Smart (nano)materials
and applications
Horst-Gűnter Rubahn
NanoSYD, The Mads Clausen Institute
University of Southern Denmark
What are smart materials ?
Materials that can significantly change their mechanical, thermal, optical, or
electromagnetic properties, in a predictable or controllable manner in response to
their environment.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
material
environmental change
effect
Piezoelectric materials (*)
Dielectric elastomers (*)
Polymers: pH and temperature-responsive (*)
Voltage
Voltage
pH and Temperature
Shape
Strain
Swell
Shape memory alloys or shape polymers
Electrochromic (liquid crystals), thermochr.,
photochromic (sunglasses)
Ferrofluids
Temperature and stress
Voltage, Temperature
Light
Magnetic field
Shape
Color,
Opacity
Magnetization
Application: LCD
Ferrofluids
d=10 nm
surfactant
No solidification:
Liquid seals on
rotating shafts of
Harddiscs; no wear
'water'
Fe3O4
High magnetic
susceptibility;
coexistence of
solid and liquid
How smart are ‘usual’ materials ?
phase transitions in materials
induce new properties
water as material with smart
properties
Materials that show tailored new properties, useful for smart device applications.
Advanced smart materials
Polarizable media: NLO and lasing materials
- e.g., the absorption changes as a function of light intensity
- frequency doubling and tripling, self focussing, chirping ...
Photonic band gap (PBG) materials
- the periodicity changes as a function of pressure
2μm diameter water
drops in polymer
Incoming wave
dielectric
Dielektrikum
In phase reflected
partial waves
Reflektierte
Teilwellen
Transmittierte
Welle
transmitted
wave annihilated
opals
dielectric
Out of phase reflected partial waves
transmitted wave not affected
Morpho retenor
Micron-scaled materials
- the properties change as a function of size and size depends on
external effects (the ’squeezed butterfly’)
Nano-scaled materials
- the properties depend on size and agglomeration and size and
agglomeration might depend on external effects (ferrofluids as
example)
Nanoparticular materials
C60 clusters
CdSe quantum dots
d=0.7 nm
Supersmall ball bearings:
Frictionless gliding
Composite for solar cells (PCBM)
Next generation dyes
Small size changes have strong optical effects
Quantum dots
quantum dots: reduced bleaching,
stable, simple('atomic') termscheme
2 nm
5 nm
-S-(CH2)n(CdTe)n
-COOH-
CdTe nanoparticles with stabilizing shell
2.5 - 6 nm
CdTe
Summary: Nanoscaled smart materials
quantum mechanics
New physics
via changed
- color, transparency
- hardness
- magnetism
- electr.conductivity
surface
New chemistry
via changed
- melting points
- reactivity
- catalysis
molecular recognition
Newbiology
via combination with
- self organisation
- self healing
- adaptation
- recognition
VDI & BMF: journey into nanocosmos
Smart nanomaterials can be produced via
top down & bottom up methods
or a combination of both
50 μm
Bottom up grown organic nanofibers
Organic molecular beam epitaxy
as
Mica
bs
dipoles
p-6P
nanofiber
γ
am
p-6P
Balzer and Rubahn,
Appl.Phys.Lett. ,2001
Surf.Sci., 2002.
Schiek et al., SMALL, 2008
Bottom up growth of organic nanoaggregates
Synthetic chemistry
makes this a
versatile technology ...
MOP4
Lighting, lasing,
waveguiding,
plasmonic,
electronic
applications.
5 μm
50 μm
para-hexaphenylene
50 μm
TTPPTT
sexithiophene
Smart nanofibers via synthetic chemistry
and surface growth
Nonlinear optically active materials:
Scalable optical frequency doublers
The idea:
λ
λ/2
The data:
Intensity [arb.units]
60000
50000
40000
30000
p6P
20000
10000
0
400
420
440
Wavelength [nm]
460
480
The idea:
λ
λ/2
Intensity [arb.units]
5000
4000
3000
2000
1000
MOP4Cl
0
400
420
440
Wavelength [nm]
460
480
The idea:
λ
λ/2
Intensity [arb.units]
60000
50000
40000
30000
p6P
20000
10000
MOP4Cl
0
400
420
440
Wavelength [nm]
460
480
The idea:
and the two-dimensional image
λ
λ/2
60000
Intensity [arb.units]
MOP4NH2
50000
40000
30000
p6P
20000
10000
MOP4Cl
0
400
420
440
Wavelength [nm]
460
480
Nanofiber frequency doublers at nanosecond irradiation
500
550
33.00
30.64
28.46
26.42
24.54
22.78
21.16
19.65
18.24
16.94
15.73
14.61
13.56
12.60
11.70
10.86
10.09
9.366
8.697
8.076
7.499
6.964
6.466
6.005
5.576
5.178
4.808
4.465
4.146
3.850
3.575
3.320
3.083
2.862
2.658
2.468
2.292
2.128
1.976
1.835
1.704
1.583
1.470
1.365
1.267
1.177
1.093
1.015
0.9422
0.8749
0.8124
0.7544
0.7005
0.6505
0.6040
0.5609
0.5209
0.4837
0.4491
0.4171
0.3873
0.3596
0.3339
0.3101
0.2880
0.2674
0.2483
0.2306
0.2141
0.1988
0.1846
0.1714
0.1592
0.1478
0.1373
0.1275
0.1184
0.1099
0.1021
0.09478
0.08801
0.08172
0.07589
0.07047
0.06544
0.06076
0.05643
0.05240
0.04866
0.04518
0.04195
0.03896
0.03618
0.03359
0.03119
0.02897
0.02690
0.02498
0.02319
0.02154
0.02000
CNHP4
460
440
420
400
380
(log scale)
MOCNP4
Emission Wavelength (nm)
Emission Wavelength (nm)
MOCNP4 24 nm on Mica
CNHP4 on Mica
Normalized to quartz
(log scale)
480
1.950
1.850
1.755
1.665
1.579
1.498
1.42
1.348
1.279
1.213
1.15
1.092
1.036
0.982
0.932
0.884
0.838
0.795
0.754
0.716
0.679
0.644
0.61
0.579
0.550
0.52
0.495
0.469
0.445
0.422
0.400
0.380
0.360
0.342
0.324
0.308
0.292
0.277
0.262
0.249
0.236
0.224
0.212
0.202
0.19
0.18
0.172
0.163
0.155
0.147
0.139
0.132
0.125
0.119
0.113
0.107
0.10
0.096
0.09
0.086
0.082
0.078
0.074
0.070
0.066
0.063
0.060
0.056
0.054
0.05
0.048
0.046
0.043
0.04
0.039
0.037
0.035
0.033
0.03
0.030
0.028
0.027
0.025
0.024
0.023
0.022
0.020
0.019
0.018
0.017
0.016
0.016
0.015
0.014
0.013
0.013
0.012
0.01
0.01
0.010
0.010
500
450
400
360
350
SHG
340
720
740
760
780
800
820
840 860
540
880
720
900
510
Emission Wavelength (nm)
TPL
740
760
780
2.740
2.590
2.449
2.315
2.189
2.069
1.957
1.850
1.749
1.653
1.563
1.478
1.397
1.321
1.249
1.181
1.116
1.055
0.9976
0.9431
0.8917
0.8430
0.7970
0.7535
0.7123
0.6735
0.6367
0.6019
0.5691
0.5380
0.5087
0.4809
0.4546
0.4298
0.4064
0.3842
0.3632
0.3434
0.3246
0.3069
0.2902
0.2743
0.2594
0.2452
0.2318
0.2192
0.2072
0.1959
0.1852
0.1751
0.1655
0.1565
0.1480
0.1399
0.1322
0.1250
0.1182
0.1117
0.1056
0.09988
0.09443
0.08927
0.08440
0.07979
0.07544
0.07132
0.06743
0.06375
0.06027
0.05698
0.05387
0.05093
0.04815
0.04552
0.04303
0.04069
0.03846
0.03636
0.03438
0.03250
0.03073
0.02905
0.02747
0.02597
0.02455
0.02321
0.02194
0.02074
0.01961
0.01854
0.01753
0.01657
0.01567
0.01481
0.01400
0.01324
0.01252
0.01183
0.01119
0.01058
0.01000
MOCLP4
MOCLP4
480
450
420
390
360
Pedersen et al., Appl.Phys.B 2009
330
720
740
760
780
800
820
840
860
880
800
900
820
840
860
880
900
Smart nanofibers via nanostructure formation
parallel surface growth
perpendicular surface growth
Applications:
OLETS and self growing photonics
Advanced Organic Solarcells
Controlled growth via microstructures
Controlled growth via microstructures
388 K
435 K
Ti 'pinning' lines
435 K
388 K
5000 nm
50 nm
433 K
Nucleation structures refine growth control
Alignment via nucleation structures
500 nm
500 nm
effective
structures
Device 1: self growing polarized light emitter
Madsen et al., Nanotechnology, 2009; R.O.Hansen et al., Nanoscale, 2009
Device 1: self growing polarized light emitter
Madsen et al., Nanotechnology, 2009; R.O.Hansen et al., Nanoscale, 2009
Device 2: Dedicated growth on electric contacts
Electrical properties depend on aggregate morphology
gap 200 nm
electrode width
2400 nm
gap 200 nm
electrode width
150 nm
electrode width
above 1000 nm
needed for low
onset voltage
Smart OLEFETs
J.Kjelstrup-Hansen, Phys.Stat.Sol.,
Org. Electronics 2010
Smart OLEFETs
NaT2
PPTPP
RGB characteristics due to different molecules
P6P
Perpendicular growth: flexible solar cells
Increase efficiency of BHJ solar cells
via nano structure formation
Goal: 15 % efficiency
Template-assisted growth of nano solar cells
PTCDI/ZnPC flexible solar cell
Al, 500 nm
Au
flexible substrate
30 nm
tubes
AlOx, 1 μm
1μm
ZnPC
ITO
30 nm holes
in Al2O3
PTCDI
Template-assisted growth of nano solar cells
P3HT nanotubes
Generation of smart nanotubes and nanorods
template assisted
self organization
of organic materials
ZnPC
laying nanotubes (tetrabenzofluorene)
upright nanotubes
Polyfluorene nanotubes
Smart materials
Materials that show tailored new properties, useful for smart device applications.
Liquid crystals
Ferrofluids
C60
Quantum dots
PBG materials
Organic nanofibers and nanotubes
Combination of bottom up and top down technologies
from smart materials to smart devices
acknowledgements: NanoSYD (FB,JKH, MM, LT,RH,MS, KTH,XL ...)
Nano products
Particles (0D)
Medicine & cosmetics, sprays
Quantum dots
'functional food'
Fibers (1D)
Textiles (polymers)
composite materialies (carbon nanotubes)
Sensors
Films (2D)
coatings (super-hydrophob or –hydrophil, thin films, 'packaging')
magnetic storage media
light emitting layers
Structures (3D)
ICs
Lasers and light diodes
bio-mimetic nanostructures
Nanoparticles change shape and properties
Au colloids
2 nm
30 nm