Transcript Graphene based transistor

The development of skin-like
electronic devices(E-skin)
e-skin: electronic devices with flexible&stretchable networks
and sensing functionalities that akin to human skin
Yuhang Sun
April/15/2016
Basic sense
Touch
(tactition)
Sight
Movement
(vision)
(balance)
sense
Hearing
Taste
(audition)
(gustation)
Smell
(olfaction)
Skin: largest sensory organ in human body ,full of different types of sense receptors.
Outline
• Originality
• Materials mainly used
• Four Transduction mechanisms
• Novel Desirable Properties for E-Skin
originality
applicable for autonomous artificial intelligence(robots)
apply on/in human body to provide an unprecedented level
of diagnostic and monitoring capabilities
Luke skywalker was installed a hand with full sensory receptions
First e-skin in history
• In 1985, General Electric(GE) built the first sensitive
skin with 64 infrared sensor pairs on it, the
resolution is 5cm.
Materials & Considerations
Goal: mechanical compliant(flex & stretch)
Materials
How to make it stretchable
1.Dielectrics(elastomers, polymers)
• With addition of inorganic high k particles, especially suitable
for flexible transistors. Elastomers(PDMS, PVDF)mixed with
(TiO2, BaTiO3 or ionic liquid)
PVDF+inoic liquid by Lee’s group [1]
2. CNT based or Graphene based active material
• Carrier mobility:
CNT: 10000cm2V-1s-1, graphene: 20000cm2V-1s-1
Graphene films deposit on Ni film(left)&SiO2(right)substrate by CVD[2]
3.Nanowire based-active materials
Difficult to fabricate NWs into ordered array, LBL make it
possible for NW to integrated on flexible substrate; expensive
Layer by Layer(LBL) assembly for 3D structure Nam’s group [3]
Transduction mechanism
• 1.Piezoresistivity
• transduce a change in the resistance of a device into a
measurement of strain
• Most extensively investigated
• have been incorporated into highly flexible and stretchable
devices using connections made from liquid metal, stretchable
helical electrodes, stitched metallic electrodes
2.capacitance
• C = ε 0 ε r A / d,
• The change in d is commonly used to measure normal forces,
• changes in A are typically used to measure shear forces
• This method is not widely pursued:
• I. reducing the pixel size of these devices for miniaturization reduces the
capacitance and the signal-to-noise ratio
• II. capacitive sensors are susceptible to interference from external sources
3.Piezoelectricity
• Piezoelectricity refers to the ability of a material to
generate a voltage in response to an applied force.
• The force causes a change in the length and
separation between dipoles in the material, leading
to the build-up of compensating charges on the
electrodes
• Most popular piezoelectric materials: PZT(lead
zirconate titanate)&ZnO
4. Optics
• convert a tactile input into an electrical output using
light as an intermediate
• Consist of light source, transmission medium, and
detector
Work reported by Bao’s group
Novel Desirable Properties for E-Skin
• 1. biodegradable
2.Highly-integrated & 3. wireless detection
• Which means e-skin can be transferred onto human body in
a manner similar with human skin.
it’s like a tattoo, made based on a water soluble based PVA, it can detect
Other ones
• 4. self-powered
• 5. self-healing
• 6. temperature-detection
• ……
citations
•
•
•
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[1] K. H. Lee, M. S. Kang, S. P. Zhang, Y. Y. Gu, T. P. Lodge, and C. D. Frisbie, ""Cut
and Stick" Rubbery Ion Gels as High Capacitance Gate Dielectrics," Advanced
Materials, vol. 24, pp. 4457-4462, Aug 2012.
[2] A. Reina, X. T. Jia, J. Ho, D. Nezich, H. B. Son, V. Bulovic, et al., "Large Area,
Few-Layer Graphene Films on Arbitrary Substrates by Chemical Vapor Deposition,"
Nano Letters, vol. 9, pp. 30-35, Jan 2009.
[3] A. Javey, S. Nam, R. S. Friedman, H. Yan, and C. M. Lieber, "Layer-by-layer
assembly of nanowires for three-dimensional, multifunctional electronics," Nano
Letters, vol. 7, pp. 773-777, Mar 2007.
[4] J. A. Rogers, "Epidermal electronics," Abstracts of Papers of the American
Chemical Society, vol. 243, p. 1, Mar 2012.
[5] X. L. Wang, H. Hu, Y. D. Shen, X. C. Zhou, and Z. J. Zheng, "Stretchable
Conductors with Ultrahigh Tensile Strain and Stable Metallic Conductance Enabled
by Prestrained Polyelectrolyte Nanoplatforms," Advanced Materials, vol. 23, pp.
3090-+, Jul 2011.
[6] K. S. Kim, Y. Zhao, H. Jang, S. Y. Lee, J. M. Kim, K. S. Kim, et al., "Large-scale
pattern growth of graphene films for stretchable transparent electrodes," Nature,
vol. 457, pp. 706-710, Feb 2009.
Five key points
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1.what is e-skin(definition)
2.originality of developing e-skin(two aspects)
3.three main types of materials used
4. four transduction methods
5.novel properties