Post on 14-Aug-2020
Semitransparent Solar Cells over 12% Efficiency based on a New
Low Bandgap Fluorinated Small Molecule Acceptor Mei Luo+1, Chunyan Zhao2+, Jun Yuan1, Jiefeng Hai3, Fangfang Cai1, Yunbin Hu1,
Hongjian Peng1, Yiming Bai2,4, Zhan'ao Tan*2,4,Yingping Zou1*
1. College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. Email: yingpingzou@csu.edu.cn(Y.Zou) 2. Beijing Key Laboratory of Energy Safety and Clean Utilization, North China Electric Power University, Beijing 102206, China. Email: 3. Guangxi Key Laboratory of Electrochemical and Magneto-chemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, China 4. Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China. Email: tanzhanao@mail.buct.edu.cn (Z.Tan) + The authors contributed equally.
EXPERIMENTAL SECTION
1. Materials
PCE10, PBDB-T, PBPB-T-2F were purchased from Solarmer Materials
Inc. 1-Chloronaphthalene (CN) was obtained from Sigma-Aldrich Inc. All
Chemicals and solvents were commercially available products and used
without further purification. The synthetic of compound 1and compound
3 are according to the reported literature.[1]Starting from compound 1, the
abstraction of one α-proton with n-butyllithium afforded the mono
anion intermediate, which was quenched with tributyltin chloride to
furnish compound 2. Stille cross-coupling of two equivalents of
compound 2 with dibromides compound 3 using Pd(PPh3)4 as the catalyst
precursor afforded compound 4. Compound 5 was obtained via triethyl
Electronic Supplementary Material (ESI) for Materials Chemistry Frontiers.This journal is © the Partner Organisations 2019
phosphate mediated Cadogan reductive cyclization and the N-alkylation
with an excess amount of 2-ethylhexyl bromide in the presence of
potassium hydroxide. The treatment of compound 5 with n-butyllithium
produced the dianion intermediates, which were converted to dialdehydes
compound 6, by quenching with dimethylformamide (DMF). Subsequent
Knoevenagel condensation of compound 6 with 2-(fluoro-3-oxo
-2,3dihydro-1H-inden-1-ylidene)malononitrile (FIC) afforded the target
acceptor molecule Y14.
2. Device fabrication
Indium tin oxide (ITO) coated glass ITO (glass) substrates were cleaned
in an ultrasonic bath by standard chemical means. The substrates were
dried by the nitrogen gas. Then, they experienced a plasma oxidation in
an enclosed chamber for1 min. SnO2 layers were spin-coated onto the
ITO(glass) substrates. After this, they were immediately transferred into a
pure nitrogen-filled glove-box. PBDB-T and Y14 with certain percentage
were dissolved in the organic solvent CHCl3. The mixtures were
spin-coated onto ITO(glass)/SnO2 substrates with a spin-speed of 2500
rpm for 30 s. The thickness of polymer donor:Y14 based film was
measured to be approximately 100 nm. Finally, all samples were
transferred into an integrated thermal evaporation system; 10 nm
thickMoO3 films and 100 nm thick Al electrodes were thermally
evaporated onto ITO(glass)/SnO2/PBDB-T:Y14. With the same
fabrication method, other inverted polymer solar cells were fabricated by
changing the organic blends to (i) PM6:Y14, (ii) PCE10:Y14 and
changing electron transport layer (TIPD).
3. Instruments and general methods
1H NMR and 13C NMR spectra were recorded using a Bruker
AV-400 spectrometer in deuterated chloroform solution at 298 K, unless
specified otherwise. Chemical shifts were reported as δ values (ppm) with
tetramethylsilane (TMS) as the internal reference. Mass spectra were
measured using by using an Autoflex III matrix-assisted.UV-Vis
absorption spectra were recorded on the SHIMADZU UV-2600
spectrophotometer. The electrochemical cyclic voltammetry (CV) was
conducted on an electrochemical workstation (CHI660E) with Pt plate as
working electrode, Pt slice as counter electrode, and Ag/AgCl electrodes
reference electrode in tetrabutylammonium hexafluorophosphate
(Bu4NPF6, 0.1 M) acetonitrile solutions.
S
S
C11H23
S
S
C11H23
NN
N
Br Br
O2N NO2
THF, Pd(PPh3)4
NN
NS
C2H5
C4H9
S
C11H23S
S
C11H23
O2N NO2
NN
N
NN
S
S
S
S
C2H5
C4H9
C11H23C11H23
DMF, POCl3
1 2
3
4 5
81.2% 10%
45%
NN
N
NN
S
C4H9
C2H5
S
S
S
C11H23C11H23
CHOOHC
ONC
NC
NN
N
NN
S
C4H9
C2H5
S
S
S
C11 H
23
CHCl3, pyridine
6
50%
Y14
C4H9
C2H5
ONC
CNF
2. EHBr, DMF,KOH,KISn(C4H9)3Cl89%
C 11H 23
OCN
NC
(C4H9)3Sn
C4H9
C2H5
C2H5
C4H9 C4H9
C2H5
C4H9
C2H5
C4H9
C2H5
C4H9
C2H5
n-BuLi, THF
F F
1. P(OEt)3, o-DCB
Figure S1 Synthetic route of Y14.
Synthesis of Compound 4
compound 2 (9.26, 17.83 mmol) and compound 3 (2.7 g, 5.64 mmol)
Pd(PPh3)2Cl2(0.17 g, 0.5 mmol) were dissolved in 30 mL of dry THF(40
ml) and stirred at 70℃ overnight ,under argon. The mixture was refluxed
for 24 h and then allowed to cool to room temperature. Water (100 mL)
was added and the mixture was extracted with CHCl3 (3×100 mL). The
organic phase was dried over anhydrous MgSO4. After removing the
solvent, the residue was purified using column chromatography on silica
gel employing petroleum ether/CH2Cl2 (1:1, v/v) as an eluent, yielding a
yellow solid (4.06 g, 81.2%).
1HNMR (400 MHz, CDCl3) δ 7.22 (d, J = 8.1 Hz, 2H), 6.94 (s, 2H), 2.71
(dd, J = 16.5, 8.7 Hz, 6H), 1.39-1.22 (m, 44H), 0.95-0.89 (m, 12H).
Synthesis of Compound 5
Compound 4 (8.577 g, 9.46 mmol) and triethyl phosphate (7.8 g, 47.3
mmol)were dissolved in the o-dichlorobenzene (o-DCB, 50 mL) under
nitrogen. After being heated at 180°C for 12 h, the aqueous phase was
extracted with ethylacetate and the organic layer was dried over Na2SO4.
The solvent was removed under vacuum. Crude product was obtained as
a dark green liquid without further purification.
Crude product, 1-bromo-2-ethylhexane (16.6 g, 86.25 mmol), potassium
iodide (0.6 g, 3.8 mmol) and potassium carbonate (5.26 g, 94.6 mmol)
were dissolved in the N,N-dimethylmethanamide (DMF, 30 mL). After
being heated at 90°C overnight, the solution was removed under vacuum
and extracted with ethylacetate and H2O. The organic layers were
combined and dried over MgSO4, filtered and purified with column
chromatography on silica gel using dichloromethane/petroleum ether (1/5,
v/v) as the eluent to give a light-yellow solid (1.5 g, 15% yield).
1HNMR (400 MHz, CDCl3) δ 6.98 (s, 2H), 4.71 (s, 2H), 4.57 (s, 3H),
2.83 (s, 4H), 1.87 (s, 4H), 1.69-1.10 (m, 48H), 0.90 (t, J = 38.7 Hz, 36H).
Synthesis of Compound 6
To a solution of compound 5 (1.5 g, 1.47 mmol) in DMF (50 mL) at 0°C
was added phosphorus oxychloride (2.1 ml, 22.05 mmol) dropwise
slowly under nitrogen. The mixture was stirred at 0°C for 2 h, and then
the solution was heated to 90°C and stirred overnight. The reaction
mixture was poured to ice water (100 mL), neutralized with saturated
sodium hydroxide solution, and then extracted with dichloromethane
twice. The combined organic layer was washed with water and brine,
dried over MgSO4, and evaporated under reduced pressure. The crude
product was purified by column chromatography (petroleum/
dichloromethane) to obtain compound 6 (540 mg, 45%) as a yellow solid.
1HNMR (400 MHz, CDCl3) δ 10.12 (s, 2H), 4.74-4.59 (m, 6H), 3.19 (t,
J=7.7 Hz,3H), 1.95-1.90 (m, 4H), 1.46-1.24 (m, 44H), 0.91 (dddd, J =
22.2, 17.4, 12.8, 4.9 Hz, 28H), 0.59 (ddd, J=37.5, 15.8, 7.2 Hz, 12H).
Synthesis of compound Y14
Compound 6 (0.138g, 0.12 mmol) and FIC (0.234 g, 1.21 mmol),
pyridine (1 mL) and chloroform (30 mL) were dissolved in a
roundbottom flask under nitrogen. Then the mixture was stirred and
refluxed overnight. After removing the solvent, the crude product was
purified on a silica-gel column chromatography to afford 80 mg of
compound Y14 in 50% yield as a dark blue solid.1H NMR (400 MHz,
CDCl3) δ 8.73 (d, J = 12.9 Hz, 1H), 8.40 (d, J = 9.0 Hz, 1H), 7.94 (dd, J
= 8.1, 5.2 Hz, 1H), 7.58 (d, J = 6.7 Hz, 1H), 7.42 (d, J = 6.6 Hz, 1H), 4.72
(d, J = 6.2 Hz, 3H), 3.21 (s, 2H), 1.89 (s, 2H), 1.56-1.30 (m, 14H), 1.16-
0.55 (m, 28H).13C NMR (101 MHz, CDCl3) δ 186.16, 158.81, 154.17,
145.18, 139.33, 138.88, 138.04, 136.92, 136.02, 135.68, 133.58, 130.06,
126.81, 124.89, 119.45, 115.21, 114.73, 112.16, 68.20, 59.75, 55.54,
40.40, 31.90, 31.27, 30.51, 30.09, 29.1, 28.42, 27.65, 24.03, 23.40, 22.92,
22.69, 14.03, 13.64, 10.53, 10.27, 1.00.
400 600 800 1000 12000.0
0.2
0.4
0.6
0.8
1.0
Norm
alize
d Ab
sorp
tion
(a.u
.)
Wavelength (nm)
Y9 Film Y9 Solution
(a)
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
Potential (V vs. Ag/AgCl)
Curre
nt
LUMO HOMO
(b)
Figure S2 the absorption spectra of Y9(a) and Ered anEox of the Y14(b).
-0.2 0.0 0.2 0.4 0.6 0.8-30
-25
-20
-15
-10
-5
0
5
10
Cur
rent
den
sity
(mA
/cm
2 )
Voltage (V)
110°C 120°C 130°C 140°C 150°C
(a)
300 400 500 600 700 800 900 1000
0
20
40
60
80
110°C 120°C 130°C 140°C 150°C
EQ
E (%
)
Wavelength (nm)
(b)
FigureS3 (a) the J-V curves;(b) EQE of the PBDB-T:Y14-based devices at different temperatures. TableS1 Photovoltaic parameters of the PBDB-T:Y14-based devices at different temperatures.
Condition Voc(V) Jsc(mA/cm2) PCE(%) FF(%) Integrated Jsc(mA/cm2)
110℃ 0.818 26.09 13.81 64.73 23.986
120℃ 0.815 26.27 14.05 65.58 24.664
130℃ 0.809 26.24 14.43 67.90 24.856
140℃ 0.801 26.25 14.49 68.93 24.847
150℃ 0.790 26.34 14.72 70.76 25.268
Table S2 Summary of photovoltaic properties of the semitransparent OSCs Active layer Voc
[V] Jsc
[mAcm-2] FF PCE
[%] AVT [%]
Ref.
PSBTBT:PC71BM 0.608 10.7 0.42 2.8 _ [2] PBDTTT-C-T:PC71BM 0.76 13.01 0.63 6.22 25 [3] PIDT-PhanQ:PC71BM 0.84 9.99 0.61 5.10 24.35 [4]
P3HT:PCBM 0.61 8.4 0.54 2.7 11 [5] PCDTBT:PC71BM 0.90 6.6 0.51 3.0 16 [5] PBDTTT-CT:PC71BM 0.82 13.8 0.46 5.2 14 [5] PBDTTT-EFT:PC71BM 0.84 11.0 0.61 5.6 10 [5] PBT7-Th:ATT-2 0.712 18.53 0.59 7.74 37 [6] PffBT4T-2OD:PC71BM 0.764 13.7 0.56 5.8 6 [7] PDTP-DFBT:PC71BM 0.67 12.4 0.45 3.7 54 [8] PM6:Y6 PTB7-Th:IEICO-4F PBDB-T:IEICO-4F J71:IT-M J71:IEICO-4F J51:IEICO-4Cl PBDB-T:IEICO-4Cl PTB7-Th:IEICO-4Cl
0.825 0.713 0.711 0.930 0.769 0.673 0.724 0.725
21.56 19.52 17.85 12.75 11.12 17.2 15.4 19.6
72.41 62.76 52.30 60.98 52.01 0.551 0.560 0.590
12.88 8.74 6.64 7.23 4.45 6.37 6.24 8.38
25.6 25.08 26.50 25.05 27.26 35.1 35.7 25.6
[9] [9] [9] [9] [9] [10] [10] [10]
Figure S4 1HNMR spectrum of 4 in CDCl3.
Figure S5 1HNMR spectrum of 5 in CDCl3.
NN
NS
C2H5
C4H9
S
C11H23S
S
C11H23
O2N NO2
NN
N
NN
S
S
S
S
C11H23C11H23
C4H9
C2H5
C2H5
C4H9 C4H9
C2H5
Figure S6 1HNMR spectrum of 6 in CDCl3.
NN
N
NN
S
C4H9
C2H5
S
S
S
C11H23C11H23
CHOOHC
C4H9
C2H5
C4H9
C2H5
Figure S71HNMR spectrum ofY14 in CDCl3.
Figure S8 13C NMR spectrum of Y14 in CDCl3.
NN
N
NN
S
C2H5
C4H9
S
S
S
C 11H 23
C11 H
23
O O
CN
NCCN
CNC4H9
C2H5
C4H9
C2H5
F F
NN
N
NN
S
C2H5
C4H9
S
S
S
C 11H 23
C11 H
23
O O
CN
NCCN
CNC4H9
C2H5
C4H9
C2H5
F F
Figure S9 Mass spectrum of Y14.
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