Professor Sirringhaus is a renowned expert in charge transport physics of organic semiconductors and other functional materials processed at low temperature. He is the Hitachi Professor of Electron Device Physics at the Cavendish Laboratory, University of Cambridge. Sirringhaus was awarded a Royal Society Research Professorship in 2020 and Faraday Medal in 2015.
Professor Sirringhaus is FlexEnable’s Chief Scientist and sits on the company’s Board of Directors.
In this Q&A, Sirringhaus shares some personal insights into his career and explains why he’s excited about the future of organic semiconductor materials.
How did you first become interested in organic electronics?
I first ran across organic semiconductors during a post-doctoral position in Princeton in 1995. I was working on amorphous silicon transistors at the time and felt a bit bored with this, at least in terms of basic science, because pretty much everything was already known about amorphous silicon at that time. Organics on the other hand were much less understood and looked really exciting and fresh. I started to work on organics on the side in Princeton, but then chose to investigate them further as part of my second post-doctorate in Cambridge.
What makes organic electronics unique? Why should we be excited about it?
What keeps me fascinated about organic semiconductors is this incredible versatility of the materials chemistry. Chemists can synthesize a very rich variety of molecules and we continue to discover new families of organic semiconductors with really surprising properties and better and better performance. This has kept the field exciting and dynamic over the last three decades.
What have been the most significant breakthroughs you have seen during your career?
When I started working on organic field-effect transistors carrier mobilities were more than 100 times less than amorphous silicon. Over the years we’ve discovered families of organic semiconductors that had higher and higher carrier mobilities, and today the best organic semiconductors are 10 times better than amorphous silicon. That is quite an amazing advance.
What is the performance potential of organic semiconductor materials? Can they get even better?
It is difficult to know how high the mobility of organic semiconductors could go. It is certainly not easy to discover new and better materials, but from time to time it happens. I would certainly argue that mobilities between 10-20 cm2/Vs should be achievable in a reliable and manufacturable manner and it is quite possible that even higher values could be achieved in the next 5-10 years.
What other applications there are for organic semiconductor materials beyond displays and sensors?
There is currently a lot of excitement about applications in bioelectronics, where the mechanically soft and stretchable nature of organic materials enables very gentle contacts and interfaces to human tissue, both for unobtrusive on-skin electronics for health monitoring or even in-vivo applications for treating serious medical conditions. Organics are also very interesting for energy applications, such as solar cells or thermoelectrics, as the materials are environmentally very benign (they do not contain any toxic, heavy metal elements) and their performance in these applications is starting to rival that of inorganic semiconductors.
What is the most important thing happening in your field at the moment?
Scientifically, what is very exciting is that we are gaining a similarly microscopic and detailed understanding of the underpinning materials and device physics to that which is already available for inorganic semiconductors such as silicon. Many aspects of the physics turn out to be quite unique and rather different from silicon. Ultimately, this is important as well for applications, because a deep understanding of the materials physics is important for controlling the technology.
What are your predictions for organic electronics in the next three years?
Organic electronics is definitely here to stay and will find uses in more and more mass-market applications beyond displays. Organic semiconductors will keep surprising us.
What would you advise students considering a career in organic electronics?
When I first started working seriously in this field back in Cambridge 1997, one of the first things I did was to buy myself an organic chemistry textbook, because I was a bit scared of chemists. They turned out to be very nice people with whom it is a lot fun to work, but it is important to be able to at least understand their language. It is an interdisciplinary field, in which you work most productively if you can engage with scientists from related disciplines.