Alan J. Heeger and his colleagues discovered conducting polymers, a novel class of materials with electrical and optical properties like metals and semiconductors, coupled with the mechanical and processing advantages of polymers. They won the Nobel Prize in Chemistry 2000 "for the discovery and development of conductive polymers".

1936-1962: Education
1957 - B.S. with High Distinction, University of Nebraska
1961 - Ph.D., University of California, Berkeley

ALAN J. HEEGER was raised in Nebraska, whence he had come from his hometown of Sioux City, Iowa. Here he took an early interest in science and mathematics. "I didn't find it particularly easy," he said. "In fact, that was part of the reason I wanted to go farther with it. There must be something here I can understand."

He went to the University of Nebraska for his undergraduate studies, where he picked engineering as his major - for one quarter. With no experience in the subject, he changed his major to physics. But something bothered him. "Somehow," he said, "I always felt this wasn't the real stuff yet, and I was looking forward to graduate school for that." Intellectually curious, he early attracted attention in the physics department. Retired physics professors today recall him as "outstanding", "enthusiastic"; even teachers he did not know knew of him.

As a graduate student at UC Berkeley, Heeger got his chance. "I remember the first day in the laboratory," he said. "The courses are very important, but I just didn't feel I was really doing science until I was doing my own science, and that was such a thrill for me. I got a big kick out of it."

1962-1982: University of Pennsylvania Professor

His lab work at UC Berkeley led to a degree in condensed matter physics and a position as assistant professor at the University of Pennsylvania, where he would stay for the next 20 years, climbing the ranks from assistant to associate professor, to professor, and finally, for his last year, to vice provost for research.

Much of the groundwork for the Nobel Prize came in those years; it was at Pennsylvania that Heeger met and began to work with his fellow Nobel laureates Alan MacDiarmid and Hideki Shirakawa. It was also at Pennsylvania that Heeger began his work on plastics. In 1975, he took a polymer he had been working on, made up of repeated units of sulfur and nitrogen, to a chemistry professor named Alan MacDiarmid, who had some expertise in synthesis.

The two talked for a couple of hours. But all of a sudden, Heeger realized something. He had been saying SN-SN (a chain of disulfur nitride molecules bonded together), while MacDiarmid had been hearing Sn-Sn (a chain of tin atoms). He had been trying to convince MacDiarmid that he had made a metal, when, as "any chemist knows, and he was a chemist, that tin should be a metal. What's the big deal?"

1970s: First Experiments With Polyacetylene

A polymer, like polyacetylene, is a long string of molecules chained together, with one unit repeated over and over again. For polyacetylene, the repeating unit is a carbon atom bonded to one hydrogen atom, and connected to two other carbon atoms in the chain. Because carbon has enough electrons to form four bonds, it has one extra electron, which, Heeger suspected, could be moved. The movement of electrons leads to an electric current.

In 1977, MacDiarmid went to Japan to give a lecture on the future of polymers. There, he met a young Japanese man named Hideki Shirakawa, who had conducted his own work on polyacetylene. After MacDiarmid and Heeger convinced Shirakawa to join them in Pennsylvania, their work got one step closer to the ultimate prize in chemistry.

At the same time, Heeger had climbed the ranks to a spot as professor, and he tried work as an administrator for a year. During that time, a colleague and friend named Robert Schrieffer, a UCSB professor and also a Nobel laureate, asked Heeger to come to Santa Barbara.

He flew out to the school and looked around, and decided against it. But a few months later, there was a scientific conference in Colorado, and after that Heeger was "keyed up" on the experimental science. "This was what I wanted to do," Heeger said. "I didn't want to go back and do administration anymore, so I called up Schrieffer, and I said, 'I'm on my way to Santa Barbara to talk business.' We did it in a few days, and I came a few months later in July 1982, and have never been sorry since. It's been great here."

1982-2000: UCSB (University of California, Santa Barbara)

Plastics are polymers, molecules that repeat their structure regularly in long chains. For a polymer to be able to conduct electric current it must consist alternately of single and double bonds between the carbon atoms. It must also be "doped", which means that electrons are removed (through oxidation) or introduced (through reduction). These "holes" or extra electrons can move along the molecule - it becomes electrically conductive.
 

Alan Heeger, 1982

Heeger and two other scientists, MacDiarmid and Shirakawa, made their seminal findings at the end of the1970s and have subsequently developed conductive polymers into a research field of great importance for chemists as well as physicists. The area has also yielded important practical applications. Conductive plastics are used in, or being developed industrially for, e.g. anti-static substances for photographic film, shields for computer screen against electromagnetic radiation and for "smart" windows (that can exclude sunlight). In addition, semi-conductive polymers have recently been developed in light-emitting diodes, solar cells and as displays in mobil telephones and mini-format television screens. Research on conductive polymers is also closely related to the rapid development in molecular electronics. In the future we will be able to produce transistors and other electronic components consisting of individual molecules - which will dramatically increase the speed and reduce the size of our computers. A computer corresponding to what we now carry around in our bags would suddenly fit inside a watch

The 1980s were a decade of advances in polymer science, where researchers uncovered many of the underlying chemical and physical principles of the plastics. "It looked like the materials were coming to a point of maturity where you could see the possibility of commercial products or applications," Heeger said.

In the 1990s, scientists like Heeger began to first consider the applications of polymers - a wildly successful consideration. The new polymers have all the conducting properties of metal semiconductors, but they keep the properties of plastic as well. They can be melted, put in solutions and processed cheaply.

He now predicts by 2001, people will be able to buy cellular phones with polymer light emitting diode (LED) displays. There has also been work to make plastic integrated circuits, plastic displays and plastic labels. In recent years, Heeger has moved into applications, exploring the use of polymers in bio-sensors with his son Peter. It's a new way of doing science, reaching across disciplines, but one that has always been a hallmark of Heeger's career. Research on conductive polymers is closely related to the new developments in molecular electronics. To the lay person this will mean transistors and other electronic components consisting of individual molecules. These will dramatically speed up and miniaturize our computers; a computer like one we now carry around will one day fit inside a watch.
 

"You're learning," he said. "It's a little dangerous, because you're pushing into directions you know little about, so you can make a mistake. So, you really need colleagues to interact with, to help the whole thing keep on the right track. But basically, my whole scientific life has been an example of interdisciplinary science. I started out as a physicist, but I guess I am what I have become."

Professor Heeger and his colleagues at the University of California, Santa Barbara have done pioneering research in the area of semiconducting and metallic polymers. This class of novel materials has the electrical and optical properties of semiconductors and metals in combination with the processing advantages and mechanical properties of polymers. He has not only been a leading personality in the discovery of conducting polymers, but also a pioneer in exploring the basic science underlying their properties and in establishing the conceptual and theoretical framework of the entire field. In addition, he encouraged the development of these novel polymers into stable materials suitable for broad use by industry in a wide range of applications.

Heeger and associates discovered "counter-ion induced processible polyaniline technology" to the point it can be used in many industrial products. Examples of applications include conducting polymers blends for electromagnetic shielding and for anti-static packaging; conducting polymers for use in electrochemistry (including electrochromic windows and novel polymers batteries) and semiconducting polymers for use in the emerging field of "plastic electronic devices" which already include diodes, photodiodes, light-emitting diodes and transistors. As a result of this process, a new field has developed at the interface of chemistry and physics. A host of new concepts has evolved which are of broad and fundamental scientific importance in fields ranging from quantum chemistry to polymer chemistry; from electrochemistry to condensed matter physics, from semiconductor devices physics to electronic materials engineering. UNIAX Corporation, founded by Heeger and his colleague Paul Smith in 1990 focuses on bringing plastic electronics into commercial products.

His current research interests lie in the area of transport in semiconducting polymers and light emission from semiconducting polymers (both photoluminescence and electroluminescence). His research group focuses on issues related to the fundamental electronic structure of this novel class of materials and carries out studies of light emitting diodes (LEDs), light-emitting electrochemical cells (LECs), and lasers, all fabricated from semiconducting (conjugated) polymers. Experimental facilities provide the capability for a broad range of spectroscopic studies (including ultrafast, fs, time resolved spectroscopy), quantitative measurement of photoluminescence and electroluminescence quantum efficiencies, optical gain/loss of conjugated polymer/oligomer laser materials, and photoconductivity (steady state and time resolved with sub-ns time resolution).

Heeger has won numerous awards including the Alfred P. Sloan Foundation Fellowship; the Balzan Prize, Science of New Materials, from Switzerland; Fellow of the American Physical Society, and the John Simon Guggenheim Foundation Fellowship, among many others.
 

Diploma with original artwork representing polyacetylene

Heeger won the 2000 Nobel Prize in Chemistry together with MacDiarmid and Shirakawa. The 2000 Nobel Prize in chemistry was awarded "for the discovery and development of conductive polymers." Plastics were long thought to be non-conductors of electricity and indeed have been used as insulation. Heeger and his fellow Nobel Laureates were rewarded for their revolutionary discovery that plastic can be made electrically conductive. Such a finding creates a new research field for chemists as well as physicists.

 

Alan Heeger receives the Nobel prize in Chemistry from the King of Sweden

Alan Heeger shows the medal to his granddaughters Aliceand Julia

See also the 2000 Nobel Prize in Chemistry Presentation Speech presented by Professor Bengt Nordén, The Royal Swedish Academy of Sciences.