KR20100088050A - Organic photovoltaic device containing fullerene derivatives - Google Patents

Abstract

PURPOSE: An organic solar cell device is provided to improve an open voltage property when an organic solar cell device is implemented by increasing a LUMO energy level. CONSTITUTION: A fullerene derivatives includes two cyclohexane form substituents. Fullerene derivatives are combined with a polymer material for a doner. A fullerene derivative compound for an organic solar cell device is a dopant. The fullerene derivatives for an organic solar cell device is formed with one which is selected among a group which is formed with a solution process mode and a deposition method.

Description

Organic Photovoltaic Device Containing Fullerene Derivatives

The present invention relates to an organic semiconductor material and an organic electronic device including the same, and more particularly, to an organic semiconductor material having a fullerene structure to which an aromatic fused ring compound is connected and an organic solar cell device including the same.

In recent decades, the development of organic materials with semiconductor properties and various application studies using them have been actively conducted. The scope of application research using organic semiconductors such as electromagnetic shielding films, capacitors, OLED displays, organic thin film transistors (OTFTs), solar cells, and memory devices using multiphoton absorption phenomena continues to expand. In particular, the OLED field is expected to commercialize large-scale displays, and thus serves as a catalyst for activating application research using organic materials.It is started as an active driving circuit for OLED and is expected to be applied to next-generation smart cards. There is also a sudden rise. In addition, after the announcement of the electrical power generation characteristics using the organic semiconductor as an active layer, it is also drawing a lot of attention to the application as a laser diode. Compared with inorganic materials, the cost of producing the material is significantly lower, which is a change in the future solar cell market.

The research on the organic semiconductor thin film transistor has been started since 1980, but in recent years, full-scale research is being conducted worldwide. It is anticipated that electronic circuit boards that are simple to manufacture, inexpensive, and that can be bent or folded without impact are expected to be essential to the industry of the future, and the development of organic transistors to meet these needs is very important. It is emerging as a research field. Organic transistors cannot be used in devices requiring high speeds such as Si or Ge due to their low charge mobility due to the characteristics of organic semiconductors. However, it can be useful when the device needs to be fabricated over a large area, when low process temperatures are required, and when bending is required, especially when low-cost processes are required. Recently, researchers at Philips surprised the world by designing and publishing programmable code generators consisting of 326 transistors using substrates, electrodes, dielectrics (insulators), and semiconductors all using polymers. This completely reverses the stereotype that semiconductors are hard so far, foreshadowing endless applications based on human imagination.

Organic semiconductor transistors are organic semiconductors such as light emitting organic materials used in organic electroluminescent transistors because of the characteristics of the material, so the deposition method is the same, and the physical and chemical properties are similar, so that the device can be manufactured while maintaining the same process conditions. In addition, since both process can be performed at room temperature and low temperature (less than 100 ℃), it is possible to manufacture a plastic-based organic electroluminescent device using an organic transistor. In the same vein, it is also possible to use a liquid crystal display device that can be bent using plastic as a substrate. In addition, the driving of electronic paper, which has attracted great attention recently, is not only driving current but driving voltage, and not only a display device requiring high charge mobility or fast switching speed, but also a large area that can be bent. The organic transistor is the most suitable technology because it is applied to. In addition, micro cards for smart cards, which are currently used as silicon bases through semiconductor processes, are expected to be used because organic transistors can be used to reduce costs associated with bonding silicon processors to plastic bases. Furthermore, it is thought that it can be applied to various parts of the computer.

In order to obtain a high performance device, an organic semiconductor must satisfy the following general matters regarding charge injection and current mobility. (Iv) Organic semiconductor materials must have molecular orbital (HOMO / LUMO) energy that facilitates the injection of holes and electrons when an electric field is applied. (Ii) The crystal structure of a substance must have sufficient overlap of frontier orbitals so that effective charge transfer between neighboring molecules can occur. (Iii) Solids must be pure because impurities act as charge traps. (Iii) Molecules should be selectively arranged along the lengthening side-by-side on the device substrate so that effective charge transfer can occur along the direction of intra-molecular pi-pi stacking. (Iii) The crystal region of the organic semiconductor should be covered between the source and drain electrodes in the form of a film with a thin film like single crystal. In addition, it is desirable that the solubility of the organic material is also excellent. Since the solution process can be a low temperature process during device fabrication, a thin film can be easily formed on a plastic substrate, thereby making it possible to fabricate an inexpensive device.

Pentacene, polythiophene, polyacetylene, α-hexathienylene, and fullerene (C60) thin films since OTFT began in earnest in the early 1980s Has been applied in the direction to increase the charge mobility and the flashing ratio, which are important characteristics of the OTFT device. The best p-type channel material at present is pentacene, but has a problem of stability in that electrical properties change due to reaction with oxygen. When the organic semiconductor is oxidized in this manner, the bond is broken and thus the charge mobility is lowered. In addition, lattice distortion occurs in the crystal to form charge traps, and charge scattering caused by these causes a decrease in mobility. In addition, researches to improve charge mobility of organic semiconductors have been conducted to increase the temperature of the substrate during deposition or to induce crystallization of organic molecules using a self-assembly method. But first of all, it is important to design the molecules so that inter-molecular conduction occurs easily.

On the other hand, solar cells are devices that can directly convert solar energy into electrical energy by applying a photovoltaic effect. Typical solar cells are made of p-n junctions by doping crystalline silicon (Si), an inorganic semiconductor. Electrons and holes generated by absorbing light diffuse to the p-n junction and are accelerated by the electric field to move to the electrode. The power conversion efficiency of this process is defined as the ratio of the power given to external circuits and the solar power entered into the solar cell, and has been achieved by up to 24% when measured under current virtualized solar irradiation conditions. However, since the conventional inorganic solar cell has already shown its limitations in terms of economic and material supply and demand, organic semiconductor solar cells having easy processing, low cost, and various functionalities have been spotlighted as alternative energy sources in the long term.

The possibility of an organic solar cell was first proposed in the 1970s, but its efficiency was so low that it was not practical. However, in 1986, Eastman Kodak's Tang showed a double-layer structure using copper phthalocyanine (CuPc) and perylene tetracarboxylic acid derivatives, showing the possibility of practical application as various solar cells. Interest and research on solar cells has increased rapidly and brought about a lot of development. Since 1995, the concept of bulk-heterojunction (BHJ) was introduced by Yu et al., And fullerene derivatives with improved solubility, such as PCBM, were developed as n-type semiconductor materials. there was. In particular, in the case of polymer solar cells, the improvement of efficiency is remarkable due to the change of new device configuration and process conditions in recent 3-4 years, and the donor having low bandgap to replace the existing material. The development of new acceptor materials with good material and charge mobility is constantly being studied.

An object of the present invention is an electrically conductive material that is thermally stable, has high solubility, has high electron mobility, and exhibits excellent electrical properties. An organic semiconductor material and an organic solar cell device including the same are provided.

In order to solve the above problems, the present invention is a fullerene structure in which an aromatic fused ring compound is introduced, more specifically, a structure of a cyclohexane (cyclohexane) is introduced into the fullerene, and the aromatic ring compound or heteroaromatic An organic semiconductor material of a compound in which a ring compound is fused and an organic solar cell device including the same are provided.

[Formula 1]

[In Formula 1, R ¹ to R ⁴ is independently selected from a hydrogen atom, a straight chain or a (C1-C20) alkyl of the chain, or connected to adjacent substituents (C4-C8) alkenylene to form an aromatic fused ring The alkenylene is substituted with 1 to 3 heteroatoms selected from an oxygen atom, a nitrogen atom or a sulfur atom to form a heteroaromatic fused ring; A is the fullerene of C60 or C70.]

The fullerene compound into which the aromatic fused ring compound according to the present invention is introduced may be specifically exemplified as the following compound, but the following compound does not limit the scope of the present invention. In addition, in this invention, the position of the aromatic fused ring cyclohexane substituent of a fullerene compound is not limited. The fullerene derivative compound according to the present invention may be substituted at any position of the double bond of the fullerene where the aromatic fused ring is substituted by the Diels-Alder reaction, which is not limited to the position shown below. It can be a mixture of positional isomers, including those that can be, but the electrochemical properties as fullerene derivatives for organic solar cell devices are the same.

In the method for preparing a fullerene derivative in which the aromatic fused ring compound of Formula 1 is introduced according to the present invention, the fullerene derivative of C60 is illustrated as an example in Schemes 1 to 5, and as shown in Schemes 1 to 5, Diels- Fullerene derivatives may be prepared by a Diels-Alder reaction.

The Diels-Alder reaction is a reaction in which a diene compound having a paired double bond such as butadiene and a dienophile having a double bond or a triple bond cause an addition reaction to form a 6-membered ring or 5-membered ring compound. As the reaction conditions for preparing the fullerene derivative of the present invention, any of the conventional Diels-Alder reaction conditions which can be carried out by those skilled in the art can be used by any method, for example, can be obtained by heating the reactants in an organic solvent. If necessary, a catalyst may be further used. The organic solvent is an aliphatic hydrocarbon such as pentane, octane, decane and cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, chloromethane, methylene chloride, chloroform, carbon tetrachloride, 1,1-dichloro Ethane, 1,2-dichloroethane, ethylchloride, trichloroethane, 1-chloropropane, 2-chloropropane, 1-chlorobutane, 2-chlorobutane, 1-chloro-2-methylpropane, chlorobenzene and bro Halogenated hydrocarbons such as parent benzene can be used.

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

In the above Schemes 1 to 5, the adduct added to the fullerene of C60 or C70 may be used by using a commercially available product or by directly preparing. The reaction for the synthesis of the fullerene and the adduct may be carried out by heating to a boiling point of the solvent under a selected solvent from the organic solvent and reacting for 6 to 48 hours to obtain the fullerene derivative of the present invention.

In Schemes 1 to 5, mono-adducts and di-adducts may be simultaneously produced, which is according to the present invention according to a separation process such as conventional recrystallization and column chromatography. It is possible to obtain di-adducts according to the above compounds.

The fullerene derivative in which the aromatic fused ring compound of Chemical Formula 1 is prepared according to the present invention may be used as an organic solar cell device. The fullerene derivative of the present invention and the organic solar cell device using the same as the photoactive layer have excellent electrochemical characteristics compared with the conventional PCBM. The fullerene derivative has a LUMO energy level of about -3.50 to -3.52 eV, which is about 5% higher than that of the conventional PCBM -3.70 eV. When the organic solar cell device is used as a photoactive layer, a higher open voltage than the conventional organic solar cell device using PCBM as a photoactive layer can be expected. As a result of analyzing the characteristics of the organic solar cell device fabricated using the fullerene derivative and rr-P3HT [regioregular Poly (3-hexylthiophene)] as a photoactive layer, the open voltage (Voc) was 800 to 850 mV. 50 to 60 percent better than PCBM.

Therefore, when the fullerene derivative compound of the present invention is used as the photoactive layer of the organic solar cell, the energy conversion efficiency can be further improved, and the solubility is excellent, and thus, a low cost, high efficiency organic solar cell device can be manufactured as a material suitable for a low cost printing process. Could be.

In conclusion, in the present invention, fullerene derivatives having two cyclohexane-type substituents have a higher level of open circuit voltage (Voc) through combination with donor polymer materials. The present invention can provide an organic solar cell device having improved energy conversion efficiency.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are not intended to limit the invention only.

[ Production Example  1] Preparation of Compound 1-1

Benzocyclobutene (Benzocyclobutene, 0.51 g, 5 mmol) and fullerene C60 (Fullerene C60, 0.3 g, 0.42 mmol) were dissolved in 50 ml of 1,2-dichlorobenzene and reacted at 190 ° C. for 24 hours. After completion of the reaction, the solvent was concentrated under reduced pressure and developed using a 1: 7 mixed solvent of benzene and hexane using column chromatography on silica gel (40 × 10 cm) to give a mono-adduct of brown solid. (83 mg, 21%) and di-adduct (Compound 1-1) (110 mg, 28%) were obtained.

Di-adduct (Compound 1-1):

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.94-7.28 (m, 8H), 5.08-3.91 (m, 8H).

¹³ C-NMR 500 MHz (CDCl ₃ = 77.00 ppm) δ 146.71, 145.41, 144.97, 144.57, 143.74, 142.43, 141.84, 141.28, 138.41, 138.05, 128.03, 127.75, 127.68, 65.06, 64.84, 64.56, 64.45, 64.45 45.31, 45.11, 44.76, 30.92.

FABMS m / z : 928 (M ⁺ H): calcd. (C ₇₆ H ₁₆ ), 928.

[ Production Example  2] Preparation of Compound 1-2

(4- methyl -1,2- Phenylene ) Dimethanol  [(4- methyl -1,2- phenylene ) dimethanol Manufacturing of]]

Dissolve 4-methylphthalic anhydride (4-Methylphthalic anhydride, 5 g, 30.84 mmol) in ether (90 mL), add lithium aluminum hydride (LiAlH ₄ , LAH, 2.9 g, 77.09 mmol) at -78 ^o C. After stirring for 30 minutes, the temperature is gradually raised and reacted at room temperature for 24 hours. After the reaction, after cooling with ammonium chloride solution, the solvent was concentrated under reduced pressure, washed twice with ethyl acetate, and once again with distilled water. The organic layer was separated, dried over sodium sulfate, and the solvent was concentrated under reduced pressure. Then, the mixture was developed using a silica gel (40 x 10 cm) using a 2: 5 mixed solvent of ethyl acetate and hexane to form a white solid (4-methyl). -1,2-phenylene) dimethanol (3.73 g, 80%) was obtained.

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.21-7.11 (m, 3H), 4.62 (s, 4H), 3.48 (brs, 1H), 3.40 (brs, 1H), 2.34 (s, 3H)

1,2- Vis ( Bromomethyl ) -4-methylbenzene [1,2- bis ( bromomethyl )-4- methylbenzene Manufacture of

(4-methyl-1,2-phenylene) dimethanol (3 g, 19.71 mmol), tetrabromomethane (1308 g, 39.42 mmol), triphenylphosphine (10.34 g, 39.42 mmol) It is dissolved in 150 mL of tetrachloromethane and reacted at room temperature for 24 hours. After the reaction, the solvent was concentrated under reduced pressure, washed twice with ethyl acetate, and once again with distilled water. The organic layer was separated, dried over sodium sulfate, and the solvent was concentrated under reduced pressure. Then, the mixture was developed using a silica gel (40 x 10 cm) using a 2: 5 mixed solvent of ethyl acetate and hexane to develop a white solid 1,2- Bis (bromomethyl) -4-methylbenzene (1.44 g, 26%) solid was obtained.

Dills - The Alels-Alder reaction  Used C60  Preparation of Derivatives

1,2-bis (bromomethyl) -4-methylbenzene (0.76 g, 2.76 mmol), potassium iodide (KI, 0.69 g, 4.17 mmol), 18-crown-6 (1.82 g, 6.9 mmol), fullerene C60 (Fullerene C60, 0.5 g, 0.69 mmol) was dissolved in toluene (100 mL) and reacted at 110 ^° C. under reflux for 24 hours. After the reaction was completed, the solvent was concentrated under reduced pressure, washed twice with dichloromethane, and once again with distilled water. The organic layer was separated, dried over sodium sulfate, and the solvent was concentrated under reduced pressure, and then expanded using a silica gel (40 x 10 cm) using a 2: 7 mixed solvent of benzene and hexane to expand the solvent to a brown solid mono-adduct. (mono-adduct) (10 mg) and di-adduct (compounds 1-2, 7 mg) were obtained.

Di-adduct (Compound 1-2):

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.59-7.32 (m, 2H), 7.52 (s, 2H), 7.41-7.33 (m, 2H), 4.81-4.77 (m, 4H), 4.42-4.38 (m , 4H), 2.55 (s, 6H).

FABMS m / z : 957 (M ⁺ +1); calcd. (C ₇₈ H ₂₀ ) 956.

[ Production Example  3] Preparation of Compound 1-3

Dimethyl 4,5- Dimethylcyclohexa -1,4- Dien -1,2- Dicarboxylate  [ Dimethyl  Preparation of 4,5-dimethylcyclohexa-1,4-diene-1,2-dicarboxylate]

Dimethyl acetylendicarboxylate (5 g, 35.18 mmol) is dissolved in benzene (50 mL), and then under nitrogen, 2,3-dimethyl-1,3-butadiene (2,3-Dimethyl-1,3- butadiene, 2.72 g, 33.07 mmol) was added and the mixture was stirred at reflux for 24 hours. After the reaction After the reaction the solvent was concentrated under reduced pressure, washed twice with ethyl acetate, once again with distilled water. The organic layer was separated, dried over sodium sulfate, and the solvent was concentrated under reduced pressure. Then, the mixture was developed with a silica gel (40 x 10 cm) using a 1: 5 mixed solvent of ethyl acetate and hexane to form a dimethyl 4, white solid. 5-Dimethylcyclohexa-1,4-diene-1,2-dicarboxylate (5.68 g, 72%) was obtained.

¹ H-NMR 300 MHz (CDCl ₃ ) δ 3.77 (s, 6H), 2.92 (s, 4H), 1.66 (s, 6H)

Preparation of Dimethyl 4,5-dimethylbenzene-1,2-dicarboxylate [Dimethyl 4,5-Dimethylbenzene-1,2-dicarboxylate]

To dimethyl 4,5-dimethylcyclohexa-1,4-diene-1,2-dicarboxylate (Dimethyl 4,5-dimethylcyclohexa-1,4-diene-1,2-dicarboxylate, 2 g, 8.92 mmol) After dissolving in 50 mL of chlorobenzene, DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone 4 g, 17.84 mmol) was slowly added slowly at room temperature, followed by stirring under reflux for 24 hours. After the reaction, the solvent was concentrated under reduced pressure, washed twice with ethyl acetate, and once again with distilled water. The organic layer was separated, dried over sodium sulfate, and the solvent was concentrated under reduced pressure. Then, the mixture was developed with a silica gel (40 x 10 cm) using a 1: 5 mixed solvent of ethyl acetate and hexane to develop a transparent oil. , 5-dimethylbenzene-1,2-dicarboxylate (1.29 g, 65%) was obtained.

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.49 (s, 2H), 3.88 (s, 6H), 2.31 (s, 6H)

Preparation of 1,2-bis (bromomethyl) -4,5-dimethylbenzene [1,2-bis (bromomethyl) -4,5-dimethylbenzene]

Into LAH (0.54 g, 14.29 mmol) was added dried tetrahydrofuran (20 mL) at -78 ^o C, dimethyl 4,5-dimethylbenzene-1,2-dicarboxylate (1.27 g, 5.71 mmol) Was dissolved in dried tetrahydrofuran (10 mL), and slowly added to the reaction solution, and then the reaction temperature was slowly raised to room temperature and stirred under reflux for 24 hours. After the reaction, the mixture was cooled with sodium hydroxide solution, concentrated under reduced pressure, washed twice with ethyl acetate, and then washed once with distilled water. The organic layer was separated, dried over sodium sulfate, and the solvent was concentrated under reduced pressure to give (4,5-dimethyl-1,2-phenylene) dimethanol ((4,5-dimethyl-1,2-phenylene) dimethanol, 0.95 g, quantitative). It was then brominated with tribromophosphine to give 1,2-bis (bromomethyl) -4,5-dimethyl benzene as 56% oil.

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.13 (s, 2H), 4.27 (s, 4H), 2.23 (s, 6H).

Dills - The Alels-Alder reaction  Used C60  Preparation of Derivatives

1,2-bis (bromomethyl) -4,5-dimethylbenzene (0.6 g, 2.06 mmol), potassium iodide (KI, 0.69 g, 4.17 mmol), 18-crown-6 (1.82 g, 6.9 mmol), Using a fullerene 60 (Fullerene C60, 0.5 g, 0.69 mmol) mono-adduct (mono-adduct, 9 mg) and di-adduct (compound 1-) in the brown solid phase in the same manner as in Preparation Example 2 3, 5 mg).

Di-adduct (Compound 1-3):

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.59-7.52 (m, 4H), 4.55-4.36 (m, 8H), 2.64-2.51 (m, 6H).

FABMS m / z : 984 (M ⁺ ); calcd. (C ₇₈ H ₂₀ ), 984.

[ Production Example  4] Preparation of Compound 1-4

2,3- Bis (bromomethyl) naphthalene  [2,3-bis ( bromomethyl ) naphthalene Manufacture of

2,3-dimethylnaphthalene (2,3-Dimethylnaphthalene, 3 g, 19.2 mmol), N-bromosuccinimide (N-Bromosuccimide, 6.84 g, 38.4 mmol), 2,2'-azobis (2-methyl Propionitrile (AIBN, 321 mg, 0.19 mmol) was dissolved in carbon tetrachloride (60 mL) and reacted for 24 hours at reflux at 80 ^° C. After completion of the reaction, the solvent was concentrated under reduced pressure, recrystallized with hexane, 2,3-bisbromomethylnaphthalene (4.47 g, 74%) was obtained as a beige solid.

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.86 (s, 2H), 7.81-7.78 (m, 2H), 7.52-7.49 (m, 2H), 4.87 (s, 4H)

Dills - The Alels-Alder reaction  Used C60  Preparation of Derivatives

2,3-bisbromomethylnaphthalene (2,3-bis (bromomethyl) naphthalene, 1.3 g, 4.17 mmol), potassium iodide (KI, 0.69 g, 4.17 mmol), 18-Crown-6 (1.82 g, 6.9 mmol ), Mono-adduct (140 mg, 20%) and di-addition of a brown solid in the same manner as in Preparation Example 2 using fullerene C60 (Fullerene C60, 0.5 g, 0.69 mmol) di-adduct) (Compound 1-4, 85 mg, 10%).

Di-adduct (Compound 1-4):

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.89-7.70 (m, 8H), 7.53-7.17 (m, 4H), 4.88-4.79 (m, 8H).

FABMS m / z : 1028 (M ⁺ H): calcd. (C ₈₄ H ₂₀ ), 1028.

[ Production Example  5] Preparation of Compound 1-5

Preparation of 1,2-bis (bromomethyl) naphthalene [1,2-bis (bromomethyl) naphthalene]

1,2-dimethylnaphthalene (1,2-Dimethylnaphthalene, 2 g, 12.8 mmol), N-bromosuccinimide (N-Bromosuccimide, 4.56 g, 25.6 mmol), 2,2'-azobis (2-methyl 1,2-bis (bromomethyl) naphthalene (3.5 g, 87%) was obtained in the same manner as in Preparation Example 1 using propionitrile (AIBN, 11 mg, 0.064 mmol).

¹ H-NMR 300 MHz (CDCl ₃ ) δ 8.13 (d, J = 8.4 Hz, 1H), 7.83 (t, J = 8.4 Hz, 2H), 7.66-7.60 (m, 1H), 7.55-7.50 (m, 1H), 7.42 (d, J = 8.4 Hz, 1H), 5.09 (s, 2H), 4.76 (s, 2H)

Preparation of C60 Derivatives by Diels-Alder Reaction

1,2-bisbromomethylnaphthalene (1,2-bis (bromomethyl) naphthalene, 0.87 g, 2.76 mmol), potassium iodide (KI, 0.69 g, 4.17 mmol), 18-Crown-6 (1.82 g, 6.9 mmol ), Mono-adduct (102 mg, 14%) and di-additive of brown solid phase in the same manner as in Preparation Example 2 using fullerene C60 (Fullerene C60, 0.5 g, 0.69 mmol) di-addcut) (compound 1-5, 68 mg) were obtained.

Di-adduct (Compound 1-5):

¹ H-NMR 300 MHz (CDCl ₃ ) δ 8.75-7.48 (m, 12H), 5.29-4.01 (m, 8H).

FABMS m / z : 1028 (M ⁺ H): calcd. (C ₈₄ H ₂₀ ), 1028.

[ Production Example  6] Preparation of Compound 1-6

Mono-addcut (112 mg, 18%) and diol in brown solid phase in the same manner as in Preparation Example 1, except fullerene 70 (Fullerene C70, 0.5 g, 0.69 mmol) was used instead of fullerene C60. -Di-adduct (compound 1-6, 220 mg, 35%) was obtained.

Di-adduct (Compound 1-6):

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.58-7.36 (m, 8H), 4.18-3.66 (m, 8H).

FABMS m / z : 1048 (M ⁺ H): calcd. (C ₈₆ H ₁₆ ), 1048.

[ Production Example  7] Preparation of Compound 1-7

Mono-addcut (23 mg) and di-addition of brown solid phase in the same manner as in Preparation Example 2 except that fullerene C70 (0.58 g, 0.69 mmol) was used instead of fullerene C60. adduct) (Compound 1-7, 15 mg).

Di-adduct (Compound 1-7):

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.60-7.29 (m, 2H), 7.55-7.47 (m, 2H), 7.41-7.30 (m, 2H), 4.83-4.72 (m, 4H), 4.45-4.33 (m, 4H), 2.59-2.44 (m, 6H).

FABMS m / z : 1076 (M ⁺ ); calcd. (C ₈₈ H ₂₀ ) 1076.

[ Production Example  8] Preparation of Compound 1-8

Mono-addcut (19 mg) and di-addition of brown solid phase in the same manner as in Preparation Example 3, except that fullerene C70 (0.58 g, 0.69 mmol) was used instead of fullerene C60. adduct) (Compound 1-8, 25 mg).

Di-adduct (Compound 1-8):

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.57-7.47 (m, 4H), 4.59-4.29 (m, 8H), 2.61-2.57 (m, 6H).

FABMS m / z : 1104 (M ⁺ ); calcd. (C ₉₀ H ₂₄ ), 1104.

[ Production Example  9] Preparation of Compound 1-9

Mono-addcut (85 mg, 12%) and di-additive in brown solid phase in the same manner as in Preparation Example 4, except fullerene C70 (0.58 g, 0.69 mmol) was used instead of fullerene C60. (di-adduct) (compound 1-9, 168 mg, 21%) was obtained.

Di-adduct (Compound 1-9):

¹ H-NMR 300 MHz (CDCl ₃ ) δ 7.93-7.65 (m, 8H), 7.59-7.10 (m, 4H), 4.91-4.70 (m, 8H).

FABMS m / z : 1148 (M ⁺ H): calcd. (C ₈₄ H ₂₀ ), 1148.

[ Production Example  10] Preparation of Compound 1-10

Mono-addcut (77 mg, 11%) and di-additive in brown solid phase in the same manner as in Preparation Example 4, except fullerene C70 (0.58 g, 0.69 mmol) was used instead of fullerene C60. (di-adduct) (compound 1-10, 192 mg, 24%) was obtained.

Di-adduct (Compound 1-10):

¹ H-NMR 300 MHz (CDCl ₃ ) δ 8.79-7.43 (m, 12H), 5.31-4.00 (m, 8H).

FABMS m / z : 1148 (M ⁺ H): calcd. (C ₈₄ H ₂₀ ), 1148.

[ Example  One] Fullerene  Electrochemical Properties of Derivative Compounds

In order to observe the electrochemical properties of the fullerene compounds prepared in Preparation Example 1, Preparation Example 5 and Preparation Example 6, the oxidation / reduction characteristics using a cyclovoltameter (CV) were observed. CV equipment was BAS 100 cyclovoltametry, 0.1M Bu ₄ NBF ₄ (Tetrabutylammonium tetrafluoroborate) and acetonitrile (Acetonitrile) solvent was used as the electrolyte, the sample was 1,2-dichloro at a concentration of 10 ^-3 M Dissolved in benzene. Measured at a scan rate of 100 mV / s under Ar at room temperature, using a glass carbon electrode (0.3 mm in diameter) as a working electrode, using a Pt and Ag / AgCl electrode as a counter electrode and a reference electrode Figure 1 And in Table 1 below.

[Table 1] Electrochemical Properties of Fullerene Compounds Containing Aromatic Fusion Rings

^a Half wave potential was determined using a Ferrocene reference material with 0.1 M Bu ₄ NPF ₆ Obtained under CH ₂ Cl ₂ solution.

^b Energy level of Ferrocene calculated as -4.8 eV.

In general, the open circuit voltage (Voc) of organic solar cells is known to be due to the difference between the HOMO energy level of the donor material and the LUMO energy level of the acceptor material (CJ Brabec et al, Adv . Func . Mater . , 2001, 11 , 374). As shown in Table 1, the fullerene compounds including the aromatic fused ring of the present invention have a LUMO energy level of about 0.18 to 0.20 eV higher than that of the conventional PCBM, thereby obtaining a higher open voltage in the organic solar cell device.

Example 2 Organic Solar Cell Device Using P3HT and Compound 1-1 as Photoactive Layers

After spin-coating PEDOT-PSS (Bayer Baytron P, Al 4083) about 40 nm on an indium tin oxide (ITO) glass substrate (surface resistance of 7 μs / sq), poly (3-hexylthiophene) [Poly Fullerene (Compound 1-1) containing -3- (hexylthiophene), P3HT, and Rieke Metal Co., Ltd. and the aromatic fused ring prepared in the present invention may be 1,2-dichlorobenzene, chlorobenzene, chloroform alone or a mixed solvent thereof. Melted in to form an organic thin film by spin coating or the like. LiF / Al was deposited on the organic film thus formed as an electrode at 0.7 nm and 120 nm under vacuum, and then encapsulated with a glass cap attached with a moisture absorbent. The encapsulated device was annealed at 150 ° C. for 10 minutes, and then IV characteristics were measured under a light source of AM 1.5G 100 mW / cm ² using Newport's Class A artificial solar simulator. Light quantity of the light source was corrected using a BS520 silicon photodiode of Bunkoh-Keiki.

As a result, the electrochemical characteristics of the organic solar cell device are as shown in Figure 2, summarized in Table 2 below.

Example 3 Organic Solar Cell Device Using P3HT and Compound 1-6 as Photoactive Layers

As in Example 2, except that Compound 1-6 was used instead of Compound 1-1 as the photoactive layer acceptor material.

As a result, the electrochemical characteristics of the organic solar cell device are as shown in Figure 2, summarized in Table 2 below.

Comparative Example 1 Organic Solar Cell Device Using P3HT and PCBM as Photoactive Layer

As in Example 2, except that PCBM was used instead of Compound 1-1 as the photoactive layer acceptor material.

As a result, the electrochemical characteristics of the organic solar cell device are as shown in Figure 2, summarized in Table 2 below.

In general, the energy conversion efficiency (PCE, power conversion efficiency) of the solar cell can be obtained through the following equation (1).

[Calculation 1]

[Equation 1, Voc represents an open circuit voltage (V), a voltage in a state in which no current flows; Jsc is short circuit current density (mA / cm ² ), indicating current density at 0 V; FF is the fill factor, the maximum power divided by the product of Voc and Jsc ; Pinc represents the light intensity (mW / cm ² ) split.]

[Table 2] Comparison of characteristics of organic solar cell devices manufactured by mixing with P3HT.

As shown in Table 2, in the case of a device using a fullerene compound containing the aromatic fused ring of the present invention, it can be seen that showing a higher Voc value than the conventional PCBM. In particular, when using di-adducts such as compounds 1-1 and 1-6 as electron acceptor materials, high Voc values of 0.267 V and 0.276 V, respectively, were obtained. The result is a 50% improvement compared to the open circuit voltage of the organic solar cell device. Due to the improved open-circuit voltage, the short-circuit current is similar to that of PCBM, but the energy conversion efficiency of the organic solar cell device is 2.99% when the PCBM is improved by about 5%.

In addition, as a result of measuring the internal energy conversion efficiency (IPCE), the device using the compound 1-1 as the electron accepting material is somewhat lower in the 350 ~ 480 nm region than the device using the PCBM as the electron accepting material, 570 ~ 650 nm In the range of, the value was higher and the maximum efficiency was similar to 60%. Through this result, the short-circuit current (Jsc) of the two devices was able to verify similar results (FIG. 3).

The fullerene compound including the aromatic fused ring of the present invention is an n-type organic semiconductor material which is easy to synthesize and has excellent electron mobility, and is a device capable of obtaining high open voltage (Voc) as an acceptor material of an organic solar cell. It was possible to improve the energy conversion efficiency of the organic solar cell device, it is expected to be suitable for the production of large-area high efficiency organic solar cell as a material suitable for low-cost printing process because of excellent solubility.

1 is a Cyclicvoltamogram of Compounds 1-1, 1-5, 1-6 and PCBM of the present invention,

Figure 2 compares the organic solar cell characteristics of Examples 2, 3 and Comparative Example 1 of the present invention,

Figure 3 compares the results of the measurement of IPCE (internal energy conversion efficiency) of the organic solar cell of Example 2 and Comparative Example 1 of the present invention.

Claims (6)

Fullerene derivative for an organic solar cell device of the compound of Formula 1. [Formula 1]

[In Formula 1, R ¹ to R ⁴ are independently selected from a hydrogen atom and linear or crushed (C1-C20) alkyl, or are connected to adjacent substituents with (C4-C8) alkenylene to form an aromatic fused ring The alkenylene is substituted with 1 to 3 heteroatoms selected from an oxygen atom, a nitrogen atom or a sulfur atom to form a heteroaromatic fused ring; A is the fullerene of C60 or C70.] The method of claim 1, In Chemical Formula 1, R ¹ to R ⁴ are independently selected from hydrogen and methyl, or R ² and R ³ are connected to alkenylene of C 4 to form an aromatic fused ring fullerene for an organic solar cell device. derivative. The method of claim 1, The compound of formula 1 is a fullerene derivative for an organic solar cell device, characterized in that selected from the following compounds.

An organic solar cell device comprising a fullerene derivative for an organic solar cell device according to claim 1. The method of claim 4, wherein The organic solar cell device, characterized in that the fullerene derivative compound for organic solar cell device is a dopant. An organic solar cell device formed by any one selected from the group consisting of a solution process method and a deposition method of the fullerene derivative for an organic solar cell device according to claim 1.

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