New breakthrough to boost solar cells' efficiency by more than 30 pc

Researchers have found an easy way to modify the molecular structure of a polymer commonly used in solar cells, which could lead to more than 30 percent increase in solar cell efficiency.

A team of chemists led by Jianhui Hou from the Chinese Academy of Sciences created a polymer known as PBT-OP from two commercially available monomers and one easily synthesized monomer.

Wei Ma, a post-doctoral physics researcher from NC State and corresponding author on a paper describing the research, conducted the X-ray analysis of the polymer's structure and the donor:acceptor morphology.

PBT-OP was not only easier to make than other commonly used polymers, but a simple manipulation of its chemical structure gave it a lower HOMO level than had been seen in other polymers with the same molecular backbone.

PBT-OP showed an open circuit voltage (the voltage available from a solar cell) value of 0.78 volts, a 36 percent increase over the ~ 0.6 volt average from similar polymers.

According to North Carolina State University physicist and co-author Harald Ade, said that in this case, they found a chemically easy way to change the electronic structure and enhance device efficiency by capturing a lager fraction of the light's energy, without changing the material's ability to absorb, create and transport energy.

The researchers' findings appear in Advanced Materials.