Novel ferrocene derivatized poly(2,5-dithienylpyrrole)s: Optoelectronic properties, electrochemical copolymerization

Article abstract of DOI:10.1016/j.electacta.2011.12.097

In this study a novel ferrocene-substituted electrochromic polymer, poly(4-(2,5-di-thiophen-2-yl-pyrrol-1-yl)-N-(ferrocenyl methyl)-phenylamine), poly(SNS-An-Fc), was electrochemically synthesized and its electrochromic properties were investigated in det

Full text of DOI:10.1016/j.electacta.2011.12.097

Electrochimica Acta 63 (2012) 245–250
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Electrochimica Acta
journal homepage: www.elsevier.com/locate/electacta
Novel ferrocene derivatized poly(2,5-dithienylpyrrole)s: Optoelectronic
properties, electrochemical copolymerization
Pinar Camurlu∗, Zeynep Bicil, Cemil Gültekin, Nese Karagoren
Akdeniz University, Department of Chemistry, 07058, Antalya, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
In this study a novel ferrocene-substituted electrochromic polymer, poly(4-(2,5-di-thiophen-2-yl-pyrrol-
1-yl)-N-(ferrocenyl methyl)-phenylamine), poly(SNS-An-Fc), was electrochemically synthesized and its
electrochromic properties were investigated in detail. The cyclic voltammogram of SNS-An-Fc involves a
reversible FeII/III wave and an irreversible SNS based oxidation wave at higher potentials. Contrary to some
of the previous thiophene based systems, the homopolymer was successfully synthesized and the redox
activity of the homopolymer film virtually did not change upon repeated cycling between 0.0 and 1.1 V
while showing the characteristic of a surface–confined redox couple. The homopolymer has a band gap
of 2.02 eV and it displays yellow to blue coloration upon doping. Copolymerization, which is known as an
effective method to tune the electrochromic properties of the material, was also realized in the presence
of 3,4-ethylenedioxythiophene (EDOT). The copolymer revealed multichromic behavior displaying four
different colors. Our studies have shown that SNS-An-Fc based polymers are promising candidates for
electrochromic applications.
Received 24 September 2011
Received in revised form
25 November 2011
Accepted 22 December 2011
Available online 30 December 2011
Keywords:
Ferrocene
Dithienylpyrrole
3,4-Ethylenedioxythiophene
Electrochemical polymerization
Electrochromic device
© 2011 Elsevier Ltd. All rights reserved.
1. Introduction
materials reveal low redox potential, high electron-donor ability
and they generally show the redox properties of both ferrocene
Since 1977 [1] conducting polymers continue to fascinate many
scientists and it has become the center of attraction of many tech-
nological and academic researches. Great efforts have been devoted
especially for the design and synthesis of novel polymers in order to
achieve desirable properties for commercial applications. Adjust-
ment of optoelectronic properties of a conjugated polymer could
be achieved by specific structural changes within the polymer
backbone or by the use of distinct functional groups [2–4]. Other
than laborious chemical approach, electrochemical copolymeriza-
tion also provides an effective method for controlling the properties
of conducting polymers. Contrary to synthetic approach, especially
electrochemical copolymerization is an easy, facile method to unite
the electrochromic properties of the parent polymers [5].
The incorporation of organometallic units into conjugated poly-
mers have been particularly investigated owing to their potential
application in areas such as electrocatalysis [6], biosensors [7,8], gas
sensors [9], photovoltaic devices [10,11], reference electrodes [12].
Among various metallocenes, ferrocene is known for its high stabil-
ity against humidity and air, therefore it is especially preferred and
utilized in most of the pioneer studies. Recently, an interest in fer-
rocene functionalized conducting polymers has aroused since these
and the conducting polymer [13].
It is often the case that the ferrocene groups which are covalently
tethered to the monomers cause an interference during electro-
chemical polymerization and some problems in the deposition of
films on electrodes [14,15]. The underlying reason for this circum-
stance was considered to be due to the large potential difference
that the aromatic cation radical produced at the electrode solution
interface were scavenged by the neutral ferrocene groups present
in the bulk of solution. Hence in most of the previous studies poly-
merization ferrocene-derivatized pyrrole and EDOT could only be
achieved through co-electropolymerization with similar hetero-
cyclic units without ferrocene unit [8,16,17].
Materials based on poly(2,5-dithienylpyrrole) derivatives
(polySNS) have developed into one of the most promising elec-
trochromic materials, owing to their low oxidation potential
and facile electrochemical polymerization. In order to explore
the effect of substitution through pyrrole unit, a number of
SNS derivatives have been synthesized with substituted phenyl
derivatives [18–25], aryl derivatives [26–29], BODIPY [30], 1,10-
phenanthrolinyl [31], anthraquinone [32]. These polymers are
reported to have satisfying electrochromic ability. Introduction of a
redox group into a conducting polymer could be used to control the
electrochromic properties of the polymer and to achieve an addi-
tional electrochemical activity. Up to date, utilization of a redox
active group such as ferrocene and investigation of its effects on
∗
Corresponding author. Tel.: +90 242 3102308; fax: +90 242 2278911.
E-mail address: pcamurlu@akdeniz.edu.tr (P. Camurlu).
0013-4686/$ – see front matter © 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.electacta.2011.12.097

246
P. Camurlu et al. / Electrochimica Acta 63 (2012) 245–250
O
S
AlCl3
Cl
2
Cl
+
DCM
S
S
O
O
O
toluene
reflux
H2N
NH2
+
1-Methanol, reflux
2-NaBH4
S
S
N
N
S
S
+
O
H
NH2
NH
Fe
SNS-An
SNS-An-Fc
Fe
Scheme 1. The synthetic route of SNS-An-Fc.
electrochromic and electrochemical properties on polySNS deriva-
tives were not reported.
measurements were recorded on a Minolta CS-100A Chroma meter
in a proper box having D-50 illumination. Measurements were
performed with a 0/0 (normal/normal) viewing geometry as rec-
ommended by CIE.
Hence, in this study we disclose the synthesis and
characterization of optoelectronic properties of
a
novel
ferrocene-functionalized conducting polymer based on 4-(2,5-di-
thiophen-2-yl-pyrrol-1-yl)-N-(ferrocenyl methyl)-phenylamine
(SNS-An-Fc) in detail (Scheme 1). Additionally, novel multi-
colored electrochromic copolymer based on SNS-An-Fc and
3,4-ethylenedioxythiophene (EDOT) was achieved by electro-
chemical copolymerization. Electrochromic properties of all
polymers were investigated by spectroelectrochemistry, switching
studies and colorimetry measurements.
2.3. Synthesis of
4-(2,5-di-thiophen-2-yl-pyrrol-1-yl)-N-(ferrocenyl
methyl)-phenylamine (SNS-An-Fc)
0.326 g
(1 mmol)
4-(2,5-di-thiophen-2-yl-pyrrol-1-yl)-
phenylamine and 0.214 g (1 mmol) ferrocene carbaldehyde
and ethanol (20 ml) was charged in round-bottomed flask and
refluxed for 24 h under nitrogen. Later on 0.0378 g (1 mmol) NaBH4
was added and stirred for another 2 h. Evaporation of the ethanol,
followed by column chromatography made it affordable for the
title compound to yield in 40%. 1H NMR (in CDCl3) (ı/ppm): 7.14
(d), 7.04 (dd), 6.85 (dd), 6.67 (d), 6.66 (d), 6.54 (s), 4.29 (t), 4.21
(s), 4.19 (t), 4.02 (s). 13C NMR (in CDCl3) (ı/ppm): 148.80, 135.40,
130.89, 130.56, 126.83, 123.70, 123.61, 112.80, 109.03, 68.57,
68.29, 68.08, 43.40. FT-IR (KBr, cm−1): 3407, 3100, 3080, 2820,
1611, 1521, 1461, 1409, 1310, 1254, 1197, 1174, 1104, 1040, 924,
821,757, 692 cm−1. MS· C29H23FeN2S2 (m/z) calculated: 521.12
found: 521.
2. Experimental
2.1. General
All chemicals were purchased from Aldrich, Merck Chemical
as analytical grade. Tetrabutylammonium hexafluorophosphate
(TBAPF6) was electroanalytical grade and thiophene, succinyl
chloride, p-diaminophenylene, EDOT were used as received. Ace-
˚
tonitrile (ACN) was distilled over calcium hydride and kept on 4 A
molecular sieves. 1,4-di(2-thienyl)-1,4-butanedione [33,34] and
4-(2,5-di-thiophen-2-yl-pyrrol-1-yl)-phenylamine [24] were syn-
thesized according to literature.
2.2. Equipments
2.4. Synthesis of homopolymer (poly(SNS-An-Fc))
NMR spectra were recorded with a Bruker Spectrospin Avance
DPX-400 spectrometer at 400 MHz for 1H NMR and 100 MHz for
13C NMR. Chemical shifts (ı) were given relative to tetramethylsi-
lane (TMS) as the internal standard. Mass spectroscopy (MS) was
performed on DP-MS 5973 HP quadruple MS. The FTIR spectra were
recorded on a Brucker Tensor 27 spectrometer. Ivium stat poten-
tiostat/galvanostat was used to supply a constant potential during
electrochemical synthesis and cyclic voltammetry. Spectroelec-
trochemical and kinetic studies of the polymers were performed
on Varian Cary 100 UV–vis spectrophotometer. Colorimetry
Poly(SNS-An-Fc) films were prepared potentiodynamically on
ITO electrodes, using 0.01 M monomer in a solution containing
TBAPF6 in dichloromethane (DCM). A platinum wire was used
as the counter electrode and Ag/Ag+ electrode calibrated against
ferrocene was used as the reference electrode. During the electro-
chemical process, the color of the solution in the vicinity of working
the electrode darkened progressively. However, as the polymer-
ization proceeded, part soluble oligomers became insoluble and
deposited on the working electrode.

P. Camurlu et al. / Electrochimica Acta 63 (2012) 245–250
247
2.5. Synthesis of copolymers (poly(SNS-An-Fc-co-EDOT))
SNS-An-Fc (50 mg) was dissolved in 5 ml of DCM and 5 ␮l of
EDOT was introduced into the electrolysis cell containing TBAPF6.
The films were either prepared potentiodynamically scanning the
potential between 0.0 and 1.1 V or potentiostatically at 1.1 V on
ITO glass electrodes. Electrochromic measurements; spectroelec-
trochemistry, and switching studies of the polymer film deposited
on ITO coated glass slide were performed using a UV–cuvette with
three-electrodes placed in the sample compartment of a spec-
trophotometer. In these studies platinum and Ag wires were used
as the counter and reference electrodes respectively due to geo-
metrical restrictions [35].
3. Results and discussion
3.1. Synthesis of SNS-An-Fc
4-(2,5-di-Thiophen-2-yl-pyrrol-1-yl)-N-(ferrocenyl methyl)-
phenylamine (SNS-An-Fc) was synthesized by four-step synthetic
route, as shown in Scheme 1. The first step involves synthe-
sis of 1,4-di(2-thienly)-1,4-butanedione through thiophene
and 1,4-dichlorobutanedione and the second step includes a
Paal–Knorr reaction between 1,4-di(2-thienly)-1,4-butanedione
and p-phenylenediamine in the presence of catalytical amount
of propionic acid. Finally ferrocene carbaldehyde condenses with
SNS-An to form a Schiff base which is subsequently reduced by
NaBH4 to yield SNS-An-Fc as an orange powder. Formation of the
Schiff base and reduction were carried out in a one-pot without
isolation of the Schiff base. Structural investigation of monomer
was performed via 1H, 13C NMR, FTIR and MS analyses.
3.2. Redox properties of SNS-An-Fc
The cyclic voltammogram (CV) of SNS-An-Fc in DCM shows a
reversible redox process at Ep½ = 0.57 V which is followed by an
irreversible oxidation peak at 0.88 V (Fig. 1a). In order to evaluate
the true nature of these redox processes, cyclic voltammogram of
the SNS-An (a monomer having the very similar structure, except
the ferrocene unit) was also recorded under same conditions. When
we compare CV of both monomers it is evident that the reversible
redox wave observed in case of SNS-An-Fc is due to presence of
electroactive ferrocene moiety. As we could see both monomers
revealed an irreversible oxidation processes taking place within the
same potential window. Similarity of this oxidation wave in both
monomers confirms the absence of direct electronic effect of the
ferrocene group on the electron density of the SNS moiety [36,37].
Upon successive cycling homogeneous, adherent thin film coating
on the electrode was observed and the color of the solution close
to the working electrode changed probably due to some dissolved
oligomers.
Cyclic voltammetry studies, which are given in Fig. 1b, were con-
ducted on the polymer coated electrodes in the same supporting
electrolyte system. Similar to the monomer itself a symmetric oxi-
dation wave at around Ep,a = 0.67 V which we attribute to Fc/Fc+
oxidation was observed along with the associated reduction wave
with approximately equal area to the oxidation wave at around
Ep,c = 0.65 V at a scan rate of 100 mV/s. Moreover the redox behav-
ior of the ferrocene group (both the peak maximum and the peak
width) did not alter upon variation of potential scan range. How-
ever, as in the case of other studies [14] a well defined redox
couple related to the poly(2,5-dithienylpyrrole) backbone was not
observed. The redox activity of the homopolymer film virtually
did not change upon repeated cycling between 0.0 and 1.1 V. Con-
versely, if the applied potential were to be increased furthermore;
Fig. 1. (a) Cyclic voltammogram of SNS-An-Fc and SNS-An at a scan rate of 100 mV/s,
(b) cyclic voltammogram of the homopolymer at various scan rates, (c) plot of anodic
and cathodic peak current density vs. scan rate in 0.1 M· TBAPF6/DCM.
reduction of the peak was observed. As seen in Fig. 1c the redox
wave showed the characteristic of a surface–confined redox cou-
ple, with the expected linear relationship of peak current with the
potential scan rate having an anodic and cathodic least squares
fit of R = 0.999; R = 0.999, respectively [38]. However, as expected,
increase of scan rate beyond 100 mV/s resulted in a shift of peak

248
P. Camurlu et al. / Electrochimica Acta 63 (2012) 245–250
Fig. 2. Cyclic voltammogram of (a) SNS-An-Fc and EDOT, (b) EDOT at a scan rate of 100 mV/s, (c) the copolymer at various scan rates, (d) plot of anodic and cathodic peak
current density vs. scan rate of the copolymer in 0.1 M· TBAPF6/DCM.
maximum and deviation from the linear dependence between the
current and the scan rate. All these voltammetric studies clearly
indicate the success in the synthesis of ferrocene containing elec-
troactive poly(2,5-dithienylpyrrole) and its the surface confined
nature.
backbone may be overlapped by that of ferrocene. As seen both the
anodic and cathodic current densities of the copolymer shows a lin-
ear dependence with the scan rate, having an anodic and cathodic
least squares fit of R = 0.997; R = 0.997, respectively. Such obser-
vation indicates that migration of the electroactive species is not
diffusion controlled, the electroactive polymer is well adhered and
electrode supported.
3.3. Electrochemical copolymerization of SNS-An-Fc with EDOT
Electrochemical copolymerization is an effective, robust
approach to attain pristine polymers having sophisticated prop-
erties compared to the homopolymers. Fig. 2a and b displays
potentiodynamic scans of the monomer in the presence of EDOT
and pure EDOT in TBAPF6/DCM system with ITO working electrode
at a scan rate of 100 mV/s, respectively. During potentiodynamic
scan the anodic peaks of the copolymer appeared at 0.50 and
0.71 V. As seen redox potentials of copolymer is noticeably different
from PEDOT and poly(SNS-An-Fc) which could be interpreted as a
proof for the formation of a true copolymer [24,39,40]. The redox
activity of the copolymer was investigated in monomer free 0.1 M·
TBAPF6/DCM and the related cyclic voltammograms, plots of wave
current density versus potential scan rate are illustrated in Fig. 2c
and d. Contrary to the homopolymer, the copolymer film revealed
a broad, quasi-reversible redox behavior. The discrete redox peaks
of the conjugated copolymer backbone and ferrocene were not
observed, it was considered that the peaks of the copolymer
3.4. Electrochromic properties
The optoelectronic behavior (Fig. 3) of the poly(SNS-An-Fc)
was investigated by UV–vis spectrophotometer in a monomer-
free electrolyte system while incrementally increasing the applied
potential between −0.2 and 1.1 V. In the neutral state, poly(SNS-
An-Fc) showed a single broad absorption peak at 440 nm, which
corresponded to the ␲–␲* transition (Eg = 2.02 eV) and the polymer
appeared yellow in color. On the other hand, poly(SNS-An) syn-
thesized and characterized under same conditions revealed single
broad transition at 425 nm, which could be considered an effect of
ferrocene substitution. Upon increase of the applied potential, the
peak height of the interband transition was suppressed and simul-
taneously a new absorption peak appeared due to charge carrier
band formations. At 1.1 V the homopolymer appeared in blue color
revealing a transition 661 nm. Absence of isosbestic point during
electrochemical oxidation might indicate the occurrence of more

P. Camurlu et al. / Electrochimica Acta 63 (2012) 245–250
249
Table 1
Electrochromic properties of the polymers.
b
Material
ꢀmax (nm)
Eg (eV)
Switching time (s)ct100, t95, t90
Optical contrast (%T)
L, a, bd
Poly(SNS-An-Fc)
440a
2.02
0.78, 0.50, 0.45
13.7
86, 6, 28 (n)
82, −4, 5 (i)
76, −5, 2 (o)
47, 13, −3 (n)
68, −5, −2 (i)
66, −9, −2 (o)
Poly(SNS-An-Fc-EDOT)
524a
1.72
0.87, 0.59, 0.50
43.0
a
For the neutral polymer films.
Band gap, estimated from the optical absorption band edge of the films.
The switching time of the copolymers at t100: 100%, t95: 95%, t90: 90% of ultimate contrast.
Colorimetry study results at n: neutral, i: intermediate, o: oxidized states.
b
c
d
Fig. 4. Spectroelectrochemistry of poly(SNS-An-Fc-co-EDOT) film on an ITO coated
glass slide in monomer-free 0.1 M· TBAPF6/ACN electrolyte solution at applied
potentials: (a) −0.2 V, (b) 0.0 V, (c) 0.1 V, (d) 0.2 V, (e) 0.3 V, (f) 0.4 V, (g) 0.5 V, (h)
0.6 V, (i) 0.7 V, (j) 0.8 V, (k) 0.9 V and (l) 1.0 V.
Fig. 3. Spectroelectrochemistry of poly(SNS-An-Fc) film on an ITO coated glass slide
in monomer-free 0.1 M· TBAPF6/ACN electrolyte solution at applied potentials: (a)
−0.2 V, (b) 0.0 V, (c) 0.2 V, (d) 0.4 V, (e) 0.6 V, (f) 0.8 V, (g) 0.9 V, (h) 1.9 V, and (i) 1.1 V.
than two spectroscopically distinct charge carriers or the dielectric
effect in condensed phases which also leads to the disappearance
of the isosbestic point in two-component systems [41] Contrary
to the most of the ferrocene containing polymers poly(SNS-An-Fc)
did not rapidly lose its electroactivity. The switching ability of the
polymer was evaluated by monitoring the changes in the percent
transmittance (at 440 nm) of the polymer while applying potential
in square wave form between −0.5 and 0.8 V. The polymer’s switch-
ing time and optical contrast were calculated to be 0.78 s and 13.7%,
respectively.
represent the percent transmittance change (at 524 nm), applied
potential profile and the current density of the copolymer as a
function of time. As seen the copolymer is persistent and uni-
form transmittance and current change upon alternation of applied
potential. The switching time of the copolymer was measured at
90% of ultimate contrast and it was found to be 0.5 s and the optical
On the other hand, poly(SNS-An-Fc-co-EDOT), synthesized at
1.1 V, revealed maximum absorption at 524 nm (Fig. 4). Upon
increase of the applied potential, the peak height of the interband
transition was suppressed and simultaneously a new absorption
peak appeared at around 760 nm due to charge carrier band forma-
tions. Fig. 5 represents the normalized spectra and colors of the
copolymer and the parent homopolymers in their neutral state.
The copolymer’s band gap was calculated as 1.72 eV and it was in
between the two parent polymers (PEDOT: 1.6 eV and poly(SNS-
An-Fc): 2.02 eV). The optoelectronic properties of the copolymer
confirmed that the copolymer has intermediate characteristics
between the homopolymers, implying that polymer backbone may
accordingly be composed of SNS-An-Fc and EDOT units. The copoly-
mer displayed distinct multichromism, revealing maroon, cupper
rose, gray, blue colors in neutral, mid and highly oxidized state.
In order to measure these colors in an accurate-quantitative man-
ner and represent the track of doping induced state, we performed
colorimetry analysis and provided the relevant data in Table 1.
Kinetic studies were performed in order to evaluate the switch-
ing ability of the copolymer synthesized at 1.1 V. Fig. 6a, b and c
Fig. 5. Normalized UV–vis spectrum of homopolymer, copolymer and PEDOT in
neutral state.

250
P. Camurlu et al. / Electrochimica Acta 63 (2012) 245–250
Fig. 6. (a) T%, (b) applied potential, (c) current density, during repetitive electrochromic switching of the copolymer deposited at 1.1 V on ITO electrode, monitored at 555 nm
in 0.1 M· TBAPF6/ACN.
contrast was calculated to be 43.0%. Such definition was proposed
[42,43] due to limitation of human eye to perceive any variations
beyond this limit.
[8] J. Chen, C.O. Too, G.G. Wallace, G.F. Swiegers, B.W. Skelton, A.H. White, Elec-
trochim. Acta 47 (2002) 4227.
[9] S. Radhakrishnan, S. Paul, Sens. Actuators B 125 (2007) 60.
[10] E. Ramasamy, J. Lee, Carbon 48 (2010) 3715.
[11] R.A. Afre, Y. Hayashi, T. Soga, Synth. Met. 160 (2010) 779.
[12] T. Inagaki, M. Hunter, X.Q. Yang, T.A. Skotheim, Y. Okamoto, J. Chem. Soc. Chem.
Commun. (1988) 126.
4. Conclusions
[13] C. Peng, X. Zhou, G.Z. Chen, F. Moggia, F. Fages, H. Brisset, J. Roncali, Chem.
Commun. 48 (2008) 6606.
[14] A. Iraqi, D.F. Pickup, Polym. Int. 55 (2006) 780.
[15] G. Zotti, S. Zecchin, G. Schiavon, A. Berlin, G. Pagani, A. Canavesi, Chem. Mater.
7 (1995) 2309.
[16] H. Brisset, A.E. Navarro, C. Moustrou, I.F. Perepichka, J. Roncali, Electrochem.
Commun. 6 (2004) 249.
[17] J. Chen, C.O. Too, G.G. Wallace, G.F. Swiegers, Electrochim. Acta 49 (2004) 691.
[18] S. Tarkuc, E. Sahmetlioglu, C. Tanyeli, I.M. Akhmedov, L. Toppare, Sens. Actua-
tors B 121 (2007) 622.
[19] B. Yigitsoy, S. Varis, C. Tanyeli, I.M. Akhmedov, L. Toppare, Thin Solid Films 515
(2007) 3898.
[20] S. Tarkuc, E. Sahmetlioglu, C. Tanyeli, I.M. Akhmedov, L. Toppare, Electrochim.
Acta 51 (2006) 5412.
[21] A. Arslan, O. Turkarslan, C. Tanyeli, I.M. Akhmedov, L. Toppare, Mater. Chem.
Phys. 104 (2007) 410.
In this study, we disclosed synthesis and characterization
of a novel ferrocene containing poly(2,5-dithienylpyrrole) which
formed stable films on the electrode surfaces during electrochemi-
cal polymerization. Contrary to most of the literature studies based
on pyrrole and EDOT derivatives, SNS-An-Fc revealed facile, rapid
homopolymerization, electrochemical stability and yellow to blue
coloration upon doping. Additionally, electrochemical copolymer-
ization of SNS-An-Fc and EDOT was achieved and investigation
of electrochromic properties of both the homopolymer and the
copolymers were performed via spectroelectrochemistry, kinetic
and colorimetry studies. Our studies have shown that SNS-An-Fc
based polymers are promising candidates as electrochromic device
applications. Owing to superior properties of these polymers we are
now focused on detailed studies on both electrochromic devices
and biosensors.
[22] E. Sahin, E. Sahmetlioglu, I.M. Akhmedov, C. Tanyeli, L. Toppare, Org. Electron.
7 (2006) 351.
[23] S. Varis, M. Ak, C. Tanyeli, I.M. Akhmedov, L. Toppare, Eur. Polym. J. 42 (2006)
2352.
[24] E. Yildiz, P. Camurlu, C. Tanyeli, I.M. Akhmedov, L. Toppare, J. Electroanal. Chem.
612 (2008) 247.
Acknowledgment
[25] N.A. Lengkeek, J.M. Harrowfield, G.A. Koutsantonis, Synth. Met. 160 (2010) 72.
[26] A. Cihaner, F. Algı, Electrochim. Acta 53 (2008) 2574.
[27] A. Cihaner, F. Algı, J. Electroanal. Chem. 614 (2008) 101.
[28] S. Koyuncu, C. Zafer, E. Sefer, F.B. Koyuncu, S. Demic, I. Kaya, E. Ozdemir, S. Icli,
Synth. Met. 159 (2009) 2013.
We are grateful to Akdeniz University (Project no.:
2008.01.0105.009) for the support of this study.
[29] A. Cihaner, F. Algı, Electrochim. Acta 54 (2008) 665.
[30] A. Cihaner, F. Algı, Electrochim. Acta 54 (2008) 786.
[31] J. Hwang, J.I. Son, Y. BoShim, Solar Energy Mater. Solar Cells 94 (2010) 1286.
[32] G. Wang, X. Fu, J. Huang, L. Wu, Q. Du, Electrochim. Acta 55 (2010) 6933.
[33] P. Camurlu, A. Cirpan, L. Toppare, Synth. Met. 146 (2004) 91.
[34] P.E. Just, K.I.C. Ching, P.C. Lacaze, Tetrahedron 58 (2002) 3467.
[35] E. Sahin, P. Camurlu, L. Toppare, Synth. Met. 156 (2006) 1073.
[36] B. Jousselme, P. Blanchard, E. Levillain, R.D. Bettignies, J. Roncali, Macro-
molecules 36 (2003) 3020.
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.electacta.2011.12.097.
References
[37] H. Brisset, A.E. Navarro, F. Moggia, B. Jousselme, P. Blanchard, J. Roncali, J. Elec-
troanal. Chem. 603 (2007) 149.
[38] P. Chandrasekhar, Conducting Polymers, Fundamentals And Applications: A
Practical Approach, Spring, 1999, p. 83.
[39] P. Camurlu, S. Tarkuc, E. S¸ ahmetlioglu, I.M. Akhmedov, C. Tanyeli, L. Toppare,
[1] H. Shirakawa, E.J. Louis, A.G. MacDiarmid, C.K. Chiang, A.J. Heeger, Chem. Com-
mun. 578 (1977).
˙
[2] J. Roncali, Macromol. Rapid Commun. 28 (2007) 1761.
[3] A. Balan, D. Baran, L. Toppare, Polym. Chem. 2 (2011) 1029.
[4] M.P. Beaujuge, R.J. Reynolds, Chem. Rev. 110 (2010) 268.
[5] C.L. Gaupp, J.R. Reynolds, Macromolecules 36 (2003) 6305.
[6] T.K. Maishal, B. Mondal, V.G. Puranik, P.P. Wadgaonkar, G.K. Lahiri, A. Sarkar, J.
Organomet. Chem. 690 (2005) 1018.
Solar Energy Mater. Solar Cells 92 (2008) 154.
˙
[40] P. Camurlu, E. S¸ ahmetliog˘lu, E. S¸ ahin, I.M. Akhmedov, C. Tanyeli, L. Toppare,
Thin Solid Films 516 (2008) 4139.
[41] I.A. Vinokurov, J. Kankare, J. Phys. Chem. B 102 (1998) 1136.
[42] D.M. DeLongchamp, M. Kastantin, P.T. Hammond, Chem. Mater. 15 (2003) 1575.
[43] Y. Coskun, A. Cirpan, L. Toppare, Polymer 45 (2004) 4989.
[7] N.C. Foulds, C.R. Lowe, Anal. Chem. 60 (1988) 2473.