In best circles: First integrated circuit from self-assembled polymer
For the first time, a team of researchers at the Max Planck Institute for Polymer Research in Mainz, Germany has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used for logic operation in digital circuits and are the building blocks of an integrated circuit. The radical concept of self-assembled electronics has been around since 1976. For decades, the challenge has been to form a self-assembled monolayer of a semiconducting polymer in a transistor. “The idea is that all components of a transistor come together and arrange themselves in a hierarchical order”, said Kamal Asadi, leader of the Humboldt research group at the Max Planck Institute for Polymer Research. The monolayer is highly ordered and is able to conduct electric charge carriers well. The research team has used solution of a polymer. By dipping the transistor substrate in the solution in a controlled manner, the researchers could grow and produce a complete polymeric monolayer.
To achieve their scientific breakthrough, the scientists have intentionally dissolved the semiconducting polymer in an organic solvent that could not fully dissolve the polymer. In this way, the scientists have made the first self-assembled monolayer polymer field-effect transistor (PoM-FET). Nevertheless, one PoM-FET does not make a functional integrated circuit. Therefore, the research team has integrated hundreds of PoM-FETs and has operated them at the same time to demonstrate a 15-bit code generator, an integrated circuit that converts a voltage into a digital code. The landmark scientific result has applications in flexible electronics and fast response sensors.
International research collaboration
The scientific work was a collaboration of several international research groups worldwide. The semiconducting polymer was synthesized by the group of Professor He Yan at the Hong Kong University of Science and Technology, Hong Kong. The polymeric monolayers were analyzed by the group of Professor Harald Ade at the North Carolina State University in USA, and by the group of Professor Wojtek Pisula at the Lodz University of Technology, Poland. The PoM-FETs and the integrated circuits were fabricated at the Max Planck Institute for Polymer Research, Mainz, Germany. Post-doctoral researcher Mengmeng Li conducted the research work that was led by Kamal Asadi together with Wojtek Pisula.
Text: Kerstin Felix