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Y. H. KIM ET AL.
2. Experimental
2.1. Materials
Chemicals were purchased from Alfa Aesar and were used as received unless otherwise
described. PTB7 (Cat. No. OS0007) and PC71BM (Cat No. nano-cPCBM-SF) were purchased
from 1-materialCo. and nano-C, Inc., respectively.
... Synthesis of ,ꢀ,ꢀꢀ,ꢀꢀꢀ-(phenyl-,-diylbis(H-fluorene-,,-triyl))tetrakis(N,N,N-
trimethylhexan--aminium) bromide (FBF-NBr)
This oligomer was synthesized by the Suzuki coupling reaction. The benzeneboronic ester
(0.33 gr, 1 mmol), the 2-bromo-9,9-bis-(6-bromo-hexyl)-9H-fluorene (1.43 g, 2.5 mmol), 5%
mol of tetrakis(triphenylphospine) palladium [Pd(PPh3)4] (0.058 g, 0.050 mmol), and sev-
eral drops of aliquat 336 in 20 mL of degassed 1:1 (by volume) mixed solvent of toluene and
2M K2CO3 aqueous was stirred for 72 hours at 110°C under the N2. A portion of 100 mL
of water was added the mixture and allowed to cool to room temperature. The mixture was
extracted with methylene chloride (MC) and the extracted organic layer was dried over anhy-
drous MgSO4. The organic solvent was removed by using a rotary evaporator. The crude prod-
uct was purified by column chromatography on silica gel using MC/n-hexane. Then, the ionic
FBF salt (FBF-NBr) was obtained by treating 2,5-bis-[9,9-bis-(6-bromo-hexyl)-9H-fluoren-
2-yl]-benzene with trimethylamine in tetrahydrofuran (THF) for 6 days, followed by extrac-
tion with water. The water was then removed under reduced pressure. The trimer was dried
1
in vacuum overnight and was obtained as a yellow solid. H NMR (600 MHz, CD3OD) δ
7.88∼7.84 (m, 2H), 7.81∼7.78 (d, J = 7.6 Hz, 1H), 7.79∼7.75 (m, 2H), 7.72∼7.66 (m, 2H),
7.48∼7.40 (m, 1H), 3.24∼3.16 (m, 4H), 3.02 (s, 18H), 2.23∼2.03 (m, 4H), 1.61∼1.46 (m, 4H),
1.19∼1.08 (m, 8H), 0.72∼0.56 (m, 4H).
... Synthesis of ,ꢀ,ꢀꢀ,ꢀꢀꢀ-(thiophene-,-diylbis(H-fluorene-,,-triyl))tetrakis
(N,N,N-trimethylhexan--aminium) bromide (FTF-NBr)
A mixture of 2,5-bis-tributylstannanyl-thiophene (0.4 mmol) and 2-bromo-9,9-bis-(6-
bromo-hexyl)-9H-fluorene (1 mmol) were dissolved in degassed toluene. [Pd(dppf)Cl2]
(22 mg) were added to the mixture as catalyst. The reaction mixture was stirred and heated
to reflux for 48 h under N2 atmosphere. A portion of 100 mL of water was added the mixture
and allowed to cool to room temperature. The mixture was extracted with MC and the
extracted organic layer was dried over anhydrous MgSO4. The organic solvent was removed
by using a rotary evaporator. The crude product was purified by recrystallization using
methanol. Then, the ionic FTF salt (FTF-NBr) was obtained by treating 2,5-bis-[9,9-bis-(6-
bromo-hexyl)-9H-fluoren-2-yl]-thiophene with trimethylamine in THF for 6 days, then the
solvent was removed. The trimer was dried in vacuum overnight and was obtained as a red
solid. 1H NMR (600 MHz, CD3OD) δ 7.78∼7.71 (m, 2H), 7.69∼7.67 (m, 1H), 7.44∼7.27 (m,
4H), 3.19∼3.08 (m, 4H), 2.99 (s, 18H), 2.16∼1.98 (m, 4H), 1.47∼1.42 (m, 4H), 1.18∼1.02
(m, 8H), 0.59∼0.52 (m, 4H).
2.2. Fabrication of PSCs
In the iPSCs with the structure of ITO/ZnO (40 nm)/FBF or FTF-NBr/active layer
(PTB7:PC71BM) (70 nm)/MoO3 (10 nm)/Ag(100 nm) fabrication process, ITO-coated glass