G.I. Nosova et al.
Polymer 210 (2020) 122978
equipped with the Styragel columns and three detectors: refractometric,
viscometric, and light-scattering. Tetrahydrofuran (THF) was used as an
eluent (elution rate: 1.0 mL/min). The sample concentration was 2 mg/
purchased from Sigma-Aldrich. Catalyst SiliaCatDPP-Pd was purchased
from SiliCycle® Inc. 4-Bromo[2-phenyl-1,3,4-oxadiazole-5]-tert-butyl-
′
′
phenyl (R
1
), 4-bromo(4-tert-butyl-phenyl)-1,8-naphthalimide (R
2
), N-
mL; 100
μ
L of a sample solution was introduced into the column. THF
[6-(2,7-dibromocarbazol-9-yl)-hexyl]-(4-pyrrolidine-1-yl)-1,8-naph-
thalimide (NI2), 2,7-dibromo-9-(6-bromohexyl)-9H-carbazole, 6-bromo
hexyl-(4-piperidine-1-yl)-1,8-naphthalimide, 2-[4-(6-bromohexyloxy)
distilled over KOH was stabilized by the solvent (0.02%, 2,6-di-tert-
butylhydroxytoluene). Molecular masses and molar-mass dispersity
characteristics were calculated using the calibration curve based on
polystyrene standards (Agilent Technologies). Elemental analysis was
performed on a Carlo Erba 1108 elemental analyzer. Photoluminescence
′
phenyl]-5-phenyl-1,3,4-oxadiazole, and 2,7-dibromo[9,9-bis(6 -(dieth-
oxyphosphoryl)hexyl)]fluorene were synthesized according to the pre-
viously reported method [36]. 2,7-dibromo[9,9-bis(4-diphenylamino
phenyl)]fluorene (Т3), 2,7-dibromo[9,9-bis(4-hydroxyphenyl)]fluo-
rene, and 4-(diphenylamino)phenyl-methanol were prepared accord-
ing to the techniques described in Refs. [37–39], respectively. Toluene
and THF were distilled in the argon atmosphere over sodium metal in
the presence of benzophenone. Syntheses of 2,7-dibromo-9,
9-bis-{4-phenoxy[6-hexyloxy-(2,5-diphenyl-1,3,4-oxadiazole)]}fluo-
rene (Т1) and 2,7-dibromo-9,9-bis[6-(4-phenoxy)-hexyl-(9H-carba-
zole)]fluorene (Т2) are described in ESM (Fig. S0).
(
PL) emission and excitation spectra of CPFs were detected using an LS-
00 BASE luminescence spectrophotometer (PTI® Lasers INC, Lon-
1
don—Toronto, Canada). The luminescence intensity Ilum was recorded
in the fluorescence mode from the exciting light beam incidence side
using a solid sample holder. A grazing angle between the exciting light
◦
beam and the sample was ~30 . The wavelength range of emission
spectra was 400–750 nm at the excitation wavelength of λexc = 380 nm;
for the excitation spectra, the span was 210–400 nm at a luminescence
observation wavelength λmax = 430 nm. The spectral widths of excita-
tion and luminescence monochromator slits were 5 and 2 nm, respec-
tively; the PMT gain was 500. For comparison, the Ilum values were
reduced to an internal laboratory standard. UV–vis spectra were taken
using a Shimadzu UV 1900 spectrophotometer. Polymer films were
obtained by spin coating from the 6 mg/mL solutions in toluene and
2.3.1. Syntheses of 2,7-dibromo-9-(4-nitrophenyl)-9Н-carbazole (1)
2 3
Freshly calcined K CO (13.06 g, 194.6 mmol) and dry dime-
thylformamide (DMF) (100 mL) were loaded into a flask. The suspension
◦
was stirred at 70 С for 15 min, then 2,7-dibromocarbazole (6.15 g, 18.9
mmol) was added, and in 10 min, 4-fluoronitrobenzene (10.62 g, 75.5
mmol) was also placed into the reaction vessel. The solution was boiled
for 48 h in argon atmosphere, then poured into water. The precipitate
was filtered off, washed with hot water and ethanol. Pure 2,7-dibromo-
9-(4-nitrophenyl)-9H-carbazole was obtained by chromatographic pu-
◦
dried at 40 (20 min), 80 (5 h), 120 (5 min), and 150 C (5 min); spectra
were recorded after each heating time.
2
.2. Fabrication and characterization of PLED devices
rification on a silica gel column (eluent: toluene/petroleum ether, 2/3).
1
PLED samples were prepared in two configurations: ITO/PEDOT:
Yield: 78%. H NMR (CDCl
3 H
, 400 Hz): δ 8.56 (2H, d), 7.98 (2H, d), 7.78
PSS/CPF/РF-EP/LiF/Al and ITO/PEDOT:PSS/PTPD/PVK/CPF/РF-EP/
LiF/Al. The diagram of working layers in the two types of devices,
together with an indication of energy levels, is given in Fig. S2 in
Electronic Supplementary Material’s file (ESM). The hole-injection layer
of the PEDOT:PSS complex was spin-coated onto the ITO-coated glass
(2H, d), 7.59 (2H, s), 7.49 (2H, d). Anal. calcd for C₁₈H₁₀N₂O₂Br₂: C,
48.45; H, 2.29; N, 6.28. Found: C, 48.24; H, 2.39; N, 6.15.
2.3.2. Syntheses of 2,7-dibromo-9-(4-aminophenyl)-9H-carbazole (2)
A solution of compound 1 (3.1 g, 6.89 mmol) in ethanol (100 mL)
◦
substrates at 2000 r.p.m. for 60 s and baked at 110 C for 30 min. The
and SnCl
2
× 2H
2
O (7.9 g, 35.0 mmol) were placed into a flask. The re-
PEDOT:PSS-coated substrates were transferred into the argon-filled
action mixture was stirred at boiling temperature for 48 h, then ethanol
was removed under vacuum, and the resulting precipitate was ground
together with 100 mL of 50% NaOH and washed with water repeatedly.
The reaction product was extracted from the precipitate with acetone.
2 2
glove box (O < 1 p.p.m., H O < 1 p.p.m.). PTPD (solution in chloro-
1
1
benzene, 8 mg mL⁻ ) and PVK (solution in o-xylene, 1.5 mg mL⁻ ) were
spin-coated at 2000 r.p.m. for 45 s layer by layer. The PTPD and PVK
◦
◦
◦
1
layers were baked at 110 C for 20 min and 140 C for 30 min, respec-
tively, before the deposition of the next layer. The CPF layer was spin-
cast over the PVK layer from a solution in toluene at 1500 r.p.m for 1
Yield: 90%, Т
7.95 (2H, d), 7.44 (2H, s), 7.38 (2H, d), 7.25 (2H, d), 6.90 (2H, d),
3.94 (2Н, s, NH ). Anal. calcd for C18 Br : C, 51.96; H, 2.91; N,
6.73. Found: С, 51.79; H, 2.80; N, 6.54.
m
= 198–200 C (from toluene). H NMR (CDCl
3
, 400 Hz):
δ
H
2
H
12
N
2
2
◦
min and dried at 80 C for 4 h. Then a thin layer of the PF-EP was
1
deposited by spin coating from the 5 mg mL⁻ ethanol solution at 1000 r.
◦
p.m and dried at 60 C for 3 h. Finally, LiF (1 nm)/Al (80 nm) cathode
2.3.3. Syntheses of 4-(N-piperidine-1-yl)-1,8-naphthalanhydride (3)
A solution of 4-bromo-1,8-naphthalanhydride (65 g, 0.02 mol) and
piperidine (5.0 mL 0.05 mol) in dimethylacetamide (DMAA) was
refluxed for 8 h. The formed precipitate was filtered off, washed with
was deposited onto the PF-EP layer through a shadow mask by thermal
ꢀ 6
evaporation under vacuum (2 × 10 mbar). The device area was 9
2
mm . The electroluminescence (EL) spectra of PLEDs were recorded
using an Avantes 2048 fiber-optic spectrofluorimeter (Netherlands).
Voltage–current and voltage–brightness characteristics were recorded
with a Keithley 2601 SourceMeter (USA), a Keithley 485 picoammeter,
and a TKA-04/3 luxmeter-brightness meter (Russia). Film thicknesses
were determined using an MII-4 interferometer (LOMO, St. Petersburg,
Russia). Preparations of the PLED samples and the measurements of
their spectral and optoelectronic characteristics were performed at room
temperature in the argon atmosphere.
water, and extracted with CHCl
3
; After concentration, the residue was
washed with a hexane/ethanol mixture. Yield: 4.41 g (79%), Т
m
=
◦
1
168–169 C. H NMR (CDCl
(H, d), 7.72 (H, t), 7.21 (H, d), 3.32 (4Н, m, NCH
1.78 (2Н, m, CH ). Anal. calcd for C₁₇H₁₅NO₃: C, 72.58; H, 5.37; N, 4.98.
3
, 400 Hz): δ
H
8.59 (H, d), 8.52 (H, d), 8.45
2
), 1.93 (4Н, m, CH ),
2
2
Found: C, 72.39; H, 5.48; N, 4.77.
2.3.4. Syntheses of N-[4-(2,7-dibromocarbazole-9-yl)phenyl]-[(4-
piperidine)-1-yl]-1,8-naphthalimide (NI1)
2
.3. Materials and synthesis of monomers
The solution of compounds 2 (0.86 g, 0.002 mol) and 3 (0.56 g,
0
.002 mol) and zinc acetate (0.04 g) in dry DMAA (35 mL) was refluxed
Monomers as 9,9-dioctyl-2,7-dibromofluorene, 9,9-dioctylfluorene-
for 6 h. The reaction mixture was poured into water, washed with hot
water and ethanol. Yield: 71%, Т
H
(CDCl , 400 Hz): δ 8.70 (2H, d), 8.62 (2H, d), 8.50 (2H, d), 7.97 (2H, d),
m
= 324–325 ◦C (DMF). H NMR
1
2
,7-bis(trimethylborate)-fluorene,
4,7-bis-(5-bromo-2-thienyl)-2,1,3-
benzothiadiazole (TBTT), 4,7-dibromo-2,1,3-benzothiadiazole (BT), 4-
3
′
bromophenyl-(diphenyl)amine (R
as the starting compounds for the syntheses 2,7-dibromo-9-fluorenone,
-bromo-1,8-naphthalic anhydride, 2,7-dibromo-9H-carbazole, 1,6-
dibromohexane, triphenylamine, and catalyst Pd(PPh were
5
), and triphenylphosphine, as well
7.78 (1H, t), 7.70 (4H, m), 7.62 (2H, d), 7.45 (2H, d), 3.33 (4Н, m,
NCH ) 1.95 (4Н, m, CH ), 1.80 (2Н, m, CH ). Anal. calcd for
2
2
2
4
C₃₅H₂₅N₃O₂Br₂: С, 61.86; Н, 3.72; N, 6.19. Found: С, 61.59; Н, 3.85; N,
)
4
5.98.
3
3
Berezin, Ivan A.
