1. Synthesis and Investigation of Nanomaterials for
Potential Optoelectronic Applications
Dr. Bassam Alameddine

2. Research Interests: Functional Nanomaterials
Flat panel
displays (FED,
OLED, LCD)
Photovoltaics
Optoelectronic Organic
materials Transistors
Sensors

3. Research Interests: Functional Nanomaterials
Build on-
demand
functional
molecules
Control
Improve
down to
adhesion at
molecular
interfaces
level
Nano-
materials
Study the Understand
self- the
assembly structure /
and properties
packing relationship

4. Synthesis of Non-Covalent Polymers

5. Synthesis of Perfluoroalkylated HBC
R= Abbreviation
R
perfluoroalkylated chains
R R -(CH2)2(CF2)6F Rf2,6
-(CH2)2(CF2)8F Rf2,8
-p-Ph(CH2)2(CF2)8F Ph-Rf2,8
-(CH2)3(CF2)6F Rf3,6
-(CH2)3(CF2)8F Rf3,8
-(CH2)4(CF2)4F Rf4,4
R R -(CH2)4(CF2)6F Rf4,6
-(CH2)4(CF2)8F Rf4,8
R -(CH2)4(CF2)10F Rf4,10
-(CH2)5(CF2)6F Rf5,6
-(CH2)5(CF2)8F Rf5,8
 Multistep syntheses (7-12 steps) -(CH2)6(CF2)6F Rf6,6
-(CH2)6(CF2)8F Rf6,8
-(CH2)8(CF2)4F Rf8,4
 Insertion of CH2’s discard the EW -(CH2)8(CF2)6F Rf8,6
-(CH2)8(CF2)8F Rf8,8
effect of the perfluoro chains and
perfluoroalkoxyphenyl substituents
improve both solubility and yield
-p-PhO(CH2)4(CF2)8F PhORf4,8
-p-PhO(CH2)6(CF2)6F PhORf6,6
 Relatively good overall yields (13- branched perfluoralkylated chains
43%) -(CH2)3CH[CH2(CF2)4F]2 Rf3,3,4,4
-(CH2)3CH[CH2(CF2)6F]2 Rf3,3,6,6
B. Alameddine, O. Aebischer, T. A. Jenny, Chimia 2008, 62, 967.
O. F. Aebischer, P. Tondo, B. Alameddine, T. A. Jenny, synthesis 2006, 17, 2891

6. Properties of Perfluoroalkylated HBCs
 All the perfluorinated HBCs are liquid crystalline over a wide temperature range (~280˚C)
 Introducing a phenyl group and increasing CF2 part leads to the formation of a lamellar phase
(HBC-PhRf2,8 & HBC-PhORf4,8)
 Lateral aggregation highly affected by the solvent, conc., T and the perfluoroalkylated chain length
 Cryo-SEM: A new tool to detect nanofilaments
A 10-4 M in BTF affords free standing nanofilaments with a uniform size l ~ 750 nm and d ~ 30 nm
B. Alameddine, et al., Chem. Mater. 2005, 17, 4798
O. Aebischer, A. Aebischer, B. Alameddine, M. Dadras, H.-U. Güdel, T. Jenny, Chem. Commun. 2006, 4221
O. Aebischer, A. Aebischer, B. Donnio, B. Alameddine, M. Dadras, H.-U. Güdel, D. Guillon, T. A. Jenny, J. Mat. Chem. 2007, 17, 1262

7. Synthesis of Hole Transport Layers for OLEDs

8. Triarylamines for OLEDs: Properties
Six step synthesis with good overall yields (50-60%)
Both compounds emit in the blue (BNP at 430 nm and TND at 455 nm)
Completely amorphous
Rf8 Rf8
Rf8
N
Glassy solid produces
fibers at RT
N
N
Rf8 Rf8
Rf8
BNP-Rf2,8
Rf8
X 100
TND-Rf2,8
• Preliminary tests showed low efficiencies than standard HTL used in the market
• A shift in the redox potential by ~200 mV with the same molecules but with alkylated chains
 The CH2/CF2 ratio has to be tuned to decrease the EW effect of the fluorinated part
B. Alameddine, C. Savary, O. Aebischer, T. A. Jenny, synthesis 2007, 2, 271

9. Synthesis of Oligomers for Organic Transistors

10. Organic Materials for OTFTs
h h h h h h
h hh hh hh hh hh
h h h h h h
hh h h h h h h h h h h Amplification effect
h h h h h h
Source (Au) h h h h h hh h h hh h h Drain (Au) upon increasing Vg
Organic Film (~40 nm)
Thermally Passivated SiO2 (100 nm, 30 nF/cm2)
Heavily n-doped Si (Gate, Res.= 2-4 Ω)
In a two step synthesis:
C12H25 C12H25
S S
S S
Thermal evaporation on SiO2 treated with HMDS
μ ≈ 10-2 cm2.V-1.s-1
-6
-7.0x10 VG= 0V
-6 VG= -20V
-6.0x10 VG= -40V
-5.0x10
-6 VG= -60V
-4.0x10
-6
VG= -80V
VG= -100V on/off ratio ≈ 2.6 x 104
ID (A)
-6
-3.0x10
-2.0x10
-6
Ink-jet printed solution of the oligomer in TCB
-6
-1.0x10
0.0
-6
μ ≈ 5.4 x 10-4 cm2.V-1.s-1
1.0x10
0 -20 -40 -60 -80 -100
VD (V)
on/off ≈ 6 x 103
S. Sanaur, A. Whalley, B. Alameddine, M. Carnes, C. Nuckolls, Organic Electronics 2006, 7, 423

11. Organic Materials for Monolayer Transistors
In a three step synthesis:
~3.1 nm
C8H17 C8H17
S S
S S
HO OH
30 – 100 nm spacing
Source (Au) Drain (Au)
3 nm Aluminum Oxide (ALD deposited)
Heavily n-doped Si with 1 nm SiO2(Gate)
μ ≈ 10-5 cm2.V-1.s-1
on/off ≈ 103

12. Acquired Skills
 Advanced synthesis and characterization of organic and polymeric materials by
employing cutting-edge techniques
 Trained on working in a clean room
 Familiar with the different methods used for the deposition and characterization of
organic thin films
 Capability to design and assemble reactors for CVD processes and related techniques
 Set international collaborations necessary to excel in such a multidisciplinary field

13. Acknowledgment and Collaborations
Dr. Walter Amrein Prof. Geoffrey Bodenhausen Prof. Tomasz Wesolowski
Oliver Scheidegger (MALDI-TOF analysis) Dr. Jens Dittmer (SS-NMR) Dr. Fabien Tran (Computational study)
Dr. Noella Lemaitre Prof. Louis Schlapbach
Prof. Titus A. Jenny
(OLED) Dr. Oliver Groening
Corinne Savary (Lab. technician)
Dr. Pascal Ruffieux
Dr. Olivier Aebischer
(STM, FEDs)
Patrick Tondo, Mauro Schindler
(PhD students)
Dr. Massoud Dadras Prof. Robert Deschenaux Prof. Daniel Guillon
Mireille LeBoeuf (SEM & TEM) Dr. David Scanu (POM & DSC) Dr. Bertrand Donnio (Powder XRD)

14. Acknowledgment and Collaborations
Center for Electron Transport Dr. Cherie Kagan
in Molecular Nanostructures
Dr. George Tulevski
Prof. Horst Stormer
Dr. Rachel Steiner
Adam Whalley
Dr. Graciela Blanchet
Dr. Sébastien Sanaur Dr. Xiang-Zheng Bo