were still waiting for a grant to help with production.