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PUBLISHED ONLINE: 12 SEPTEMBER 2010 | DOI: http://www.nature.com/doifinder/10.1038/nmat2834
Web End =10.1038/NMAT2834
Highly sensitive exible pressure sensors with microstructured rubber dielectric layers
Stefan C. B. Mannsfeld1, Benjamin C-K. Tee2, Randall M. Stoltenberg3, Christopher V. H-H. Chen1, Soumendra Barman1, Beinn V. O. Muir1, Anatoliy N. Sokolov1, Colin Reese1 and Zhenan Bao1*
The development of an electronic skin is critical to the realization of articial intelligence that comes into direct contact with humans, and to biomedical applications such as prosthetic skin. To mimic the tactile sensing properties of natural skin, large arrays of pixel pressure sensors on a exible and stretchable substrate are required. We demonstrate exible, capacitive pressure sensors with unprecedented sensitivity and very short response times that can be inexpensively fabricated over large areas by microstructuring of thin lms of the biocompatible elastomer polydimethylsiloxane. The pressure sensitivity of the microstructured lms far surpassed that exhibited by unstructured elastomeric lms of similar thickness, and is tunable by using different microstructures. The microstructured lms were integrated into organic eld-effect transistors as the dielectric layer, forming a new type of active sensor device with similarly excellent sensitivity and response times.
To produce electronic skin that emulates the properties of natural skin, large arrays of pressure-sensitive pixels on a flexible and stretchable substrate are required. Promising
routes towards stretchable matrix-type substrates1 and stretchable electrodes24 have been demonstrated in the past. However, there is still a need for a low-cost and large-area-compatible technology for producing pressure-sensitive pixels with sufficient sensitivity in both medium- (10100 kPa, suitable for object manipulation) and low-pressure regimes (<10 kPa, comparable to gentle touch5).
Organic field-effect transistors (OFETs) have been successfully used as active elements in display panels and sensor devices6,
and are considered key elements in large-area fabrication of logic elements on plastic and flexible substrates. Recently, OFETs were demonstrated to operate stably even under water7. The
OFET architecture is, therefore, an ideal choice for the active pixel element in a pressure-sensor array on flexible substrates for potential application as electronic skin. OFET technology has been used as the readout element for conductive rubber pressure sensors in pioneering works1,8, but neither pressure sensitivity in the low-pressure regime nor sufficient sensor responsiveness have been reported.
We present a new type of organic thin-film pressure-sensing device structure,...