|15 November 2016|

Scotland

Groundbreaking new research points to the possibility of harnessing renewable energy from the sun through solar cells worn on the body or even painted onto windows.

A Scottish-led team has made a discovery using quantum mechanics that could lead to the development of cheap and efficient solar cells capable of tapping into this most abundant of renewable energy sources.

Researchers from Heriot-Watt, Oxford, Harvard and St Andrews universities have found a way to potentially overcome the inefficiency created by using cheaper organic polymers for solar cells, which throw away around 90% of the power they absorb.

The team has found a method to retain energy that would otherwise be lost ‘using interference between the excited states of molecules to stop them re-emitting sunlight’.

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 build a quantum-enhanced solar cell, and hopefully we will see one being made in the next few years.”

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.

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 hope to see a quantum-enhanced solar cell being made in the next few years.