Stanford’s Thinner Than The Wavelength of Sound Solar Cells

One thing we know about solar cells is that thinner it is less expensive it gets; thin film solar is cheaper than the standard silicon cells. Stanford University’s team of Researchers has come up with Solar cells thinner than the wavelengths of light which are also more efficient! They say Ultra-thin solar cells can absorb sunlight more efficiently than the thicker, more expensive-to-make silicon cells used today, because light behaves differently at scales around a nanometer (a billionth of a meter).

The team consists of Shanhui Fan, associate professor of Electrical engineering and postdoctoral researcher Zongfu Yu who is the lead on the PNAS paper. Aaswath Raman, a graduate student in applied physics, also worked on the research and is a coauthor of the paper.

Everyone worked with the assumption that light travels in a straight line i.e. if a ray of light hits a mirror it bounces back as another ray. When Yu began investigating the behavior of light inside a material of deep subwavelength-scale – substantially smaller than the wavelength of the light – that it became evident to him that light could be confined for a longer time, increasing energy absorption beyond the conventional limit at the macroscale. On further research Yu figured out that he could increase absorption rate by 12% by sandwiching the organic thin film between two layers of material – called “cladding” layers – that acted as confining layers once the light passed through the upper one into the thin film. Atop the upper cladding layer, he placed a patterned rough-surfaced layer designed to send the incoming light off in different directions as it entered the thin film.

The project was supported by funding from the King Abdullah University of Science and Technology, which supports the Center for Advanced Molecular Photovoltaics at Stanford, and by the U.S. Department of Energy.

Source – The Stanford News

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