Doping boost for flexible organic semiconductors
Researchers in Japan have developed a room temperature doping technique to boost the performance of organic flexible electronics.
The team from the Research Centre for Materials Nanoarchitectonics (MANA) have introduced a doping method to achieve accurate and consistent conductivity for organic semiconductors. This can be used for wireless sensors, energy-harvesting modules, biomolecular devices, displays, and solar cells.
- PragmatIC to make plastic driver chips for flexible plastic displays
- Flexible TFT boosts durability
- Single atom thin semiconductors enable flexible devices
Organic semiconductors consisting of polymers are important for the development of flexible electronic devices. However, achieving consistent conductivity using current doping methods is challenging. Doping involves the addition of dopants to the semiconductor via a redox reaction to increase the density of charge carriers. However, the process is sensitive to the reaction atmosphere and impurities, particularly water, which deactivates the dopants.
The team developed a simple doping method capable of producing organic semiconductors of desired conductivity levels. The method is based on the proton-coupled electron transfer reaction (PCET) and precise doping was achieved in ambient air for the first time for scalability suitable for device manufacturing.
In PCET, protons and electrons are simultaneously transferred between two molecules. This reaction provides a way to convert an organic semiconductor into a p-type doped state by encouraging a molecule to accept electrons from the semiconductor.
For the doping process, the researchers immersed PBTTT, an organic semiconductor, in an aqueous solution containing benzoquinone (BQ), hydroquinone (HQ), and hydrophobic molecular anions. BQ receives protons from the aqueous solution along with electrons from PBTTT. The electron transfer from the organic semiconductor increases the number of holes in the organic semiconductor, changing its conductivity.
The advantage of this method lies in its reproducibility and pH-dependent controllability. Adjusting the solution’s pH allows precise control over the doping amount and, subsequently, the conductivity. “The Fermi level of the semiconductors was precisely and reproducibly tuned by the pH of the doping solution,” says Dr Yu Yamashita from MANA who led the team in collaboration with Dr. Masaki Ishii.
www.nims.go.jp/mana/index.html
If you enjoyed this article, you will like the following ones: don't miss them by subscribing to :
