KR101490470B1 - Silole Derivatives and Organic Photovoltaic cell - Google Patents

Abstract

The present invention relates to a silole derivative having a low band gap and a high-efficiency organic solar cell including the same in a photoactive layer, wherein the silole derivative according to the present invention is a compound represented by the following formula: Is a compound having a wide band gap, a wide band gap, an excellent hole mobility, and a suitable molecular level, and is useful as an organic solar cell having excellent efficiency when used as a photoactive layer of an organic solar battery. This is possible.
(I)

Description

Silole Derivatives and Organic Solar Cells Including the Silole Derivatives and Organic Photovoltaic Cells [

The present invention relates to a silole derivative and an organic solar cell comprising the same, and more particularly, to a silole derivative having a low band gap and a high efficiency organic solar cell including the same in a photoactive layer.

Recently, the need for the development of environmentally friendly alternative energy has been emphasized due to environmental problems such as the fineness of the representative energy source fossil raw material, carbon dioxide emission from burning of fossil raw materials, and the greenhouse effect. As part of efforts to overcome these problems, various energy sources such as hydroelectric power and wind power have been studied, and solar energy that can be used infinitely has been actively studied as an energy source of renewable energy.

Solar cells using solar light can be divided into inorganic solar cells using inorganic materials such as silicon and solar cells using organic materials. Organic thin film solar cells can be bent at a low production cost and freely compared with inorganic solar cells using silicon More research is being done in particular because of the advantage of being able to be large-sized with a flexible device.

Most of the organic thin film solar cell has been studied wateuna around the polymer material (G. Li, V. Shrotriya, JS Huang, Y. Yao, T. Moriarty, K. Emery and Y. Yang, Nat. Mater., 2005 , 4, 864-868; WLMa, CYYang, X. Gong, K. Lee and AJ Heeger, Adv . Funct . Mater . , 2005, 15, 1617-1622; H.-Y.Chen, J.Hou, S.Zhang ,. Y.Liang, G.Yang, Y.Yang, L.Yu, Y.Wu, G.Li, Nat. Photon, 2009, 3,649), the molecular weight control and catalyst removal difficult by this arrangement different efficiency solar cell element The reproducibility of the performance of the apparatus is deteriorated.

In order to overcome these disadvantages and make a high efficiency organic solar cell, it is inevitable to develop a new single molecule having a wide absorption band, a low band gap, a high hole mobility and a suitable molecular level.

Accordingly, a problem to be solved by the present invention is to provide a novel silole derivative having a wide band gap with a wide light absorbing region when used in a photoactive layer of an organic solar cell, and a process for producing the same.

The present invention also provides a high-efficiency organic solar cell containing the silole derivative in the photoactive layer.

In order to solve the above problems,

There is provided a silole derivative compound represented by the following formula (I).

(I)

In the above formula (I)

R ₁ and R ₂ are the same or different and each independently represents a linear or branched, saturated or unsaturated alkyl group having 1 to 20 carbon atoms,

Ar ₁ and Ar ₂ are the same as or different from each other and each independently selected from the following structural formulas.

[constitutional formula]

In the above structural formula,

Wherein R is hydrogen or a linear or branched, saturated or unsaturated alkyl group having 1 to 20 carbon atoms.

According to one embodiment of the present invention, the above-mentioned formula (I) may be any one selected from compounds represented by the following formulas (Ia) to (Id).

≪ RTI ID = 0.0 >

≪ RTI ID = 0.0 &

[Chemical Formula Ic]

≪ RTI ID = 0.0 &

Further, in order to solve the above problems,

The present invention provides a process for preparing a silole derivative compound represented by the following formula (I), which is produced according to the following reaction scheme A:

[Reaction Scheme A]

(I)

In the above Reaction Scheme A,

Wherein R ₁ is a 2-ethylhexyl group or an n-octyl group, and R ₂ is a 2-ethylhexyl group or an n-octyl group.

According to one embodiment of the present invention, the reaction according to the above Reaction Scheme A can be performed by catalyzing bis (triphenylphosphine) palladium (II) dichloride (PdCl ₂ (PPh ₃ ) ₂ ).

Further, in order to solve the above problems,

A first electrode and a second electrode facing each other; And a photoactive layer disposed between the first electrode and the second electrode,

Wherein the photoactive layer comprises the silole derivative compound according to any one of claims 1 to 3. [

According to an embodiment of the present invention, the photoactive layer may further include a fullerene derivative.

The silole derivative compound according to the present invention is a compound having a wide light absorption region, a low band gap, an excellent hole mobility and an appropriate molecular level. When the compound is used as a photoactive layer of an organic solar cell, The battery can be implemented.

1 is a graph of absorbance on a film and a solution of Si1TDPP-EE (Synthesis Example 1) synthesized according to the present invention.
2 is a graph of absorbance on a film and a solution of Si1TDPP-EO (Synthesis Example 2) synthesized according to the present invention.
3 is a graph of absorbance on a film and a solution of Si1TDPP-OE (Synthesis Example 3) synthesized according to the present invention.
4 is a graph of absorbance on a film and a solution of Si1TDPP-OO (Synthesis Example 4) synthesized according to the present invention.
5 is a graph of current density-voltage ( JV) curves for an organic solar cell (Example 1) using a silole derivative compound according to the present invention as a photoactive layer.

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

The present invention relates to a novel compound which is applied to the photoactive layer of an organic thin film solar cell to obtain a high photoelectric conversion efficiency of the organic thin film solar cell and relates to a thiophene monomer which is reported to exhibit excellent hole mobility and high light absorption rate A dipyrrolopyrrole monomer, and a silolecene structure having a high hole conductivity, and is a novel silole derivative compound having a low band gap.

The silole derivative compound according to the present invention is characterized by being represented by the following formula (I).

(I)

In the above formula (I)

R ₁ and R ₂ are the same or different and each independently represents a linear or branched, saturated or unsaturated alkyl group having 1 to 20 carbon atoms,

Ar ₁ and Ar ₂ are the same as or different from each other and each independently selected from the following structural formulas.

[constitutional formula]

In the above structural formula,

Wherein R is hydrogen or a linear or branched, saturated or unsaturated alkyl group having 1 to 20 carbon atoms.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It will be clear to those who have knowledge.

<Examples>

Synthetic example. Synthesis of silole derivative compounds according to the present invention

[Reaction Scheme 1]

[Reaction Scheme 2]

[Reaction Scheme 3]

The compounds of the formulas (1), (5) and (7) shown in the above Reaction Schemes 1 to 3 were purchased from Aldrich or Lumtec.

Synthetic example  1: 3,6-di ( Thiophene -2 days) Pirolo [3,4-c] pyrrole-1,4 (2H, 5H) - die Synthesis of On (Formula (2))

A condenser was placed in a 500 mL flask containing a magnetic stirring bar, t-amyl alcohol (250 mL) was added, and the sodium flakes were added slowly after heating to 60 ° C. After the addition of the sodium flakes, the reaction was allowed to proceed for 12 hours at 120 ° C. Then, 2-thiophenecarbonitrile (3) (10.0 mL, 107.4 mmol) and di-n-butyl succinate (12.6 mL, 53.69 mmol) were slowly added thereto and reacted at 120 ° C for 12 hours. After cooling, acetic acid mL, 195.7 mmol) and methanol (7.7 mL, 134.2 mmol) were added thereto, followed by reaction at room temperature for about 30 minutes. (Thiophene-2-yl) pyrrolo [3,4-c] pyrrole-2-carboxylic acid was prepared in 8.2 g, 51% yield by filtration and vacuum drying, 1,4 (2H, 5H) -dione (formula (2)).

^{1 H-NMR (DMSO, δ} ppm) 4.85 (dd, 2H), 5.51 (d, 2H, aromatic proton), 5.76 (d, 2H, aromatic proton), 8.79 (s, 2H, -NH-)

Synthetic example  2: 2,5- Dioctyl -3,6-di ( Thiophene -2 days) Pirolo [3,4-c] pyrrole-1,4 (2H, 5H) -dione Ion Synthesis of learning (3))

(Thiophen-2-yl) pyrrolo [3,4-c] pyrrole-1,4 (2H, 5H (2.39 g, 7.95 mmol) and bromooxane (5.67 g, 26.24 mmol) were dissolved in dimethylformamide (50 mL) The reaction was allowed to proceed for a period of time. After the reaction, the reaction mixture was gradually cooled to room temperature. The resulting precipitate was filtered to remove the solvent and extracted with ether and water. Thereafter, the resultant product was separated by column chromatography (developing solvent: chloroform / hexane (1: 1)) to obtain 2.53 g of 2,5-dioctyl-3,6-di (thiophen- [3,4-c] pyrrole-1,4 (2H, 5H) -dione (formula (3)).

_{^{1 H-NMR (CDCl 3,}} δ ppm) 0.89 (t, 6H), 1.28 ~ 1.43 (m, 20H), 1.77 (m, 4H), 4.09 (d, 4H), 7.26 (dd, 2H, aromatic proton) , 7.62 (d, 2H, aromatic proton), 8.85 (d, 2H, aromatic proton)

Synthetic example  3: 3- (5- Bromothiophene Yl) -2,5- Dioctyl -6- ( Thiophene -2 days) Pyrrole in[ 3,4-c] pyrrole -1,4 (2H, 5H) - Of the polyion (formula (4))  synthesis

3,4-c] pyrrole-1,4 (2H, 5H) -dione was added to a 100 mL flask containing a magnetic stirring bar. (2.53 g, 4.82 mmol) was dissolved in chloroform (350 mL) as a solvent and cooled to 0 占 폚. After dissolving N-bromosuccinimide (0.37 g, 2.10 mmol) in chloroform (20 mL) as a solvent, the solution was added dropping funnel, and then slowly added dropwise to the flask. The reaction was allowed to proceed for about two hours and then extracted with chloroform and water. The chloroform layer was collected and the solvent was removed through a rotary evaporator. The residue was purified by column chromatography (developing solvent: dichloromethane / hexane 1: 1) to obtain 0.6 g of 3- (5-bromothiophen-2-yl) Pyrrole-3,4 (2H, 5H) -dione (formula (4)) was obtained.

¹ H-NMR (CDCl ₃ ,? Ppm) 0.89 (t, 6H), 1.28-1.43 (m, 20H), 1.77 (m, 4H), 4.02 , Aromatic proton), 8.56 (d, 1H, aromatic proton), 7.62 (d, 1H, aromatic proton)

Synthetic example  4: 4,4- Bis (2- Ethylhexyl ) -2,6- Bis ( Trimethyltin ) -4H-silolo [3,2-b: 4,5-b '] dithiophene (Formula (6))

A 50 mL flask containing a magnetic stir bar was frame dried for anhydrous conditions and then 2,6-dibromo-4,4-bis (2-ethylhexyl) -4H-silolo [3,2- 5-b '] dithiophene (1.0 g, 1.73 mmol) was added thereto, followed by the addition of 20 mL of anhydrous tetrahydrofuran as a solvent, followed by cooling to -78 ° C using dry ice and acetone. After cooling, n-butyllithium (0.3 g, 4.34 mmol) and the intermediate stabilizer tetramethylethylenediamine (0.5 g, 4.34 mmol) were slowly added dropwise. After stirring for 2 h, trimethyltin chloride (0.9 g, 4.34 mmol) was added dropwise. After the temperature was slowly raised to room temperature, the reaction was allowed to proceed for about 8 hours. After the reaction, the reaction solution was extracted three times with chloroform and water, and the chloroform layer was dehydrated with MgSO _4. Then, the solvent was removed through a rotary evaporator to obtain 1.1 g of 4,4-bis (2-ethylhexyl Silane (3,2-b: 4,5-b '] / dithiophene (formula (6)) was synthesized.

¹ H-NMR (CDCl ₃ ,? Ppm) 0.32 (t, 18H), 0.74 (m, 4H), 0.83 m, 2H), 7.06 (s, 2H, aromatic proton)

Synthetic example  5: 4,4- Dioctyl -2,6- Bis ( Trimethylstannyl ) -4H- Silollo  [3,2-b: 4,5-b '] Isaiah Synthesis of Pen (Formula (8))

A 50 mL flask containing a magnetic stir bar was dried in a frame for anhydrous conditions and 2,6-dibromo-4,4-dioctyl-4H-silolo [3,2-b: 4,5- Dithiophene (1.0 g, 1.73 mmol) was added thereto, followed by the addition of 20 mL of anhydrous tetrahydrofuran as a solvent, followed by cooling to -78 ° C using dry ice and acetone. After cooling, n-butyllithium (0.3 g, 4.34 mmol) and the intermediate stabilizer tetramethylethylenediamine (0.3 mg, 0.22 mmol) were slowly added dropwise. After stirring for 2 h, trimethyltin chloride (0.2 g, 0.80 mmol) was added dropwise. After the temperature was slowly raised to room temperature, the reaction was allowed to proceed for 8 hours. After the reaction, the reaction solution was extracted three times with chloroform and water, and the chloroform layer was dehydrated with MgSO _4. Then, the solvent was removed through a rotary evaporator to obtain 0.6 g of 4,4-dioctyl-2,6 (Trimethylstannyl) -4H-silolo [3,2-b: 4,5-b '] dithiophene (formula (8)).

_{^{1 H-NMR (CDCl 3,}} δ ppm) 0.32 (t, 18H), 0.74 (m, 4H), 0.90 (t, 6H), 1.13 ~ 1.40 (m, 20H), 1.68 (m, 4H), 7.06 ( s, 2H, aromatic proton)

Synthetic example  6: 6,6 '- (5,5' - (4,4- Bis (2- Ethylhexyl ) -4H- Silolo [3,2-b: 4,5-b '] dithiophene -2,6- Dai ) Bis ( Thiophene -5,2- Dai )) Bis (2,5- Bis (2- Ethylhexyl ) -3- (thiophen-2-yl) Pirolo [3,4-c] pyrrole-1,4 (2H, 5H) - (Si1TDPP-EE) &lt; / RTI &gt; of formula &lt; RTI ID =  synthesis

A 50 mL flask containing a magnetic stirring bar was subjected to frame drying for anhydrous conditions, and then 4,4-bis (2-ethylhexyl) -2,6-bis (trimethyltin) -4H-silolo [ (5-bromothiophen-2-yl) -2,5-dihydro-3,2-b: 4,5-b '] / dithiophene (Formula (6)) (0.3 g, 0.457 mmol) 3,4-c] pyrrole-1,4 (2H, 5H) -dione (0.6 g, 1.00 mmol) represented by the following formula ((2-ethylhexyl) 9) was added thereto, and toluene / N, N'-dimethylformamide (12 mL / 3 mL) was added as a solvent. After cooling, oxygen was removed through digeshing.

Then, bis bis (triphenylphosphine) palladium (II) dichloride (PdCl ₂ (PPh ₃ ) ₂ ) (12.8 mg, 0.018 mmol) was added as a catalyst and heated to 80 ° C. for 4 hours. Then, the reaction mixture was cooled to room temperature, and then reprecipitated with methanol (150 mL). A dark brown solid was filtered and dissolved in chloroform. The filtrate was separated by column chromatography (developing solvent: dichloromethane / hexane (2: 1) , Yielding the final material in the form of a black powder, Si1TDPP-EE (Formula Ia), in a yield of 50%.

¹ H-NMR (CD ₂ Cl ₂ ,? Ppm) 0.83-0.91 (m, 36H), 0.99 (t, 4H), 1.22-1.46 (m, 48H), 1.47-1.48 (d, 2H, aromatic proton), 7.31 (d, 2H, aromatic proton), 7.35 (s, 2H, aromatic proton), 7.65 proton), 8.83 (d, 2H, aromatic proton), 8.96 (d, 2H, aromatic proton)

Synthetic example  7: 6,6 '- (5,5' - (4,4- Bis (2- Ethylhexyl ) -4H- Silolo [3,2-b: 4,5-b '] dithiophene -2,6- Dai ) Bis ( Thiophene -5,2- Dai )) Bis (2,5- Dioctyl -3- ( Thiophene -2 days) Pirolo [3,4-c] pyrrole-1,4 (2H, 5H) - Dioion (Si1TDPP-EO) (Ib)  synthesis

A 50 mL flask containing a magnetic stirring bar was subjected to frame drying for anhydrous conditions, and then 4,4-bis (2-ethylhexyl) -2,6-bis (trimethyltin) -4H-silolo [ (5-bromothiophen-2-yl) -2,5-dihydro-3,2-b: 4,5-b '] / dithiophene (Formula (6)) (0.3 g, 0.403 mmol) (2H, 5H) -dione (0.5 g, 0.85 mmol) (formula (4)) was added to a tetrahydrofuran After adding toluene / N, N'-dimethylformamide (16 mL / 4 mL) as a solvent, it was cooled and then deoxygenated to remove oxygen. Then, bis bis (triphenylphosphine) palladium (II) dichloride (PdCl ₂ (PPh ₃ ) ₂ ) (14.2 mg, 0.020 mmol) was added as a catalyst and heated to 80 ° C. for reaction for about 4 hours. Then, the reaction mixture was cooled to room temperature and re-precipitated with methanol (150 mL). The resulting solid was filtered and dissolved in chloroform. The filtrate was separated by column chromatography (developing solvent: dichloromethane / hexane 2: 1) , Yielding the final material in the form of a black powder, Si1TDPP-EO (formula Ib), in a yield of 72%.

¹ H-NMR (CDCl ₃ ,? Ppm) 0.86-0.91 (m, 24H), 0.99 (t, 4H), 1.22-1.46 (m, 56H), 1.47-1.48 2H, aromatic protone), 7.35 (s, 2H, aromatic proton), 7.60 (d, 2H, aromatic proton) , 8.83 (d, 2H, aromatic proton), 8.96 (d, 2H, aromatic proton)

Synthetic example  8: 6,6 '- (5,5' - (4,4- Dioctyl -4H- Silolo [3,2-b: 4,5-b '] dithiophene -2,6-diyl) Bis ( Thiophene -5,2- Dai )) Bis (2,5- (2- Ethylhexyl ) -3- ( Thiophene Yl) pyrrolo [ 3,4-c] pyrrole -1,4 (2H, 5H) - Dioion (Si1TDPP-OE) (Ic)  synthesis

A 50 mL flask containing a magnetic stirring bar was subjected to frame drying for anhydrous conditions to obtain 4,4-dioctyl-2,6-bis (trimethyltin) -4H-silolo [3,2-b (5-bromo-thiophen-2-yl) -2,5-bis (2-ethyl) (2H, 5H) -dione (1.8 g, 2.81 mmol) (Formula (9)) in tetrahydrofuran After adding toluene / N, N'-dimethylformamide (16 mL / 4 mL) as a solvent, the solution was degassed by degassing after cooling. Then, bis bis (triphenylphosphine) palladium (II) dichloride (PdCl ₂ (PPh ₃ ) ₂ ) (14.2 mg, 0.020 mmol) was added as a catalyst and heated to 80 ° C. for 4 hours. After cooling, the reaction mixture was cooled to room temperature and re-precipitated with methanol (150 mL). The resulting solid was filtered and dissolved in chloroform. The residue was separated by column chromatography (developing solvent: dichloromethane / hexane (2: 1) , Yielding the final material in the form of a black powder, Si1TDPP-OE (formula Ic), in a yield of 45%.

¹ H-NMR (CDCl ₃ ,? Ppm) 0.83-0.91 (m, 30H), 0.99 (t, 4H), 1.22-1.52 (m, 56H), 1.83-1.90 (D, 2H, aromatic proton), 7.35 (s, 2H, aromatic proton), 7.65 (d, 2H, aromatic proton) ), 8.93 (d, 2H, aromatic proton)

Synthetic example  9: 6,6 '- (5,5' - (4,4- Dioctyl -4H- Silolo [3,2-b: 4,5-b '] dithiophene -2,6-diyl) Bis ( Thiophene -5,2- Dai )) Bis (2,5- Dioctyl -3- ( Thiophene Yl) pyrrolo [ 3,4-c] pyrrole -1,4 (2H, 5H) - (Si1TDPP-OO) &lt; RTI ID = 0.0 &gt; (Id)  synthesis

A 50 mL flask containing a magnetic stirring bar was subjected to frame drying for anhydrous conditions, and then 4,4-dioctyl-2,6-bis (trimethyltin) -4H-silolo [3,2- b): 4,5-b '] / dithiophene (formula (8)) (0.3 g, 0.34 mmol) and 3- (5-bromothiophen- 3,4-c] pyrrole-1,4 (2H, 5H) -dione (0.5 g, 0.74 mmol) (Formula (4)) was added to a mixture of toluene / N , N'-dimethylformamide (16 mL / 4 mL) was added as a solvent, and after cooling, oxygen was removed through degassing. Then, bis bis (triphenylphosphine) palladium (II) dichloride (PdCl ₂ (PPh ₃ ) ₂ ) (14.2 mg, 0.020 mmol) was added as a catalyst and heated to 80 ° C. for 4 hours. Thereafter, the reaction mixture was cooled to room temperature and then reprecipitated with methanol (150 mL). A dark brown solid was filtered and dissolved in chloroform. The filtrate was separated by column chromatography (developing solvent: dichloromethane / hexane 2: 1) to obtain 182 mg , Yielding the final material in the form of a black powder, Si1TDPP-OO (Formula Id), in a yield of 38%.

¹ H-NMR (CDCl ₃ ,? Ppm) 0.83-0.91 (m, 18H), 0.99 (t, 4H), 1.22-1.52 (m, 64H), 1.83-1.90 (D, 2H, aromatic proton), 7.18 (d, 2H, aromatic proton), 7.18 (d, 2H, aromatic proton) ), 8.93 (d, 2H, aromatic proton)

Examples 1 to 4: Production of solar cell using silole derivatives

The ITO / PEDOT: PEGO 3 film was formed using the silole derivatives (Si1TDPP-EE (Ia), Si1TDPP-EO (Formula Ib), Si1TDPP-OE (Formula Ic) or Si1TDPP- PSS / Silorene derivative: PC ₆₀ BM (1: 1) / Al structure.

The ITO substrate was washed with isopropyl alcohol for 10 minutes, acetone for 10 minutes, finally with isopropyl alcohol for 10 minutes, and dried. The PEDOT: PSS solution was diluted 1: 1 in methanol on a dry ITO substrate, spin-coated at 4000 rpm, and dried at 110 ° C for 10 minutes. On the dried substrate, chloroform solution of 12 mg / mL mixed with silole derivative and PC ₆₀ BM in a ratio of 1: 1.0 was spin-coated at 2500 rpm, and after drying, TiO ₂ was dissolved in 0.4 wt% After spin coating at 3500 rpm, an aluminum electrode was deposited to a thickness of 100 nm.

Evaluation example. Evaluation of solar cell characteristics

(Si1TDPP-EE), Synthetic Example 7 (Si1TDPP-EO) (Ib), Synthetic Example 8 (Si1TDPP-OE) Synthesis Example 9 (absorbance graph on film and solution of Si1TPP-OO (Id)).

The absorption maximum and the optical band gap on the solution and the film determined from the above data are shown in Table 1 below. From these results, it can be seen that the silole derivative according to the present invention is suitable as a material having a low band gap for realizing a high efficiency organic solar cell.

 division Solution (λ _max ) Solution (λ _onset ) Film (λ _onset ) The optical bandgap (E _{g , opt} ) Example 1
(Si1TDPP-EE) 631 nm 716 nm 768 nm 1.61 eV Example 2
(Si1TDPP-EO) 636 nm 718 nm 790 nm 1.57 eV Example 3
(Si1TDPP-OE) 632 nm 717 nm 772 nm 1.61 eV Example 4
(Si1TDPP-OO) 630 nm 719 nm 785 nm 1.58 eV

The results of measurement of characteristics of the solar cells manufactured in Examples 1 to 4 are shown in FIG. 5, and the solar cell performance indexes of the graphs are shown in Table 2 below.

 division V _oc (V) J _sc (mA / cm 2) FF PCE (%) Example 1
(Si1TDPP-EE) 0.75 1.27 0.27 0.53 Example 2
(Si1TDPP-EO) 0.70 3.70 0.47 1.22 Example 3
(Si1TDPP-OE) 0.77 7.47 0.60 3.45 Example 4
(Si1TDPP-OO) 0.69 2.42 0.36 0.50

Claims (6)

delete A monomolecular organic solar cell comprising any one of the compounds represented by the following formulas (Ib) to (Id) as a photoactive layer:
&Lt; RTI ID = 0.0 &

[Chemical Formula Ic]

&Lt; RTI ID = 0.0 &

. delete delete delete delete

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