Conformable, flexible, large-area networks of pressure and thermal sensors with organic transistor active matrixes

doi:10.1073/pnas.0502392102

Conformable, flexible, large-area networks of pressure and thermal sensors with organic transistor active matrixes

^*Quantum-Phase Electronics Center, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; and ^‡Center for Collaborative Research, University of Tokyo, Tokyo 153-8505, Japan

Edited by George M. Whitesides, Harvard University, Cambridge, MA, and approved July 16, 2005 (received for review March 23, 2005)

Abstract

Skin-like sensitivity, or the capability to recognize tactile information, will be an essential feature of future generations of robots, enabling them to operate in unstructured environments. Recently developed large-area pressure sensors made with organic transistors have been proposed for electronic artificial skin (E-skin) applications. These sensors are bendable down to a 2-mm radius, a size that is sufficiently small for the fabrication of human-sized robot fingers. Natural human skin, however, is far more complex than the transistor-based imitations demonstrated so far. It performs other functions, including thermal sensing. Furthermore, without conformability, the application of E-skin on three-dimensional surfaces is impossible. In this work, we have successfully developed conformable, flexible, large-area networks of thermal and pressure sensors based on an organic semiconductor. A plastic film with organic transistor-based electronic circuits is processed to form a net-shaped structure, which allows the E-skin films to be extended by 25%. The net-shaped pressure sensor matrix was attached to the surface of an egg, and pressure images were successfully obtained in this configuration. Then, a similar network of thermal sensors was developed with organic semiconductors. Next, the possible implementation of both pressure and thermal sensors on the surfaces is presented, and, by means of laminated sensor networks, the distributions of pressure and temperature are simultaneously obtained.

Footnotes

↵ † To whom correspondence should be addressed at: Quantum-Phase Electronics Center, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Engineering Building 8, Room 315, Tokyo 113-8656, Japan. E-mail: someya{at}ap.t.u-tokyo.ac.jp.
Author contributions: T. Someya designed research; T. Someya, Y.K., T. Sekitani, S.I., Y.N., Y.M., H.K., and T. Sakurai performed research; and T. Someya wrote the paper.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations: E-skin, electronic artificial skin; I _DS, source–drain current; PTCDI, 3,4,9,10-perylene-tetracarboxylic-diimide; parylene, polychloro-para-xylylene; CuPc, copper phthalocyanine; V _DS, source–drain voltage; V _GS, source–gate voltage.
Freely available online through the PNAS open access option.