Jointly published by Akadémiai Kiadó, Budapest Scientometrics, Vol. 79, No. 2 (2009) 365–375 and Springer, Dordrecht DOI: 10.1007/s11192-009-0424-0 Received December 5, 2007 Address for correspondence: HENRY SMALL E-mail: henry.small@Thomson.com 0138–9130/US $ 20.00 Copyright © 2008 Akadémiai Kiadó, Budapest All rights reserved Citation structure of an emerging research area on the verge of application HENRY SMALL, a PHINEAS UPHAM b a Thomson Reuters, 3501 Market St., Philadelphia, Pa. 19104, USA b The Wharton School, University of Pennsylvania, 3620 Locust Walk, Philadelphia, Pa. 19104, USA A case study of an emerging research area is presented dealing with the creation of organic thin film transistors, a subtopic within the general area called “plastic electronics.” The purpose of this case study is to determine the structural properties of the citation network that may be characteristic of the emergence, development, and application or demise of a research area. Research on organic thin film transistors is highly interdisciplinary, involving journals and research groups from physics, chemistry, materials science, and engineering. There is a clear path to industrial applications if certain technical problems can be overcome. Despite the applied nature and potential for patentable inventions, scholarly publications from both academia and industry have continued at a rapid pace through 2007. The question is whether the bibliometric indicators point to a decline in this area due to imminent commercialization or to insurmountable technical problems with these materials. Introduction Organic semiconductors have been known since the 1940s, and the first transistor based on an organic semiconductor was reported in 1986 [COLLINS, 1986]. The 2000 Nobel Prize in Chemistry recognized the contributions to this area by Heeger, MacDiarmid, and Shirakawa for work done in the late 1970s. They were able to create semiconductors by doping the polymer polyacetylene. Conducting plastics have already been used in a number of applications, such as light emitting diodes. However, research in this field has recently picked up pace with new discoveries and the introduction of new materials. Organic thin film transistors hold out the promise of the inexpensive manufacture of electronic and computing devices by printing on plastic. They have attracted much interest due to their potential applications in low-cost, light-weight, flexible, large-area applications such as smart cards, radio-frequency identification tags, flat panel displays, and computing in clothing. Hence, this is an example of a basic science field with great practical potential. However, despite this progress and potential, several technical issues remain to be resolved before organic thin film transistors can be in wide scale use.