Increasing efficiency of solar cells via randomness
Researchers at the University of St Andrews have been working on a new method to increase the efficiency of solar cells.
The new approach, states the university, achieves highly efficient broad-band light trapping in thin films. They say more light is captured in the film in order to maximise absorption and electricity generation.
The new method builds on research into a class of materials known as quasi-crystals, which offer advantages in terms of the spectrum of light they are able to capture. However, the problem with these structures is that their properties are difficult to tailor towards specific applications.
To solve this problem, the researchers created a new structure called a quasi-random structure, which combines the rich spatial frequencies associated with quasi-crystals with a high level of control.
“The control of propagating light is a crucial aspect in photonics. Disordered and quasi-periodic media provide many advantages over ordered structures to control and manipulate light propagation,” said postgraduate researcher Emiliano Martins, of the School of Physics and Astronomy at St Andrews.
“We have demonstrated that by a careful design of their Fourier spectra, quasi-random nanostructures can achieve such control very efficiently.”
It is expected this could have applications in LED and lasers as well as solar cells.
The work results from an international collaboration involving scientists from China and Belgium
“Other than solar cells, our design can also be used in many light trapping areas, like LED and DFB lasers,” said Dr Juntao Li, from the State Key Laboratory of Optoelectronic Materials and Technology, Sun Yat-sen University, China.
It is reported in Nature Communications (Thursday 24 October 2013) and was supported by the Scottish Universities Physics Alliance (SUPA), the National Key Basic Research Special Foundation, the National Natural Science Foundation of China and Guangdong Natural Science Foundation.
Image: Dr Li Juntao – A quasi-random structure to maximise performance of a thin film silicon solar cell.