Rainbow Absorption

Scientists at Ohio State University led by Prof. Malcolm Chisholm have discovered material that efficiently absorbs energy from the complete visual spectrum of light – or quite literally absorbs the entire rainbow.

The material is made up of two very strongly bonded Molybdenum ions and pairs of two ligands with interesting steric (very basically, their size) and electronic properties. It overcomes the two major roadblocks involved in capturing solar energy: taking in all energy from sunlight and producing easily-capturable electons. Thus, the new material may have the potential to revolutionise how manufactured solar cells obtain energy from the sun.

The researchers from Ohio State University and National Taiwan University first explored different molecular configurations on a computer synthesising the hybrid material.

This is the first material that can simultaneously absorb the entire visible spectrum and turn them into energy.

“There are other such hybrids out there, but the advantage of our material is that we can cover the entire range of the solar spectrum,” explained Malcolm Chisholm, the OSU chemistry professor who led the research team.

Currently solar cells based upon silicon absorb only certain frequencies of light. The new material favourably compares with currently available solar cell materials that can only capture a small range of light-wave frequencies, thereby only benefiting from a small fraction of the energy contained in sunlight. Today’s solar cells actually contain, on average, three different types of material in order to provide greatest conversion efficiency.

The material is still years away from commercial development. But the research, cited by the Proceedings of the National Academy of Sciences, provides a proof of the concept that hybrid solar cell materials can offer unusual and promising properties.