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?