Controlling organic semiconductor band gaps by electron-acceptor fluorination

October 17, 2018, Osaka University
Chemical structures and photovoltaic characteristics. Credit: Osaka University

Organic semiconductor materials have the potential to be used in innovative applications such as transparent and flexible devices, and their low cost makes them particularly attractive. The properties of organic semiconductor materials can be tuned by controlling their structure at the molecular level through parts of the structure known as electron-accepting units. A group of researchers centered at Osaka University has specifically tailored an electron-accepting unit that was then successfully used in an organic semiconductor applied in solar cell device that showed high photovoltaic performance. Their findings were published in NPG Asia Materials.

"Electron-accepting units are important elements of organic semiconductors," corresponding author Yoshio Aso says. "Through the controlled addition of electronegative fluorine groups to a widely used electron-accepting material, we were able to show precise control of the energy levels within the resulting . This ability to tune the band gap translates to selectivity over the injection and transport of holes and/or electrons within the material, which is important in potential applications."

The fluorinated electron-acceptor unit was used to prepare a thin film solar cell that was compared with a cell based on a non-fluorinated analogue. The researchers found that the fluorinated material showed enhanced power conversion efficiency, up to 3.12%. The morphology of the fluorinated film was also found to be good, which supported the efficient charge generation and transport that is necessary for successful application.

"The more we are able to fine tune behavior on the molecular level, the more possibilities there will be for demonstrating their macroscopic applications," co-author Yutaka Ie says. "It is our hope that the band gap control and high photovoltaic performance we have demonstrated will lead to our material being applied in devices such as organic light-emitted diodes, field-effect transistors, and thin film solar ."

The straightforward demonstration of the link between high electronegativity, greater electron-accepting tendency, and enhanced semiconductor performance, highlights both the potential and versatility of organic semiconductors. Further elegant solutions such as this one could substantially broaden the range of ƒÎ-conjugated materials, and reinforce the case for organic electronics.

Explore further: Printable solar materials could soon turn many parts of a house into solar panels

More information: Shreyam Chatterjee et al, Fluorinated naphtho[1,2-c:5,6-c']bis[1,2,5]thiadiazole-containing π-conjugated compound: synthesis, properties, and acceptor applications in organic solar cells, NPG Asia Materials (2018). DOI: 10.1038/s41427-018-0088-4

Related Stories

Part-organic invention can be used in bendable mobile phones

October 5, 2018

Engineers at ANU have invented a semiconductor with organic and inorganic materials that can convert electricity into light very efficiently, and it is thin and flexible enough to help make devices such as mobile phones bendable.

New efficiency record for organic photovoltaic cells

August 10, 2018

A team of researchers affiliated with several institutions in China has established a new efficiency record for organic photovoltaic cells. In their paper published in the journal Science, the group describes their approach ...

Eco-friendly waterborne semiconductor inks using surfactant

November 28, 2017

A research team of Energy Science and Engineering at DGIST has developed a technology to produce environmentally friendly water-borne semiconductor inks using surfactants, additives that mix substances of different properties ...

Recommended for you

3-D culturing hepatocytes on a liver-on-a-chip device

January 17, 2019

Liver-on-a-chip cell culture devices are attractive biomimetic models in drug discovery, toxicology and tissue engineering research. To maintain specific liver cell functions on a chip in the lab, adequate cell types and ...

This computer program makes pharma patents airtight

January 17, 2019

Routes to making life-saving medications and other pharmaceutical compounds are among the most carefully protected trade secrets in global industry. Building on recent work programming computers to identify synthetic pathways ...

Cultivating 4-D tissues—the self-curving cornea

January 17, 2019

Scientists at Newcastle University have developed a biological system which lets cells form a desired shape by moulding their surrounding material—in the first instance creating a self-curving cornea.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.