Note: Descriptions are shown in the official language in which they were submitted.
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
HIGH PERFORMANCE WIDE-BANDGAP POLYMERS FOR ORGANIC
PHOTO VOLTAICS
CROSS-REFERENCE TO RELATED APPLICATIONS
100011 This application is a PCT International application which claims the
benefit of and
priority to U.S. Provisional Application Ser. No. 65/538,362 filed July 28,
2017 and U.S. Patent
Application Ser. No. 16/038,364, entitled "High Performance Wide-Bandgap
Polymers for
Organic Photovoltaics", both of which are hereby incorporated by reference in
its entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR
DEVELOPMENT
100021 None.
FIELD OF THE INVENTION
100031 This invention relates to high performance wide-bandgap polymers for
organic
photovoltaics.
BACKGROUND OF THE INVENTION
100041 Solar energy using photovoltaics requires active semiconducting
materials to convert
light into electricity. Currently, solar cells based on silicon are the
dominating technology due to
their high-power conversion efficiency. Recently, solar cells based on organic
materials showed
interesting features, especially on the potential of low cost in materials and
processing.
100051 Organic photovoltaic cells have many potential advantages when
compared to
traditional silicon-based devices. Organic photovoltaic cells are light
weight, economical in the
materials used, and can be deposited on low cost substrates, such as flexible
plastic foils. However,
organic photovoltaic devices typically have relatively low power conversion
efficiency (the ratio
of incident photons to energy generated). This is, in part, thought to be due
to the morphology of
the active layer. The charge carriers generated must migrate to their
respective electrodes before
recombination or quenching occurs. The diffusion length of an exciton is
typically much less than
the optical absorption length, requiring a tradeoff between using a thick, and
therefore resistive,
cell with multiple or highly folded interfaces, or a thin cell with a low
optical absorption efficiency.
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
[0006]
The first reported use of a quinoxalinedithiophene co-polymer for organic
photovoltaics was in 2008. One attractive feature of the
quinoxalinedithiophene structure is that
it can easily be functionalized with either bromine atoms or trimethylstannyl
groups, thus allowing
it to be copolymerized with a wide variety of co-monomers. There exists a need
to find
quinoxalinedithiophene co-polymers that are able to increase open circuit
voltage.
BRIEF SUMMARY OF THE DISCLOSURE
Xi X2
X3 X4
A copolymer comprising a repeat unit A, wherein repeat unit A comprises
R5
R
R2 4 S /
/
a repeat unit B, wherein repeat unit B comprises R3
or R6
and
at least one optional repeat unit D, wherein repeat unit D comprises an aryl
group. In this
copolymer, Xi, X2, X3, and X4 are independently selected from the group
consisting of: H, Cl, F,
CN, alkyl, alkoxy, ester, ketone, amide and aryl groups and RI, R2, R3, R4, R5
and R6 are
independently selected from the group consisting of: H, Cl, F, CN, alkyl,
alkoxy, alkylthio, ester,
ketone and aryl groups.
[0007]
A copolymer comprising a repeat unit E, wherein repeat unit E comprises
Xi X2
R4
X34? R2 S
I ¨
S S
R3 ; a repeat unit H, wherein repeat unit H comprises
2
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
Xi X2
N)/ µN
R1 R4 X3 \ X4
S S S
R3
, an optional repeat unit J, wherein a repeat unit
Xi X2
X3 X4
comprises
3-; and a repeat unit K, wherein a repeat unit K comprises
X1 X2
NI)/ ____ (N
X3 X4
s
. In this copolymer, Xi, X2, X3, and X4 are independently selected from the
group consisting of H, Cl, F, CN, alkyl, alkoxy, ester, ketone, amide and aryl
groups; Ri, R2, R3,
and R.4 are independently selected from the group consisting of: T-I, Cl, F,
CN, alkyl, alkoxy,
alkylthio, ester, ketone and aryl groups; and D comprises an aryl group.
[0008]
A copolymer comprising a repeat unit F, wherein repeat unit :F comprises
X1 X2
N)/ µN Ri
R2 s R4
I _________________________ S
S S
R3
; a repeat unit G, wherein repeat unit G comprises
X1 X2
N)/ µN
Ri
R4 X3
R2 S / ____________ I __
S S S
R3
, an optional repeat unit J, wherein a repeat unit J
3
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
Xi X2
X3 X4
comprises -
-Y; and a repeat unit K, wherein a repeat unit K comprises
Xi X.2
N HN
X3 X4
I D s
. In this copolymer, XI, X2, X3, and X4 are independently selected from the
group consisting of: H, Cl, F, CN, alkyl, alkoxy, ester, ketone, amide and
aryl groups; R5, and R6
are independently selected from the group consisting of: H, Cl, F, CN, alkyl,
alkoxy, alkylthio,
ester, ketone and aryl groups; and D comprises an aryl group.
BRIEF DESCRIPTION OF THE DRAWINGS
100091 A more complete understanding of the present invention and benefits
thereof may be
acquired by referring to the follow description taken in conjunction with the
accompanying
drawings in which:
100101 Figure 1 depicts a conventional device architecture and an inverted
device architecture.
[0011] Figure 2 depicts the formation of a functionalized QDT monomer.
10012] Figure 3 depicts the 1H NMR spectrum of compound 1
1001311 Figure 4 depicts the 1H NMR spectrum of compound 2
[00141 Figure 5 depicts the 41 NMR spectrum of compound 3
100151 Figure 6 depicts the NMR spectrum of compound 4.
100161 Figure 7 depicts the IFINIvIR spectrum of QDT-Br.
100171 Figure 8 depicts the IFINMR spectrum of QDT-SnMe3.
100181 Figure 9 depicts the NIvIR spectrum of the first step of forming an
asymmetrical
bithiophene monomer.
100191 Figure 10 depicts the NMR spectrum of the second step of forming an
asymmetrical
bithiophene monomer.
4
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
100201 Figure 11 depicts the NMR spectrum of the third step of forming an
asymmetrical
bithiophene monomer.
100211 Figure 12 depicts the NMR spectrum of an asymmetrical bithiophene
monomer.
100221 Figure 13 depicts different methods of forming benzodithiophene.
100231 Figure 14 depicts the UV-Visible absorption of different polymers.
DETAILED DESCRIPTION
100241 Turning now to the detailed description of the preferred arrangement
or arrangements
of the present invention, it should be understood that the inventive features
and concepts may be
manifested in other arrangements and that the scope of the invention is not
limited to the
embodiments described or illustrated. The scope of the invention is intended
only to be limited by
the scope of the claims that follow.
100251 "Alkyl," as used herein, refers to an aliphatic hydrocarbon chains.
In one embodiment,
the aliphatic hydrocarbon chains are of 1 to about 100 carbon atoms,
preferably 1 to 30 carbon
atoms, more preferably, 1 to 20 carbon atoms, and includes straight and
branched chains such as
methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-
pentyl, isopentyl, neo-
pentyl, n-hexyl, and isohexyl. In this application alkyl groups can include
the possibility of
substituted and unsubstituted alkyl groups.
(00261 "Alkoxy," as used herein, refers to the group R-0¨ where R is an
alkyl group of 1
to 100 carbon atoms. In this application alkoxy groups can include the
possibility of substituted
and unsubstituted alkoxy groups.
100271 "Aryl" as used herein, refers to an optionally substituted, mono-,
di-, tri-, or other
multicyclic aromatic ring system having from about 5 to about 50 carbon atoms
(and all
combinations and subcombinations of ranges and specific numbers of carbon
atoms therein), with
from about 6 to about 10 carbons being preferred. Non-limiting examples
include, for example,
phenyl, naphthyl, anthracenyl, and phenanthrenyl. Aryl groups can be
optionally substituted with
one or with one or more Rx. In this application aryl groups can include the
possibility of substituted
aryl groups, bridged aryl groups and fused aryl groups.
(00281 "Ester", as used herein, represents a group of formula ¨COOR wherein
R represents
an "alkyl", "aryl", a "heterocycloalkyl" or "heteroaryl" moiety, or the same
substituted as defined
above
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
[0029] "Ketone" as used herein, represents an organic compound having a
carbonyl group
linked to a carbon atom such as ¨C(0)Rx wherein Rx can be alkyl, aryl,
cycloalkyl, cycloalkenyl
or heterocycle.
[0030] "Amide" as used herein, represents a group of formula "¨C(0)NR"RY,"
wherein IV
and RY can be the same or independently H, alkyl, aryl, cycloalkyl,
cycloalkenyl or heterocycle.
[0031] The following examples of certain embodiments of the invention are
given. Each
example is provided by way of explanation of the invention, one of many
embodiments of the
invention, and the following examples should not be read to limit, or define,
the scope of the
invention.
[0032] Device architecture
[0033] When used as a photovoltaic device the architecture may be a
conventional architecture
device, while in others it may be an inverted architecture device. A
conventional architecture
device typically comprised of multilayered structure with a transparent anode
as a substrate to
collect positive charge (holes) and a cathode to collect negative charge
(electrons), and a photo-
active layer sandwiched in between two electrodes. An additional charge
transport interlayer is
inserted in between active layer and electrode for facile hole and electron
transport. Each charge
transport layer can be consisted of one or more layers. An inverted device has
the same
multilayered structure as the conventional architecture device whereas it uses
a transparent cathode
as a substrate to collect electrons and a cathode to collect holes. The
inverted device also has the
photo-active layer and additional charge transport layers sandwiched in
between two electrodes.
Figure 1 depicts a conventional device architecture and an inverted device
architecture.
[0034] Repeat Unit A:
[0035] In one embodiment repeat unit A are quinoxalinedithiophene (QDT)
monomers
xi X2
N?/ (N
X3 X4
In repeat unit A, Xi, X2, X3, and X4 are independently selected from the
group consisting of: H, Cl, F, CN, alkyl, alkoxy, ester, ketone, amide and
aryl groups.
[0036] The QDT monomer can be functionalized with a variety of halides and
stannanes in
order to prepare it for the eventual polymerization reaction. In one non-
limiting example, the
formation of a functionalized QDT monomer is shown in Figure 2.
6
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
100371 As shown in Figure 2, the formation of compound 1 begins by forming
a 2-
ethylhexylmagnesium bromide solution prepared by adding 2-ethylhexyl bromide
(17.3 mL, 0.097
mol) dropwise to a mixture of freshly ground magnesium (2.61 g, 0.107 mol) in
dry
tetrahydrofuran (250 mL). Once the addition was complete, the 2-
ethylhexylmagnesium bromide
solution was stirred at room temperature for around 2 hours. Meanwhile, a
solution of LiBr (17 g,
0.196 mol) in dry tetrahydrofuran (100 mL) was added to a solution of CuBr in
dry tetrahydrofuran
(150 mL). Then, the CuBr/LiBritetrahydrofuran solution was cooled to -78 C
and the 2-
ethylhexylmagnesium bromide solution was added dropwise. Once that transfer
was finished,
oxalyl chloride (3.33 mL, 0.039 mol) was added. The reaction gradually warmed
to room
temperature and was stirred for around 18 hours. The reaction was quenched by
pouring it into an
aqueous saturated NH4C1 solution (500 mL). The tetrahydrofuran layer was then
removed and the
aqueous layer was extracted with ethyl ether. The combined organic extracts
were dried, filtered,
and concentrated. The crude material was diluted with hexanes and loaded onto
a 340 g Biotage
cartridge, then purified with a 5-20% dichloromethanethexanes gradient.
Fractions containing
product were concentrated to afford a yellow oil (1.63 g; 15% yield). The 41
NMR spectrum of
compound 1 is shown in Figure 3.
100381 The formation of compound 2 can be formed by charging a hot, oven-
dried Schlenk
flask with FeCl3 (10.9 g, 67.481 mmol) then evacuated and refilled with argon
(3x). Dry
dichloromethane (140 mL) was added to the flask via cannula, and then 3,3'-
thenil (5 g, 22.494
mmol) was added in one portion. The reaction stirred at room temperature under
argon. After
around 2 hours, the reaction was quenched with water (-100 mL) and stirred.
The solvent was
removed via rotovap, and the solid was suspended in water and left at room
temperature overnight.
The solid was filtered and washed with water, then air-dried, and washed with
diethyl ether (-200
mL). The black solid was then recrystallized from acetonitrile. The resulting
black solid (4.5 g,
91% yield) was collected by filtration, washed with acetonitrile, and dried
under vacuum. The 11-1
NMR spectrum of compound 2 is shown in Figure 4.
100391 The formation of compound 3 is formed by adding compound 2(2 g,
0.009 mol), 200-
proof ethanol (100 mL), and hydroxylamine hydrochloride (1.577g. 0.023 mol) to
a 250 mL round
bottom flask under the flow of argon. The flask can then be topped with a
water condenser and
argon inlet, and the reaction was heated to refluxed for 22 hours. The
reaction can then be cooled
to room temperature and 10% palladium on carbon (200 mg) is added. An addition
funnel was
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
added to the top of the condenser and the funnel was filled with a solution of
hydrazine
monohydrate (15 mL) in ethanol (25 mL). After heating the reaction to 65 C,
the hydrazine
solution was added dropwise. Once the addition was complete, the reaction was
heated to 85 C
for 20 h. The reaction mixture was cooled, then filtered through filter paper,
and the residue was
washed with ethanol. The solvent was removed in vacuo and the resulting solid
was dispersed in
water and filtered. The solid was washed with water and cold ethanol, and then
transferred to a
flask and left under vacuum for a few hours. The resultant product was a tan
solid (1.75 g, 87%
yield). The Ill NMR spectrum of compound 3 is shown in Figure 5.
[0040] The formation of compound 4 is formed by combining compound 3(1.6 g,
7.262 mmol)
and compound 1 (2.154 g, 7.625 mmol) in a 50 tnL Schlenk flask. The flask was
evacuated and
refilled with argon, then acetic acid was added, and the reaction was heated
to 100 C for 16 h.
The reaction mixture was cooled to room temperature, then diluted with water
and transferred to
a separatory funnel. The aqueous layer was extracted with dichloromethane. The
aqueous layer
was neutralized with Na2CO3 and extracted with dichloromethane. The combined
organic extracts
were dried (MgSO4), filtered, and concentrated. The crude material was
dissolved in
dichloromethane, adsorbed onto silica gel and purified on a 100 g Biotage
cartridge with a 0-60%
dichloromethane/hexanes gradient. Fractions containing the desired product
were concentrated to
afford a yellow solid (1.55 g, 46% yield). The 11-1 NMR spectrum of compound 4
is shown in
Figure 6.
[0041] The formation of QDT-Br was formed by dissolving compound 4 (400 mg,
0.857
mmol) was dissolved in tetrahydrofuran (9 mL), then treated with N-
bromosuccinimide (0.32 g,
0.002 mol) and stirred at room temperature for 16 h. The reaction mixture was
poured into water
and extracted with dichloromethane (3x). The combined organic extracts were
dried (MgSO4),
filtered, and concentrated. The crude material was dissolved in
dichloromethane, adsorbed onto
silica gel, and purified on a 100 g Biotage column with a 0-50%
dichloromethane/hexanes
gradient. Fractions from the main peak were concentrated to afford a yellow
solid (440 mg, 82%
yield). The 'I-1 NMR spectrum of QDT-Br is shown in Figure 7.
[0042] The formation of QDT-SnMe3 was formed by combining in an argon-
filled Schlenk
flask, compound 4(1.15 g, 2.464 mmol) and dry tetrahydrofuran (25 mL). The
solution was cooled
to -78 C, then treated dropwise with a solution ofn-BuLi (2.5 M in hexanes,
2.4 mL, 5.913 mmol).
The reaction was stirred at -78 C for 1 h, followed by 1.5 h at room
temperature. The reaction
8
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
mixture was again cooled to -78 C and treated slowly with a SnMe3CI solution
(1 M in hexanes,
7.392 mL, 7.392 mol). The reaction gradually warmed to room temperature and
was stirred for 16
h. The reaction mixture was poured into water and extracted with
dichloromethane (3x). The
combined organic extracts were washed with water, dried (MgSO4), and filtered,
and concentrated
to afford a yellow oil. RecrystaIlization was attempted from isopropanol,
methanol, and ethanol,
but the material always oiled out. The resulting greenish oil (850 mg, 44%
yield) was used without
further purification. The 11-1 NIvIR spectrum of QDT-SnMe3 is shown in Figure
8.
[00431 Repeat Unit B:
[00441 In one embodiment repeat unit B are asymmetrical bithiophene
monomers
R2 I R5
Ri
R4
S
S
R3 or benzodithiophene R6
. In repeat unit B, RI, R2, R3, R4,
R5 and R6 are independently selected from the group consisting of, Cl, F, CN,
alkyl, alkoxy,
alkylthio, ester, ketone and aryl groups.
[00451 In a non-limiting example, the formation of the asymmetrical
bithiophene monomer
are is described below. The formation of the asymmetrical bithiophene monomer
can begin with
the synthesis of 3-(2-hexyldecyl)thiophene. In a three-neck 500 mL flask
magnesium turnings
(3.184 g, 0.131 mol) were added. 7-(Bromomethyl)pentadecane (20 g, 0.066 mol)
was added into
an addition funnel. The system was vacuumed and backfilled with argon three
times. A small
amount of iodine was added before 10 mL of anhydrous THF was added to flask
and 90 mL of
anhydrous THF was added into the addition funnel. The reaction was initiated
by heating to
refluxing after the first 10 mL of 7-(bromomethyl)pentadecane solution was
added. After refluxing
for 2 h, it was cooled down to room temperature. In another 100 mL Schlenk
flask, 3-
bromothiophene (10.68 g, 0.066 mol) and Ni(dppp)a2 (1.78 g, 3.3 mmol) was
solubilized in 100
mL of anhydrous THF and then transferred into the reaction mixture slowly. The
reaction mixture
was further refluxed 70 C for 3 hours before stirred at room temperature
overnight. The reaction
was quenched by pouring onto crushed ice. A cold HCI aq. solution was added to
dissolve the
solid. The product was extracted with hexane and dried over anhydrous MgSO4.
The crude product
was purified by column chromatography using hexane as the eluent, and then by
vacuum
9
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
distillation, to give a clear colorless liquid as product (6.80 g, 33.6%). The
NMR spectrum is shown
in Figure 9.
100461 The second step of the formation of the asymmetrical bithiophene
monomer can begin
with the synthesis of 2-bromo-3 -(2-hexy I decypthi ophene. 3-(2-
Hexyldecyl)thiophene (5 g, 0.016
mol) was added to a 200 mL Schlenk flask. The system was vacuumed and
backfilled with argon
three times before 200 mL of anhydrous THF was added. The solution was cooled
down to -78 C
before N-bromosuccinimide (2.884 g, 0.016 mol) was added in portions in the
absence of light.
The reaction mixture was stirred overnight. The reaction was quenched by
adding an aqueous
solution of Na2CO3. The product was extracted with hexane and then dried over
anhydrous MgSO4
before the removal of solvent. The product was further purified with silica
gel column with hexane
as eluent and colorless liquid (5.48 g, yield of 87.3%) was obtained after
dried in vacuum. The
NMR spectrum is shown in Figure 10.
100471 The third step of the formation of the asymmetrical bithiophene
monomer can begin
with the synthesis of 3-(2-hexyldecy1)-2,2'-bithiophene. 2-Bromo-3-(2-
hexyldecyl)thiophene
(5.68 g, 0.015 mol), tributyl(thiophen-2-ypstannane (5.471 g, 0.015 mol) and
Pd2(dba)3 (0.268 g,
0.293 mmol), P(o-to1)3 (0.357 g, 1.173 mmol) were combined in 200 mL Schlenk
flask. After the
system was vacuumed and backfilled with argon three times, 100 niL of
anhydrous toluene was
injected. The reaction was heated at 105 C for 24 hours and cooled down to
room temperature.
The toluene solvent was removed by rotary evaporator and the resulting residue
was purified by
silica gel column with pure hexane as eluent. Vacuum distillation of the crude
offered colorless
liquid as the final product (4.34 g, 74.1%). The NMR spectrum is shown in
Figure 11.
100481 The last step of the formation of the asymmetrical bithiophene
monomer can begin with
the synthesis of (3-(2-hexyldecy1)-[2,2'-bithiophene]-5,5'-
diy1)bis(trimethylstannane)(HDTT). 3-
(2-Hexyldecy1)-2-(thiophen-2-yl)thiophene (4.15 g, 10.6 mmol) was added to a
200 mL Schlenk
flask. The system was vacuumed and backfilled with argon three times before
100 mL of
anhydrous THF was added. The solution was cooled down to -78 C before n-butyl
lithium (9.35
mL, 2.5 M in THF, 23.4 mmol) was added dropwise. The reaction was stirred at
room temperature
for 1.5 hour before cooled down to -78 C again. Trimethyltin chloride (26.56
mL, 1.0 M in THF,
26.556 mmol) solution was added drop-wise. The resulting mixture was stirred
overnight. 50 mL
of water was added. The product was extracted with hexane. The organic layers
were washed with
water three times before dried over anhydrous Na2SO4. The solvent was removed
and then
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
dissolved with hexane and washed with methanol twice. Green liquid (5.05 g,
yield 66.4%) was
obtained as product after the removal of solvent. The NAIR spectrum is shown
in Figure 12.
[0049] In a non-limiting example Figure 13 depicts different methods of
forming
benzodithiophene. While conventional methods are shown in Figure 13, the
invention is not
limited to any one specific method of forming benzodithiophene In Figure 13,
(i) Oxalyl Chloride;
(ii) Diethylarnine; (iii) n-Butyllithium then water; (iv) Alkyne Lithium; (v)
SnC12, HC1; (vi) Pd/C,
H2; (vii) Zn, NaOH, 1-120; (viii) Brornoalkane, TBAB; (ix) Aromatic Lithium;
(x) n-Butyllithium,
Chlorotrimethylstannane or 2-Isopropoxy-4,4,5,5-tetramethy1-1,3,2-
dioxaborola.ne; and (xi)
PdCatalyst.
[0050] Optional Repeat Unit I):
10051] In one embodiment, at least one optional repeat unit D refers to an
optionally
substituted, mono-, di-, tri-, or other rnulticyclic aromatic ring system
having from about 5 to about
50 carbon atoms (and all combinations and subcombinations of ranges and
specific numbers of
carbon atoms therein), with from about 6 to about 20 carbons being preferred.
Non-limiting
examples include, for example, phenyl, naphthyl, anthracenyl, and
phenanthrenyl. Aryl groups can
be optionally substituted with one or with one or more Rx. In this application
aryl groups can
include the possibility of substituted aryl groups, bridged aryl groups and
fused aryl groups. While
it is feasible that there is only one repeat unit D in the copolymer, it is
also envisioned that multiple
repeat unit D's can exist within the copolymer.
R'
10052] In one embodiment the aryl group can consist of: S
R` R'
R\eS
R"
R' R'
R'
hR)
\
R" R"
11
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
R'
R'
\ \
SN).1
R`
_
S ,
S
S
................15-. \ \
S.....,..õ---1..., ..--....õ----n
__ I , I
r S S S N
S ¨
R" R"
N N
\ /
R" N N R"" N\ /N
\ / R'" R"' R' / s
N, N
and
combinations thereof, wherein R', R", R" and R" are independently selected
from the group
consisting of: 1-1, Cl, F, CN, alkyl, alkoxy, alkylthio, ester, ketone and
aryl groups. In another
embodiment, the aryl group is a 3,3' difluror-2,2'-bithiophene.
[0053] Copolymer
[00541 When combined, repeat unit A, repeat unit B and optional repeat unit
D produce a
copolymer. The copolymer can be regio-random or regio-regular. it is
envisioned that the
copolymer can be used as a photovoltaic material. It is also envisioned that
the copolymer can be
used in the active layer in an electronic device. In one embodiment the number
of repeat units A,
B and C can range from about 3 to about 10,000 in the copolymer. in an
alternate embodiment,
the copolymer can form a polymer bandgap greater than 1.8 eV.
12
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
[0055] in some embodiments, the copolymer can contain a combination of
repeat units A and
Xi X2
X3 X4 R2 R4
S
I ¨
B as repeat unit E: R3
[0056] in an alternate embodiment, the copolymer can contain a combination
of repeat units
X1 X2
N)/ (N
R4 X3
R2 $ / I ¨
/ S S
R3
A and B as repeat unit F:
[0057] in some embodiments, the copolymer can contain a combination of
repeat units A and
Xi X2
N (N
X3 X4
D as repeat unit G:
[00581 In an alternate embodiment, the copolymer can contain a combination
of repeat units
Xi X2
N)/ (N
X3 X4
s
A and D as repeat unit H:
[0059] in one embodiment, the amount of repeat unit A in the copolymer can
range from l
wt% to 99 wt%.
[0060] In one embodiment, the amount of repeat unit B in the copolymer can
range from I
wt% to 99 wt%.
[0061] in one embodiment, the amount of repeat unit D in the copolymer can
range from 0
wt% to 99 wt. (.)4).
[0062] Anode
13
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
[0063] When used in an organic photovoltaic device the copolymer can be
used in conjunction
with an anode. The anode for the organic photovoltaic device can be any
conventionally known
anode capable of operating as an organic photovoltaic device. Examples of
anodes that can be
used include: indium tin oxide, aluminum, carbon, graphite, graphene,
PEDOT:PSS, copper, metal
nanowires, Zn99In0x, Zn98In20x, Zn97In30x, Zn95Mg50x, Zn9oMg100x, and
Zn85Mg150x.
[0064] Cathode
[0065] When used in an organic photovoltaic device the copolymer can be
used in conjunction
with a cathode. The cathode for the organic photovoltaic device can be any
conventionally known
cathode capable of operating as an organic photovoltaic device. Examples of
cathodes that can be
used include: indium tin oxide, carbon, graphite, graphene, PEDOT:PSS, copper,
silver, gold,
metal nanowires.
[0066] Electron transport layer
100671 When used in an organic photovoltaic device the copolymer can be
deposited onto an
electron transport layer. Any commercially available electron transport layer
can be used that is
optimized for organic photovoltaic devices. In one embodiment, the electron
transport layer can
comprise (A0x)yB0(11). In this embodiment, (A0x)y and B0(L-y) are metal
oxides. A and B can
be different metals selected to achieve ideal electron transport layers. In
one embodiment A can
be aluminum, indium, zinc, tin, copper, nickel, cobalt, iron, ruthenium,
rhodium, osmium,
tungsten, magnesium, indium, vanadium, titanium and molybdenum.
[0068] In one embodiment B can be aluminum, indium, zinc, tin, copper,
nickel, cobalt, iron,
ruthenium, rhodium, osmium, tungsten, vanadium, titanium and molybdenum.
[0069] Examples of (A0x)yB0(11) include: (SnOx)yZn0(L-y), (A10x)yZn0(L-y),
(A10x)yInOz(1-y),
(Al Ox)yS1110z(1-y), (Al Ox)yCUOz(1-y),
(Al Ox)yWOz( 1-y), (In0x)yZn0(11), (In0x)ySnOz(11),
(InO4Ni041-y), (Z1104CUOz(1-y), (Zn0x)yNiOz(1-y), (Z110x)yFeOz(1-y), (WO4V0z(1-
y),
(W0x)yT1Oz(1-y), and (WO4M00z(1-y).
[0070] In an alternate embodiment, various fullerene dopants can be
combined with
(A0x)yB0(11) to make an electron transport layer for the organic photovoltaic
device. Examples
14
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
R'
R"
0
OWII0
OA"
of fullerene dopants that can be combined include Ilik=1"-
and [6,6]-phenyl-
C6o-butyric-N-2-trimethylammonium ethyl ester iodide.
1.1
R"
40,r4 4111;14., 0
OAP
[0071] in the embodiment of 111µ4= -
R' can be selected from either N, 0,
S. C, or B. In other embodiment R" can be alkyl chains or substituted alkyl
chains. Examples of
substitutions for the substituted alkyl chains include halogens, N, Br, 0, Si,
or S. In one example
H
R7 can be selected from , or
Other examples of fullerene dopants that can be used include: [6,6]-phenyl-C6o-
butyric-N-(2-
aminoethypacetamide, [6,6]-phenyl-C6o-butyric-N-triethyleneglycol ester and
{6,61-phenyl-C6o-
butyric-N-2-dimethy 1 aminoethyl ester.
[0072] S nthesis of Polymers
100731 Sample A: In a Schlenk flask, QDT-Br (53.53 mg, 0.086 mmol), (3-(2-
h.exyldecy1)-
[2,2'-bithiophene]-5,5'-diyObis(trimethylstannane) (61.40 mg, 0.086 mmol), P(o-
to1)3 (4.17 mg,
0.014 mmol), and Pd2dba.3 (3.14 mg, 0.003 mmol) were combined, then degassed
for 2 h. After
refilling with argon, dry chlorobenzene (1.7 ML) was added, and the reaction
mixture was degassed
via three freeze-pump-thaw cycles, using liquid nitrogen to freeze the
solution, The solution was
then heated to 125 C and stirred for 21 Ii under argon atmosphere. The
reaction mixture was
cooled to room temperature, poured into methanol (50 mL), and the polymer was
collected by
filtration. The polymer was purified by Soxhlet extraction, washing
sequentially with acetone and
hexanes. The polymer, Sample A, was recovered in the hexanes fraction (62 mg,
82% yield).
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
C4H9 C4H9
C4H9 C4H9
1-1)5/ ___________________________________ C(C2H5
C21-1)5/ __ C(C2H5 C2 N N
N _______ N
_(
n
S
S ______ SS _____
I Y
x
061-113
C6I-113
C8F-117
C8I-117
[0074] Sample B: In a Schlenk flask, QUT-Br (55.42 mg, 0.089 mmol),
stannane, 1,1'43,3"1-
bis(2-octyldodecyl)[2,2':5',2":5",2m-quaterthiophene]-5,5m-diylibis[1,1,1-
trimethyl (108.00 mg,
0.089 mmol), P(o-to1)3 (4.32 mg, 0.014 mmol), and PC12dba3 (3.25 mg, 0.003
mmol) were
combined, then degassed for 2 h. After refilling with argon, thy chlorobenzene
(1.8 nit) was
added, and the reaction mixture was degassed via three freeze-pump-thaw
cycles, using liquid
nitrogen to freeze the solution. The solution was then heated to 125 C and
stirred for 21 h under
argon atmosphere. The reaction mixture was cooled to room temperature, poured
into methanol
(50 m1_,), and the polymer was collected by filtration. The polymer was
purified by Soxhlet
extraction, washing sequentially with acetone and hexanes. The polymer, Sample
B, was
recovered in the hexanes fraction (89 mg, 72% yield).
04.H9 C4H9
C2Hhi __ r(C2H5
N N
I \ I n
I \ I
C81-117
CioHzi
C8F-117
CioH21
[0075] Sample C: In a Schlenk flask, QDT-Br (50.00 mg, 0080 minol),
Stannane, 1,1'-
nap htho[],2-1):5,6-bldi thi ophene-2,7-diylbi s [1, 1,1-tri.m ethyl (45.31
mg, 0.080 mmol), P(o-to1)3
(3.90 mg, 0.013 mmol), and Pd2dba3 (2.93 mg, 0.003 mmol) were combined, then
degassed for 2
h. After refilling with argon, dry chi orobenzen.e (1.6 nit) was added, and
the reaction mixture was
degassed via three freeze-pump-thaw cycles, using liquid nitrogen to freeze
the solution. The
16
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
solution was then heated to 125 C and stirred for 23 h under argon
atmosphere. The reaction
mixture was cooled to room temperature, poured into methanol (50 mL), and the
polymer was
collected by filtration. The polymer was purified by Soxhlet extraction,
washing sequentially with
acetone, hexanes, and chloroform. The polymer, Sample C, was recovered in the
chloroform
fraction (22 mg, 37% yield).
C4H9
C2F15--/ __ C(C2H5
N N
lSbsln
10076] Sample D: In a Schlenk flask, QDT-SnMe3 (40.00 mg, 0.050 mmol),
2,1,3-
Benzothiadiazole, 4,7-bis[5-bromo-4-(2-octyldodecy1)-2-thienyl]-5,6-difluoro
(45.31 mg, 0.080
mmol), P(o-to1)3 (2.46 mg, 0.008 mmol), and Pd2dba3 (1.85 mg, 0.002 mmol) were
combined, then
degassed for 2 h. After refilling with argon, dry chlorobenzene (1.0 mL) was
added, and the
reaction mixture was degassed via three freeze-pump-thaw cycles, using liquid
nitrogen to freeze
the solution. The solution was then heated to 125 C and stirred for 23 h
under argon atmosphere.
The reaction mixture was cooled to room temperature, poured into methanol (50
mL), and the
polymer was collected by filtration. The polymer was purified by Soxhlet
extraction, washing
sequentially with acetone and hexanes. The polymer, Sample I), was recovered
in the hexanes
fraction (55 mg, 78% yield).
C4H9 C4H9
C2F15--/ __ r(C2H5
N N
N N
\ /
C81-117
Cio1-121 C8H17 C101-121
17
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
[0077] Sample E: In a Schlenk flask, QDT-Br (100.3 mg, 0.161 mmol), (3-(2-
h.exyldecy1)-
[2,2'-bithiophene]-5,5'-diyObis(trimethylstannane) (57.5 mg, 0.08 mmol),
Stannane,
bi s[5-(2-ethylhexyl)-2-thieny 1 Thenzo[1,2-b:4,5-11dithiophen.e-2,6-
diAbis[1,1,1-tri methyl (72.6
mg, 0.08 mmol), P(o-to1)3 (7.8 mg, 0.026 mmol), and Pd2dba3 (5.9 mg, 0.006
mmol) were
combined, then degassed for 1 h. After refilling with argon, thy chlorobenzene
(3.2 mL) was
added, and the reaction mixture was degassed via three freeze-pump-thaw
cycles, using liquid
nitrogen to freeze the solution. The solution was then heated to 130 'V and
stirred for 24 h under
argon atmosphere. The reaction mixture was cooled to room temperature, poured
into methanol
(50 mL), and the polymer was collected by filtration. The polymer was purified
by Soxhlet
extraction, washing sequentially with acetone, hexanes, and chloroform. The
polymer, Sample
was recovered in the chloroform fraction (130 mg, 85% yield).
C4H9 C4H9
C4H9 C4H9 C4H9
c4H9 C4F-I9
C2 O2Hn/ __________ r<C2H5
1-1h/ __________________________________ r(C2H5 N N
C2115--/ __ C(C2H5 N N
N N
I \
I \
I
SS
SS I \ I Y
I \ I x
C6H13
C6F-113
C8F-117
C8F-117
C2H5
C4H9
[0078] Sample F: In a Schlenk flask, QDT-Br (100.1 mg, 0.160 m_rnol), (3-(2-
hexyldecy1)-
[2,2'-bithiophene]-5,5'-diyObis(trimethylstannane) (80.4 mg, 0.11 mmol),
Stannane, 1,11-(3,3'-
difluoro[2,21-bithiophene]-5,5'-diy1)bis[1,1,1-trimethyl (25.4 mg, 0.05 mmol),
P(o-to1)3 (7.8 mg,
0,026 mmol), and :Pd2dba.3 (5.9 mg, 0.006 inniol) were combined, then degassed
for I h. After
refilling with argon, dry chlorobenzene (3.2 mL) was added, and the reaction
mixture was degassed
via three freeze-pump-thaw cycles, using liquid nitrogen to freeze the
solution. The solution was
then heated to 130 C and stirred for 24 h under argon atmosphere. The
reaction mixture was
cooled to room temperature, poured into methanol (50 mL), and the polymer was
collected by
filtration. The polymer was purified by Soxhlet extraction, washing
sequentially with acetone,
hexanes, and chloroform. The polymer, Sample F, was recovered in the
chloroform fraction (100
mg, 99% yield).
18
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
C41-19 C4H9
C4H9 C4H9
C4H, C4H,
r(C2H5
F-1)5/ __ r(C2H5 N N
C2Eb C2
i ______ (--(C2H5 N N
N N
S
I \ I \
I __________________________________________ \ I Y
___________________ \ I x
C8H13
C8H13
C8H17
C8H17
100791 Organic Photovoltaic Device Fabrication
[0080] Zinc/tin oxide (ZTO):phenyl-C60-butyric-N-(2-hydroxyethypacetamide
(PCBNOH)
sol-gel solution was prepared by dissolving zinc acetate di hydrate or tin(H)
acetate in 2-
methoxyethanol and ethanolamine. Specifically, the ZTO:PCBNOH sol-gel electron
transport
layer solution was prepared by mixing 3.98 g of Zn(0Ac)2, 398 mg of Sn(0Ac)2
and 20.0 mg
PCBNOH in 54 mL of 2-methoxyethanol with adding 996 !IL of ethanolamine.
Solutions were
then further diluted to 65% by adding more 2-methoxyethanol and stirred for at
least an hour before
spin casting onto indium tin oxide substrate to form the electron transport
layer.
100811 The polymer and the acceptor, PC7oBM and a non-fullerene acceptor
3,9-bis(2-
methyl ene-(3-(1,1-di cyanomethyl ene)-i ndanone))-5,5,11,11-tetraki s(4-hexyl
pheny1)-
dithieno[2,3-d:2',3'-dl-s-indaceno[1,2-b:5,6-bl dithiophene (ITIC) in a ratio
of 1:1.2 were
dissolved in chlorobenzene at the concentration of 26 mg/mL to obtain the
photoactive layer
solution. The solution was stirred and heated at 80 C overnight in a nitrogen
filled glove box.
The next day 3.0 vol% of 1,8-diiodooctane (DIO) was added before spin-coating
of the photoactive
layer.
[0082] Indium tin oxide patterned glass substrates were cleaned by
successive ultra-
sonications in acetone and isopropanol. Each 15-min step was repeated twice
and the freshly
cleaned substrates were left to dry overnight at 60 C. Preceding fabrication,
the substrates were
further cleaned for 1.5 min in a UV-ozone chamber and the electron transport
layer was
immediately spin coated on top.
100831 Sol-gel electron transport layer solution was filtered directly onto
the indium tin oxide
with a 0.25 JIM poly(vinylidene fluoride) filter and spin cast at 4000 rpm for
40 s. Films were then
annealed at 250 C for 15 min, and directly transferred into a nitrogen filled
glove box.
19
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
[0084] The photoactive layer was deposited on the electron transport layer
via spin coating at
600 rpm for 40 s with the solution and the substrate being preheated at 110 C
and directly
transferred into a glass petri dish for overnight solvent annealing.
100851 After annealing, the substrates were loaded into the vacuum
evaporator where Mo03
(hole transport layer) and Ag (anode) were sequentially deposited by thermal
evaporation.
Deposition occurred at a pressure of < 4 x 10-6 ton. Mo03 and Ag had
thicknesses of 5.0 nm and
120 nm, respectively. Samples were then encapsulated with glass using an epoxy
binder and
treated with UV light for 3 min.
[0086] UV-Visible Absorption Spectroscopy
[0087] Absorption spectroscopy was performed and measured in the wavelength
region from
300 to 1000 nm. A blank glass slide background was subtracted from all
spectra. The polymer
thin film samples were prepared by spin casting a 10 mg/mL solution of polymer
(in 50:50
chlorobenzene:dichlorobenzene) onto a glass slide at 1200 rpm. Figure 14
depicts the UV-Visible
absorption spectra of the polymers.
[0088] Representative current density
[0089] Representative current density - voltage characteristics are shown
below in table 1.
Sample Jsc Voc (V) FF CVO PCE (%) Rs (0 cm2) Rsh cm2)
with (mA/cm2)
PCBM Avg Max Avg Max Avg Max Avg Max Avg Max Avg Max
A 9.82 11.4 0.76 0.78 72.0 73.2 5.4 6.01 7.34 801 3280 5630
4.45 4.55 0.69 0.80 45.2 49.2 1.38 1.69 52.6 70.5 858 1300
3.19 3.65 0.56 0.63 35.8 41.7 0.63 0.69 89.4 131 352 388
1.99 2.24 0.84 0.88 36.1 41.6 0.60 0.72 165 201 916 1250
12.2 13 0.82 0.83 65.8 67.8 6.60 6.79 6.12 7.98 2013 2586
13.23 13.66 0.70 0.71 57.6 58.9 5.36 5.59 5.30 8.23 640.3 996.9
Table 1
Sample J sc Voc (V) FF (%) PCE N) Rs
(0 cm2) Rsb (f/ cm2)
with (mA/cm2)
1TIC Avg Max Avg Max Avg Max Avg Max Avg Max Avg Max
CA 03071093 2020-01-24
WO 2019/023025 PCT/US2018/042724
A 11.36 13.05 0.935 0.943 64.2 65.8 6.79 7.41 6.89 7.57 961 1099
13.85 14.66 0.934 0.937 61.1 62.8 7.90 8.47 8.66 9.58 1015 1269
Table 2
[0090] Jsc (mA/cm2) Short-circuit current density (Jsc) is the current
density that flows out of
the solar cell at zero bias. Voc (V) Open-circuit voltage (Voc) is the voltage
for which the current
in the external circuit is zero. FF (%) fill factor (FF) is the ratio of the
maximum power point
divided by the open circuit voltage and the short circuit current. PCE CVO The
power conversion
efficiency (PCE) of a photovoltaic cell is the percentage of the solar energy
shining on a
photovoltaic device that is converted into usable electricity. Rs (SI cm2)
series resistance (Rs)
through the photovoltaic cell. Rsh (S) cm2) parallel resistance though the
photovoltaic cell.
[0091] In closing, it should be noted that the discussion of any reference
is not an admission
that it is prior art to the present invention, especially any reference that
may have a publication
date after the priority date of this application. At the same time, each and
every claim below is
hereby incorporated into this detailed description or specification as an
additional embodiment of
the present invention.
[0092] Although the systems and processes described herein have been
described in detail, it
should be understood that various changes, substitutions, and alterations can
be made without
departing from the spirit and scope of the invention as defined by the
following claims. Those skilled
in the art may be able to study the preferred embodiments and identify other
ways to practice the
invention that are not exactly as described herein. It is the intent of the
inventors that variations
and equivalents of the invention are within the scope of the claims while the
description, abstract
and drawings are not to be used to limit the scope of the invention. The
invention is specifically
intended to be as broad as the claims below and their equivalents.
21
