North Carolina State University increase solar cells efficiency modifying polymer molecular structure

New research increases the efficiency of solar cells

10:15 AM, 6th January 2014
North Carolina State University research on solar cells
Side chain modification improves solar cell efficiency from 5.6% to 7.5%

NORTH CAROLINA, US: Researchers from North Carolina State University and the Chinese Academy of Sciences have found an easy way to modify the molecular structure of a polymer commonly used in solar cells. Their modification can increase solar cell efficiency by more than 30 per cent.

Polymer-based solar cells have two domains, consisting of an electron acceptor and an electron donor material. Excitons are the energy particles created by solar cells when light is absorbed. In order to be harnessed effectively as an energy source, excitons must be able to travel quickly to the interface of the donor and acceptor domains and retain as much of the light’s energy as possible.

One way to increase solar cell efficiency is to adjust the difference between the highest occupied molecular orbit (HOMO) of the acceptor and lowest unoccupied molecular orbit (LUMO) levels of the polymer so that the exciton can be harvested with minimal loss. One of the most common ways to accomplish this is by adding a fluorine atom to the polymer’s molecular backbone, a difficult, multi-step process that can increase the solar cell’s performance, but has considerable material fabrication costs.

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.

“The possible drawback in changing the molecular structure of these materials is that you may enhance one aspect of the solar cell but inadvertently create unintended consequences in devices that defeat the initial intent. In this case, we have 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,” said Harald Ade, Physicist, NC State University.

© North Carolina State University News

0 Comments

Login

Your Comments (Up to 2000 characters)
Please respect our community and the integrity of its participants. WOC reserves the right to moderate and approve your comment.

Related News


PMC completes acquisition of Arkema Beijing Chemicals

BEIJING, CHINA: PMC Group NA Inc has completed the purchase of Arkema Beijing Chemical Co Ltd. This completes the final portion of PMC’s previou ...

Read more
POET-DSM to start cellulosic bio-ethanol plant in early 2014

EMMETSBURG, US: POET-DSM Advanced Biofuel’s first commercial cellulosic bio-ethanol plant remains on schedule for startup in the first part of 2 ...

Read more
Dual catalyst converts alpha-olefins into new organic compounds

CHESTNUT HILL, US: Boston College chemists have developed a new chemical synthesis methodology that converts chemicals known as alpha-olefins into new ...

Read more
Compressing salt forms new compound, finds new study

STONY BROOK, US: Artem R Oganov, Professor, Stony Brook has documented his predictions about, and experiments in, compressing sodium chloride (rock sa ...

Read more
Neogen acquires insecticide manufacturers, Chem-Tech

LANSING, US: Neogen Corporation has acquired the stock of Chem-Tech Ltd, a manufacturer of insecticides for the animal and food industries. Neogen is ...

Read more
Chemtura completes sale of consumer products business for $300 million

PHILADELPHIA, US: Chemtura Corporation has completed the sale of its Consumer Products business, including dedicated manufacturing plants in the US an ...

Read more