KR20220046976A - Conjugated polymer for all-polymer solar cell, active layer composition for all-polymer solar cell comprising thereof, and uses thereof - Google Patents

Abstract

The present invention relates to a conjugated polymer for an all-polymer solar cell, an active layer composition for an all-polymer solar cell including the same, and use thereof. Particularly, the present invention relates to a conjugated polymer for an all-polymer solar cell which can improve the performance, such as power conversion efficiency (PCE), crystallinity and electron mobility, by controlling the crystallinity and orientation of an active layer acceptor.

Description

Conjugated polymer for all-polymer solar cell, active layer composition for all-polymer solar cell comprising same, and use thereof

The present invention relates to a conjugated polymer for an all-polymer solar cell, an active layer composition for an all-polymer solar cell comprising the same, and a use thereof, and more specifically, to control the crystallinity and orientation of the active layer acceptor to convert power It relates to a conjugated polymer for a pre-polymer solar cell capable of improving performance such as efficiency (PCE), crystallinity and electron mobility, an active layer composition for a pre-polymer solar cell comprising the same, and uses thereof .

Recently, all-polymer solar cells (all-PSCs) composed of polymer donors and polymer acceptors have shown great progress and potential as energy sources for high-performance flexible devices. In particular, pre-PSCs have advantages over conventional fullerene-PSCs in aspects such as tunable energy levels, high light-absorbing capacity, mechanical flexibility and thermal stability. Despite these advantages, the power conversion efficiencies (PCEs) of pre-PSCs were still lower than those of fullerene-PSCs. The strong immiscibility between long polymer chains, lower electron mobility of polymer acceptors than fullerenes, and the suboptimal blend shape of the active layer caused by inefficient free charge generation have prevented the realization of the overall performance of pre-PSCs. It is the main identified factor hindering. Exciton dissociation efficiency and charge transport strongly depend on the crystallinity and molecular orientation of polymer donors and acceptors. Therefore, developing approaches to optimize the blend shape as well as the crystalline assembly of polymers is an urgent and important requirement for improving the electrical properties of pre-PSCs and PCEs.

Therefore, in order to supplement the above problems, the present inventors control the crystallinity and orientation of the active layer acceptor to control power conversion efficiency (PCE), crystallinity and electron mobility, etc. Recognizing that there is an urgent need to develop a material capable of improving the performance of the present invention, the present invention has been completed.

Republic of Korea Patent Publication No. 10-2008-0094237 Republic of Korea Patent Publication No. 10-2011-0038043

An object of the present invention is to control the crystallinity and orientation of the active layer acceptor to improve performance such as power conversion efficiency (PCE), crystallinity and electron mobility. To provide a conjugated polymer for an all-polymer solar cell.

Another object of the present invention is to provide an active layer composition for an all-polymer solar cell capable of improving performance such as power conversion efficiency, crystallinity, and electron mobility by controlling the crystallinity and directionality of the active layer acceptor.

Another object of the present invention is an all-polymer solar cell comprising an active layer composition for an all-polymer solar cell capable of improving performance such as power conversion efficiency, crystallinity and electron mobility by controlling the crystallinity and directionality of the active layer acceptor to provide batteries.

The technical problems to be achieved by the invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those of ordinary skill in the art from the description of the present invention.

In order to achieve the above object, the present invention provides a conjugated polymer for a pre-polymer solar cell, an active layer composition for a pre-polymer solar cell comprising the same, and uses thereof.

Hereinafter, the present specification will be described in more detail.

The present invention provides a conjugated polymer for all-polymer solar cells (all-PSCs), characterized in that represented by the following [Formula 1].

[Formula 1]

Wherein R ₁ is phenyl, tolyl, xylene or naphthyl,

Wherein R ₂ is C, O, N or S,

Wherein R ₃ and R ₄ are each independently hydrogen, halogen, -C _1-20 straight or branched chain alkyl, -C _1-10 alkoxy or -NH ₂

wherein R ₅ is -C _1-20 straight or branched chain alkyl or -C _1-10 alkoxy;

wherein X is F, Cl, Br or I;

and n is 1 to 1,000.

In addition, the present invention is a polymer donor (polymer donor) comprising a conjugated polymer represented by the following [Formula 1]; A polymer acceptor represented by the following [Formula 2]; and 1-phenylnaphthalene (1-phenylnaphthalene) additive.

[Formula 1]

[Formula 2]

Wherein R ₁ is phenyl, tolyl, xylene or naphthyl,

Wherein R ₂ is C, O, N or S,

Wherein R ₃ and R ₄ are each independently hydrogen, halogen, -C _1-20 straight or branched chain alkyl, -C _1-10 alkoxy or -NH ₂

wherein R ₅ is -C _1-20 straight or branched chain alkyl or -C _1-10 alkoxy;

wherein X is F, Cl, Br or I;

and n is 1 to 1,000.

In the present invention, the ratio of the polymer donor: the polymer acceptor is 1: 0.3 to 1.2 (wt: wt) is characterized in that it contains.

In the present invention, the 1-phenylnaphthalene additive is characterized in that it is included in a ratio of 0.2 to 0.6% by volume based on the total volume% of the active layer composition for the pre-polymer solar cell.

In addition, the present invention provides all-polymer solar cells (all-PSCs) comprising a photoactive layer employing the active layer composition.

In the present invention, the photoactive layer is characterized in that the thickness of 150 to 250 nm.

In the present invention, the photoactive layer is characterized in that the surface is modified with toluene (toluene).

All matters mentioned in the conjugated polymer for a pre-polymer solar cell, an active layer composition for a pre-polymer solar cell including the same, and uses thereof apply equally unless contradictory.

The conjugated polymer for a pre-polymer solar cell of the present invention, an active layer composition for a pre-polymer solar cell comprising the same, and a use thereof are the power conversion efficiency (PCE), crystallization by controlling the crystallinity and orientation of the active layer acceptor Performance such as crystallinity and electron mobility may be improved.

In addition, the pre-polymer solar cell including the active layer composition for the pre-polymer solar cell of the present invention can be obtained through the optimal photoactive layer thickness, surface modification solvent, thermal annealing time, etc. circuit current, J _SC ), open-circuit voltage, V _OC , and power conversion efficiency (PCE) may be improved.

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a ¹ H NMR spectrum of the compound represented by (a) [Formula 4], (b) [Formula 3] and (c) [Formula 1] prepared in Example 1 according to the present invention.
FIG. 2 is a cross-sectional image of a cross-section of the all-polymer solar cell prepared in Example 3 according to the present invention measured with a Field Emission Scanning Electron Microscope (FE-SEM).
3 is (a) Thermal Gravimetric Analysis (TGA) and (b) Differential Scanning Calorimetry (DSC) of the conjugated polymer represented by [Formula 1] prepared in Example 1 according to the present invention; It is a graph.
Figure 4 is a graph of measuring the cyclic voltammetry (Cyclic voltammetry) of the conjugated polymer represented by [Formula 1] prepared in Example 1 according to the present invention.
5 is a conjugated polymer (green line) represented by [Formula 1] prepared in Example 1 according to the present invention, a polymer acceptor (red line) represented by [Formula 2] and the pre-prepared in Example 2 - UV-visible absorption spectra in a solution state of the active layer composition for a polymer solar cell (blue line).
6 is a diagram illustrating the calculation of density functional theory (DFT) of the conjugated polymer represented by [Formula 1] prepared in Example 1 according to the present invention.
7 shows the electrical characteristics of the pre-polymer solar cell (blue line), the comparative pre-polymer solar cell 1 (green line), and the comparative pre-polymer solar cell 2 (black line) prepared in Example 3 according to the present invention; This is the confirmed JV curve.
8 is an atomic force microscope of (a) the pre-polymer solar cell prepared in Example 3 according to the present invention, (b) comparative pre-polymer solar cell 3 and (c) comparative pre-polymer solar cell 4; It is an image measured by Microscope, AFM).
9 shows (a) the all-polymer solar cell prepared in Example 3 surface-modified with toluene, (b) 2-methyltetrahydrofuran (2-MeTHF) and (c) cyclopentyl methyl ether; , CPME) is a graph of charge carrier mobility confirmed through the space-charge-limited current (SCLC) method for comparative pre-polymer solar cells 3 and 4 formed by surface modification.
10 is a pre-polymer solar cell (Example 3) in which thermal annealing was performed at 120° C. for 10 minutes, a comparative pre-polymer solar cell 5 in which thermal annealing was performed for 20 minutes, and a comparison in which thermal annealing was performed for 30 minutes; (a) Ground incidence X-ray diffraction (GIXD) patterns for the photoactive layer of the all-polymer solar cell 6 and (b) 1D profile graphs extracted through them.

The terms used in this specification have been selected as currently widely used general terms as possible while considering the functions in the present invention, but these may vary depending on the intention or precedent of a person skilled in the art, the emergence of new technology, and the like. In addition, in a specific case, there is a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description of the corresponding invention. Therefore, the term used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, rather than the name of a simple term.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Numerical ranges are inclusive of the values defined in that range. Every maximum numerical limitation given throughout this specification includes all lower numerical limitations as if the lower numerical limitation were expressly written. Every minimum numerical limitation given throughout this specification includes all higher numerical limitations as if the higher numerical limitation were expressly written. Any numerical limitation given throughout this specification shall include all numerical ranges within the broader numerical range, as if the narrower numerical limitation were expressly written.

Hereinafter, examples of the present invention will be described in detail, but it is obvious that the present invention is not limited by the following examples.

Conjugated polymer for all-polymer solar cells

The present invention provides a conjugated polymer for all-polymer solar cells (all-PSCs) represented by the following [Formula 1].

[Formula 1]

Wherein R ₁ is phenyl, tolyl, xylene or naphthyl,

Wherein R ₂ is C, O, N or S,

Wherein R ₃ and R ₄ are each independently hydrogen, halogen, -C _1-20 straight or branched chain alkyl, -C _1-10 alkoxy or -NH ₂

wherein R ₅ is -C _1-20 straight or branched chain alkyl or -C _1-10 alkoxy;

wherein X is F, Cl, Br or I;

and n is 1 to 1,000.

The conjugated polymer is a p-type π-conjugated donor polymer (π-conjugated donor polymer), toluene, 2-methyltetrahydrofuran (2-Methyltetrahydrofuran, 2-MeTHF), cyclopentyl methyl ether (Cyclopentyl methyl) It has excellent solubility in nonhalogenated solvents such as ether, CPME).

Active layer composition for all-polymer solar cells

The present invention is a polymer donor (polymer donor) comprising a conjugated polymer represented by the following [Formula 1]; A polymer acceptor represented by the following [Formula 2]; And 1-phenylnaphthalene (1-phenylnaphthalene) additive; provides an active layer composition for all-polymer solar cells (all-PSCs) comprising a.

[Formula 1]

[Formula 2]

Wherein R ₁ is phenyl, tolyl, xylene or naphthyl,

Wherein R ₂ is C, O, N or S,

Wherein R ₃ and R ₄ are each independently hydrogen, halogen, -C _1-20 straight or branched chain alkyl, -C _1-10 alkoxy or -NH ₂

wherein R ₅ is -C _1-20 straight or branched chain alkyl or -C _1-10 alkoxy;

wherein X is F, Cl, Br or I;

and n is 1 to 1,000.

The ratio of the polymer donor to the polymer acceptor may be 1:0.3 to 1.2 (wt:wt).

The 1-phenylnaphthalene additive may be included in a ratio of 0.2 to 0.6% by volume based on the total volume% of the active layer composition for the pre-polymer solar cell.

all-polymer solar cells (all-PSCs)

The present invention provides all-polymer solar cells (all-PSCs) including a photoactive layer employing the active layer composition having effects such as excellent photoelectric conversion efficiency and lifetime stability.

The active layer composition is the same as the above-mentioned active layer composition for an all-polymer solar cell.

More specifically, the pre-polymer solar cell may include a substrate, a first electrode, a first buffer layer, a photoactive layer, a second buffer layer, and a second electrode.

In the all-polymer solar cell of the present invention, an electron is a first electrode and a hole exits a second electrode, or a hole is a first electrode and an electron is a second electrode. It may be a reverse solar cell exiting the electrode.

The first electrode is sputtering, E-beam, thermal evaporation, spin coating, screen printing, inkjet printing, using a method selected from the group consisting of doctor blade or gravure printing method is applied to the transparent electrode material on one surface of the substrate or a film It can be formed by coating in the form.

The first electrode includes indium tin oxide (ITO), fluorine doped tin oxide (FTO), aluminum doped zink oxide (AZO), indium zink oxide (IZO), ZnO -Ga ₂ O ₃ , ZnO-Al ₂ O ₃ or antimony tin oxide (ATO), preferably ITO or FTO.

The first buffer layer formed over the first electrode may be formed as a hole transport layer or an electron transport layer according to a forward or reverse structure. When the first buffer layer is a hole transport layer, it may be poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)[PEDOT:PSS], which prevents electrons from moving to the first electrode It can help the transport of holes smoothly. In addition, when the first buffer layer is an electron transport layer, it may be polyethylenimine ethoxylated (PEIE) or ZnO, which prevents holes from moving to the first electrode while helping to facilitate electron transition and transport. can

A photoactive layer may be stacked on the first buffer layer. The photoactive layer is an active layer composition for an all-polymer solar cell according to the present invention, and can provide a photovoltaic effect through very fast charge transfer and separation between an electron donor and an electron acceptor.

The photoactive layer may have a thickness of 150 to 250 nm, preferably 160 to 230 nm.

The photoactive layer was formed using toluene as a non-halogenated solvent, and the photoactive layer having a low surface roughness can be formed despite the use of a non-halogenated solvent. , short-circuit current (J _SC ), open-circuit voltage (V _OC ) and power conversion efficiency (PCE).

The photoactive layer may be formed by applying or coating a solution in which the active layer composition for a pre-polymer solar cell is dissolved by at least one method selected from the group consisting of a printing method, a spin coating method, a screen printing method, and a doctor blade method. .

The second buffer layer formed on the photoactive layer may be formed as a hole transport layer or an electron transport layer depending on the forward or reverse structure of the solar cell. When the second buffer layer is a hole transport layer, it may be MoO ₃ , and when the second buffer layer is an electron transport layer, it may be a metal oxide layer including a metal oxide. The metal oxide may be formed of a nanoparticle oxide such as titanium dioxide (TiO2), tin dioxide (SnO2), or zinc oxide (ZnO), but is not limited thereto.

A second electrode may be deposited on the second buffer layer using a thermal evaporator. The second electrode may include lithium fluoride/aluminum, lithium fluoride/calcium/aluminum, calcium/aluminum, barium/aluminum fluoride, barium fluoride/barium/aluminum, barium/aluminum, aluminum, gold, silver, magnesium: silver or lithium: It may be aluminum, preferably aluminum, silver or lithium fluoride/aluminum.

Advantages and features of the present invention, and a method of achieving them, will become apparent with reference to the embodiments described below in detail. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only the embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

Example 1. Preparation of conjugated polymer for pre-polymer solar cell

1.1. Preparation of a compound represented by [Formula 4]

[Preparation of 5,6-difluoro-1H-benzo [d] [1,2,3] triazole (compound No. 2)]

4,5-difluorobenzene-1,2-diamine (compound #1) (10 g, 70.0 mmol) was dissolved in acetic acid (9 mL, 140 mmol), and water (360 mL) was added and heated. Then, the mixture was cooled, and NaNO ₂ (5 g, 77 mmol) and water (150 mL) were added to the mixture. Then, the mixture was stirred at room temperature for 1 hour to turn dark green, cooled to filter the precipitate, dried and recrystallized with water to 5,6-difluoro-1H-benzo[d][1,2 ,3]triazole (compound No. 2) was obtained as a white solid (8.0 g, yield 80%).

¹ H NMR (300 MHz, CDCl ₃ ): δ (ppm) 15.81 (s, 1H), 7.89 (t, 2H).

[Preparation of 5,6-difluoro-2-(hex-5-en-1-yl)-2H-benzo[d][1,2,3]triazole (Compound No. 3)]

The compound No. 2 (8.0 g, 51.2 mmol) was dissolved in 100 mL of methanol, and potassium tert-butoxide (14.4 g, 128.8 mmol) and 6-bromo-1- in the lysate. Hexane (6-bromo-1-hexane) (16.59 g, 103.2 mmol) was added and stirred at 65 °C for 24 hours. Then, the mixture was cooled to room temperature, water was added, and the organic layer was extracted with ethyl acetate. The organic layer was dried over MgSO ₄ and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography using hexane:ethyl acetate (50:1 v/v) as an eluent to 5,6-difluoro-2-(hex-5-en-1-yl)- 2H-benzo[d][1,2,3]triazole (compound 3) was obtained as a pale yellow oil (5.3 g, yield 70%).

¹ H NMR (300 MHz, CDCl ₃ ): δ (ppm) 7.59-7.53 (t, 2H), 5.79-5.70 (m, 1H), 5.02-4.93 (m, 2H), 4.70-4.65 (t, 2H) , 2.10-2.06 (m, 2H), 1.47-1.37 (m, 4H).

[5,6-difluoro-2-(6-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)hexyl)-2H-benzo[d][1, 2,3] Triazole (Compound No. 4) Preparation]

The compound 3 (6.6 g, 27.80 mmol) was dissolved in 80 mL of toluene, and a small amount of Karstedt's catalyst (2.42 mL, 0.005 eq.) and 1,1,1,3,5,5,5 in the lysate. -Heptamethyltrisiloxane (7.11 g, 31.98 mmol) was added. The mixture was stirred at 50° C. for 24 hours, and concentrated to remove toluene in vacuo to prepare an oil mixture. The oil mixture was purified by silica gel column chromatography using nucleic acid:ethyl acetate (50:1 v/v) as eluent to 5,6-difluoro-2-(6-(1,1,1,3, 5,5,5-heptamethyltrisiloxan-3-yl)hexyl)-2H-benzo[d][1,2,3]triazole (compound 4) was obtained as a pale yellow oil (3.2 g, yield 64) %).

¹ H NMR (300 MHz, CDCl ₃ ): δ (ppm) 7.59-7.54 (t, 2H), 4.69-4.64 (t, 2H), 2.09-2.05 (m, 2H), 1.33-1.24 (m, 8H) , 0.43-0.41 (m, 3H), 0.059-0.033 (t, 18H).

[5,6-difluoro-2-(6-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)hexyl)-4,7-bis(trimethylsilyl) -2H-benzo[d][1,2,3]triazole (compound 5) preparation]

Lithium diisopropylamide (2.0M, 14.50 mL, 29.04 mmol) was added dropwise to compound 4 (4.5 g, 9.68 mmol), and THF (50 mL) was dried at -78 ° C. under N ₂ environment. did Then, trimethylsilyl chloride (3.15 g, 29.03 mmol) was added dropwise at -78 °C, stirred at the temperature for 5 hours, and quenched with 10 mL of saturated NH ₄ Cl solution. The reaction was warmed to room temperature, saturated NH ₄ Cl solution was additionally added, and CHCl ₃ was added to the mixture to extract the organic layer and washed twice with water. The organic layer was dried over MgSO ₄ and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography using hexane:ethyl acetate (60:1 v/v) as an eluent, and 5,6-difluoro-2-(6-(1,1,1,3, 5,5,5-heptamethyltrisiloxan-3-yl)hexyl)-4,7-bis(trimethylsilyl)-2H-benzo[d][1,2,3]triazole (compound 5) to yellow It was obtained as an oil (2.3 g, 68% yield).

¹ H NMR (300 MHz, CDCl ₃ ): δ (ppm) 4.64-4.59 (d, 2H), 2.05-2.03 (m, 2H), 1.35-1.25 (m, 8H), 0.67-0.41 (t, 18H) , 0.073-0.017 (t, 21H).

[4,7-dibromo-5,6-difluoro-2-(6-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)hexyl)-2H -benzo[d][1,2,3]triazole (compound 6) preparation]

The compound No. 5 (3.6 g, 5.96 mmol) was dissolved in CHCl ₃ (10 mL), bromine (2.86 g, 17.88 mmol) was added, and the light was blocked from the reaction product at 60° C. for 24 hours. stirred. After the mixture was cooled to room temperature, an aqueous NaOH solution was added, and the organic layer was extracted with CHCl ₃ , the organic layer was dried over MgSO ₄ and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography using hexane:methylene chloride (50:1 v/v) as an eluent, and 4,7-dibromo-5,6-difluoro-2-(6-( 1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)hexyl)-2H-benzo[d][1,2,3]triazole (compound 6) as pale yellow oil It was obtained (1.9 g, yield 70%).

¹ H NMR (300 MHz, CDCl ₃ ): δ (ppm) 4.74-4.71 (d, 2H), 2.11 (m, 2H), 1.35 (m, 8H), 0.45-0.41 (m, 3H), 0.06-0.04 (t, 18H).

[5,6-difluoro-2-(6-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)hexyl)-4,7-di(thiophene- 2-yl) -2H-benzo [d] [1,2,3] triazole (compound 7) preparation]

Compound 6 (0.5 g, 0.81 mmol), tributyl (thiophen-2-yl) stannane (1.06 g, 2.85 mmol), DMF (20 mL) and PdCl ₂ (PPh ₃ ) ₂ (28 mg, 0.040 mmol) was added to a 100 mL two-necked flask under N ₂ environment, and the mixture was stirred at 80° C. for 24 hours. Water was added to the mixture, and the organic layer was extracted using ethyl acetate. The organic layer was dried over MgSO ₄ and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography using hexane:methylene chloride (7:3 v/v) as an eluent to 5,6-difluoro-2-(6-(1,1,1,3, 5,5,5-heptamethyltrisiloxan-3-yl)hexyl)-4,7-di(thiophen-2-yl)-2H-benzo[d][1,2,3]triazole (No. 7 compound) was obtained as a yellow oil (0.27 g, yield 62%).

¹ H NMR (300 MHz, CDCl ₃ ): δ (ppm) 8.31 (m, 2H), 7.54-7.53 (m, 2H), 7.25 (m, 2H), 4.81-4.76 (t, 2H), 2.17 (m) , 2H), 1.40-1.31 (m, 8H), 0.47-0.44 (m, 3H), 0.06-0.02 (t, 18H).

[4,7-bis(5-bromothiophen-2-yl)-5,6-difluoro-2-(6-(1,1,1,3,5,5,5-heptamethyltrisiloxane) -3-yl) hexyl) -2H-benzo [d] [1,2,3] triazole [Formula 4] preparation]

N-bromosuccinimide (0.15 g, 0.87 mmol) was added to the compound 7 (0.4 g, 0.415 mmol) in CHCl ₃ (15 mL), and the light was blocked and 24 It was stirred at room temperature for hours. Then, NaHCO ₃ aqueous solution was added to the mixture, and the organic layer was extracted with methylene chloride. The organic layer was purified by silica gel chromatography using hexane:methylene chloride (50:1 v/v) to 4,7-bis(5-bromothiophen-2-yl)-5,6-difluoro-2 -(6-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)hexyl)-2H-benzo[d][1,2,3]triazole [Formula 4] was obtained (0.21 g, yield 85%).

¹ H NMR (300 MHz, CDCl ₃ ): δ (ppm) 8.04 (d, 2H), 7.25-7.16 (d, 2H), 4.76 (t, 2H), 2.15 (m, 2H), 1.40-1.24 (m) , 8H), 0.44 (m, 3H), 0.06-0.02 (t, 18H).

1.2. Preparation of conjugated polymer represented by [Formula 1]

A compound represented by [Formula 3] (1.00 eq), a compound represented by [Formula 4] (1.00 eq) and (4,8-bis(5-(6-((2-hexyldecyl)oxy) Naphthalen-2-yl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene-2,6-diyl)bis(trimethylstannane)((4,8-bis (5-(6-((2-hexyldecyl)oxy)naphthalen-2-yl)thiophen-2-yl)benzo [1,2-b:4,5-b']dithiophene-2,6-diyl)bis (trimethylstannane)) was dissolved in anhydrous chlorobenzene. The reaction mixture was purged with N ₂ for 30 minutes, Pd ₂ (dba) ₃ (2 mol %) and P( o -tolyl) ₃ (16 mol %) were added, followed by further purging with N ₂ did Then, after heating the microwave vessel and cooling to room temperature again, methanol was added to the reaction mixture to obtain a primary precipitate. The first precipitate was subjected to soxhlet extraction with methanol, acetone, hexane, ethyl acetate and chloroform. The extract was fractionated with chloroform, concentrated, and then a secondary precipitate was obtained with methanol. The secondary precipitate was filtered and dried under vacuum to prepare a conjugated polymer represented by [Formula 1].

Example 2. Preparation of active layer composition for pre-polymer solar cells

The polymer donor, which is the conjugated polymer prepared in Example 1, and the polymer acceptor represented by the following [Formula 2] were mixed at 1:0.5 (wt:wt), and 1-phenylnaphthalene was added to the mixture to pre-polymer An active layer composition for a solar cell was prepared. At this time, the 1-phenylnaphthalene was added in an amount of 0.5% by volume to the total volume% of the finally prepared active layer composition for an all-polymer solar cell.

[Formula 2]

Example 3. Preparation of pre-polymer solar cell

Indium-tin oxide (ITO) was laminated on the substrate as a first electrode, and ZnO (electron transport layer) was spin-coated on the first electrode as a first buffer layer. Then, the photoactive layer was formed by dissolving the active layer composition for a pre-polymer solar cell prepared in Example 2 in toluene on the buffer layer and laminating it, and the photoactive layer was heat-treated at 120° C. for 10 minutes (thermal annealing, TA) was performed. Next, molybdenum oxide (MoO ₃ ) (hole transport layer) as a second buffer layer and silver as a second electrode were sequentially stacked on the upper surface of the photoactive layer to prepare an all-polymer solar cell according to the present invention. At this time, the photoactive layer was laminated to a thickness of 200 nm.

Experimental Example 1. Thermal, electrochemical and optical properties of conjugated polymer

1.1. thermal properties

In order to confirm the thermal properties of the conjugated polymer prepared in Example 1 according to the present invention, thermal gravimetric analysis (TGA) and differential scanning calorimetry (Differential Scanning) under N ₂ atmosphere at a heating rate of 10 °C/min Calorimetry, DSC) was measured, and it is shown in FIG. 2 .

Referring to FIG. 2, (a) the decomposition temperature (Td) at 5% weight loss of the conjugated polymer prepared in Example 1 according to the present invention is 333 ° C. From the results, the conjugated polymer according to the present invention is 333 ° C. It can be confirmed that thermal stability up to In addition, (b) the characteristic phase transition of the conjugated polymer prepared in Example 1 according to the present invention was not observed up to 200 °C. This suggests that the conjugated polymer of Example 1, which is a π-conjugated donor polymer functionalized with silonic acid, has excellent heat resistance and is very stable, and can prevent deterioration of photovoltaic performance when the conjugated polymer is applied to an all-polymer solar cell. it can be said that

1.2. electrochemical properties

In order to confirm the electrochemical properties of the conjugated polymer prepared in Example 1 according to the present invention, the electrochemical properties of the conjugated polymer prepared in Example 1 in CHCl ₃ solution using ferrocene as an internal standard were measured. It was confirmed through cyclic voltammetry, which is shown in FIG. 3 .

Referring to FIG. 3 , it can be seen that the conjugated polymer prepared in Example 1 according to the present invention has a stable voltage-current curve.

1.3. optical properties

In order to confirm the optical properties of the conjugated polymer prepared in Example 1 according to the present invention, the conjugated polymer prepared in Example 1, the polymer acceptor represented by [Formula 2] used in Example 2, and implementation For the active layer composition for a pre-polymer solar cell prepared in Example 2, a UV-visible absorption spectrum was measured in a CHCl ₃ solution (1x10 ^-5 M) state, and this is shown in FIG. 4 .

4, it can be seen that the conjugated polymer (green line) prepared in Example 1 according to the present invention shows a light absorption spectrum in the range of 300-650 nm and a weak absorption peak at 350 nm, and at 550 nm The maximum absorption peak was shown, which indicates strong self-aggregation properties in the solution state. In particular, the conjugated polymer (green line) prepared in Example 1 exhibits complementary absorption with the polymer acceptor (red line) represented by [Formula 2], and thus finally prepared in Example 2 - It can be seen that the maximum absorption wavelength (λ _max ) of the active layer composition (blue line) for a polymer solar cell is improved over a wide area. A high absorption coefficient is a configuration that helps to increase the light harvesting ability through intermolecular interactions, which suggests that it may have an improved short-circuit current (J _SC ).

In addition, the polymer in the film state exhibits a shoulder absorption peak at 600 nm, confirming that it has strong intermolecular π-π stacking and molecular interactions.

1.4. Electrical properties through HOMO and LUMO structures

In order to confirm the electrical properties according to the structural form of the conjugated polymer prepared in Example 1 according to the present invention, the density using the B3LYP/6-31G(d) basic set for the conjugated polymer prepared in Example 1 Density functional theory (DFT) was calculated, which is shown in FIG. 5 .

Referring to FIG. 5 , it can be seen that the highest energy level of the conjugated polymer prepared in Example 1 is -4.90 eV for HOMO, and -2.25 eV for LUMO, which is the lowest energy level, and the same result is π It can be confirmed that very well ordered molecular packing was generated by -π stacking.

Experimental Example 2. Photovoltaic performance of all-polymer solar cells according to active layer thickness

In order to confirm the photovoltaic performance of the all-polymer solar cell according to the thickness of the active layer, the all-polymer solar cell (black line) prepared in Example 3 was simulated with solar illumination (AM 1.5G, 100 mW/cm ² ) Fill factor (FF), short-circuit current (J _SC ), open-circuit voltage (V _OC ) and power conversion efficiency (PCE) were measured under In this case, as a comparative group, comparative pre-polymer solar cells 1 and 2 having all the same configurations as those of the pre-polymer solar cells prepared in Example 3, but having different photoactive layer thicknesses of 100 nm and 300 nm, respectively, were prepared. Thus, the same experiment was performed, which is shown in FIG. 7 and [Table 1] below.

[Table 1]

Referring to [Table 1] and FIG. 7, the comparative pre-polymer solar cell 1 in which the photoactive layer was formed to a thickness of 100 nm in the pre-polymer solar cell (Example 3) according to the present invention in which the photoactive layer was formed to a thickness of 200 nm And compared with the comparative pre-polymer solar cell 2 in which the photoactive layer was formed to a thickness of 300 nm, it can be confirmed that there are significant differences in FF, J _SC , V _OC and PCE.

From the above results, it can be confirmed that in the all-polymer solar cell according to the present invention, the photoactive layer is preferably formed to have a thickness of 200 nm.

Experimental Example 3. Photovoltaic performance of all-polymer solar cells according to the reforming solvent

3.1. Confirmation of the surface shape of the active layer

In order to confirm the surface morphology of the all-polymer solar cell according to the modifying solvent, (a) an atomic force microscope (Atomic Force Microscope) for the photoactive layer of the all-polymer solar cell formed using toluene as a solvent in Example 3 , AFM) were measured. In this case, as a comparative group, all the configurations of the all-polymer solar cell prepared in Example 3 were the same, but (b) 2-methyltetrahydrofuran (2-MeTHF) and (c) cyclopentyl methyl ether (Cyclopentyl methyl ether) , CPME) was used as a solvent to prepare photoactive layers 3 and 4 of a comparative pre-polymer solar cell, and AFM was measured in the same manner, which is shown in FIG. 8 .

8, comparative pre-polymer solar cells 3 and 4 having a photoactive layer formed using (b) 2-methyltetrahydrofuran (2-MeTHF) and (c) cyclopentyl methyl ether (CPME) solvents It can be seen that the root-mean-square (RMS) values of the photoactive layer are 1.49 nm and 1.18 nm, respectively. On the other hand, (a) it can be seen that the surface roughness of the photoactive layer of the pre-polymer solar cell (Example 3) formed using toluene as a solvent according to the present invention has a remarkably low 0.33 nm.

The low surface roughness value (RMS) suggests that it can have excellent miscibility in the film. It can be seen that Mars can be expected.

3.2. Check the charge carrier mobility

In order to confirm the charge carrier mobility of the all-polymer solar cell according to the solvent, (a) the all-polymer solar cell including a photoactive layer formed of toluene as a solvent in Example 3, (b) 2-methyltetrahydro Space-charge-limited currents for comparative pre-polymer solar cells 3 and 4 with photoactive layers formed with furan (2-MeTHF) and (c) cyclopentyl methyl ether (CPME) solvents. , SCLC) method was used to confirm the charge carrier mobility, which is shown in FIG. 9 and [Table 2] below.

[Table 2]

Referring to FIG. 9 and [Table 2], (a) 2.99×10 ^-3 cm ² /V·S holes in the case of an all-polymer solar cell based on the photoactive layer formed using the toluene solvent prepared in Example 3 It has hole mobility (μ _h ) and 2.65×10 ^-3 cm ² /V·S electron mobility (μ _e ), and thus charge carrier mobility (μ _h /μ _e ) is 1.13 It can be confirmed that On the other hand, in the case of comparative pre-polymer solar cells 3 and 4 based on a photoactive layer formed with (b) 2-methyltetrahydrofuran (2-MeTHF) and (c) cyclopentyl methyl ether (CPME) solvents (a ) It has hole mobility and electron mobility with significant differences compared to the photoactive layer-based pre-polymer solar cell formed using the toluene solvent prepared in Example 3, and a more balanced value in charge carrier mobility. can

From the above results, it can be confirmed that the photoactive layer-based all-polymer solar cell formed using toluene as a solvent according to the present invention can increase FF and J _sc by high charge transfer.

3.3. Confirmation of photovoltaic performance of all-polymer solar cells

In order to confirm the photovoltaic performance of the pre-polymer solar cell according to the modifying solvent, (a) a photoactive layer-based pre-polymer solar cell formed using the toluene solvent prepared in Example 3 above, (b) 2-methyltetrahydro Fill factor (FF), short-circuit current ( short-circuit current, J _SC ), open-circuit voltage, V _OC ) and power conversion efficiency (PCE) were checked, and are shown in Table 3 below.

[Table 3]

Referring to [Table 3], the filling factor (Fill Factor, FF), short-circuit current (J _SC ), open-circuit voltage (V _OC ) and power conversion efficiency (PCE) ), it can be seen that the all-polymer solar cell (Example 3) has remarkably excellent performance due to the low surface roughness of the photoactive layer formed using the toluene solvent according to the present invention in all photovoltaic performance parameters. In particular, it can be confirmed that it is most preferable to form a photoactive layer with toluene in the all-polymer solar cell according to the present invention, since it has significantly improved values in the charging rate and power conversion efficiency.

Experimental Example 4. Photovoltaic performance of all-polymer solar cells according to heat treatment temperature

In order to check the photovoltaic performance of the all-polymer solar cell according to the thermal annealing temperature, the fill factor (FF) of the photoactive layer of the all-polymer solar cell prepared in Example 3, which was heat-treated at 120 ° C. (Fill Factor, FF), Short-circuit current (J _SC ), open-circuit voltage (V _OC ) and power conversion efficiency (PCE) were checked. In this case, as a comparative group, comparative pre-polymer solar cells 5 and 6 having all the same configurations as those of the pre-polymer solar cells prepared in Example 3, except that only the heat treatment temperature was performed at 80 ° C and 200 ° C, were prepared and the same The parameters were measured, and are shown in [Table 4] below.

[Table 4]

Referring to [Table 4], the fill factor (FF), short-circuit current (J _SC ), open-circuit voltage (V _OC ) and power conversion efficiency (PCE) ), it can be seen that the all-polymer solar cell (Example 3) subjected to the heat treatment at 120° C. according to the present invention has remarkably excellent performance in all photovoltaic performance parameters. In particular, since it has significantly improved values in short-circuit current, charging rate, and power conversion efficiency, it can be confirmed that heat treatment is most preferably performed at 120° C. for the all-polymer solar cell according to the present invention.

Experimental Example 5. Photovoltaic performance of all-polymer solar cells according to heat treatment time

5.1. Confirmation of molecular packing stability according to heat treatment time

In order to confirm the charge carrier mobility of the pre-polymer solar cell according to the heat treatment time, the photoactive layer of the pre-polymer solar cell prepared in Example 3 was thermally annealed at 120 ° C. for 10 minutes (a) Grazing incidence X-ray diffraction (GIXD) patterns were measured, and (b) a 1D profile graph extracted through this was prepared. In this case, as a comparative group, comparative pre-polymer solar cells 7 and 8 having all the same configurations as those of the pre-polymer solar cells prepared in Example 3, but in which only the heat treatment time was performed for (b) 20 minutes and (c) 30 minutes were used. GIXD was measured in the same way as prepared, and this is shown in FIG. 10 .

Referring to FIG. 10( a ), it is confirmed that the active layer is in the "face-on" direction at all heat treatment times, but broad reflection in the high q region in the out-of-plane direction as the heat treatment time increases. It can be seen that is widened along the arc direction, and as the heat treatment time increases, it can be seen that the regular X-ray diffraction peaks appearing in the in-plane direction are weakened. In addition, referring to FIG. 10(b), high order peaks disappear in the in-plane profile for comparative pre-polymer solar cells 7 and 8 that were thermally annealed for 20 minutes and 30 minutes. This means that the molecular packing deteriorates as the heat treatment time increases. That is, it can be confirmed that the thermal annealing time of the all-polymer solar cell according to the present invention is most preferably 10 minutes.

5.2. Check photovoltaic performance as a function of thermal annealing time

In order to confirm the photovoltaic performance of the all-polymer solar cell according to the thermal annealing time, the all-polymer solar cell (black line) prepared in Example 3, the comparative pre-polymer solar cells 7 and 8, and thermal annealing were performed. The non-comparison pre-polymer solar cell 9 was measured under simulated sunlight illumination (AM 1.5G, 100 mW/cm ² ) and the Fill Factor (FF) and Power Conversion Efficiency (PCE). It is shown in [Table 5] below.

[Table 5]

As can be seen in [Table 5], the charge factor (FF) and power conversion efficiency (Power) of the pre-polymer solar cell (Example 3) according to the present invention subjected to heat treatment at 120 ° C. for 10 minutes It can be seen that the conversion efficiency (PCE) is 7.08% and 11.66%, respectively. It can be confirmed that the above results are significantly different from those of the comparative pre-polymer solar cells 7 to 9.

From the above description, those skilled in the art to which the present invention pertains will be able to understand that the present invention may be implemented in other specific forms without changing the technical spirit or essential characteristics thereof. In this regard, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (7)

Conjugated polymer for all-polymer solar cells (all-PSCs), characterized in that it is represented by the following [Formula 1]:
[Formula 1]

In the above [Formula 1]
Wherein R ₁ is phenyl, tolyl, xylene or naphthyl,
Wherein R ₂ is C, O, N or S,
Wherein R ₃ and R ₄ are each independently hydrogen, halogen, -C _1-20 straight or branched chain alkyl, -C _1-10 alkoxy or -NH ₂
wherein R ₅ is -C _1-20 straight or branched chain alkyl or -C _1-10 alkoxy;
wherein X is F, Cl, Br or I;
and n is 1 to 1,000. A polymer donor comprising a conjugated polymer represented by the following [Formula 1];
A polymer acceptor represented by the following [Formula 2]; and
An active layer composition for all-polymer solar cells (all-PSCs) comprising a 1-phenylnaphthalene additive:
[Formula 1]

[Formula 2]

In [Formula 1] and [Formula 2]
Wherein R ₁ is phenyl, tolyl, xylene or naphthyl,
Wherein R ₂ is C, O, N or S,
Wherein R ₃ and R ₄ are each independently hydrogen, halogen, -C _1-20 straight or branched chain alkyl, -C _1-10 alkoxy or -NH ₂
wherein R ₅ is -C _1-20 straight or branched chain alkyl or -C _1-10 alkoxy;
wherein X is F, Cl, Br or I;
and n is 1 to 1,000. 3. The method of claim 2,
The polymer donor: polymer acceptor ratio is 1: 0.3 to 1.2 (wt: wt) of the active layer composition for an all-polymer solar cell, characterized in that it comprises a ratio. 3. The method of claim 2,
The 1-phenylnaphthalene additive is an active layer composition for a pre-polymer solar cell, characterized in that it is included in a ratio of 0.2 to 0.6% by volume based on the total volume% of the active layer composition for a pre-polymer solar cell. All-polymer solar cells (all-PSCs) comprising a photoactive layer employing the active layer composition for an all-polymer solar cell according to any one of claims 2 to 4. 6. The method of claim 5,
The photoactive layer is an all-polymer solar cell, characterized in that the thickness of 150 to 250 nm. 6. The method of claim 5,
An all-polymer solar cell characterized by low surface roughness of a photoactive layer formed using the non-halogenated solvent, toluene, as a solvent.

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