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Carbon-Based Materials for Flexible Electronics
Dr. Nan Liu Professor Zhenan Bao Group
Department of Chemical Engineering, Stanford University Sep 10, 2015
Flexible Electronics in Life
Approach to Flexible Electronics
Our Approach to Flexible Electronics
Silicon mould
ITO/PET
On OffFly on sensor
Cap
acita
nce
(× 1
0¬1
1 F)
10 20 30
Time (s)
40 50
2.88
2.87
2.86
2.85
2.84
2.89
2.83
PETApply pressure
ITO
Microstructured PDMS
Laminate
Pil2TSi semiconductingpolymer Thin PDMS
BCB
Polyimide
Au source / drain
Carbon-Based Materials: CNTs
Source/Drain
0
1
2
3
4
5
(1,1)(1,0)(0,1)
Vol
tage
(V)
(0,0)
0
1
2
3
4
5
(1,1)(1,0)(0,1)
Vol
tage
(V)
(0,0)
NAND Gate
Highly Robust All-CNT Stretchable Transistors
0->100% strain
Carbon-Based Materials: Graphene
•
•
Better Interaction between Carbon-Based Materials
Graphene-CNT Stretchable Transistors
Graphene toward Ideal Electronic Materials
Importance of Controlled Fermi Level
•
•
Design New n-type Dopant
Process of Doping Graphene
Transport Behavior Before and After n-doping
UPS Study Before and After n-doping
• •
Application 1: Inverter
Application 2: p-n Junction
•
•
Fabrication of Graphene p-n Junctions
• •
Formation of p-n Junctions
Photoresponse of p-n Junctions
Photocurrent density (10-4A/cm2) †
Photoresponsivity (mA/W)
(5.50±0.47) 104 (1.20±0.11) ) 104
• • •
Transparent and Flexible IR Photodetectors
• •
Summary I
• •
Outline
Why Bandgap?
• •
Bandgap in GNR
Eg(eV ) =0.8
w(nm)
Synthetic Approaches to GNRs — Bottom up
DNA Bio-template to GNRs
GNRs from DNA
Electrospinning
Electrospun Polymer to GNRs
Overview of the GNRs - Morphology
Overview of the GNRs – Electronic Properties
Effect of Chemical Structure on the Graphitization Degree
Ω
Effect of Chemical Structure on the Graphitization Degree
Summary II
• •
Conclusion
Acknowledgement
Any questions?