Photosensitive in wide spectral region composites based on polyphenylenevinylene
Optical and photovoltaic properties of polyphenylenevinylene derivative –
 poly(2-methoxy-5-(3-,7-dimethyl-octyloxy)-1,4-phenylenevinylene (MDMO-PPV) and
 its composites with high (40 %) concentration polymethine dyes (PD) – meso-Cl and
 hexaindoletricarbocyanine (HITC) films...
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Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
2009
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| Cite this: | Photosensitive in wide spectral region composites
 based on polyphenylenevinylene / V. Syromyatnikov, I. Pomaz, A. Verbitsky, Ya.Vertsimakha,S. Nespurek, S. Pochekaylov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2009. — Т. 12, № 1. — С. 01-07. — Бібліогр.: 16 назв. — англ. |
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| author | Syromyatnikov, V. Pomaz, I. Verbitsky, A. Vertsimakha, Ya. Nešpůrek, S. Pochekaylov, S. |
| author_facet | Syromyatnikov, V. Pomaz, I. Verbitsky, A. Vertsimakha, Ya. Nešpůrek, S. Pochekaylov, S. |
| citation_txt | Photosensitive in wide spectral region composites
 based on polyphenylenevinylene / V. Syromyatnikov, I. Pomaz, A. Verbitsky, Ya.Vertsimakha,S. Nespurek, S. Pochekaylov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2009. — Т. 12, № 1. — С. 01-07. — Бібліогр.: 16 назв. — англ. |
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| description | Optical and photovoltaic properties of polyphenylenevinylene derivative –
poly(2-methoxy-5-(3-,7-dimethyl-octyloxy)-1,4-phenylenevinylene (MDMO-PPV) and
its composites with high (40 %) concentration polymethine dyes (PD) – meso-Cl and
hexaindoletricarbocyanine (HITC) films have been studied. Two H-aggregates of dyes
with different energies that weakly depend on the molecular structure of dyes, is formed
in MDMO-PPV with PD in composites films. The efficiency of photogeneration of
charge carrier by these aggregates is greater than the efficiency of photogeneration of
charge carriers by the quasi-isolated molecules of dye. It results in substantial expansion
of the absorption region (in comparison with the absorption region of molecules in
solution) and photosensitivity in the side of higher energies. The presence of PD
aggregates in the films MDMO-PPV influences on their photosensitivity that depends on
PD molecular structure. This dependence can be caused by interaction between the
molecules of MDMO-PPV and dye. In composites MDMO-PPV/HITC, the value of
interaction is low and practically does not influence the efficiency of photogeneration of
charge carriers by MDMO-PPV molecules, which give a considerable contribution to
formation of the photovoltage in 2-3 eV regions. The interaction of meso-Cl and
MDMO-PPV molecules is stronger, and this, probably, results in considerable decrease
of photovoltage in the region of the excitation of MDMO-PPV.
|
| first_indexed | 2025-12-07T17:59:33Z |
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| fulltext |
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2009. V. 12, N 1. P. 01-07.
© 2009, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
1
PACS 78.66.-w, 79.60.Jv
Photosensitive in wide spectral region composites
based on polyphenylenevinylene
V. Syromyatnikov 1, I. Pomaz 1, A. Verbitsky 2, Ya. Vertsimakha 2, S. Nešpůrek 3, S. Pochekaylov 3
1Taras Shevchenko Kyiv National University, 64, Volodymyrska str., 01033 Kyiv, Ukraine
2Institute of Physics, NAS of Ukraine, 46, prospect Nauky, 03650, Kyiv-39, Ukraine
3Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic,
Heyrovský Sq. 2, 162 06 Prague 6, Czech Republic
Abstract. Optical and photovoltaic properties of polyphenylenevinylene derivative –
poly(2-methoxy-5-(3-,7-dimethyl-octyloxy)-1,4-phenylenevinylene (MDMO-PPV) and
its composites with high (40 %) concentration polymethine dyes (PD) – meso-Cl and
hexaindoletricarbocyanine (HITC) films have been studied. Two H-aggregates of dyes
with different energies that weakly depend on the molecular structure of dyes, is formed
in MDMO-PPV with PD in composites films. The efficiency of photogeneration of
charge carrier by these aggregates is greater than the efficiency of photogeneration of
charge carriers by the quasi-isolated molecules of dye. It results in substantial expansion
of the absorption region (in comparison with the absorption region of molecules in
solution) and photosensitivity in the side of higher energies. The presence of PD
aggregates in the films MDMO-PPV influences on their photosensitivity that depends on
PD molecular structure. This dependence can be caused by interaction between the
molecules of MDMO-PPV and dye. In composites MDMO-PPV/HITC, the value of
interaction is low and practically does not influence the efficiency of photogeneration of
charge carriers by MDMO-PPV molecules, which give a considerable contribution to
formation of the photovoltage in 2-3 eV regions. The interaction of meso-Cl and
MDMO-PPV molecules is stronger, and this, probably, results in considerable decrease
of photovoltage in the region of the excitation of MDMO-PPV.
Keywords: composite, photovoltage, polymer, organic dye, film.
Manuscript received 02.12.08; accepted for publication 18.12.08; published online 30.01.09.
1. Introduction
For two last decades, the technology of manufacturing
the films of polymeric composites promising for the
production of cheap plastic solar cells is being actively
developed [1, 2].
However, the most effective inorganic solar cells
based on Si and CuInSe2 absorb efficiently the solar
irradiation creating charge carriers in the region from
400 up to 1100-1200 nm. At the same time, the best of
organic solar devices explored now absorb light with
creation of charge carriers only within the range lower
400 to 750 nm [3]. It is one of the reasons for their
smaller efficiency of light transformation by organic
solar cells. Therefore, the actual problem is the
development of films of the composites photosensitive
in a wide spectral range (400-1100 nm) in order to
design and produce organic solar devices.
The composites consisting of conductive polymeric
compounds and C60 derivatives are studied in the
majority of works to make the most effective organic
solar cells [3]. In these systems, the effective transfer of
a charge occurs between molecules of a polymer and
fullerene.
For further enhancement of the efficiency of such
solar cells, it is necessary to synthesize new derivatives
of C60, which are characterized by a good solubility and
a greater diffusion length (lifetime) of photogenerated
charge carriers and by a wider region of absorption of
solar radiation.
The first of the above-mentioned problems is
practically solved, but, to solve the others, it is necessary
to search for new materials.
The new strategy aimed at increasing the efficiency
of organic solar cells has been proposed in the paper [4].
This strategy consists in the following: at first, to
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2009. V. 12, N 1. P. 01-07.
© 2009, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
2
develop polymeric composites which will provide the
effective light absorption and the photogeneration of
charge carriers in the region of 550-1000 nm, where the
maximal intensity of the flux of Sun’s photons is
observed. After that, if necessary, the ways to enhance
their photosensitivity and absorbance of sunlight in the
short-wave region (400-550 nm) should be developed.
Earlier [4-6] we have developed the physical basis
to create the composites from polymethine dyes and
carbazol-contained polymers photosensitive in the range
550-950 nm.
The aim of the present paper is the complex study
of the composites based on polymethine dyes and
conjugated MDMO-PPV polymer as well as experi-
mental checking the possibility to widen the spectral
range of photosensitivity of such composites comparing
carbazole-containing polymers [4-6].
2. Experimental
As a photosensitive component, we used the poly-
methine dyes which have substituents specially modified
to increase their solubility in organic solvents, the
maximum of absorption in solutions in the region of
850-1050 nm, and no bulky substituents in the meso-
position [7, 8]. The last circumstance is a necessary
requirement, according to [7], for the effective formation
of H-type dimer-like aggregates due to the almost flat
shape of a molecule.
The most homogeneous and photosensitive films of
composites were obtained with the following dyes
hexaindoletricarbocyanine (HITC) and meso-Cl (Fig. 1).
HITC and meso-Cl dyes were synthesized in the
Institute of Organic Chemistry, NAS of Ukraine [5-7]
and MDMO-PPV was produced by Sigma-Aldrich.
The films of composites based on polymethine
dyes and MDMO-PPV polymer were prepared by the
deposition from their solution in ethylene dichloride by
the method of spin casting.
N+
N
Cl
B- F
F
F
F
Meso-Cl
HITC
Fig. 1. Structural formulae of polymethine dyes.
The thickness of studied films was 0.5-1 µm. For
their deposition, two types of substrates were used: glass
substrates for the deposition of samples to measure the
absorbance and substrates with a conductive ITO layer
which was deposited by magnetron sputtering and used
as the electrode under measuring the photovoltaic
properties of composites.
The absorption spectra were measured with the
help of a spectrophotometer “Unicam UV-300” and the
spectral dependence of a luminescence and its excitation
were measured on a spectrofluorometer “Hitachi”.
Photovoltaic properties of composites were
measured by the Bergman method improved by Akimov
[9]. As an advantage of this method, we indicate that
there is no necessity to deposit the top ohmic electrode,
for which the preparation technology is not yet designed.
During measurements, a sample was illuminated by
modulated monochromatic light (80 Hz) created with the
help of an MDR-4 monochromator. Photovoltage (Vs)
was measured by a Unipan 232B nanovoltmeter supplied
by a preamplifier with a high input impedance. The
spectral dependences of V were normalized on the equal
number of incident photons by using a calibrated
pyroelement.
3. Results and discussion
3.1. Properties of MDMO-PPV films
The results of complex studies of spectral dependences
of the absorption spectra, spectra of photoluminescence
excitation (EPL) and Vs of MDMO-PPV films are shown
in Fig. 2. It is seen that the absorption spectrum of
MDMO-PPV film in the range 2.0-3.4 eV is described
by the wide and asymmetrical band with the maximum
at 2.61 eV (curve 1).
Nevertheless, two clear maxima at 2.28 and 2.48 eV
and shoulder at 2.84 eV are clearly seen on the spectral
dependence of Vs (curve 2), and maxima at 2.52 and
2.65 eV and a couple of shoulders near 2.3 and 2.9 eV
are seen well on EPL spectrum (curve 3). V and PL arise
only at absorption of light and consequently their values
are not influenced with presence of a diffused light.
Hence, presence of extrema on the spectral
dependences of V and excitation of PL testifies, that 4
electronic transitions with various efficiency of radiation
and photogeneration of charge carriers.
Both diffused light and luminescence give the
contribution in a measured signal at the standard
technique of the absorption study.
Besides, elementary bands of absorption are
strongly overlapped. Therefore, in the absorption one
wide band is observed.
To consider electronic processes, in particular
processes of light absorption, photogeneration and
transport of charge carriers in conductive polymers such
as PPV, there are the competition of excitonic and
polaronic models (see, for example, [10]).
Occurrence of new bands (electronic states) can be
explained by interaction between the neighboring
N
Me Me
Me
N
Me
Me
Me
BF4
+
-
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2009. V. 12, N 1. P. 01-07.
© 2009, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
3
polymeric chains (so-called interchain interaction) [11].
This interaction can result in the formation of interchain
aggregates [12].
The aggregation in the frameworks of the excitonic
model can result in an occurrence of new states caused
by the charge transfer in the aggregate – charge transfer
states (CT-states) formation [13].
The so-called interchain polarons coupling [14] is
considered in the terms of the polaronic model that
results in splitting the levels and in occurrence of new
bands, for example, in spectra of photoinduced absorp-
tion [15].
Since the difference in the energetic position of
observable extrema in various spectra does not exceed
3 %, it allows us to deconvolute the absorption by Gauss
components and to estimate relative efficiency of
various transitions. Results of deconvolution are shown
in Table 1.
The energies of the extrema, as well as their
energies and relative intensities in the different spectra
are summarized in this table, too.
The comparison of the intensity of Gaussian
components of absorption with the intensity of bands on
the spectra of V and EPL (Fig. 2) shows that the
efficiency of photogeneration of charge carriers and the
efficiency of radiation essentially differ for different
Table 1. Energy position of the maxima on spectral
dependences of absorption, PL excitation, V and their
ratios for MDMO-PPV and its composites with dyes and in
brackets their relative intensity.
States 1 2 3 4
Parameters of
extrema in
the spectra
MDMO-PPV films
D 2.61 (1.0)
EPL 2.3
(0.70)
2.52
(0.94)
2.65 (1.0) 2.91 (0.45)
Vs 2.28
(0.99)
2.44 (1.0) 2.58
(0.71)
2.79 (0.71)
Vs/D 2.26
(1.0)
– – 2.86 (0.35)
EPL/D 2.26
(1.0)
2.52
(0.85)
2.65
(0.88)
–
Gaussian
components
of D
2.30
(0.43)
2.48
(0.98)
2.65
(0.81)
2.85 (1.00)
HITC+MDMO-PPV composite films
D 2.58
(0.99)
2.8 (1.0)
V 2.27
(0.99)
2.46 (1.0) 2.84 (0.63)
V /D 2.24
(1.0)
2.45
(0.62)
2.84 (0.42)
Meso-Cl+MDMO-PPV composite films
D 2.52
(0.97)
2.78 (1.0)
V 2.66
(0.48)
2.8 (1.0)
Vs/D 2.66
(0.45)
2.90 (1.0)
states. So, the highest efficiency of photogeneration of
charge carriers is observed for the lowest state with the
energy 2.26 eV, and is minimal for the state with the
energy 3.2 eV. On the contrary, the efficiency of
radiation is maximal for the states with energies 2.48 and
2.65 eV. For convenience of the analysis, in Table 1 we
summarized energies of maxima in various spectra and
their intensities concerning a maximum in each spectrum
(in brackets).
PL with a maximum near 2.11 eV and smooth
increase in the region of low energy on which the
shoulders at about 2.0 and 1.85 eV are well-expressed is
observed in spectra of a photoluminescence MDMO-
PPV films and composites.
Introduction of dye practically does not influence
energy position of PL maxima and shoulders, but results
in the decrease of PL intensity.
Intensity of PL in its peak decreases at introduction
of HITC by 1.7 times, and meso-Cl – almost by 4 times.
It is possible to explain this essential decrease only
partially by absorption of radiation of molecules
MDMO-PPV by the aggregates of dyes since in this
region their absorption are low. Hence, it is necessary to
assume that it is also caused by weak interaction of
molecules MDMO-PPV and dye, which is stronger for
molecules MDMO-PPV and meso-Cl.
The deconvolution on the Gaussian components for
PL spectra shown, that PL band is well described by the
2,0 2,2 2,4 2,6 2,8 3,0 3,2
0
200
400
600
0,00
0,06
0,12
3
2
D, a.u.
2. Vs
3. EPL
V, EPL a.u.
hν, eV
1
1. AS
Fig. 2. Spectral dependences of absorption D (1), Vs (2) and PL
excitation EPL (3) measured at the equal energy of incident
monochromatic illumination.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2009. V. 12, N 1. P. 01-07.
© 2009, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
4
electronic transition at 2.11 eV and intramolecular
oscillation with the energy 0.13±0.01 eV. Since PL is
caused by transitions from the lowest excited state to the
highest occupied state, it is possible to assume that the
density of states in the valence band of MDMO-PPV
will consist of three narrow levels, two of which with
lower density are related with intramolecular oscilla-
tions. This is typical for organic crystals with a weak
interaction between molecules.
3.2. Influence interaction of molecules of dye and
polymer on properties MDMO-PPV films
From mentioned in the previous section it is clear that
the introduction of molecules of dye or their aggregates
which absorb light in the region of a transparency
MDMO-PPV films can result both in partial absorption
of a diffused light and a luminescence, and an
occurrence of the interaction between molecules of
MDMO-PPV and dye. Partial absorption of light by dye
aggregates should lead to the occurrence of structure in
spectra of absorption of composites and practically not
influence spectral dependence of V in the region of
absorption MDMO-PPV films since it is defined only by
light absorbed by MDMO-PPV molecules. On the other
hand weak interaction between molecules of MDMO-
PPV and dye should not influence practically spectra of
absorption of MDMO-PPV films, but can influence
essentially properties of electronic states of MDMO-
PPV, for example, on efficiency of generation by them
of charge carriers and radiation.
The results of complex measurement of MDMO-
PPV films properties with the high concentration of two
various dyes are resulted in Figs 3 and 4.
2,0 2,2 2,4 2,6 2,8 3,0
0
200
400
0,0
0,1
D, a.u.
2
3
V; V/D, a.u.
hν, eV
1
Fig. 3. Spectral dependences of optical density D (1), photo-
voltage V (2) and their ratios V/D (3) for films of composites
MDMO-PPV+HITC.
2,5 3,0
0
100
200
300
400
0,00
0,05
0,10
2
3
V, a.u.
hν, eV
1
Fig. 4. Spectral dependences of optical density D (1), photo-
voltage V (2) and their ratios V/D (3) for films of composites
MDMO-PPV+meso-Cl.
From Figs 3 and 4 it is obvious that in spectra of
absorption composite films two weakly expressed
maxima at about 2.54 and 2.8 eV instead of a maximum
2.61 eV in MDMO-PPV films practically irrespective of
molecular structure of dye, i.e. the deposit of the
influence of absorption by luminescent and a diffused
light is observed in the both composites. At the same
time, the comparison of Figs 2 and 3 shows that the
spectra of Vs are similar for films of HITC+PPV and
PPV films are similar, i.e. the properties of the barriers
between aggregates HITC and PPV and consequently
the efficiency of charge carriers by PPV molecules
practically doesn’t changed.
Although the comparison of Figs 2 and 4 shows
that the efficiency of charge carriers photogeneration by
PPV states 2.26 and 2.54 eV sufficiently decreased in
composites PPV-meso-Cl. Due to this only maximum at
2.28 eV and shoulder at 2.65 eV are observed in Vs
spectra of PPV-meso-Cl composites, i.e. the interaction
of the molecules PPV and meso-Cl didn’t influence only
the state at 2.8 eV. This is correlated with the observed
significant decrease of PL for PPV-meso-Cl composites.
Thus, the interaction of the molecules PPV and meso-Cl
mainly leads to the decrease of charge carrier photo-
generation by low energetic states of PPV molecules
2.26 and 2.54 eV.
3.3. Properties of composites
The spectrum of absorption of dyes HITC and meso-Cl
in a solution consists of a narrow intensive bands with a
maxima at 1.64 and 1.58 eV with width 0.1 and 0.08 eV,
respectively, and weak absorption band at about 1.8 and
1.75 eV, respectively, caused by intramolecular oscilla-
tions (Figs 5 and 6).
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2009. V. 12, N 1. P. 01-07.
© 2009, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
5
Naturally, owing to interaction with molecules
MDMO-PPV in a film of a composite the maximum of
their absorption is displaced in the region of smaller
energy on 0.05 and 0.075 eV, respectively. It testifies
that meso-Cl molecules interact with molecules MDMO-
PPV more strongly than molecules HITC. This is
correlated well with marked in section 3.2 stronger
influence of meso-Cl molecules with electronic states of
MDMO-PPV with energies 2.26 and 2.54 eV. Additional
absorption, the intensity of which is much higher than
that of weak absorption in a solution, is caused by
intramolecular interaction (Figs 5 and 6) and is simulta-
neously observed in spectra of absorption of composite
films in the range of 1.7 – 2.15 eV.
Three peaks are observed in spectra Vs of
composites HITC+MDMO-PPV at energies 1.62, 1.77
and 1.95 eV which, certainly, are more precisely visible
in spectra of Vs/D (Fig. 6, curve 4). Energy position of
peak 1.62 eV practically coincides with the energy of a
maximum of absorption for HITC solution, i.e. energy of
a quasi-isolated molecule of this dye, and can be caused
by photogeneration of charge carriers by these HITC
molecules. Peaks of Vs in the region of additional
absorption at 1.77 and 1.95 eV can be caused by forma-
tion of two types of aggregates. Propensity of this type
of dyes to formation of Н-aggregate type was revealed in
high-concentrated solutions [8], and later we confirmed
this fact experimentally for composites of this type of
dyes with carbazole polymers [6, 16]. As it is visible
from the spectral dependence Vs/D in Fig. 6 (curve 4),
the efficiency of photogeneration of charge carriers for
these aggregates is higher than that of photogeneration
of charge carriers from quasi-isolated HITC molecules,
as results in expansion of spectral range of Vs in the
short-wavelength region.
1,4 1,5 1,6 1,7 1,8 1,9 2,0
0
20
40
60
80
100
120
140
160
180
200
0,0
0,5
1,0
D, a.u.
4
Vs; V/D, a.u.
hν, eV
1
2
3
Fig. 5. Spectral dependences of optical density D of solution in
dichloroethane HITC (1), a film (2), photovoltage V (3) and their
ratio V/D (4) for films of composites MDMO-PPV+HITC.
1,4 1,6 1,8 2,0 2,2
0
100
200
300
400
500
600
0,0
0,1
0,2
3
4
V, a.u.
hν, eV
1
2
Fig. 6. Spectral dependences of optical density D of a solution
dichloroethane (1), a film (2), photovoltage V (3) and their
ratio V/D (4) for films of composites MDMO-PPV+meso-Cl.
Already precisely 4 peaks with maxima near 1.47,
1.65, 1.88 and 2.13 eV are seen in spectra Vs of
composites meso-Cl+MDMO-PPV. Thereof, the peak
1.65 eV corresponds to photogeneration of charge
carriers by quasi-isolated meso-Cl molecules, and 1.88
and 2.13 eV – to the formation of two types of dye
aggregates (most probably of H-type).
For convenience of parameters comparison of both
dyes composites in Table 2 energy positions of extrema
in their spectra of absorption, Vs and Vs/D and intensity
concerning the peak caused by presence quasi-isolated
molecules of dye in composites are resulted.
From the table, it is visible that the first feature of
meso-Cl+MDMO-MDMO-PPV composite is more high
efficiency of photogeneration of charge carriers of
2.13 eV state (Fig. 6, curve 4) in comparison with
efficiency of their photogeneration of quasi-isolated
molecules meso-Cl and aggregates in composites
HITC+MDMO-PPV. The second feature of composites
meso-Cl+MDMO-PPV is presence in spectra Vs and
Vs/D peak 1.45±0.02 eV, i.e. at energies that are less
than the energy of isolated molecules meso-Cl. There-
fore, it is natural to connect the formation of this peak
with the formation of charge transfer complex (CT-
complex) between molecules meso-Cl and MDMO-PPV.
Formation of similar CT-complexes were earlier
observed in composites of carbazole-contained polymers
with the same polymethine dyes [4] and polyepoxy-
propylcarbazole with TNF [13]. CT-complexes
displaying in spectra of Vs and Vs/D in composites meso-
Cl+MDMO-PPV is quite logical, since the energy of
interaction of molecules meso-Cl and MDMO-PPV is
higher than molecules HITC and MDMO-PPV.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2009. V. 12, N 1. P. 01-07.
© 2009, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
6
Table 2. Energy position of extrema on spectral
dependences of absorption, photovoltage and their ratios
for films of composites of dyes and in brackets of their
intensity with respect to the state of a qusi-isolated
molecule.
Compo-
site
HITC+MDMO-PPV
Meso-Cl+MDMO-PPV
Extremum 1 2 3 - 1 2 3
D 1.58
(1.0)
1.51
(1.0)
Vs 1.61
(1.0)
1.77
(0.9)
1.95
(0.62)
1.47
(1.0)
1.65
(0.77)
1.87
(0.62)
2.10
(0.39)
Vs/D 1.62
(1.0)
1.77
(1.09)
1.95
(1.22)
1.42
(1.17)
1.61
(1.0)
1.88
(1.19)
2.13
(2.78)
Comparison of photovoltage spectra of studied in
this work composites HITC+MDMO-PPV with
composites HITC developed by us earlier [15] with
carbazole polymers (Fig. 7) and composites based on
MDMO-PPV with С60 derivatives shows that researched
composites HITC+MDMO-PPV allow further expansion
of the photosensivity spectral range and can perspective
material for development of plastic solar cells.
Observable weak photosensivity of composites
HITC+MDMO-PPV can be increased by optimization of
manufacturing techniques for these films and/or by the
replacement of HITC with other polymethine dye with
the higher efficiency for the formation of Н-aggregates
in MDMO-PPV.
1,4 1,6 1,8 2,0 2,2 2,4 2,6 2,8 3,0
0
40
80
120
1.
2.
3.
V; Isc, a.u.
hν , eV
Fig. 7. Spectral dependences Vs of composites MDMO-
PPV+HITC (1), I-VC-OMA+HITC [16] (2), and MDMO-
PPV+PCBM [3, 4] (3).
5. Conclusions
In the region of dye weak absorption (1.4-2.1 eV) in
their composites with MDMO-PPV, formed are on two
types of Н-aggregates with various energies, in which
the efficiency for photogeneration of charge carriers is
higher than that for photogeneration of charge carriers
from their quasi-isolated molecules. It results in essential
expansion of the absorption spectral region (in
comparison with the range of absorption of molecules in
a solution) and photosensivity short wavelength side
from 1.6 up to 2 eV. Besides, in composites meso-Cl
which molecules interact with molecules MDMO-PPV
more effectively, the photosensitive complex with
charge transfer possessing the energy 1.45±0.02 eV is
formed. The latter energy is less than the minimal energy
of excitation for a dye molecule.
Besides, the introduction of dyes in the film of
MDMO-PPV composites results in appreciable changes
of efficiency of photogeneration of nonequilibrium
charge carriers of separate states of MDMO-PPV, which
depends on molecular structure of dyes. In composites
MDMO-PPV/HITC interaction between their molecules
small, also the essential contribution to occurrence of a
photovoltage in short wavelength region (2-3 eV) is ob-
served. The interaction of MDMO-PPV with molecules
meso-Cl stronger, that results in strong reduction of
efficiency of photogeneration of charge carriers of at
excitation of MDMO-PPV states at 2.3 and 2.48 eV.
The spectral region of photosensitivity of
composites HITC/MDMO-PPV is wider than carbazole-
based polymer composites with HITC and PPV with С60
derivatives. Therefore composites HITC/MDMO-PPV
can be used for development of plastic photoconverters,
including the solar cells sensitive in wide spectral range
(from 400 up to 900 nm).
Work is executed according to the Ukrainian-Czech
project in 2008.
References
1. C.J. Brabec, N. Sariciftci, Solarzellen aus Plastik //
Erneuerbare Energien 2, p. 28-34 (1997).
2. I.A. Akimov, A.M. Meshkov, I.Yu. Denisyuk,
Nanostructured composite organic semiconductors
// Functional Materials 5, p. 363-369 (1998).
3. C.J. Brabec, S.N. Sariciftci, J.C. Hummelen, Plastic
solar cells // Adv. Funct. Mater. 11, p.15-26 (2001).
4. J.G. Grote, Ya.I. Vertsimakha, The photosensitive
polymeric composites from inorganic and organic
semiconductors and prospects of their use // Proc.
of the XIV Intern. Symposium “Advance Display
Technologies”. October 10-14, 2005, Crimea,
Ukraine, p. 216-224.
5. S. Studzinsky, V. Syromyatnikov, A. Ishchenko,
N. Derevyanko, Ya. Vertsimakha, A. Verbitsky,
Effect of polymer matrix on photosensitivity of
polymethine dye based composites // Nonlinear
Optics, Quantum Optics 33(1-2), p.151-159 (2005).
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2009. V. 12, N 1. P. 01-07.
© 2009, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
7
6. N. Beresina, V. Syromyatnikov, A. Ishchenko,
A. Verbitsky, Ya. Vertsimakha, Effect of polymer
matrix on photosensitivity of meso-Cl polymethine
dye based composites // Functional Materials
13 (4), p. 676-680 (2006).
7. A.A. Ishchenko, Structure, Spectral and Lumi-
nescent Properties of Polymethine Dyes. Naukova
dumka, Kiev, 1994 (in Russian).
8. A.A. Ishchenko, Physicochemical aspects of the
creation of modern light-sensitive materials based
on polymethine dyes // Theoretical and
Experimental Chemistry 34 (4), p. 191-210 (1998)
(in Russian).
9. I.A. Akimov, The study of internal photoeffect in
semiconductors by capacitor method // Optiko-
mekhanicheskaya promyshlennost’ No. 5, p. 4-13
(1966) (in Russian).
10. A.J. Heeger, Nature of the primary photo-
excitations in poly(arylene-vinylenes): Bound
neutral excitons or charged polaron pairs, in
Primary excitation of conjugated polymers:
Molecular exciton versus semiconductor band
model (Ed. N.S. Sariciftci). World Scientific,
Singapore, 1997.
11. Thuc-Quyen Nguyen, Vinh Doan, and
B.J. Schwartz, Conjugated polymer aggregates in
solution: control of interchain interactions // J.
Chem. Phys. 110, p. 4068-4078 (1999).
12. M. Aguiar, M.C. Fugihara, I.A. Hümmelgen,
L.O. Peres, J.R. Garcia, J. Gruber, L. Akcelrud,
Interchain luminescence in poly(acetoxy-p-phe-
nylene vinylene // J. Luminescence 96, p. 219-225
(2002).
13. M. Pope and C.E. Swenberg, Electronic Processes
in Organic Crystals. Clarendon, Oxford, 1982.
14. A. Cravino, H. Neugebauer, S. Luzzati, M. Cas-
tellani, A. Petr, L. Dunsch and N.S. Sariciftci // J.
Phys. Chem. B 106, p. 3583-3592 (2002).
15. C. Winder and N.S. Sariciftci, Low bandgap
polymers for photon harvesting in bulk
heterojunction solar cells // J. Mater. Chem. 14,
p. 1077-1086 (2004).
16. A. Ishchenko, N. Derevyanko, Yu.P. Piryatinskii,
A. Verbitsky, D. Filonenko, S. Studzinsky, Optical
and photovoltaic properties of films and polymer
composites based on near infra-red polymethine
dye // Materials Science 20 (4), p. 5-12 (2002).
|
| id | nasplib_isofts_kiev_ua-123456789-118613 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1560-8034 |
| language | English |
| last_indexed | 2025-12-07T17:59:33Z |
| publishDate | 2009 |
| publisher | Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| record_format | dspace |
| spelling | Syromyatnikov, V. Pomaz, I. Verbitsky, A. Vertsimakha, Ya. Nešpůrek, S. Pochekaylov, S. 2017-05-30T17:26:00Z 2017-05-30T17:26:00Z 2009 Photosensitive in wide spectral region composites
 based on polyphenylenevinylene / V. Syromyatnikov, I. Pomaz, A. Verbitsky, Ya.Vertsimakha,S. Nespurek, S. Pochekaylov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2009. — Т. 12, № 1. — С. 01-07. — Бібліогр.: 16 назв. — англ. 1560-8034 PACS 78.66.-w, 79.60.Jv https://nasplib.isofts.kiev.ua/handle/123456789/118613 Optical and photovoltaic properties of polyphenylenevinylene derivative –
 poly(2-methoxy-5-(3-,7-dimethyl-octyloxy)-1,4-phenylenevinylene (MDMO-PPV) and
 its composites with high (40 %) concentration polymethine dyes (PD) – meso-Cl and
 hexaindoletricarbocyanine (HITC) films have been studied. Two H-aggregates of dyes
 with different energies that weakly depend on the molecular structure of dyes, is formed
 in MDMO-PPV with PD in composites films. The efficiency of photogeneration of
 charge carrier by these aggregates is greater than the efficiency of photogeneration of
 charge carriers by the quasi-isolated molecules of dye. It results in substantial expansion
 of the absorption region (in comparison with the absorption region of molecules in
 solution) and photosensitivity in the side of higher energies. The presence of PD
 aggregates in the films MDMO-PPV influences on their photosensitivity that depends on
 PD molecular structure. This dependence can be caused by interaction between the
 molecules of MDMO-PPV and dye. In composites MDMO-PPV/HITC, the value of
 interaction is low and practically does not influence the efficiency of photogeneration of
 charge carriers by MDMO-PPV molecules, which give a considerable contribution to
 formation of the photovoltage in 2-3 eV regions. The interaction of meso-Cl and
 MDMO-PPV molecules is stronger, and this, probably, results in considerable decrease
 of photovoltage in the region of the excitation of MDMO-PPV. m 400 up to 900 nm). 
 Work is executed accordin
 g to the Ukrainian-Czech 
 project in 2008. en Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України Semiconductor Physics Quantum Electronics & Optoelectronics Photosensitive in wide spectral region composites based on polyphenylenevinylene Article published earlier |
| spellingShingle | Photosensitive in wide spectral region composites based on polyphenylenevinylene Syromyatnikov, V. Pomaz, I. Verbitsky, A. Vertsimakha, Ya. Nešpůrek, S. Pochekaylov, S. |
| title | Photosensitive in wide spectral region composites based on polyphenylenevinylene |
| title_full | Photosensitive in wide spectral region composites based on polyphenylenevinylene |
| title_fullStr | Photosensitive in wide spectral region composites based on polyphenylenevinylene |
| title_full_unstemmed | Photosensitive in wide spectral region composites based on polyphenylenevinylene |
| title_short | Photosensitive in wide spectral region composites based on polyphenylenevinylene |
| title_sort | photosensitive in wide spectral region composites based on polyphenylenevinylene |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/118613 |
| work_keys_str_mv | AT syromyatnikovv photosensitiveinwidespectralregioncompositesbasedonpolyphenylenevinylene AT pomazi photosensitiveinwidespectralregioncompositesbasedonpolyphenylenevinylene AT verbitskya photosensitiveinwidespectralregioncompositesbasedonpolyphenylenevinylene AT vertsimakhaya photosensitiveinwidespectralregioncompositesbasedonpolyphenylenevinylene AT nespureks photosensitiveinwidespectralregioncompositesbasedonpolyphenylenevinylene AT pochekaylovs photosensitiveinwidespectralregioncompositesbasedonpolyphenylenevinylene |