Materiales Orgánicos Conductores

Materiales Orgánicos Conductores
NC
N
N
N
M
N
CN
N
N
N
NC
C
S
S
S
S
CN
N
CTCs
Metalomacrociclos
Materiales
orgánicos
conductores
Polímeros conjugados
Fullerenos
Conducting Charge-Transfer
Charge Transfer Complexes
S
S
NC
NC
S
Tetrathiafulvene (TTF)
S
1973
CN
CN
7,7,8,8-Tetracyanoquinodimethane (TCNQ)
1:1 Complex (crystallizes from acetonitrile)
Displays metal-like conductivity over a wide temperature range
(highest  = 1.47 x 104 S/cm at 66 K; copper wire:  = 6 x 105 S/cm at 298 K)
Complejos de transferencia de carga. TTF-TCNQ
NC
NC
CN
S
S
S
S
 = 500 S
Scm-11 (TA)
CN
“Orbitales
Cristalinos”
Conductivity
y and Electronic Structure
Solids: many bonded atoms, electronic states group into extended energy domains
Energy gap > 3 eV
Energy gap: 0,5-1.5 eV
Condu
uction ban
nd
Band Structures:
Bands
Energy
“Crystalline Orbitals”
Empty levels
Va
alence ba
and
Fermi level
Metal
Semiconductor Insulator
Occupied levels
M t l T
Metal:
C d ti it
Conductivity
Semiconductor: T
Conductivity
Conducting Charge-Transfer
Charge Transfer Complexes
NC
CN
NC
CN
e
NC
CN
NC
S
S
S
S
e
S
S
S
S
CN
Mixed-valence salts (charge transfer is not complete)
It is basic!: Knowledge about the Red-ox potentials of donor and acceptor
Disposición
p
eléctricamente conductora
D+
D+
A-
D+
A
AD+
D+
A-
D
A-
D+
A-
D
A
A-
D+
A-
D+
A
D+
D+
A-
D
A-
A-
D+
A-
D+
A-
D+
D+
A-
D+
A
A-
D+
A-
D
A-
D+A
D+A-
Aislante
D+A
D+A-
Semiconductor
D+A
3,2-3,5 Å
DA
Conductor
Sales de valencia mixta
Disposición eléctricamente conductora
Me
S
S
Me
S
S
Me
ClO 4
Me
Electrocristalización
Moléculas dadoras de electrones
S
S
S
S
Me
Me
Me
S
S
S
S
Se
Se
Me
S
S
S
S
BEDT-TTF (ET)
S
S
S
O
S
S
O
Me
Se
S
S
S
S
S
O
S
S
O
Me
Se
S
S
MDT-TTF
Me
Se
TMTSF
TTF
Me
S
Se
BEDO-TTF (BO)
DMET
S
S
S
S
Se
Se
S
Me
Se
Se
S
S
S
S
S
Se
Se
S
Me
Se
Se
S
S,S-DMBEDT-TTF
BEDT-TSF (BETS)
DMEDT-TSF
Moléculas aceptoras de electrones
NC
CN
N
CN
R1
R3
R1
R3
R2
R4
R2
R4
NC
CN
NC
TCNQ
S
S
S
DCNQI
S
M
S
S
S
S
S
M(dmit)
M(d
it) 2n
M = Ni, Pd, Pt
N
S
C60
Buckminsterfullerene
Efectos de la disminución de la Temperatura
•Deformación de Peierls: Paso de Metal a
semiconductor o aislante (deformación de la red)
al disminuir la T
•Superconductividad: Aumento drástico de la
conductividad
d i id d all disminuir
di i i la
l T (reducción
( d
ió d
dell
número de fonones o amplitud de las vibraciones
d lla red
de
d + acoplamiento
l i
electron-fonón)
l
f ó )
Superconductores
p
inorgánicos
g
y orgánicos
g
Tl2Ba2Ca2Cu3O10
T (K
K)
100
RbTl2C60
Rb3C60
NbN
 ET2Cu[N(CN)2]Cl
-ET
Nb
10
-ET2Cu(NCS)2
 ET2AuI2
-ET
Hgg
-ET2IBr 2
1
1900
-ET2I3
1920
1940
1960
Año
1980
2000
Conducting Polymers: The Basics
What is a polymer?
A polymer is a chemical comprised of repeating molecules
with the same chemical structure.
What is conductance?
Conductance is the ability of a material to carry electrical
charge.
So what is a conducting polymer?
A conducting polymer joins these things to yield an organic
material able to take on properties normally seen only in
metals.
Conducting Polymers
P l
Polymers
with
ith polyconjugated
l
j
t d chains:
h i
iisolators
l t
or semiconductors
i
d t
(( = 10-99 S/cm)
S/ )
Polyacetylene (PA)
Ti(IV)
( )
H
H
xn
Ziegler-Natta-Shirikawa
cis-PA  = 10-9 S/cm

trans-PA  = 10-5 S/cm
AsF5
(halogens, FeCl3 , XeOF4 , ...)
“Doped” all-(E)-PA (s = 10-2 – 10-3 S/cm)
(metallic sheen; unstable: in air, conductivity drops within hours)
“Doping”
Doping Process
Redox
R
d reaction
ti between
b t
doping
d i agentt and
d conjugated
j
t d system
t
(i. e. polymer is oxidized to a polymeric cation, doping agent is the counterion)
Also, electrons hopping from chain to chain
Conducting Polymers
2+
+
n
3 I2
+
n
2 I3 -
Molecular versus Band Models
2
M. Lögdlund et al.
E
3
1
4
6
5
7
8
n
E (eV)
Electron
El
t
affinity
LUMO
Bandgap
HOMO
Ionization
potential
Electronic Structure
E
Localized (l) level
Delocalized (d) level
- Key role in determining the optical properties
Nobel Prize in Chemistry 2000
“For the Discovery and Development of Conductive Polymers”
Hideki
Hid
ki Shi
Shirakawa
k
University of Tsukuba
Alan Heeger
University of California
att Santa
S t Barbara
B b
Alan MacDiarmid
University of
P
Pennsylvania
l
i
Conjugated Polymers
N
S
n
Trans-polyacetylene (t-PA)
n
H
Polythiophene (PT)
Polypyrrole (PPY)
n
n
Poly(p phenylene) (PPP)
Poly(p-phenylene)
NH
n
Poly(p phenylenevinylene) (PPV)
Poly(p-phenylenevinylene)
NH
N
y
Polyaniline (PAN)
N
1-y
n
Conducting Polymers
Relative low influence of the temperature
Electron-Phonon Coupling
Excitation
Doping
E
E
LES
+1
Relaxation
effects
Absorption
Emission
GS
Ionization
Relaxation
effects
GS
Q
Q
Chemical Doping of Conjugated Polymers
CB
VB
Radical-cation / Polaron
+
Dication / Bipolaron
++
Electronic Structure
S
S
S
S
S
S
E
L
L
L
POL2
BIP2
BIP1
POL1
H
H
H
Neutral
Polaron
Bipolaron
J. Cornil et al., Adv. Mater. 8, 447 (1996)
Optical Properties
S
S
S
S
S
S
Inttensity (arb
b. units)
Bipolaron
Neutral
Polaron
600
800
1000
1200
1400
1600
1800
2000
Energy(nm)
(eV)
Energy
 Electrochromic windows, sensors
J. Guay et al.
Chem. Mater. 4, 1097 (1992)
Advantages
Combination of properties
M l
Metals
Hi h conductivity
High
d ti it
Pl i
Plastics
Li ht
Lightness
Ease of processing (spin coating)
Low cost
Tailored synthesis
- Low oxidation potential (doping by I2, AsF5, SbF5, …)
- High
Hi h electron
l t
affinity
ffi it (d
(doping
i b
by Li
Li, N
Na, K
K, …))
- Stability of the backbone not affected upon doping
Applications
- Batteries
- Electrostatic
El t t ti coatings
ti
S
n
n
O
Baytron P (Bayer) / Orgacon (AGFA)
O
SO3-
PEDOT
PSS
- Electromagnetic shielding
- Electrochromic windows
- Actuators (Artificial muscles)
Ftalocianinas
N
N
N
N
N
M
N
N
N
N
N
Metallo
Metallophthalocyanine
(PcM)
N
N
M
N
N
N
N
N
N
N
H
N
N
H
N
N
N
Q Band
Q-Band
B or Soret-Band
Soret and Q bands

Free
Phthalocyanine
(PcH2)
Ftalocianinas
Metallophthalocyanines
N
N
N
N
N
M
N
N
N
UV-visible Spectra of Phthalocyanines and
Analogues
Subphthalocyanine
Absorb
bance
1
Naphthalocyanine
P
Pc
0.8
06
0.6
0.4
02
0.2
0
260
360
460
560
Wavelength (nm)
660
760
Organization of Phthalocyanines in Condensed Phases
Liquid Crystals
OH
O
O
O
O
N
N
N
N
Si
N
N
N
N
O
O
O
O
OH
C10H21
H21C10
C10H21 N
LB Films
LB-Films
N
C10H21 N
Langmuir film
Langmuir-Blodgett film
HOOC
N
M
N
N
C10H21
N
N
COOH
C10H21
Properties of Phthalocyanines. Applications
C d
Conducting
i
Properties
P
i
Optical Properties
Nonlinear Optical Properties
Semiconducting materials
Selective gas sensors
Electrochemical Sensors
Field Effect Transistors
Photovoltaic Devices
Optical Recording Data
Photodynamic Therapy (PDT)
Frecuency Doublers
Optical
p
Limiters
Conducting
g Metallo-Macrocycles
y
N
N
N
N
M
N
N
N
N
N
N
M
M
N
N
N
N
N
N
Phthalocyanine
y
Pc
Tetraphenylporphyrin
y
y
TPP
Tetrabenzoporphyrin
y
TBP
Conducting
g Polymeric
y
Metallo-Macrocycles
y
M
L
M
L
M
L
Porphyrin
or
Phthalocyanine
M
L
M
L
M
L
M
L
M
L
M
L
Conducting
g Polymeric
y
Metallo-Macrocycles
y
N
N
N
N
N
N
N
M
N
N
N
N
N
N
M
N
N
N
N
N
N
N
N
N
N
N
CN
CN
CN
Aplications based on Conducting Properties of
Phthalocyanines
Gas Sensing
Artificial Tongues and Noses
Gas Sensing
C10H21
H21C10
C10H21 N
N
C10H21 N
Langmuir-Blodgett film
HOOC
N
M
N
N
C10H21
N
N
COOH
C10H21
Concept of electronic nose
“Instrument
“Inst
ment formed
fo med b
by an a
array
a of chemical senso
sensors
s with
ith
cross-sensitivity coupled to a pattern recognition
software able to discriminate complex gases”.
First level
corteza
cerebro
datos
bulbo
ofatorio
epitelio
p
olfatori
o
t /s
sensore
s
nariz humana
fibras
nerviosas
nariz
electrónica
bulbo
electrodo
s
6
7
neuronas
cilios
Second level
PCA
resistenci
a
material
ibl
sensible
moléculas de
olor
* * *
Software
Aceite C
**
* Aceite B
Thi d level
Third
l l
Neural Network
*
*
*
Aceite A
Electroactive sensing materials
Development of a hybrid array of voltammetric sensors
formed by electrodes chemically modified with materials
with rich electrochemical activity
Rare earth Bisphthalocyanines
Conducting polymers
Perylenes
O
R
N
O
O
N
O
R
Ftalocianinas como Materiales Moleculares
N
N
N
H
N
N
H
N
N
N
N
N
N
N
N
2N
N
N
N
N
N
N
N
Ftalocianina
libre (PcH2)
Forma aromática
de la ftalocianina
N
M
N
N
Metaloftalocianina
(MPc)
Propiedades físicas no convencionales (semiconductoras, ópticas...)
Estabilidad térmica, química y óptica
Versatilidad de su estructura química
modulación de sus propiedades
Síntesis de ftalocianinas
CuCN/DMF
Br
NH
NH3
CN
R
R
R
CN
Br
N
MeOH/MeONa
NH 2
T
CuCN/DMF
R'
R'
N
N
N
N
M
H3O+
NH
R'
R
N
N
N
N
M
MX
N
N
HN
N
N
N
R'
N
N
N
N
disolvente
R
N
N
N
T
R
R
R
N
N
ROH/DBN
MX
R
R
R
Espectro UV-vis de las ftalocianinas
N
N
N
N
M
N
N
N
N
N
N
N
Banda B o Soret
H
N
N
H
N
N
N
Banda Q
Síntesis de ftalocianinas asimétricas
R
CN
CN
+
R
R
CN
N
CN
R
NH2
NH2
N
+
N
HN
NH
N
N
N
R
R
NH
N
NH
R
N
R
Ensamblados moleculares dador-aceptor
Materiales para ONL
Sistemas
dador-aceptor
p
Dispositivos electrónicos
Sistemas fotosintéticos
artificiales
Células solares
h
A.-
D.+
N
N
M
Dador
N
Puente
Aceptor
N
e-
Ensamblados moleculares porfirina-C60
No covalente
Covalente no conjugado
j g
CH3
Ph
N
Me
Ph
N
N
M
N
N
NH
N
O
Ph
N
Ph
Ph
N
N
M
N
N
Ph
Ph
Ph
CH3
R
N
N
Ph
M
N
N
S
S
N
S
S
n
R
Ph
Covalente conjugado