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Universities ’ research shows quantum mechanics could slash cost of solar energy
New research is offering the prospect of cheap and efficient solar cells of a conformable type that could be worn on the body or even painted onto windows . Sunlight is the most abundant source of renewable energy , and learning how best to harvest this radiation holds the key to meeting the world ’ s future power needs . For solar energy to become a viable alternative to fossil fuels , solar cells need to be both inexpensive to manufacture and efficient in terms of energy they collect . Now a Scottish-led team has taken a major step towards this goal by using quantum mechanics to design molecular solar cells to be more efficient . The researchers from Heriot-Watt , Oxford , Harvard and St Andrews universities have been looking at organic solar cells , which use organic polymers which are less expensive to produce . However , they are normally relatively inefficient , throwing away around 90 per cent of the power they absorb . The team has found a way to use interference between the excited states of molecules to stop them re-emitting sunlight , thereby wasting already absorbed energy . This disproves the assumption that absorption and emission of light by molecules must always go hand-in-hand , limiting how efficient solar cells can be . The breakthrough , published in Physical
Review Letters , centres on the discovery that asymmetric structures can outperform identical molecules ensuring more sunlight is converted into electrical energy . This has allowed the team to identify literally thousands of possible pairs of coupled molecules that could be used to improve solar cell operation . Dr Brendon Lovett , of the School of Physics and Astronomy of the University of St Andrews , explains , “ Quantum mechanics can be used to help improve the performance of solar cells , and we have shown that the effect could be harnessed in many different device designs . We are not limited to very specialised choices of material . This really simplifies how to
Image : Herriot-Watt University
build a quantum-enhanced solar cell , and hopefully we will see one being made in the next few years .” Lead-author Dr Erik Gauger , of the Institute of Photonics and Quantum Sciences at Heriot-Watt University , added , “ What really surprised us is that embracing the imperfections that distinguish realistic molecules from theoretical toy models , can lead to better-performing designs . Whilst we understand the physics behind that now , at the outset of the study we expected exactly the opposite .” The team hopes to see a quantumenhanced solar cell being made in the next few years .
Contents
NEWS 3-6 RENEWABLES 8-9 Howard Johns and the future of solar OPINION 10-11 Storage can give renewables new life THE BIG INTERVIEW 12-13 With Trina Solar ’ s UK Sales Manager Richard Rushin INSTALLER SPOTLIGHT 14-16 The York company GoEcoRenewables ENERGY STORAGE 17-19 Focus on residential-scale projects PRODUCTS 20
Electric Vehicles 21 Launch of Jaguar ’ s I _ CONCEPT NET METERING 22-24 Dougie Blair on net metering and parity COMMERCIAL 26-27 CASE STUDIES 30-31 Great projects from around the UK COMMUNITY 32-33 Installing Rehau district heating TOP 10 PRODUCTS 34,35 & 37 The best innovations for 2017 ENERGY EFFICIENCY 38-39 How smart energy could save billions FINAL WORD 42 Nick Boughton on a new paradigm
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