Renowned expert in organic semiconducting polymers from Princeton University delivers PAIR lecture

Prof. Iain McCULLOCH from Princeton University, United States, delivered the 34^th PAIR Distinguished Lecture titled “Designing Organic Semiconductors to Optimise Charge Transport” on 14 January 2025 on PolyU campus. The lecture attracted over 100 participants to join in person and captivated an online audience of over 12,700 from different countries and regions who watched the live broadcast on multiple social media platforms, including Bilibili, WeChat, Weibo and YouTube.

The lecture commenced with a warm welcome and introduction of the speaker by Prof. CHEN Qingyan, Director of PAIR. Prof. McCulloch kickstarted his presentation by giving a brief overview of the current molecular designs of organic semiconductor polymers for charge transport. He explained how they enable organic thin film transistors to achieve high charge carrier mobility and their applications in flexible screens and other electronic devices. He then elaborated on the molecular characteristics of the indacenodithiophene-co-benzothiadiazole copolymer, a semiconductor polymer that exhibits high carrier mobility and is commonly used in organic transistors.

Prof. McCulloch also emphasised the importance of “conformational coplanarity” and “side chain assisted self-assembly”. These features help enhance one-dimensional transport along the “conjugated polymer backbone” and form sterically free “crossing points”, allowing charges to hop between chains. He further highlighted that current research has shown that the molecular conformation and film microstructure are influenced by the design and processing conditions of organic semiconductor polymers, and these significant findings can help achieve optimal charge transport properties.

Following the presentation was a question-and-answer session moderated by Prof. YAN Feng, Associate Director of the Research Institute for Intelligent Wearable Systems (RI-IWEAR) and Chair Professor of Organic Electronics in the Department of Applied Physics. The audience engaged in a productive discussion with Prof. McCulloch.

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