KR102024826B1 - polymer using photo-active layer of organic solar cell and organic solar cell comprising thereof - Google Patents

Abstract

The present invention relates to a polymer for an organic solar cell photoactive layer.
The polymer for an organic solar cell photoactive layer according to the present invention has an excellent absorption capacity for visible light and has an energy level suitable for use as an electron donor compound in the photoactive layer of an organic solar cell, thereby converting light into an organic solar cell. The efficiency can be increased.

Description

Polymer for organic solar cell photoactive layer and organic solar cell comprising same {polymer using photo-active layer of organic solar cell and organic solar cell comprising

The present invention relates to a polymer for an organic solar cell photoactive layer and an organic solar cell including the same.

More specifically, the present invention is a novel polymer comprising a 1,5-naphthyridine-2,6-dione structure that can be used as an electron donor compound in the photoactive layer of an organic solar cell and excellent light containing the same The present invention relates to an organic solar cell having conversion efficiency.

Organic solar cells have received a lot of attention because of their high applicability in future-oriented fields such as electronic devices, automobiles or smart windows. In the past decades, much research has been focused on developing new polymers and device structures in order to increase the light conversion efficiency of organic solar cells.

However, the number of polymer polymers that can exhibit high-performance organic solar cell performance is limited to a few species, and in particular, since the unit material constituting the polymer polymer is limited to a few kinds of conventionally known high-performance monomers, Had a limit.

In order to achieve high performance light conversion efficiency in an organic solar cell for a solution process, the use of a polymer having good properties is essential.

More specifically, there is a need for the development of polymer polymers that have large light absorption in the solar spectrum without crystals and aggregation, and have high charge mobility, proper molecular orientation and good film morphology.

The performance of these polymers varies greatly depending on the choice of electron donor type or electron acceptor type repeating unit materials used in polymer polymerization. Therefore, polymer polymers for high performance organic solar cells using novel repeating unit materials are used. Development is needed.

The present invention provides a new polymer and a high efficiency organic solar cell using the same.

Specifically, the present invention relates to a polymer for an organic solar cell photoactive layer having excellent light absorption in the visible light region.

The present invention also relates to a polymer for an organic solar cell photoactive layer having excellent crystallinity, high charge mobility, and having an energy level suitable for use as an electron donor compound in the photoactive layer of an organic solar cell.

The present invention also relates to an organic solar cell including the polymer in a photoactive layer and to an organic solar cell having excellent light conversion efficiency.

The present invention has been made to solve the above problems, and relates to a polymer for an organic solar cell photoactive layer represented by the following chemical structural formula (1).

[Chemical Structural Formula 1]

In Chemical Formula 1,

X ₅ , X ₆ , X ₇ and X ₈ are each independently O, S, Se, NH, or NR ″,

R ₅ and R ₆ are each independently carbon number 1 To 50 An alkyl group, an aryl group having 6 to 50 carbon atoms, or-(CH ₂ CH ₂ O) _m CH ₃ ,

A ₅ , A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ , A ₁₁ , A ₁₂ , A ₁₃ , A ₁₄ , A ₁₅ and A ₁₆ are each independently H, F, Cl, CN, -COOR ", -OR", 1 carbon To 50 An alkyl group or an aryl group having 6 to 50 carbon atoms,

Each R ″ is independently an alkyl group having 1 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, or — (CH ₂ CH ₂ O) _m CH ₃ ,

M is an integer of 1 to 20,

N is an integer of 1 to 1,000.

In one example, the _{R 5, R 6, A 5} , A 6, A 7, A 8 , and R "may be aryl date having 1 to 26 alkyl or C 6 -C 32 of each independently.

In one example, R ₅ and R ₆ may be each independently an alkyl group having 5 to 14 carbon atoms.

In one example, A ₅ , A ₆ , A ₇ and A ₈ may be each independently an alkyl group having 9 to 22 carbon atoms.

In one example, any two species of A ₁₁ , A ₁₂ , A _13, and A ₁₄ may be substituted at an ortho- or para- position with each other, and each may be independently F or Cl.

In one example, the polymer may have an absorption coefficient at a maximum absorption wavelength within a wavelength of 300 nm to 1,000 nm of 1.5 × 10 ⁵ cm ^{−1 or} more.

In one example, the polymer may have a Crystalline coherence length (CCL) in the range of 18 kV to 30 kV.

The present invention also relates to an organic solar cell including the polymer as described above. The organic solar cell includes a first electrode and a second electrode disposed to face each other, and includes a photoactive layer positioned between the first and second electrodes, wherein the photoactive layer is represented by Chemical Formula 1 below. It is characterized by including a polymer.

[Chemical Structural Formula 1]

In Chemical Formula 1,

X ₅ , X ₆ , X ₇ and X ₈ are each independently O, S, Se, NH, or NR ″,

R ₅ and R ₆ are each independently carbon number 1 To 50 An alkyl group, an aryl group having 6 to 50 carbon atoms, or-(CH ₂ CH ₂ O) _m CH ₃ ,

A ₅ , A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ , A ₁₁ , A ₁₂ , A ₁₃ , A ₁₄ , A ₁₅ and A ₁₆ are each independently H, F, Cl, CN, -COOR ", -OR", 1 carbon To 50 An alkyl group or an aryl group having 6 to 50 carbon atoms,

Each R ″ is independently an alkyl group having 1 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, or — (CH ₂ CH ₂ O) _m CH ₃ ,

M is an integer of 1 to 20,

N is an integer of 1 to 1,000.

In one example, the first electrode of the organic solar cell is a transparent electrode, the second electrode is a metal electrode, the organic solar cell is located on the opposite side of the surface where the photoactive layer of the first electrode is present. It may further include a substrate.

In one example, the photoactive layer may be a bulk-heterojunctionlayer further comprising an electron acceptor compound.

In one example, the electron acceptor compound may be a fullerene, a fullerene derivative, a non-fullerene organic compound, a carbon nanotube, a carbon nanotube derivative, vasocuproin, a semiconducting element, a semiconducting compound, or a combination thereof. It may be any one selected from the group consisting of.

The organic solar cell may have a light conversion efficiency (%) of 9% or more.

The present invention can provide a polymer for an organic solar cell photoactive layer having excellent light absorption in the visible light region.

In addition, the present invention can provide a polymer for an organic solar cell photoactive layer having excellent crystallinity, high charge mobility, and having an energy level suitable for use as an electron donor compound in the photoactive layer of an organic solar cell. have.

The present invention also relates to an organic solar cell including the polymer in a photoactive layer, and can provide an organic solar cell having excellent light conversion efficiency.

Of course, the scope of the present invention is not limited by these effects.

1 is a schematic diagram of one structure of an organic solar cell according to the present invention.
2 and 3 show the results of measurement of the extinction coefficient according to the absorption wavelength of the photoactive layer polymer according to Preparation Examples 1 and 2 of the present invention.
4 and 5 show the results of cyclic voltammetry analysis for measuring the energy level of the photoactive layer polymer according to Preparation Examples 1 and 2 of the present invention.
6 and 7 illustrate Atomic force microscopy (AFM) images of organic photovoltaic cell photoactive layers according to Examples 1 and 2 of the present invention.
8 and 9 illustrate hole and electron mobility measurement results using space charge limited current (SCLC) of organic solar cells according to Examples 1 and 2 of the present invention.
10 and 11 show the results of the current density (J) -voltage (V) graph of the organic solar cell according to Examples 1 and 2 of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings and examples.

In this specification, the singular forms “a”, “an” and “the” include plural forms unless the context clearly dictates otherwise.

The polymer according to the present invention is included in the photoactive layer of the organic solar cell, and serves as an electron donor compound.

That is, the present invention relates to a polymer for an organic solar cell photoactive layer represented by Chemical Formula 1.

[Chemical Structural Formula 1]

In Chemical Formula 1,

X ₅ , X ₆ , X ₇ and X ₈ are each independently O, S, Se, NH, or NR ″,

R ₅ and R ₆ are each independently carbon number 1 To 50 An alkyl group, an aryl group having 6 to 50 carbon atoms, or-(CH ₂ CH ₂ O) _m CH ₃ ,

A ₅ , A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ , A ₁₁ , A ₁₂ , A ₁₃ , A ₁₄ , A ₁₅ and A ₁₆ are each independently H, F, Cl, CN, -COOR ", -OR", 1 carbon To 50 An alkyl group or an aryl group having 6 to 50 carbon atoms,

Each R ″ is independently an alkyl group having 1 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, or — (CH ₂ CH ₂ O) _m CH ₃ ,

M is an integer of 1 to 20,

N is an integer of 1 to 1,000.

As shown in Chemical Formula 1, the polymer according to the present invention is a novel polymer compound including a 1,5-naphthyridine-2,6-dione structure, and has excellent light absorption rate to sunlight through the chemical structure as described above. Have In addition, it has excellent crystallinity, high charge mobility, and has an appropriate energy level as an electron donor compound. Therefore, when the polymer is used as an electron donor compound in an organic solar cell photoactive layer, an organic solar cell having a high short circuit current, a fill factor, and an excellent light conversion efficiency can be manufactured.

X ₅ , X ₆ , X ₇ and X ₈ are each independently O, S, Se, NH, or NR ″, and R ″ may be an alkyl group having 1 to 50 carbon atoms or an aryl group having 6 to 50 carbon atoms.

In more specific examples, X ₅ , X ₆ , X ₇ and X ₈ may each independently be O or S.

In addition, R ₅ and R ₆ are each independently carbon number 1 To 50 An alkyl group, an aryl group having 6 to 50 carbon atoms, or-(CH ₂ CH ₂ O) _m CH ₃ , wherein each R ″ is independently an alkyl group having 1 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, or-(CH ₂ CH) ₂ O) _m CH ₃ It may be.

In one example, each of R ₅ , R ₆ and R ″ are independently 1 carbon atoms To 46 Alkyl group, 1 carbon To 42 Alkyl group, 1 carbon To 38 Alkyl group, 1 carbon To 34 Alkyl group, 1 carbon To 30 Alkyl group, 1 carbon To 26 Alkyl or C1 To 22 An alkyl group, an aryl group having 6 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, an aryl group having 6 to 44 carbon atoms, an aryl group having 6 to 38 carbon atoms , An aryl group having 6 to 32 carbon atoms, an aryl group having 6 to 26 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

In a specific example, each of R ₅ , R ₆ and R ″ may be independently an alkyl group having 1 to 26 carbon atoms or an aryl group having 6 to 32 carbon atoms.

In addition, the A ₅ , A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ , A ₁₁ , A ₁₂ , A ₁₃ , A ₁₄ , A ₁₅ and A ₁₆ are each independently H, F, Cl, CN, -COOR ", -OR", 1 carbon To 50 It may be an alkyl group or an aryl group having 6 to 50 carbon atoms.

In one example, A ₅ , A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ , A ₁₁ , A ₁₂ , A ₁₃ , A ₁₄ , A _15, and A ₁₆ are each independently carbon number 1 To 46 Alkyl group, 1 carbon To 42 Alkyl group, 1 carbon To 38 Alkyl group, 1 carbon To 34 Alkyl group, 1 carbon To 30 Alkyl group, 1 carbon To 26 Alkyl or C1 To 22 An alkyl group, an aryl group having 6 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, an aryl group having 6 to 44 carbon atoms, an aryl group having 6 to 38 carbon atoms , An aryl group having 6 to 32 carbon atoms, an aryl group having 6 to 26 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

In a specific example, A ₅ , A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ , A ₁₁ , A ₁₂ , A ₁₃ , A ₁₄ , A ₁₅ and A ₁₆ each independently represent an alkyl group having 1 to 26 carbon atoms. Or an aryl group having 6 to 32 carbon atoms.

On the other hand, R ₅ , R ₆ , A ₅ , A ₆ , A ₇ and A ₈ is a configuration that can determine the physical properties such as hydrophilicity or hydrophobicity of the polymer according to the present invention, it is preferable to have a suitable carbon number.

In a more specific example, R ₅ and R ₆ may each independently be an alkyl group having 5 to 14 carbon atoms. In addition, A ₅ , A ₆ , A ₇ and A ₈ may be each independently an alkyl group having 9 to 22 carbon atoms. Within the range as described above, it can be applied to the physical properties and the photoactive layer of the desired polymer to increase the light conversion efficiency of the organic solar cell.

Meanwhile, in one example, any two species of A ₁₁ , A ₁₂ , A _13, and A ₁₄ may be substituted at an ortho- or para- position with each other, and each may be independently F or Cl. . Preferably, any one of A ₁₁ , A ₁₂ , A _13, and A ₁₄ may be F substituted at a para- position.

M is an integer of 1 to 20. In more specific examples, m may be an integer of 1 to 16, 1 to 14, 1 to 12, or 1 to 10.

N is an integer of 1 to 1,000. In more specific examples, n may be an integer of 1 to 800, 1 to 700, 1 to 600 or 1 to 500.

Such polymers exhibit excellent light absorption to visible light.

In one example, the polymer may have an absorption coefficient at a maximum absorption wavelength within a wavelength of 300 nm to 1,000 nm of 1.5 × 10 ⁵ cm ⁻¹ or more. In another example, the polymer is 380nm to an absorption coefficient at a wavelength within the maximum absorption wavelength of 1.5 x 10 ⁵ cm ^-1 at least 1,000nm, 1.5 x 10 ⁵ cm ^-1 or more, 2 x 10 ⁵ cm ^-1 or more, 2.5 x 10 ⁵ cm ⁻¹ or more, 3 × 10 ⁵ cm ⁻¹ or more, 3.5 × 10 ⁵ cm ⁻¹ or more, 4 × 10 ⁵ cm ⁻¹ or more, or 4.5 × 10 ⁵ cm ⁻¹ or more. The upper limit of the absorption coefficient at the maximum absorption wavelength within the wavelength of 380 nm to 1,000 nm may be, for example, 5.0 × 10 ⁵ cm ⁻¹ or less.

The polymer of the present invention is included in the photoactive layer in the organic solar cell and serves as an electron donor compound. Thus, the polymer may have an appropriate energy level.

In one example, the polymer may have a HOMO energy level in the range of -5.0 eV to -5.6 eV, and an LUMO energy level in the range of -3.4 eV to -4.0 eV. In the case of using a polymer having an energy level within the above range, easy exciton separation and charge transfer can be made in the photoactive layer.

The polymer may be prepared, for example, from a 6-methoxy-1,5-naphthyridine-2,6-dione compound represented by the following formula (1).

[Formula 1]

More specifically, the polymer of the present invention may be prepared through a stille coupling reaction of the 6-methoxy-1,5-naphthyridin-2 (1H) -one compound represented by Chemical Formula 1, but is not limited thereto. It is not.

On the other hand, the polymer of the present invention is 1,5-naphthyridine-2,6-dione unsubstituted methoxy group which can be prepared from 6-methoxy-1,5-naphthyridin-2 (1H) -one It may also be prepared through.

The present invention also relates to an organic solar cell comprising the polymer. The organic solar cell has a high short circuit current, a fill factor and excellent light conversion efficiency.

The organic solar cell of the present invention includes a first electrode and a second electrode disposed to face each other, the organic solar cell comprising a photoactive layer positioned between the first and second electrodes, wherein the photoactive layer is It is characterized in that it comprises a polymer represented by the chemical formula 1.

[Chemical Structural Formula 1]

In Chemical Formula 1,

X ₅ , X ₆ , X ₇ and X ₈ are each independently O, S, Se, NH, or NR ″,

R ₅ and R ₆ are each independently carbon number 1 To 50 An alkyl group, an aryl group having 6 to 50 carbon atoms, or-(CH ₂ CH ₂ O) _m CH ₃ ,

A ₅ , A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ , A ₁₁ , A ₁₂ , A ₁₃ , A ₁₄ , A ₁₅ and A ₁₆ are each independently H, F, Cl, CN, -COOR ", -OR", 1 carbon To 50 An alkyl group or an aryl group having 6 to 50 carbon atoms,

Each R ″ is independently an alkyl group having 1 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, or — (CH ₂ CH ₂ O) _m CH ₃ ,

M is an integer of 1 to 20,

N is an integer of 1 to 1,000.

The organic solar cell of the present invention may include a polymer represented by Chemical Formula 1 as an electron donor compound in the photoactive layer, and thus may have a high short circuit current, a fill factor, and an excellent light conversion efficiency. .

In particular, the energy level may be adjusted by introducing a benzene ring in Chemical Formula 1. Specifically, when the benzene ring is introduced, the band gap becomes larger because the HOMO level is lower and the LUMO level is higher. That is, due to the deeper HOMO level, the voltage value Voc of the solar cell device is increased.

In addition, an element having a high electronegativity, for example, an element such as fluorine (F) may be substituted with the benzene ring to be introduced. As a result, the HOMO level and the LUMO level may be further lowered, and the voltage value Voc of the solar cell device may be further increased. In addition, the introduction of fluorine may cause intra-molecular interaction of elemental sulfur and fluorine-sulfur molecules of adjacent thiophenes, thereby increasing co-planarity. Accordingly, pi-pi interaction between the polymer backbones can be enhanced.

Since fluorine is the element with the highest electronegativity, it can form a strong dipole. Strong dipoles can form dipole-dipole interactions and further enhance the attraction between the polymer backbones. The enhanced attraction between the polymer main chains can increase the hole mobility of the polymer, and even if the thickness of the photoactive layer becomes thick due to the increased hole mobility, effective hole movement is possible. Therefore, due to the thicker photoactive layer thickness, the maximum light absorption can be achieved, thereby improving the efficiency of the organic solar cell to a level of 10%.

In addition, according to one embodiment of the present invention, the polymer for an organic solar cell photoactive layer represented by Chemical Structural Formula 1 may have a crystal coherence length (CCL) of about 18 kV to about 30 kPa. The smaller the crystalline coherence length (CCL), the wider the interface and the greater the current generated at the interface. That is, there is an effect of improving the efficiency of the organic solar cell.

1 is a schematic diagram of a structure of an organic solar cell according to the present invention.

As shown in FIG. 1, the organic solar cell 1 according to the present invention includes a first electrode 100 and a second electrode 200 disposed to face each other, and the first and second electrodes ( And a photoactive layer 300 positioned between 100 and 200. In addition, the photoactive layer 300 is characterized in that it comprises a polymer represented by the chemical formula (1).

The first electrode according to the present invention, for example, as shown in Figure 1, may be located in the incident sunlight direction, the second electrode is farther in the sunlight direction relatively incident than the first electrode. It can be located on the side.

In one example, the first electrode can be a transparent electrode. The first electrode may be, for example, a metal such as vanadium, chromium, copper, zinc, or gold or an alloy thereof; Metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO) or indium zinc oxide (IZO); Combinations of metals and oxides such as ZnO: Al or SnO ₂ : Sb; Conductive polymers such as PEDOT: PSS, polypyrrole or polyaniline may be exemplified, but is not limited thereto.

The first electrode may include, for example, a two-layer structure in which the above-described materials are formed in respective layers.

In a specific example, the first electrode may be made of an ITO layer and a PEDOT: PSS conductive polymer layer sequentially in the direction of incident sunlight.

The first electrode may also have a transmittance of 80% or more for light having a wavelength of 300 nm to 700 nm. Thus, a transparent material and a material having excellent conductivity may be used as the first electrode.

The method of forming the first electrode is not particularly limited, but known wet and dry coating methods such as sputtering, E-beam, thermal evaporation, spin coating, screen printing, inkjet printing, doctor bleed or gravure printing, can be used without limitation. Can be.

The first electrode may be formed, for example, on a substrate. That is, as shown in FIG. 1, the organic solar cell 1 according to the present invention may further include a substrate 400.

That is, the organic solar cell according to the present invention may further include a substrate positioned on a surface opposite to a surface on which the photoactive layer of the first electrode is present.

The substrate may be appropriately selected in consideration of transparency, surface smoothness, ease of handling and waterproofness.

In one example, the substrate may be a glass substrate or a transparent plastic substrate, for example, the plastic substrate, for example polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP), poly Mead (PI) or triacetyl cellulose (TAC) and the like can be exemplified, but is not limited thereto.

The organic solar cell of the present invention includes a second electrode disposed to face the first electrode. The second electrode may be, for example, a metal electrode.

The metal electrode may be, for example, a metal such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin and lead, or an alloy thereof, or LiF / Al, LiO ₂ / Al. , LiF / Fe, Al: Li, Al; BaF ₂ or Al: BaF ₂ may include a material having a multi-layer structure such as, but is not limited thereto.

In a specific example, the second electrode may be a multi-layered structure in which the above-described materials are individually present in each.

The second electrode may be formed by depositing, for example, by thermal deposition.

The organic solar cell of the present invention includes a photoactive layer positioned between the first electrode and the second electrode. The photoactive layer includes a polymer represented by Chemical Formula 1. The polymer represented by Chemical Structural Formula 1 serves as an electron donor compound.

Meanwhile, the photoactive layer according to the present invention may have a bulk double junction structure.

Specifically, the photoactive layer may be a bulk-heterojunction layer further comprising an electron-accepter compound.

The electron acceptor compound may be, for example, a fullerene, a fullerene derivative, a nonfullerene organic compound, a carbon nanotube, a carbon nanotube derivative, vasocuproin, a semiconducting element, a semiconducting compound, or a combination thereof. It may be any one selected from the group consisting of.

In a more specific example, the electron acceptor compound may include PCBM, PC ₇₁ BM, PCBCR, etc. as a fullerene derivative, and perylene, PBI, PTCBI, ITIC, IT-M, IT-4F, IT-OM, MeIC, ITCC, IDTBR, ATT-1 and the like can be exemplified, but is not limited thereto.

The photoactive layer may be formed, for example, by a wet coating process of a mixed solution including a polymer represented by Chemical Formula 1 and an electron acceptor compound. When the photoactive layer is manufactured through the above process, the polymer represented by Chemical Structural Formula 1, which serves as an electron donor compound, and the aforementioned electron acceptor compound are randomly selected from each other in the photoactive layer. It is possible to form a mixed bulk double junction state.

The polymer and the electron acceptor compound represented by Chemical Formula 1 may be included in the photoactive layer, for example, in a ratio (w / w) of 1:10 to 10: 1.

The organic solar cell of the present invention is represented by Chemical Formula 1 in the photoactive layer, and may include a polymer having high planarity and excellent crystallinity, thereby having excellent hole mobility.

In one example, the organic solar cell is 1 x 10 ^-4 cm ² V ^-1 s ^-1 or more, 5 x 10 ^-4 cm ² V ^-1 s ^-1 or more, 1 x 10 ^-3 cm ² V ^-1 s ^-1 or ^{more, 5 x 10 -3 cm 2 V} -1 s -1 can have more, or ^{1 x 10 -2 cm 2 V -1} s -1 or more mobility of holes (hole mobility). The upper limit of the hole mobility may be, for example, 5 × 10 ⁻² cm ² V ⁻¹ s ⁻¹ or less.

The organic solar cell according to the present invention may have an excellent light conversion efficiency by including the polymer represented by Chemical Structural Formula 1 as an electron donor compound in the photoactive layer.

In one example, the organic solar cell of the present invention may have a light conversion efficiency (%) of 9% or more. In another example, the organic solar cell may have a light conversion efficiency (%) of 9.5% or more or 10% or more.

Hereinafter, the preparation of a novel polymer compound according to the present invention and an organic solar cell including the same will be described in more detail with reference to Examples. However, the following examples are merely examples according to the present invention and limit the technical spirit of the present invention. It is obvious to those of ordinary skill in the art.

Preparation Example 1 Synthesis of New Polymer Containing 1,5-naphthyridine-2,6-dione Structure [P (NTD4T-o-2FB)]

Synthesis was carried out according to Synthesis Mechanism 1 below, and finally a new polymer (P (NTD4T-o-2FB)) serving as an electron donor compound in the organic solar cell photoactive layer was synthesized.

Synthesis Mechanism 1

Detailed synthesis method

Synthesis of 6-methoxy-1-octyl-1,5-naphthyridin-2 (1H) -one (6-methoxy-1-octyl-1,5-naphthyridin-2 (1H) -one) (1)

6-methoxy-1,5-naphthyridin-2 (1H) -one (6-methoxy-1,5-naphthyridin-2 (1H) -one, 16 g, 90.8 mmol), 1-bromooctane (1 -bromooctane, 30 g, 154 mmol) and cesium carbonate (50 g, 154 mmol) are dissolved in 100 mL of dimethyl sulfoxide (DMSO) solvent and stirred at 60 ° C for 24 hours. The temperature is lowered to room temperature and the solvent is removed in vacuo. Then, the silica gel column is purified to obtain an ocher powder. (7.8 g, yield = 30%)

1-octyl-1,5-dihydro-1,5-naphthyridine-2,6-dione (1-octyl-1,5-dihydro-1,5-naphthyridine-2,6-dione) (2) Synthesis of

Material (1) (7.8 g, 27 mmol) is dissolved in 48% aqueous HBr solution (60 mL) and stirred at 80 ° C. for 4 hours. After the temperature is lowered to room temperature, the precipitate is filtered with washing with water and dried under vacuum to obtain a yellow powder. (7 g, yield = 95%)

1,5-dioctyl-1,5-dihydro-1,5naphthyridine-2,6-dione (1,5-dioctyl-1,5-dihydro-1,5-naphthyridine-2,6-dione Synthesis of 3

Substance (2) (3.5 g, 12.7 mmol), 1-bromooctane (1-bromooctane, 7.4 g, 38 mmol) and cesium carbonate (6.2 g, 19 mmol) were added to 50 mL of toluene. Dissolve and stir at 120 ° C. for 24 hours. After the temperature is lowered to room temperature, the solvent is removed in vacuo and purified by silica gel column to obtain a yellow powder. (2 g, yield = 40%)

3,7-dibromo-1,5-dioctyl-1,5-dihydro-1,5-naphthyridine-2,6-dione (3,7-dibromo-1,5-dioctyl-1, Synthesis of 5-dihydro-1,5-naphthyridine-2,6-dione) (4)

Substance (3) (2 g, 5.1 mmol) and N-bromosuccinimide (2.5 g, 14.3 mmol) are dissolved in acetic acid (AA) (50 mL) and stirred at 90 ° C. for 24 hours. . After the temperature was lowered to room temperature, the solvent was removed in vacuo, and a silica gel column (MC: MeOH = 99: 1, v / v) gave a yellow powder. (1.7 g, yield = 60%)

3,7-bis (4- (2-decyltetedecyl) thiophen-2-yl) -1,5-dioctyl-1,5-dihydro-1,5-naphthyridine-2,6-dione Synthesis of (3,7-bis (4- (2-dectyltetradecyl) thiophen-2-yl) -1,5-dioctyl-1,5-dihydro-1,5-naphthyridine-2,6-dione) (2006.01)

Substance (4) (0.2 g, 0.36 mmol), tributyl (4- (2-octyldodecyl) thiophen-2-yl) stannan (tributyl (4- (2-octyldodecyl) thiophen-2-yl) stannane ), 0.75 g, 1.10 mmol) and Pd (PPh ₃ ) ₄ (0.025 g, 0.02 mmol) are dissolved in 15 mL of dimethyl formaldehyde (DMF) and stirred at 130 ° C. for 24 hours. After the temperature is lowered to room temperature, the orange powder is washed with methanol (MeOH) to obtain a filter. Purification by silica gel column yields an orange powder. (0.30 g, yield = 75%)

3,7-bis (5-bromo-4- (2-decyltetradecyl) thiophen-2-yl) -1,5-dioctyl-1,5-dihydro-1,5-naphthyridine-2 , 6-dione (3,7-bis (5-bromo-4- (2-dectyltetradecyl) thiophen-2-yl) -1,5-dioctyl-1,5-dihydro-1,5-naphthyridine-2, Synthesis of 6-dione) (6)

Substance (5) (0.30 g, 0.27 mmol) and N-bromosuccinimide (N-bromosuccinimide; 0.09 g, 0.54 mmol) are dissolved in 30 mL of CHCl ₃ and stirred at room temperature for 24 hours. Silica gel column (MC: MeOH = 99: 1, v / v) gives a red powder. (0.27 g, yield = 68%)

Synthesis of Polymer P (NTD4T-o-2FB)

Polymer P (NTD4T-o-2FB) polymerizes via a Stille coupling reaction.

Substance (6) (0.124 g, 0.09 mmol) and [(2,3'-difluoro-1,4-phenylene) bis (thiophen-5,2-diyl)] bis (trimethylstanna) [ Dissolve ((2,3'-difluoro-1,4-phenylene) bis (thiophene-5,2-diyl)) bis (trimethylstannane)] (0.054 g, 0.09 mmol) in 3 mL of toluene and carry out nitrogen substitution. Thereafter, P (o-tol) ₃ (0.0025 g, 0.0083 mmol) and Pd ₂ (dba) ₃ (0.0019 g, 0.0021 mmol) were added as a catalyst and stirred at 100 ° C. for 48 hours. After the temperature was lowered to room temperature, the reaction solution was slowly precipitated in 300 mL of methanol (MeOH), and the resulting solid was filtered. The filtered solid is purified in the order of methanol, acetone, n-hexane and CHCl ₃ by soxhlet extraction. The down liquid is precipitated in methanol again, filtered through a filter, and dried to obtain a black solid P (NTD4T-o-2FB). (0.121 g, yield = 90%)

Preparation Example 2 Synthesis of New Polymer Containing 1,5-naphthyridine-2,6-dione Structure [P (NTD4T-p-2FB)]

Synthesis was carried out according to Synthesis Mechanism 2 below, and finally a new polymer (P (NTD4T-p-2FB)) serving as an electron donor compound in the organic solar cell photoactive layer was synthesized.

Synthesis Mechanism 2

Detailed synthesis method

Of "Production Example 1. Synthesis of novel polymer including 1,5-naphthyridine-2,6-dione structure [P (NTD4T-o-2FB)]" In the detailed synthesis method, the materials (1) to (6) are synthesized in the same manner to finally obtain a red powder of the material (6). (0.27 g, yield = 68%)

Synthesis of Polymer P (NTD4T-p-2FB)

Polymer P (NTD4T-p-2FB) polymerizes via a Stille coupling reaction.

Substance (6) (0.124 g, 0.09 mmol) and [(2,5'-difluoro-1,4-phenylene) bis (thiophen-5,2-diyl)] bis (trimethylstanna) [ ((2,5'-difluoro-1,4-phenylene) bis (thiophene-5,2-diyl)) bis (trimethylstannane)] (0.054 g, 0.09 mmol) is dissolved in 3 mL of toluene and subjected to nitrogen substitution. Thereafter, P (o-tol) ₃ (0.0025 g, 0.0083 mmol) and Pd ₂ (dba) ₃ (0.0019 g, 0.0021 mmol) were added as a catalyst and stirred at 100 ° C. for 48 hours. After the temperature was lowered to room temperature, the reaction solution was slowly precipitated in 300 mL of methanol (MeOH), and the resulting solid was filtered. The filtered solid is purified in the order of methanol, acetone, n-hexane and CHCl ₃ by soxhlet extraction. The down liquid is precipitated again in methanol, filtered through a filter, and dried to give a black solid P (NTD4T-p-2FB). (0.125 g, yield = 93%)

Table 1 below summarizes novel polymers including the 1,5-naphthyridine-2,6-dione structure prepared according to Preparation Examples 1 and 2.

TABLE 1

Example Fabrication and Characterization of Organic Solar Cell

Preparation of Mixed Solution for Photoactive Layer

As polymers [P (NTD4T-o-2FB), P (NTD4T-p-2FB)] and acceptor materials according to Preparation Examples 1 and 2, PC ₇₁ BM was 1: 1.5 (w / w, 18 mg / mL in total). Mixed solution was prepared by mixing at the ratio of.

Fabrication of Organic Solar Cell

The solar cell device was manufactured in the structure of ITO / PEDOT: PSS / photoactive layer (PNTDT-2F2T: PC ₇₁ BM) / Ca / Al. First, the glass substrate on which the patterned ITO is formed is washed with distilled water, acetone, and isopropanol and subjected to UV-zone treatment for 20 minutes. Then, spin-coated a PEDOT: PSS conductive polymer solution to a thickness of 30nm to 40nm and remove water at 150 ° C for 20 minutes. Thereafter, the mixed solution is spin coated at a speed of 1500 rpm for 60 seconds and left at room temperature for 1 hour. Finally, Ca 5 nm and Al 100 nm electrodes are deposited one after the other. An organic solar cell prepared from a mixed solution including Preparation Examples 1 and 2 is defined as Examples 1 and 2, respectively.

Experimental Example 1. Measurement of extinction coefficient

The extinction coefficient of the polymer P (NTD4T-o-2FB) according to Preparation Example 1 was measured in a wavelength range of 300 nm to 1,000 nm, and the results are shown in FIG. 2.

As shown in Figure 2, it can be seen that the polymer P (NTD4T-o-2FB) according to Preparation Example 1 of the present invention has an absorption coefficient of 1.76 x 10 ⁵ cm ^-1 at a maximum absorption wavelength of 676 nm.

And the absorption coefficient of the polymer P (NTD4T-p-2FB) according to Preparation Example 2 was measured in the wavelength range of 300nm to 1,000nm, the results are shown in FIG.

As shown in Figure 3, it can be seen that the polymer P (NTD4T-p-2FB) according to Preparation Example 2 of the present invention has an absorption coefficient of 2.00 x 10 ⁵ cm ^-1 at 671 nm, which is the maximum absorption wavelength.

Experimental Example 2 Cyclic Voltammetry Analysis Results

Cyclic Voltammetry (CV) analysis was performed to measure the energy level of the polymer P (NTD4T-o-2FB) according to Preparation Example 1 (shown in FIG. 4), and the HOMO energy level and LUMO energy level of the polymer obtained therefrom. Is shown in [Table 2]. At this time, the optical band gap energy (eV) is 1.72 eV.

Then, CV (Cyclic Voltammetry) analysis was performed to measure the energy level of the polymer P (NTD4T-p-2FB) according to Preparation Example 2 (shown in FIG. 5), and the HOMO energy level and LUMO of the polymer obtained therefrom. Energy levels are listed in Table 2. At this time, the optical band gap energy (eV) is 1.67 eV.

TABLE 2

Experimental Example 3. Surface Morphology Analysis

In order to analyze the surface morphology of the organic solar cell photoactive layer according to Example 1, AFM images were measured and the results are shown in FIG. 6.

As shown in FIG. 6, a needle-like polymer crystal having a distinct needle shape in the photoactive layer may be identified.

In addition, in order to analyze the surface morphology of the organic solar cell photoactive layer according to Example 2, an AFM image was measured and the results are shown in FIG. 7.

As illustrated in FIG. 7, a needle-like polymer crystal having a distinct needle shape in the photoactive layer may be identified.

Experimental Example 4. Hole mobility analysis

The mobility using the space charge limited current (SCLC) of the organic solar cell according to Example 1 was measured, and the results are shown in FIG. 8. Hole mobility and electron mobility of the organic solar cell thus obtained are shown in Table 3 below.

As shown in FIG. 8, the hole mobility (shown in FIG. 8A) of the photoactive layer in the organic solar cell according to the present invention is 1.71 × 10 ⁻³ cm ² V ⁻¹ s ⁻¹ Electron mobility (shown in FIG. 8 (b)) is 3.71 × 10 ⁻³ cm ² V ⁻¹ s ⁻¹ , indicating that it has excellent hole mobility and electron mobility. .

In addition, the mobility using the space charge limited current (SCLC) of the organic solar cell according to Example 2 was measured, and the results are shown in FIG. 9. Hole mobility and electron mobility of the organic solar cell thus obtained are shown in Table 3 below.

As shown in FIG. 9, the hole mobility (shown in FIG. 9A) of the photoactive layer in the organic solar cell according to the present invention is 2.92 × 10 ⁻³ cm ² V ⁻¹ s ⁻¹ Electron mobility (shown in FIG. 9 (b)) is 2.09 × 10 ⁻³ cm ² V ⁻¹ s ⁻¹ , indicating that it has excellent hole mobility and electron mobility. .

TABLE 3

Experimental Example 5. Performance Evaluation of Organic Solar Cell

The current density-voltage characteristic (J-V) of the organic solar cell according to Example 1 was measured and shown in FIG. 10, and the efficiency thereof is shown in Table 4 below.

In addition, the current density-voltage characteristics (J-V) of the organic solar cell according to Example 2 were measured and shown in FIG. 11, and the efficiency thereof is shown in Table 4 below.

TABLE 4

Experimental Example 6. Grazing-Incidence Wide-Angle X-ray scattering (GIWAXS) analysis

Hereinafter, referring to FIG. 12, Grazing-Incidence Wide-Angle X-ray scattering (GIWAXS) of the polymer according to Examples 1 and 2 and the polymer represented by the following [Chemical Structural Formula 2] (hereinafter, Comparative Example 1) film ) The results of the analysis are described. Examples 1 and 2 and Comparative Example 1 has a difference in the presence or absence of a benzene ring substituted with fluorine (F) in the polymer unit chain.

[Chemical Structural Formula 2]

Claims (12)

It is represented by the following chemical structural formula 1,
Any one of the following A ₁₁ , A ₁₂ , A ₁₃ and A ₁₄ is independently F or Cl, and the polymer for an organic solar cell photoactive layer substituted at an ortho- or para- position with each other:
[Chemical Structural Formula 1]

In Chemical Formula 1,
X ₅ , X ₆ , X ₇ and X ₈ are each independently O, S, Se, NH, or NR ″,
R ₅ and R ₆ are each independently carbon number 1 To 50 An alkyl group, an aryl group having 6 to 50 carbon atoms, or-(CH ₂ CH ₂ O) _m CH ₃ ,
A ₅ , A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ , A ₁₁ , A ₁₂ , A ₁₃ , A ₁₄ , A ₁₅ and A ₁₆ are each independently H, F, Cl, CN, -COOR ", -OR", 1 carbon To 50 An alkyl group or an aryl group having 6 to 50 carbon atoms,
Each R ″ is independently an alkyl group having 1 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms, or — (CH ₂ CH ₂ O) _m CH ₃ ,
M is an integer of 1 to 20,
N is an integer of 1 to 1,000. The method of claim 1,
The R ₅ , R _6, A ₅ , A ₆ , A ₇ , A ₈ and R ″ are each independently an alkyl group having 1 to 26 carbon atoms or an aryl group having 6 to 32 carbon atoms, the polymer for an organic solar cell photoactive layer. The method of claim 1,
The R ₅ and R ₆ are each independently an alkyl group having 5 to 14 carbon atoms, the polymer for an organic solar cell photoactive layer. The method of claim 1,
The A ₅ , A ₆ , A ₇ and A ₈ are each independently an alkyl group having 9 to 22 carbon atoms, the polymer for an organic solar cell photoactive layer. delete The method of claim 1,
A polymer for an organic solar cell photoactive layer having an absorption coefficient at a maximum absorption wavelength within a wavelength of 300 nm to 1,000 nm of 1.5 × 10 ⁵ cm ⁻¹ or more. The method of claim 1,
Crystalline coherence length (CCL) has a range of 18 GPa to 30 GPa, the polymer for an organic solar cell photoactive layer. A first electrode and a second electrode disposed to face each other;
In an organic solar cell comprising a photoactive layer positioned between the first and second electrodes,
The photoactive layer is an organic solar cell comprising the polymer of claim 1. The method of claim 8
The first electrode is a transparent electrode, the second electrode is a metal electrode,
The organic solar cell of claim 1, further comprising a substrate positioned on a surface opposite to a surface on which the photoactive layer is present. The method of claim 8,
The photoactive layer is an organic solar cell that is a bulk double-junction layer (Bulk-hetrojuctionlayer) further comprising an electron-accepter compound. The method of claim 10,
The electron acceptor compound is, in the group consisting of fullerene, fullerene derivative, non-fullerene organic compound, carbon nanotube, carbon nanotube derivative, vasocouproin, semiconducting element, semiconducting compound, and combinations thereof Organic solar cell is any one selected. The method of claim 8,
An organic solar cell having a light conversion efficiency (%) of 9% or more.

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