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Transcript of ACS CERM Presentation
![Page 1: ACS CERM Presentation](https://reader031.fdocuments.us/reader031/viewer/2022022001/588afc751a28abf8548b6283/html5/thumbnails/1.jpg)
Surface Potential Heterogeneity in Organic Semiconductors
Paula HoffmannACS CERM
October 29, 2014
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Semiconductor IndustryInorganic Organic
synthetically tailorable
low cost
highly processable
wide-‐spread industry
high stability
ef8icient
Forrest, S.R., Nature, 2004, 428, 911-918; http://www.solarpanels.net.in/
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Semiconductor IndustryInorganic Organic
synthetically tailorable
low cost
highly processable
wide-‐spread industry
high stability
ef8icient
Forrest, S.R., Nature, 2004, 428, 911-918; http://www.solarpanels.net.in/
high cost low ef9iciency
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Semiconductor Disorder
Typical disorder caused by:
defects
traps and barriers
molecular motion/
vibration
ACS Nano, 2011 5 pp. 8579
J Phys Chem C, 2012 116 pp.11852
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!Z!Scanning!
Laser
Photodiode Detector
Cantilever
Height Feedback
Potential Feedback
X*Y!Scanning!Bias Feedback Control
Sample
Sample Holder
Height and Potential Images
Atomic Force Microscopy
Advantages: Spatial resolution Versatile-‐ many techniques
Disadvantages Instrument artifacts Max scan area-‐ 20 x 20 μm2
Substrate
Cantilever
Substrate
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Kelvin Probe AFM5
4
3
2
1
0
µm
543210µm
-10
0
10
nm
5
4
3
2
1
0
µm
543210µm
888684828078
mV
Height Scan Potential Scan
Potential Histogram
![Page 7: ACS CERM Presentation](https://reader031.fdocuments.us/reader031/viewer/2022022001/588afc751a28abf8548b6283/html5/thumbnails/7.jpg)
Kelvin Probe AFM5
4
3
2
1
0
µm
543210µm
-10
0
10
nm
5
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2
1
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µm
543210µm
888684828078
mV
10008006004002000
Cou
nts
100mV90807060Potential (V)
Height Scan Potential Scan
Potential Histogram
![Page 8: ACS CERM Presentation](https://reader031.fdocuments.us/reader031/viewer/2022022001/588afc751a28abf8548b6283/html5/thumbnails/8.jpg)
Kelvin Probe AFM5
4
3
2
1
0
µm
543210µm
-10
0
10
nm
5
4
3
2
1
0
µm
543210µm
888684828078
mV
10008006004002000
Cou
nts
100mV90807060Potential (V)
Height Scan Potential Scan
Potential Histogram
10008006004002000
Cou
nts
100mV90807060Potential (V)
![Page 9: ACS CERM Presentation](https://reader031.fdocuments.us/reader031/viewer/2022022001/588afc751a28abf8548b6283/html5/thumbnails/9.jpg)
Kelvin Probe AFM5
4
3
2
1
0
µm
543210µm
-10
0
10
nm
5
4
3
2
1
0
µm
543210µm
888684828078
mV
Height Scan Potential Scan
Potential Histogram
10008006004002000
Cou
nts
100mV90807060Potential (V)
5004003002001000
Cou
nts
80nm400-40Height (nm)
Height Histogram
![Page 10: ACS CERM Presentation](https://reader031.fdocuments.us/reader031/viewer/2022022001/588afc751a28abf8548b6283/html5/thumbnails/10.jpg)
Surface Potential Distributions
J. Phys. Chem. C, 2013 117 pp. 18367
P3HT%
PEDOT:PSS%%
A)#Varying#Materials#(ITO)#
3T%
NiPS% MgO%
SiO2%
B)#Varying#Substrates#(P3HT)#
ITO%
Au%
NN
N
NN
N
N
NNi
SO3--O3S
SO3--O3S
SSS
S
OO
SO3-
S
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Positive charges form nanoscale trap “islands” Negative charges morehomogeneous
distances
probability
-+
-
-
+
+
Energy (eV)
Surface PotentialDistribution
J. Phys. Chem. C, 2013 117 pp. 18367
Spatially Inhomogeneous Trapping
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Experimental KPFM
Simulated Surface Potentials
Experiment vs. Simulation: Mixed Disorder
J. Phys. Chem. C, 2013 117 pp. 18367
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Imprinting Process
20
15
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µm
20151050µm
-40
-20
0
20
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nm
20nm
0
-20
Height
20µm151050Position
Org. Electron. 2011 12 pp.1241
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Patterned P3HT
20
15
10
5
0
µm
20151050µm
-100-50050100
nm
20
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µm
20151050µm
-80
-40
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40
80
nm
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µm
20151050µm
-100-50050100
nm
20
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0
µm
20151050µm
-50
0
50
nm
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P3HT-‐PCBM Patterns20
15
10
5
0
µm
20151050µm
-10
0
10
nm
20
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0
µm
20151050µm
-10
0
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mV
20
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µm
20151050µm
-50
0
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nm20
15
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5
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µm
20151050µm
-196
-192
-188
-184
mV
5 µm dot
2 µm dotHeight Potential
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P3HT-‐PCBM Patterns
20
15
10
5
0
µm
20151050µm
-10
0
10
nm20
15
10
5
0
µm
20151050µm
-10
0
10
mV
20
15
10
5
0
µm
20151050µm
-50
0
50
nm20
15
10
5
0
µm
20151050µm
-196
-192
-188
-184
mV
5 µm dot
2 µm dotHeight Potential
4003002001000
Cou
nts
80mV6040200-20-40Potential (mV)
![Page 17: ACS CERM Presentation](https://reader031.fdocuments.us/reader031/viewer/2022022001/588afc751a28abf8548b6283/html5/thumbnails/17.jpg)
P3HT-‐PCBM Patterns
20
15
10
5
0
µm
20151050µm
-10
0
10
nm20
15
10
5
0
µm
20151050µm
-10
0
10
mV
20
15
10
5
0
µm
20151050µm
-50
0
50
nm
20
15
10
5
0
µm
20151050µm
-196
-192
-188
-184
mV
5 µm dot
2 µm dotHeight Potential
8006004002000
Cou
nts
-0.21V -0.20 -0.19 -0.18 -0.17Potential (V)
4003002001000
Cou
nts
80mV6040200-20-40Potential (mV)
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P3HT-‐PCBM Patterns20
15
10
5
0
µm
20151050µm
-20
0
20
nm
20
15
10
5
0
µm
20151050µm
-150
-148
-146
-144
-142
-140
mV
10
8
6
4
2
0
µm
1086420µm
-20-1001020
nm10
8
6
4
2
0
µm
1086420µm
280
260
240
220
mV
2 µm lines
StarHeight Potential
![Page 19: ACS CERM Presentation](https://reader031.fdocuments.us/reader031/viewer/2022022001/588afc751a28abf8548b6283/html5/thumbnails/19.jpg)
P3HT-‐PCBM Patterns
20
15
10
5
0
µm
20151050µm
-20
0
20
nm
20
15
10
5
0
µm
20151050µm
-150
-148
-146
-144
-142
-140
mV
10
8
6
4
2
0
µm
1086420µm
-20-1001020
nm10
8
6
4
2
0
µm
1086420µm
280
260
240
220
mV
2 µm lines
StarHeight Potential
600
400
200
0
Cou
nts
-0.160V -0.155 -0.150 -0.145 -0.140 -0.135Potential (V)
![Page 20: ACS CERM Presentation](https://reader031.fdocuments.us/reader031/viewer/2022022001/588afc751a28abf8548b6283/html5/thumbnails/20.jpg)
P3HT-‐PCBM Patterns
20
15
10
5
0
µm
20151050µm
-20
0
20
nm
20
15
10
5
0
µm
20151050µm
-150
-148
-146
-144
-142
-140
mV
10
8
6
4
2
0
µm
1086420µm
-20-1001020
nm
10
8
6
4
2
0
µm
1086420µm
280
260
240
220
mV
2 µm lines
StarHeight Potential
600
400
200
0
Cou
nts
0.30V0.280.260.240.220.20Potential (V)
600
400
200
0
Cou
nts
-0.160V -0.155 -0.150 -0.145 -0.140 -0.135Potential (V)
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Patterning and Potential Distributions
20
15
10
5
0
µm
20151050µm
-40
-20
0
20
40
nm
5004003002001000
Cou
nts
-0.40V -0.38 -0.36 -0.34 -0.32 -0.30Potential (V)
20
15
10
5
0
µm
20151050µm
-0.37
-0.36
-0.35
-0.34
V
Height Potential
5004003002001000
Cou
nts
-0.40V -0.38 -0.36 -0.34 -0.32 -0.30Potential (V)
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Implications for Transport
Evidence of “hot pathways” for transport
Long time scans show changing
shape
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ConclusionsAsymmetry in potential distributions not always
due to morphological disorder. Indicative of an electronic disorder not commonly
observed
Electronic disorder likely exists in two time domains
Future experiment:?
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Thanks! Questions?
Acknowledgements
Additional work done by: Izzy Ortiz
Rachel Wilson Dr. Geoff Hutchison
Other group members: Chris Marvin
Ilana Kanal Kyle Reese Michelle Hu
Michael Moody