A triphenylamine-capped solution-processable wholly aromatic organic molecule with electrochemical stability and its potential application in photovoltaic devices

Article abstract of DOI:10.1039/c3nj00406f

A triphenylamine-capped solution-processable wholly aromatic conjugated molecule, TPA-TVBP, was designed and synthesized. It exhibited a high thermodynamic stability and good film forming ability as expected, originating from the absence of alkyl and alkoxyl moieties. The triphenylamine cap provided a good solubility because of three-dimensional propeller structure and a donor moiety to construct the organic D-π-A molecule with the electron-deficient tribenzo[a,c,i]phenazine moiety as the acceptor. The special electrochemical stability was discussed through cyclic voltammetry and potential switching step measurements, and the photocurrent generation in photovoltaic device application was described further. Simple bulk heterojunction photovoltaic cells were fabricated using TPA-TVBP and PCBM, and the higher short circuit current and fill factor than the similar structures were achieved. Based on the mechanism of the photocurrent generation, the TPA-TVBP molecule would be a good model molecule to investigate the electrochemical properties of the triphenylamine-capped material in photovoltaic device application.

Full text of DOI:10.1039/c3nj00406f

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A Triphenylamine-capped Solution-Processable Wholly
Aromatic Organic Molecule with Electrochemical Stability
and Its Potential Application in Photovoltaic Devices
TOC：
TPA-TVBP, as a TPA-capped model material, exhibited a surprising harvest in
potential OPV application because of its electrochemical stability in solution and film
by the cyclic voltammetry and potential switching step measurements.
TOC figure

New Journal of Chemistry
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Cite this: DOI: 10.1039/c0xx00000x
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ARTICLE TYPE
A Triphenylamine-capped Solution-Processable Wholly Aromatic
Organic Molecule with Electrochemical Stability and Its Potential
Application in Photovoltaic Devices
a,b
a
c
a
b
a
b
Zhiming Wang* , Xiaohui Song , Lingling Ma , Ying Feng ,Cheng Gu , Xiaojuan Zhang , Ping Lu* ,
Yuguang Ma
b
5
Received (in XXX, XXX) Xth XXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX
DOI: 10.1039/b000000x
A triphenylamineꢀcapped solutionꢀprocessable wholly aromatic conjugated molecule, TPA-TVBP, was
designed and synthesized. It exhibited a high thermodynamic stability and good film forming ability as
expected, originating from the absent of alkyl and alkoxyl moieties. The triphenylamine cap provided a
good solubility because of threeꢀdimensional propeller structure and a donor moiety to construct the
organic DꢀπꢀA molecule with electronꢀdeficient tribenzo[a,c,i]phenazine moiety as the acceptor. The
special electrochemical stability was discussed through cyclic voltammetry and potential switching step
measurements, and the photo current generation in photovoltaic device application was described further.
Simple bulk heterojuction photovoltaic cells were fabricated using TPA-TVBP and PCBM, and the
higher short circuit current and fill factor than the similar structures were achieved. Based on the
mechanism of the photocurrent generation, the molecule TPA-TVBP would be a good model molecule to
investigate the electrochemistry properties of the triphenylamineꢀcapped material in photovoltaic device
application.
1
0
1
5
2
0
Introduction
[
7]
Solutionꢀprocessable molecules have attracted increasing
increase solutionꢀprocessability,. TPA has been reported as a
attention in organic lightꢀemitting diodes (OLED) and organic
photovoltaic (OPV) devices. With respect to their polymer
good pꢀdoping unit in photoelectric research and used as holeꢀ
[
1]
[8,9]
injection and transport moiety.
As shown in Schemeꢀ1, many
2
3
3
4
4
5
0
5
0
5
counterparts, small molecule compounds presenting a better
reproducibility of synthesis and easier purification, together with 50 excellent performance in photoelectric devices,
solutionꢀprocessable molecules containing TPA reported exhibit
[
10]
while their
their precise (monodisperse) chemical structures facilitate the
reversibility (stability) in redox process is ignored, which is
important for their service life.
[
2]
establishment of structureꢀproperties relationships.
Their
solution processability offers the possibility of avoiding the
troublesome highꢀprecision mask alignment during vacuum
deposition process, particularly to produce largeꢀarea colour
[
3]
display and solar panels. Based on the development of OLED
and OPV materials for possible commercial applications, some of
alkyl and alkoxyl moieties are introduced to enhance solution
processability, which is beneficial to adjust the efficiency and
[
4]
reduce fabricating cost. However, these alkyl and alkoxyl
moieties can be readily decomposed than their aryl block for their
instability under the sun and oxygen. Therefore, the wholly
aromatic organic molecule should be a better choice to extend
5
5
Scheme 1 The common structures of TPA and its derivatives in OPVs
Tribenzo[a,c,i]penazine (TBP) is a famous liquid crystal
molecule, which has good thermo and environmental stability.
The low electron injection barrier and the reversible reꢀdox
[
5]
service life of photoelectric material. Generally, the wholly
aromatic structure possesses high photoꢀthermal stability and
60
progress in reduction are suitable for balancing the carries
[
6]
robust morphology, while the solubility remains a key issue.
[11]
transport.
Recently, we designed a model molecule to
The triphenylamine (TPA) moiety possesses threeꢀ
dimensional propeller structure, which can effectively avoid
molecular aggregation and is usually chosen as a block to
investigate the electrochemical stability of the TPAꢀcapped
material in OPV application. With TPA unit, we chose TBP as
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an accepter unit to construct the wholly aromatic organic DꢀπꢀA
molecule TPA-TVBP (Scheme 2), which is consisting of a
rigidity moiety of TBP and a flexibility moiety of TPA via
[
12]
conjugated bridge. To be expected, TPA-TVBP exhibits good
solutionꢀprocessability and spaceꢀchargeꢀseparation capability,
high thermodynamic stability and good film forming ability. The
stable electrochemical property in doping state is discussed by
cyclic voltammetry and potential switching step measurements
further. Here, we report its synthesis, characterization and
primary photovoltaic application as a solutionꢀprocessable OPV
material.
5
1
0
35
Fig.2 The TGA and DSC (insert) graphs of TPA-TVBP
Synthesis and Characterization
Design and Synthesis
Thermal properties of the molecule were investigated using
thermoꢀgravimetric analysis (TGA) and differential scanning
calorimetry (DSC) at a heating rate of 10°C/min under nitrogen
atmosphere (Fig.2). The molecule showed a small weight loss
40
(<5%) at 510°C, and before 200°C, the lost weight, which may be
due to the lost of the trapped solvent (DMAC) in the material.
The Tg values were measured to be 178°C (Fig.2 inserted), and
this implied the TPA-TVBP molecule exhibited glass phase
1
5
45 property. Such high Td and Tg indicate that TPA-TVBP could
form morphologically stable amorphous films upon thermal
evaporation, which is very important for its application in OLED
Scheme. 2 The synthesis route of TPA-TVBP
As shown in Schemeꢀ1, TPA-TVBP was synthesized via
crossꢀcoupling of 2,7ꢀdibromotribenzo[a,c,i]phenazine (M3) with
two equivalents of 4ꢀN,Nꢀdiphenylaminostyrene (M2) under
[15]
and OPV.
20
50
Photophysical Properties
typical Heck reaction conditions, catalyzed by Pd(OAc) and
2
[
13]
K PO .
M2 was prepared as the literature reported, and M3
3
4
was started from 2,7ꢀdibromophenanthreneꢀ9,10ꢀdione and
naphthaleneꢀ2,3ꢀdiamine by a similar method as described in our
[
14]
25
previous report with a little revision.
The NMR spectrum of
TPA-TVBP was shown in Fig.1, and all of the peaks observed in
the aromatic range were corresponded well to its expected
structure as marked.
Fig. 3 Normalized absorption spectra of TPA-TVBP in THF and
film (a) and the emission spectra in different polarity solvent (b)
5
6
6
7
5
0
5
0
Benefited from its donorꢀacceptor structure linked with
conjugated bridge as designed, TPA-TVBP showed a broad
absorption band covering the wavelength range from 250 to 650
nm (Fig.3a), which is favorable for the application in
[
16]
photovoltaic devices.
The normalized optical absorption
ꢀ
5
spectra of TPA-TVBP in dilute (10 M) THF solutions exhibited
two strong absorption peaks at 308, 406 nm and an absorption
band at 505 nm respectively. In film state, they were redꢀshifted
to 312, 414, and 535 nm, respectively. The absorption edge of the
film extended to 650 nm, from which the corresponding optical
energy gap (Eg opt) was calculated to be 1.9eV.
30
1
Fig.1 H NMR spectrum TPA-TVBP in the aromatic range
TPA-TVBP showed a low and broad emission band at 495 nm
ꢀ
5
Thermal Properties
in THF (10 M), while the emission of its film was too weak to
be observed with a band around the 650 nm. Solvatochromism
experiments of the TPA-TVBP were done in different polarity
solvents and some fluorescence spectra were split two parts
obviously, which might be originated from the donor part and the
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ICT state. When increasing solvent polarity, the emission
maximum of TPA-TVBP was blueꢀshifted, from 596 nm in
and morphological stability under Joule heat and sunlight
irradiation during operation. This was derived from the all
hexane, 551 nm in toluene, 494 nm in THF to 462 nm in 55 aromatic structure and high thermodynamic stability of the
acetonitrile, accompanying the full width at half maximum
(FWHM) significantly broadened from 150 nm in hexane to 300
nm in acetonitrile. Such a change indicated that the dipole
moment or the molecule excited state structure of TPA-TVBP
had been affected by the solvent, inducing the change of
wholly aromatic structure. When the annealing temperature was
o
5
improved to 160 C in N atmosphere for 10 min, the roughness
2
changed only form 1.09 nm to 1.69 nm.
[
17]
intramolecular charge and energy transfer progress.
1
0
Meanwhile, it suggested that the quinoxaline structure (TBP) had
strong electronꢀwithdraw ability and was suitable to construct the
space charge separation system, which was also approved by the
data of electrochemistry and molecule simulation discussed
below.
1
5
Theoretical Calculations and molecule simulation
The electronic properties of compound TPA-TVBP had been
investigated by theoretical calculations. Calculations were done
using the restricted B3LYP/6ꢀ31G(d)* functions. The orbital
distribution of HOMO and LUMO levels of neutral molecule
TPA-TVBP were shown in Fig. 4. The HOMO state density
mainly distributed on the two triphenylamine (TPA) moieties and
phenanthrene part of tribenzo[a,c,i]phenazine moiety. The
electron density of LUMO was mainly localized at naphthalene
part of the tribenzo[a,c,i]phenazine moiety. This was a strong
proof of spaceꢀchargeꢀseparation and could greatly enhance
exciton dissociation and decrease the recombination of charged
species to increase the lightꢀcurrent intensity at the electrode.
60
Fig 5. The AFM of TPA-TVBP (a) at room temperature, (b) annealing at
o
o
9
0 C, (c) annealing at 160 C. The AFM of TPA-TVBP : PCBM (1:1)
2
0
o
o
(d) at room temperature, (e) annealing at 90 C, (f)annealing at 160 C.
6
7
7
5
0
5
As shown in Fig. 5, the blend film of TPA-TVBP and PCBM
(on ITO substrate 10mg/ml in chlorobenzene, 1000rps), revealed
that the surface roughness was only 0.7 nm, which implied the
PCBM had no influence on the film of TPA-TVBP.
Significantly, the blend became even flatter than original spinꢀ
2
5
o
o
coated film after annealing at 90 C and 160 C in N atmosphere
2
for 30 min and 10 min, respectively. This may be properly
ascribed to the restrained aggregation of PCBM doping. All of
this proved that the wholly aromatic structure TPA-TVBP was
suitable as a better film material with solutionꢀprocessable ability.
Electrochemical Properties
3
0
Fig 4.The calculated HOMO (a) and LUMO (b) orbital distributuion
a. Measurment of Energy Level
The optimized geometry of TPA-TVBP indicated that the two
TPA moieties at the end of the molecule were in 3ꢀD spatial
arrangement. The nonplanar conformation of TPA-TVBP could
be beneficial to increase solutionꢀprocessability and forming
amorphous film ability. While the obvious planer structure of
TVBP indicated that the molecule would be prone to aggregate in
proper condition, and increase the charge mobility when they
aggregated in blend. Such a molecular structure balanced rigidity
and flexibility, determining its excellent film forming abilities,
3
5
4
0
Morphology
As expected, TPA-TVBP was soluble in common organic
solvents such as THF, toluene, and chlorobenzene. High quality
amorphous film could be obtained by spinꢀcoating from solution 80 Fig. 6. The CV curve of TPAꢀTVBP in in CH Cl and DMF solution.
2
2
4
5
as shown in Figꢀ4. The AFM images of TPA-TVBP film on an
indiumꢀtinꢀoxide (ITO) substrate (10mg/ml in chlorobenzene,
The electrochemical behavior and the electrochemical energy
levels of the TPA-TVBP were investigated by cyclic
voltammetry (CV) in a standard threeꢀelectrode electrochemical
1
000rps), revealed that the surface roughness was 0.6 nm, the
same to the polymer roughness. This proved that the planer unit
o
had no influence on film morphology. After annealing at 90 C in 85 cell. The CV measurement in solution was conducted in CH
Cl
tetraꢀnꢀbutylammonium
as electrolyte at room
temperature. HOMO and LUMO level were estimated using the
2
2
5
0
N2 atmosphere for 30 min, the film was kept unchanged. It
suggested that the film of the molecule was suitable for
applications as thin film devices with good filmꢀforming ability
and DMF 1:1 with 0.1
hexafluorophosphate (nꢀBu NPF )
6
M
4
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energy level of the ferrocene (Fc) reference (4.8 eV) and
+
[18]
calibrated with E1/2(Fc/Fc ) = 0.11 V.
As shown in Fig. 6, in the positive potential region there was
one couple of oxidation/reꢀreduction peak with the onset
onset
5
0
5
oxidation potential (E
from TPA unit.
) at 0.53 V vs Ag wire which was
ox
[
19a]
And a couple of reduction peak in the
negative potential region with onset reduction potential (E
onset
)
red
at ꢀ1.30 V vs Ag wire was observed, which is affirmed from the
TBP unit. This was consistent with the result of molecular
simulation fact that HOMO was localized at TPA unit and
LUMO was localized at TBP unit. HOMO and LUMO levels
were calculated to be ꢀ5.10 eV and ꢀ3.41 eV, respectively, and the
electrochemical band gap was 1.69 eV.
1
Fig. 8. Potential switching step of the reduction (a) and oxidation (b) of
TPA-TVBP in spinꢀcoating film.
4
5
5
6
6
5
0
5
0
5
To discuss the stability of the TPA-TVBP film, the method
[
21]
of potential switching step was introduced, which was widely
applied in electrochromism to validate the stability of molecules.
TPA-TVBP was spinꢀcoated on ITO surface to form the film. Its
reduction state was switched by stepping the potential between ꢀ
1
b. Electrochemical Stability in Solution
1
.6 and ꢀ0.2 V during oxidation with time intervals of 10 s and
between ꢀ0.8 and 0.8 V during oxidation with time intervals of 5 s,
and the current was monitored versus time. As shown in Figure 8,
the current transient shapes of the oxidation and reduction current
peaks were different, reaching zero in a few seconds during the
potential pulses, but the charge injected in both processes were
the same. Mostly, the amount of charge (Q) in each current curve
in both processes was very similar, in agreement with the stable
[
21]
anodic electrochemical properties of molecule in film . The
current kept unchanged in the successive cycles during the
reduction process (Fig. 8a). But during the oxidation process (Fig.
8
b), on subsequent scans, the peak current was increased firstly,
indicating the crossꢀlinking reaction happened between the TPA
units. And then it was gradually decreased in the successive
cycles, which was normally observed and suggested the
[
23]
dimerization reaction was finished . This showed that the
electropolymerization process could also form the TPB-TVBP
film in the solid state.
Fig.7. Repetitive cyclic voltammograms of the reduction of TPA-TVBP
in a 1.0 mM solution (a) and oxidation (b) with 0.1 M TBAP on a Pt
electrode, V ) 0.1 V sꢀ1; (c). The crossꢀlinking mechanism of dimerization
reaction from TPA to TPB
20
Interestingly, when the repetitive cyclic voltammograms were
performed in solution, the reduction was kept unchanged on
subsequent scans, meaning TPA-TVBP at the anion state was
very stable and the doping/dedoping process was completely
reversible as shown Fig 7a. During the oxidation process, on
subsequent scans in the potential range of 0 V to +0.80 V, the
peak current was gradually increased, and in the successive
cycles the potential was decreased (Fig. 7b). As shown in Fig. 7c,
the TPA-TVBP radical cation formed by oxidation was involved
in a dimerization reaction, indicating the crossꢀlinking between
the TPA units and the growth of tetraphenylbenzidine (TPB).
The oxidation potential was gradually decreased because the
more extended πꢀelectron delocalization of TPB unit. The
2
5
30
35
40
electrochemical processes could be described by an EC E
2
[
19]
mechanism . That meant the molecule in solution would be
70
[
20]
electroꢀdeposited on electrode to form the film
.
Fig. 9. (a) The preparation of the electrochemical deposition film (TPB-
TVBP); and the potential switching step of the reduction (b) and
oxidation (c) of TPB-TVBP.
c. Electrochemical Stability in Film
75
For further understanding the electrochemical stability of the
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TPBꢀTVBP, which was formed by the crossꢀlink of TPA-TVBP
Fig. 9a), a film on an ITO electrode was got by the way of
electroꢀdeposition in CV method from the TPA-TVBP 50 TDOX , which was thought to profit from the compositive
value was very low, the short circuit current and fill factor were
[
26]
(
still higher than the similar structures of TPAꢀTH1
and
[
27]
[
24]
solution .. In the successive scans measurement, the current
was increased and the potential changed in the same way as the
scan cycles increase. The formed TPBꢀTVBP film can be treated
as the TPA-TVBP film by potential switching step method, and
peculiarity of TPAꢀTVBP involving the good solutionꢀ
processability, the spaceꢀchargeꢀseparation capability, the good
thermal and forming film stability, the broad absorption spectrum
and especially the stable electrochemistry properties in redox
5
0
5
0
5
0
the pulse time was tuned twice. The amount of charge in each 55 progress. The further optimation in OPV with TPAꢀTVBP as an
current curve in two processes was very similar as shown in Fig.
9bꢀc, and the results suggested the film of TPBꢀTVBP had better
n/p doping capability than the TPA-TVBP film. Meanwhile, this
method could be applied to the preparation of photoꢀelectro films
active layer or with electroꢀdeposited film (TPBꢀTVBP film) as a
functional layer would be reported in the next research work.
1
1
2
2
3
Conclusion
[
23,24]
devices.
In summary, the tribenzo[a,c,i]phenazine (TBP) was chosen
as an accepter unit to construct a wholly aromatic organic DꢀπꢀA
molecule with TPA unit, named TPA-TVBP as a model
molecular to investigate the electrochemistry stability of the
TPAꢀcapped material in OPV application. TPA-TVBP exhibited
Actually, the reversible redox progress of the film was
important in photovoltaic device. To get a persistent current, the
molecule must switch between the doping and neutral state, thus
the reversibility of the materials in doping and dedoping process
is inherent request for long lifeꢀtime and highꢀefficiency device.
60
[
25]
The electrochemical measurement can reflect the molecule
a good solutionꢀprocessability and spaceꢀchargeꢀseparation
doping and dedoping progress, so the method was introduced to 65 capability, high thermodynamic stability and good film forming
discuss the molecule “bipolar property”.
as expected. The special electrochemistry stability was discussed
by cyclic voltammetry and potential switching step measurements,
and the doping and dedoping progress in OPV application was
described further. Thus, the result was important not only in terms
of developing a new kind of triphenylamineꢀcapped material
containing TBP unit, but also exploring the TPA moiety as a
capped unit in OPV film application.
In nꢀdoping progress of TPA-TVBP, the film was very stable
by potential switching step measurement from the data above. In
pꢀdoping progress, the polymerization might be gained, which
meant the TPA unit possibly underwent radical cation
dimerization and became to be the dimmer TPB unit. The film of
TPB-TVBP exhibited better n/p doping capability than that of
TPA-TVBP. In other words, if the spinꢀcoating film of TPA-
TVBP were applied in solar cells, it would possess better
electrochemistry properties (stability) even after dimerization
reaction happened. This was a surprising harvest for the TPAꢀ
capped martial.
7
0
Experimental Part
Materials and measurement
7
8
8
5
0
5
All the reagents and solvents used for the syntheses were
purchased from Aldrich or Acros companies and used without
further purification. All reactions were performed under a dry
nitrogen atmosphere.
Photovoltaic properties
1
The H NMR and spectra were recorded on AVANCZ 500
spectrometers at 298K by utilizing deuterated chloroform (CDCl3)
or Dimethyl Sulphoxide (DMSO) as solvent and
tetramethylsilane (TMS) as standard. The elemental analysis was
operated by Flash EA 1112, CHNSꢀO elemental analysis
instrument for these compounds. The MALDIꢀTOF mass spectra
were recorded using an AXIMAꢀCFRTM plus instrument. UVꢀvis
absorption spectra were recorded on UVꢀ3100 spectrophotometer.
Fluorescence measurements were carried out with RFꢀ5301PC.
The differential scanning calorimeter (DSC) analysis was
o
determined using a NETZSCH (DSCꢀ204) instrument at 10 C
3
5
90 /min under nitrogen flushing. Cyclic voltammetry (CV) were
performed with a BAS 100W Bioanalytical Systems, using a
glass carbon disk (Φ=3mm) as working electrode, a platinum
Fig.10. The IꢀV curve of TPA-TVBP/ PCBM blend in OPVs.
Based on the above results of TPA-TVBP, the photovoltaic
property in OPV was attempted to be obtained. Bulkꢀ
heterojunction OPVs were fabricated based on the spinꢀcoated
blend films of TPA-TVBP and PCBM (1:1, w/w) as the active
layer, with LiF/Al as the cathode. Fig. 10 showed the currentꢀ
voltage (IꢀV) curves of the OPVs in the dark and under AM 1.5
+
wire as auxiliary electrode and Ag/Ag as reference electrode.
Cyclic voltammetric studies were carried out containing 0.1M [nꢀ
4
0
o
95
NBu ][BF ] dried in an oil pump vacuum at 80 C as supporting
4
4
electrolyte. All solutions were purged with nitrogen stream for 10
min before measurement. The procedure was performed at room
temperature and nitrogen atmosphere was maintained over the
solution during measurements. The atomic force microscopy
00 (AFM) measurement was conducted on a Nanoscope III (DI,
USA) in tapping mode with 100ꢁm scanner.
ꢀ
2
illumination of 100 mW cm . The open circuit voltage (VOC),
4
5
short circuit current (J ), fill factor (FF) and power conversion
SC
1
efficiency (PCE) of the OPVs based on TPA-TVBP reached 0.61
ꢀ
2
V, 1.48 mA cm , 0.33 and 0.29% respectively. Although its
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8
8.52; H, 6.31; N, 5.16. Found: C, 88.46; H, 6.53; N, 5.07.
OPV Device Fabrication and Measurement
6
6
7
7
8
8
0
5
0
5
0
5
2,7-dibromotribenzo[a,c,i]phenazine (M3)
The bulk heterojuction photovoltaic cells were fabricated with
the active layer consisting of the TPA-TVBP:PCBM with blend
ratios (1:1, w/w). ITO glass was cleaned by detergent, acetone
and boiled in H O . A 50 nm layer of poly(3,4ꢀethylene
In a 100 mL round bottom flask, 2,7ꢀdibromophenanthreneꢀ
,10ꢀdione 2.08 mg (10 mmol) and 3.16 mg ( 20 mmol )
9
5
0
5
0
5
naphthaleneꢀ2,3ꢀdiamine were placed, then 50 mL glacial acetic
acid wad added. The mixture was stirred vigorously at 80 C for
4h in air. The whole mixture was then poured into water and then
the precipitate was filtered. Then the solid was chromatographed
o
2
2
dioxythiophene): poly(styꢀ renesulfonate) (PEDOT: PSS) z(Bayer
PVP Al 4083) as a modified layer was spinꢀcoated onto the preꢀ
cleaned ITO glass substrate and then dried at 120 C for 15 min
o
on a silica column using CHCl as eluent and recrystallized from
3
1
1
2
2
on a hot plate. The TPA-TVBP was dissolved in chlorobenzene
DMSO twice to give deepꢀred needle crystals in 85% yield.
C H N Br : Calcd. C, 59.05; H, 2.48; Br, 32.74; N, 5.74; Found
ꢀ
1
to make 10 mg ml solutions, followed by blending with PCBM
purchased from Lumtec. Corp) in blend ratios (1:1, w/w). The
2
4
12
2
2
(
C, 59.25; H, 2.45; Br, 32.64; N, 5.62. MS(MALDIꢀTOF): m/z=
active layers were obtained by spinꢀcoating the blend solutions
and the thickness of films were about 70 nm, as measured with
the Ambios Technology XPꢀ2. Finally, the cathode of LiF (0.5
nm)/Al (100 nm) was thermally deposited to finish the device
+
1
4
2
88.93 (M ). H NMR (DMSO, ppm): δ 9.24 (dd, 2H), 8.39(s,
H), 8.30 (d, 2H), 8.08 (d, 2H), 7.68 (d, 4H) , 7.38 (d, 2H).
Synthesis of TPA-TVBP
2
fabrication. The active area was about 5 mm . Currentꢀvoltage (Jꢀ
17.8 mg (0.5 mmol) M3, 27.2 mg (1 mmol) M2, 5 mg of Pd
V) characteristics were recorded using a Keithley 2400 Source
(
OAc) , and 254.4 mg of K PO were added to a 50 mLꢀflask,
2 3 4
ꢀ
2
Meter in the dark and under 100 mW cm simulated AM 1.5 G
irradiation (Sciencetech SSꢀ0.5 K Solar Simulator). The spectral
response was recorded by a SR830 lockꢀin amplifier under short
and then 5 mL dimethylacetamide (DMAC) was injected by
syringe under nitrogen flow. The mixture solution was heated to
o
1
40 C under the dark and kept at that temperature overnight, and
circuit conditions when devices were illuminated with
a
the solution was poured into methanol after cooling to the room
temperature. The precipitate was filtered, washed with water,
dissolved in methylene chloride, and dried over MgSO . After
monochromatic light from a Xeon lamp. All fabrication and
characterizations were performed under ambient atmosphere at
room temperature.
4
column separation (petroleum ether/ ethyl acetate v:v = 3:1), 166
mg deep red powder of TPA-TVBP was obtained with a yield of
Synthesis
1
38%. H NMR (CDCl , ppm): δ 9.02 (s, 2H, naphthalene unit),
3
4
-(diphenylamino)benzaldehyde (M1)
Triphenylamine (5.0 g, 20.2 mmol) was dissolved in distill
8.71 (s, 2H, phenanthrene unit), 8.03 (d, 4H, phenanthrene unit),
7.58 (d, 2H, naphthalene unit), 7.48 (d, 2H, naphthalene unit),
7.43 (d, 2H, C=C), 7.29 (t, 4H, PhꢀH of TPA), 7.03 (m, 20H, Nꢀ
PhꢀH). MALDIꢀTOFꢀMS confirmed the chemical structure of
30
35
40
45
50
55
DMF (15 mL) in a 250 mL twoꢀnecked roundbottom flask. Under
o
ꢀ20 C in iceꢀwater bath, the phosphorus oxychloride (POCl , 14.7
3
mL) was added dropwisely to the mixture with a strong stirrer bar. 90 TPA-TVBP (m/z): 868. 6, calcd for C64
H
N
, 868.36. Anal Calc.
H N ): C, 88.45; H, 5.10; N, 6.45. Found: C, 88.31; H,
44 4
44
4
o
Then the mixture warmed to 45 C for 2 hr until the drop progress
stop. This mixture was poured into ice water to stop the reaction
with proper pH adjustment (pH=7) with 20% NaOH eq. Formed
yellow precipitate and filtered off, and the mixture was
recrystallized from ethyl acetate to afford the lightꢀyellow crystal
of M1. Yield: 89%. H NMR (CDCl , ppm), δ: 7.0ꢀ8.0 (m, 14H),
for (C64
5.32; N, 6.48.
Acknowledgements:
1
We are grateful for support from the National Science Foundation
95 of China (Grant No. 51203091, 21107050, 60906021), the
Ministry of Science and Technology of China (grant number:
3
+
9
.8 (s, 1H). MALDIꢀTOFꢀMS (m/z): [M+H] calcd for C H NO,
19
15
273.1; Found: 273.6. Anal. Calcd for C H NO: C, 83.49; H,
5
1
9
15
2
009CB623605), and PCSIRT.
.53; N, 5.12. Found: C, 83.90; H, 6.01; N, 5.07.
Notes and references
4
-N,N-diphenylaminostyrene (M2)
5
.46 g (20.0 mmol) of 4ꢀ(diphenylamino)benzaldehyde (M1)
a
School of Petrochemical Engineering, Shenyang University of
and 8.57 g (24.0 mmol) of triphenylmethylphosphonium bromide 100 Technology, 30 Guanghua Street, Liaoyang, 111003, P. R. China Fax:
+86 419 5319409; Tel: +86 419 5319409; E-mail:
were dissolved in 50 mL of dry THF. The resulting solution was
added dropwise slowly to 280 mg (2.5 mmol) of tꢀBuOK in 20 ml
of dry THF at 0 C, then the reaction mixture was warmed to
room temperature and stirred under N overnight. The mixture
was poured into water and extracted with dichloromethane. The
organic phase was washed with water, brine, and dried over
wangzm2011@yahoo.com.cn
b
State Key Laboratory of Supramolecular Structure and Materials, Jilin
o
University, 2699 Qianjin Avenue, Changchun 130012,P.R.China. Fax:
2
105 +86 431 85168480; Tel: +86 431 85168480; E-mail: lup@jlu.edu.cn
c
Research Institute of Liaoyang Petrochemical Company, Petro-China,
Liaoyang, 111003, P. R. China.
MgSO . After removing the solvent, the product was purified by
column chromatography using dichloromethane/petroleum ether
4
†
Electronic Supplementary Information (ESI) available: [details of any
1
1
10 supplementary information available should be included here]. See
DOI: 10.1039/b000000x/
1
(v:v = 1:4) gave M2 (4.06 mg, 73%) as a yellow solid.
H
NMR(CDCl , ppm) δ 5.06 (d, 1H), 5.53 (d, 1H), 6.54 (dd, 1H),
6
for C H N 271.1, Found: 271.6 Anal. Calcd for C H N: C,
3
.92ꢀ7.03(m, 10H), 7.15ꢀ7.22 (m, 4H). MALDI/TOF MS: Calcd
1. (a) V. C. Tung , J. H. Huang , J. Kim , A. J. Smith , C. W. Chu and J.
X. Huang Energy Environ. Sci., 2012, 5, 7810; (b) J. T. Chen and C. S.
Hsu. Polym. Chem., 2011, 2, 2707; (c) J. Peet, A. J. Heeger and G. C.
20
17
20 17
15
6
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Bazan. Acc. Chem. Res., 2009, 42, 1700; (d) Y. J. Pu, M. Higashidate,
K. I. Nakayama and J. Kido. J. Mater. Chem., 2008, 18, 4183; (e) S.
Gnes, H.Neugebauer and N. S. Sariciftci. Chem. Rev., 2007, 107, 1324;
Mater. 2008, 20, 4212.
10. (a) D. Sahu, C. H. Tsai, H. Y. Wei, K. C. Ho, F. C. Chang and C. W.
Chu. J. Mater. Chem., 2012, 22, 7945; (b) S. H. Zeng , L. X. Yin, C. Y.
Ji, X. Y. Jiang, K. C. Li, Y. Q. Li and Y. Wang. Chem. Commun., 2012,
48, 10627; (c) J. Zhang, D. Deng, C. He, Y. J. He, M. J. Zhang, Z. G.
Zhang, Z. J. Zhang and Y. F. Li. Chem. Mater., 2011, 23, 817.
11. E. J. Foster, R. B. Jones, C. Lavigueur and V. E. Williams. J. Am.
Chem. Soc., 2006, 128, 8569.
12. S. M. Zhang, H. J. Fan, Y. Liu, G. J. Zhao, Q. K. Li, Y. F. Li, X. W.
Zhan. J Polym Sci Part A: Polym Chem., 2009, 47, 2843.
13.H. J. Xia, J. T. He, P. Peng, Y. H. Zhou, Y. W. Li and W. J. Tian.
Tetrahedron Lett., 2007, 48, 5877.
(f) S. C. Lo and P. L.Burn. Chem. Rev., 2007, 107, 1097.
5
0
5
0
5
0
5
0
5
0
5
2. (a) T. S. Poll, J. A. Love, T. Q. Nguyen and G. C. Bazan. Adv. Mater.
60
65
2
2
012, 24, 3646; (b) Y. Z. Lin, Y. F Li and X. W. Zhan. Chem. Soc. Rev.,
012, 41, 4245; (c) B. Walker, C. K. Kim and T. Q. Nguyen. Chem.
Mater., 2011, 23, 470; (d) P. Peumans, A. Yakimov and S. R. Forrest. J.
Appl. Phys., 2003, 93, 3693.
3. (a) L. Zhao, J. H. Zou, J. Huang, C. Li, Y. Zhang, C. Sun, X. H Zhu , J.
B. Peng, Y. Cao and J. Roncali. Org.Electron., 2008, 9, 649; (b) Y. H.
Sun, X. H. Zhu, Z. Chen, Y. Zhang and Y. Cao. J. Org. Chem., 2006,
1
1
2
2
3
3
4
4
5
5
7
1, 6281; (c) M. R. Robinson, S. J. Wang, G. C. Bazan and Y. Cao. Adv.
14. Z. M. Wang, P. Lu, W. S. Zhang, F. Z. Shen, M. Hanif, Y.G. Ma.
Macromol. Chem. Phys., 2009, 23, 2029.
Mater., 2000, 12, 1701.
4. (a) B. Liu, X. W. Chen, Y. H. He, Y. F. Li, X. J. Xu , L. Xiao, L. D. Li 70 15. (a) Z. M. Wang, P. Lu, S. M. Chen, Z. Gao, F. Z. Shen, W. S. Zhang, Y.
and Y. P. Zou. J. Mater. Chem. A, 2013, 1, 570; (b) J. Y. Yuan, Z. C.
Zhai, H. L. Dong, J. Li, Z. Q. Jiang, Y. F. Li and W. L. Ma. Adv. Funct.
Mater. 2013, 23, 885; (c) H.J.Chen, Y. L. Guo, G. Yu, Y. Zhao, J. Zhang,
D. Gao, H. T. Liu, and Y. Q. Liu. Adv. Mater. 2012, 24, 4618; (d) M. H.
Chen, J. H. Hou, Z. R. Hong, G. W. Yang, S. Sista, L. M. Chen and Y. 75 17. P. Leriche, P. Frere, A. Cravino, O. Aleveque and J. Roncali. J. Org.
Yang. Adv. Mater. 2009, 21, 1; (e) S. Tang, M. R. Liu, P. Lu, C. Gu, M.
Zeng, Z. Q. Xie and Y. G. Ma. Org. Electron., 2008, 9, 241.
. (a) M. Lucarini and G. F. Pedulli. Chem. Soc. Rev., 2010, 39, 2106; (b)
J. M. Zhuo, L. H. Zhao, R. Q. Png, L. Y. Wong, P. J. Chia, J. C. Tang, S.
Sivaramakrishnan, M. Zhou, E. C. W. Ou, S. J. Chua, W. S. Sim, L. L.
Chua, and P. K. H. Ho. Adv. Mater. 2009, 21, 4747; (c) K. Norrman,. J.
Alstrup, M. Jorgensen and F. C. Krebs. Surf. Interface. Anal., 2006, 38,
X. Xu, H. S. Kwok and Ma Y. G. J. Mater. Chem., 2011, 21, 5451; (b)
D. H. Hu, P. Lu, C. L. Wang, H. Liu, H. Wang, Z. M. Wang, T. Fei, X.
Gu and Y. G. Ma. J. Mater. Chem., 2009, 19, 6143.
16. Y. F. Li, Acc. Chem. Res., 2012, 45, 723
Chem., 2007, 72, 8332.
18. Z. M. Wang, P. Lu, S. F. Xue, C. Gu, Y. Lv, Q. Zhu and Y. G. Ma.
Dyes Pigments., 2011, 91, 356.
19. (a) G. S. Liou, Yi L. Yang, W. C. Chen, Y. Oliversu. J Polym Sci Part
A: Polym Chem., 2007, 45, 3292; (b) L. Otero, L. Sereno, F. Fungo, Y.
L. Liao, C. Y. Lin and K. T. Wong. Chem. Mater., 2006, 18, 3495.
20. C. J. Xia and R. C. Advincula. Chem. Mater., 2001, 13, 1682
21. (a) G. S. Liou and H. Y. Lin. Macromolecules., 2009, 42, 125; (b) I.
Yildiz, E. Deniz and F. M. Raymo. Chem. Soc. Rev., 2009, 38, 1859.
5
80
1
302; (d) L. L. Liu, S. Tang, M. R. Liu, Z. Q. Xie, W. Zhang, P. Lu, M.
Hanif, and Y. G. Ma. J. Phys. Chem. B, 2006, 110, 13734.
6. (a) Q. X. Tong, S. L. Lai, M. Y. Chan, K. H. Lai, J. X. Tang, H. L. 85 22. G. S. Liou, C. W. Chang, H. M. Huang and S. H. Hsiao. J Polym Sci
Kwong, C. S. Lee and S. T. Lee. Chem. Mater., 2007, 19, 5851; (b) X.
B. Sun, Y. H. Zhou, W. C. Wu, Y. Q. Liu, W. J. Tian, G. Yu, W. F. Qiu,
S. Y. Chen and D. B. Zhu. J. Phys. Chem. B, 2006, 110, 7702; (c) G. S.
Liou, S. H. Hsiao, N. K. Huang and Y. L. Yang. Macromolecules.,
2006, 39, 5337.
. (a) C. He , Q. G. He, Y. P. Yi , G. L. Wu ,F. L. Bai , Z. G. Shuai and Y. F.
Li. J. Mater. Chem., 2008, 18, 4085; (b) J. Cremer and P. Bauerle. J.
Mater. Chem., 2006, 16, 874; (c) G. S. Liou, H. Y. Lin, Y. L. Hsieh, Y.
L.Yang. J Polym Sci Part A: Polym Chem., 2007, 45, 4921.
Part A: Polym Chem., 2007, 45, 2004.
23. C. Gu, T. Fei, Y. Lv, T. Feng, S. F. Xue, D. Lu and Y. G. Ma. Adv.
Mater., 2010, 22, 2702.
24.(a) C. Gu, Z. B. Zhang, S. H. Sun, Y. Y. Pan, C. M. Zhong, Y. Lv, M.
Li, K. Ariga, F. Huang and Y. G Ma. Adv. Mater., 2012, 24, 5727; (b)
C. Gu, W. Y. Dong, L. Yao, Y. Lv, Z. B. Zhang, D. Lu and Y. G. Ma.
Adv. Mater., 2012, 24, 2413; (c) C. Gu, H. Liu, D. H. Hu, W. S. Zhang,
Y Lv, P. Lu, D. Lu, and Y. G. Ma. Macromol. Rapid Commun., 2011,
32, 1014; (d) C. Gu, T. Fei, L. Yao, Y. Lv, D.Lu and Y. G. Ma. Adv.
Mater., 2011, 23, 527; (e) M. Li, S. Tang, F. Z. Shen, M. R. Liu, W. J.
Xie, H. Xia and Y. G. Ma. Chem.Commun., 2006, 32, 3393.
25. (a) A. Facchetti. Chem. Mater., 2011, 23, 733; (b) A. Gadisa, K.
Tvingstedt, K. Vandewal, F. L. Zhang, J. V. Manca and Olle Inganas.
Adv. Mater., 2009, 21, 1; (c) H. Ohkita, S. Cook, Y. Astuti, W. Duffy, S.
Tierney, W. M. Zhang, M. Heeney, I. McCulloch, J. Nelson, D. D. C.
Bradley and J. R. Durrant. J. Am. Chem. Soc., 2008, 130, 3030; (d) S.
Westenhoff, I. A. Howard, J. M. Hodgkiss, K. R. Kirov, H. A.
Bronstein, C. K. Williams, N. C. Greenham and R. H. Friend. J. Am.
Chem. Soc., 2008, 130, 13653; (e) L. W. Barbour, M. Hegadorn and J.
B. Asbury. J. Am. Chem. Soc., 2007, 129, 15884.
90
95
7
8. (a) Y. Sun, S. C. Chien, H. L. Yip, Y. Zhang, K. S. Chen, D. F. Zeigler,
F. C. Chen, B. P. Lin and A. K. Y. Jen. Chem. Mater., 2011, 23, 5006;
(b) B. Yang, S. K. Kim, H. Xu, Y. Park, H. Y. Zhang, C. Gu, F. Z. Shen,
C. L. Wang, D. D. Liu, X. D. Liu, M. Hanif, S. Tang, W. J Li, F. Li, J.
C Shen, J. W. Park, Y. G. Ma. Chem.Phys.Chem., 2008, 9, 2601; (c) H.
P. Zhao, X. T. Tao, F. Z. Wang, Y. Ren, X. Q. Sun, J. X. Yang, Y. X. 100
Yan, D. C. Zou, X. Zhao, M. H. Jiang. Chem. Phys. Lett., 2007, 439,
1
32; (d) V. Promarak, M. Ichikawa, T. Sudyoadsuk, Sayant
Saengsuwan, T. Keawin. Optical Materials , 2007, 30, 364; (e) C.
Sakong, H. J. Kim, S. H. Kim, J. W. Namgoong, J. H.o Park, J. H. Ryu,
B. Kim, M. J. Ko and Jae Pil Kim. New J. Chem., 2012, 36, 2025.
. (a) J. M. Hancock, A. P. Gifford, Y Zhu, Y. Lou and S. A. Jenekhe.
Chem. Mater. 2006, 18, 4924. (b) R. Y. Lai, X. X, Kong, S. A. Jenekhe
and A. J Bard. J. Am. Chem. Soc. 2003, 125, 12631. (c) Y. Zhu, A. P.
Kulkarni, P. T. Wu and S. A. Jenekhe. Chem. Mater. 2008, 20, 4200. (d)
A. P. Kulkarni, Y. Zhu, A. Babel, P. T. Wu and S. A. Jenekhe. Chem.
105
9
26.J. Kwon, W. Lee, J. Y. Kim, S. Noh, C. Lee and J. I. Hong. New J.
Chem., 2010, 34, 744
27.M. l. Sun, L. Wang, X. H. Zhu, B. Du, R. S. Liu, W. Yang and Y. Cao.
Sol. Energy Mater. Sol. Cells., 2007, 91, 1681
110
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