structure-function relationships in organic field effect transistors kirsten parratt summer 2011 loo...
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Structure-Function Relationships in Organic Field Effect Transistors
Kirsten ParrattSummer 2011
Loo Group
Why Organic Semiconductors?
An alternative to inorganic electronics:• Easier manufacturing• Low temperature processing• Solution processing • Lower costs• Flexible substrates
What are Organic Semiconductors?
What advantages do they offer?
Image:s http://www.konarka.com/index.php/power-plastic/about-power-plastic/http://www.physorg.com/news/2011-02-carbon-nanotube-transistors-inexpensive-flexible.html
How it works-Physical
Silicon
Silicon OxideActive Layer
Gold Contacts
-60 -40 -20 0 20 40
0
1x10-3
2x10-3
3x10-3
4x10-3
5x10-3
6x10-3
7x10-3
[IS
D]1/
2 (A1/
2)
Gate Voltage (V)
Devices
SS
Si
Si
SS
Si
Si
Cl Cl
TesADT
Cl-TesADT
Processing Steps:•Weigh out compounds•Dissolve in solution•Clean SiO2 wafer•Spincast/dropcast onto substrate•Evaporate gold contacts
Device Results
0 20 40 60 80 10010-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1M
ob
ilit
y (
cm
2 /Vs
)
%ClTesADT
AFM
0 mol%62.5 mol% 100 mol%
50 mol%
0 20 40 60 80 1001E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0.01
0.1
Mo
bil
ity
(c
m^
2/V
s)
%ClTesADT
DSC
0.0 12.5 25.0 37.5 50.0 62.5 75.0 87.5 100.0120
140
160
180
200
220
240
260
280
Me
ltin
g P
oin
t (o
C)
%ClTesADT
Eutectic Grain Boundaries
Conclusion
• At 62.5% ClTesADT and 37.5%TesADT, a eutectic point forms
• This eutectic point has the highest intermixing and therefore the greatest grain connectivity
• As a result, OFETs with this molecular structure have higher hole mobility and function better
• Future work could involve other TesADT derivatives
Acknowledgements
• Professor Loo• Stephanie Lee• Loo Lab Group• Princeton Environmental Institute
qxy
(A-1)
q z (A
-1)
0.6 0.8 1 1.2 1.4 1.6 1.8
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
qxy (A-1)q z
(A-1
)
0.6 0.8 1 1.2 1.4 1.6 1.8
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
qxy
(A-1)
q z (A
-1)
0.6 0.8 1 1.2 1.4 1.6 1.8
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
qxy
(A-1)
q z (A
-1)
0.6 0.8 1 1.2 1.4 1.6 1.80
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
qxy
(A-1)
q z (A
-1)
0.6 0.8 1 1.2 1.4 1.6 1.8
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
qxy
(A-1)
q z (A
-1)
0.6 0.8 1 1.2 1.4 1.6 1.8
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
12.5mol% 37.5mol% 50mol%
62.5mol% 87.5mol% 100mol%
GIXD