Light harvesting approach makes more efficient solar cells

December 2, 2015

By eeNews Europe

Batteries / Power Supplies

The researchers used a self-assembly approach to integrate photon upconversion – a light harvesting approach traditionally accomplished using an external filter – into a solar cell. Using their process in an optimized solar cell, the researchers claim they can increase the maximum efficiency from 33% to more than 45%.

"We’re looking not only for new materials but also new light harvesting processes to make solar cells better," says Kenneth Hanson, Assistant Professor of Chemistry and Biochemistry.

A typical solar cell, at maximum, converts less than 33% of light into electricity, so researchers have been working to find ways to surpass this limit and make cells more efficient. In the past, scientists have put an extra photon upconversion filter before or after the cell to catch the low energy, unused light and convert it into usable, high-energy light.

With the new approach, the researchers used a soaking procedure to assemble two molecules – an acceptor and sensitizer – on a surface. Once assembled, the molecules work in concert to perform photon upconverion, combining two low-energy, green photons to generate a higher-energy, blue photon, which can then be used to generate electricity.

"It is definitely a stepping stone toward making more efficient solar cells," says Hanson. "Our current work demonstrates a feasible method."

For more, see the paper published in The Journal of Physical Chemistry Letters: "Photon Upconversion and Photocurrent Generation via Self-Assembly at Organic–Inorganic Interfaces."