KR101608504B1 - Organic solar cell and the manufacturing method thereof - Google Patents

Abstract

The present invention provides an organic solar cell and a manufacturing method thereof. The organic solar cell comprises: a substrate; a cathode that is stacked on top of the substrate; an electron transporting layer which is stacked on top of the cathode and is made of a single molecule or macromolecule including a fourth ammonium compound within the molecule; a photoactive layer which is stacked on top of the electron transporting layer; a hole transporting layer which is stacked on the photoactive layer; and an anode which is stacked on top of the hole transporting layer. The organic solar cell according to the present invention is a solar cell in which a single molecule or macromolecule including a fourth ammonium compound within the molecule is introduced in an electron transporting layer in place of a metallic oxide conventionally used in an electron transporting layer. The organic solar cell has an effect in which electron transfer capability is improved via work function control of the cathode. Accordingly, provided is an effect that the photoelectric conversion efficiency of the organic solar cell is improved. Furthermore, the organic solar cell enables a low-temperature process and is thus economical since the single molecule or macromolecule including the fourth ammonium compound within the molecule is used as the electron transporting layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic solar cell,

The present invention relates to an organic solar cell and a method of manufacturing the same, and more particularly to an organic solar cell including an electron transport layer made of a single molecule or a polymer containing a quaternary ammonium compound.

Recently, the need to develop environmentally friendly new and renewable energy is emerging in order to cope with various environmental problems such as global warming due to the energy supply and demand due to the surge in oil prices and the greenhouse effect caused by carbon dioxide emitted from the use of fossil fuels. Among the renewable energy sources such as hydroelectric power, wind power, fuel cell, and solar cell, which are replacing fossil fuels that are beginning to reveal the limit of reserves, the solar power generation is not only environmentally friendly and safe, but also infinite energy It is widely regarded as a circle.

Silicon solar cells are currently commercialized because they realize high energy conversion efficiency, but they are easily found in real life. However, the demand for silicon is continuously increasing in the semiconductor industry and the price of raw materials is rising. Silicon has a low light absorption coefficient, The manufacturing cost is high because it must be made thick. In addition to the economic difficulties in raw material supply and demand, it has limitations in terms of not only high-priced manufacturing process, capacity of batteries but also size. As an alternative to overcome the limitations of such inorganic solar cells, nano thin film type organic solar cells using polymeric materials have been actively studied.

Organic solar cells can be expected to have high productivity because they can be made into a large area through solution-based printing processes such as spin coating, roll-to-roll, and ink-jet printing while using cheap polymers. Conjugated polymer, which is the core material of organic solar cell, has a high extinction coefficient and can sufficiently absorb solar light even at a thin thickness, making it possible to fabricate a thin device with a thickness of several hundreds of the entire device, It can be applied to various fields because it is limited in weight, thickness, and shape.

In general, the basic structure of an organic solar cell is a metal / photoactive layer / metal (metal / insulator / metal) structure. The photoactive layer generally uses a conjugated polymer as a hole acceptor, and as an electron acceptor, a polymer having a higher electron affinity than a conjugated polymer, a fullerene derivative, or an inorganic nano-particle is used . (For example, ITO, PEDOT: PSS or the like) having a high work function is used as the anode and a metal electrode (for example, Al, Ca or the like) having a low work function is used for the cathode This is called a conventional structure. However, metal electrodes such as aluminum (Al) and calcium (Ca), which are mainly used in conventional structures, are easily oxidized in the air, so that there is a problem that it is difficult to fundamentally solve the problem of lifetime of the device.

Accordingly, an inverted structure using a transparent electrode as a cathode and a metal having a high work function such as gold (Au) as an anode has been introduced as opposed to a conventional structure. In the organic solar cell of the invert structure, various metal oxides such as TiO ₂ , ZnO, NiO and MoO ₃ are actively studied as the electron transport layer because the metal oxide is very stable in air and excellent in mechanical and electrical properties, Because it has a merit of being inexpensive and transparent in the visible light region.

In the conventional invert organic solar cell, since a difference in energy band gap is large between a transparent electrode such as ITO used as a cathode and a fullerene derivative used as an electron acceptor of a photoactive layer, a band gap is required to form a good junction A buffer layer is needed between the two materials. In the organic solar cell, various metal oxides such as TiO ₂ and ZnO are used as the buffer layer as the electron transport layer. However, due to the inherent incompatibility between the organic photoactive layer and the inorganic metal oxide, high interface resistance is exhibited, Therefore, there is a problem that the metal oxide alone has a limitation. Further, the metal oxide is generally formed through heat treatment at a high temperature of 200 ° C or higher.

In order to solve the above problems, Korean Patent No. 10-1130516 discloses a high efficiency organic solar cell device and a manufacturing method thereof. More particularly, the present invention relates to an organic solar cell in which a self-assembled layer containing a silane-based material is formed between a photoactive layer of an invert organic solar cell and an n-type metal oxide layer to improve structural stability and charge transport efficiency.

In order to improve the efficiency of an organic solar cell, the present inventors have found that when a quaternary ammonium compound having a functional group capable of chemical bonding with a surface of a negative electrode is contained in a molecule instead of a metal oxide generally used as an electron transporting layer The present inventors have developed an organic solar cell having improved performance by improving the electron transporting ability by controlling a work function of a cathode by introducing a single molecule or a polymer.

An object of the present invention is to provide an organic solar cell with improved performance and a method of manufacturing the same.

In order to achieve the above object,

Board;

A cathode stacked on the substrate;

An electron transport layer composed of a single molecule or a polymer containing in the molecule a quaternary ammonium compound stacked on the cathode;

A photoactive layer stacked on the electron transport layer;

A hole transport layer deposited on the photoactive layer; And

And a cathode stacked on the hole transport layer.

In addition,

Forming a cathode on the substrate (step 1);

A step (step 2) of forming an electron transport layer made of a single molecule or a polymer containing a quaternary ammonium compound in the molecule on the anode formed in the step 1;

Forming a photoactive layer on the electron transporting layer formed in step 2 (step 3);

Forming a hole transport layer on the photoactive layer formed in Step 3 (Step 4); And

And forming an anode on the hole transporting layer formed in step 4 (step 5).

The organic solar cell according to the present invention is a solar cell in which a single molecule or a polymer containing a quaternary ammonium compound in its molecule is introduced into an electron transport layer instead of a metal oxide conventionally used as an electron transport layer, There is an effect that the electron transfer ability is improved through work function control. Thereby, the photoelectric conversion efficiency of the organic solar battery is improved. In addition, the organic solar cell is economical because a low-temperature process can be performed by using a single molecule or a polymer containing a quaternary ammonium compound in the molecule as an electron transport layer.

1 is a schematic view showing the structure of an organic solar cell according to the present invention;
2 is a photograph of the shape of an electron transport layer made of a single molecule or a polymer containing a quaternary ammonium compound according to the present invention in a molecule by an atomic force microscope (AFM);
FIG. 3 is a graph showing the effect of an electron transport layer made of a single molecule or a polymer containing a quaternary ammonium compound according to the present invention in a molecule by UPS spectrum;
4 to 7 are graphs showing optical power conversion efficiencies of the organic solar cells manufactured in Examples 1 to 4 and Comparative Example 1 according to the present invention under standard conditions.

The present invention

Board;

A cathode stacked on the substrate;

An electron transport layer composed of a single molecule or a polymer containing in the molecule a quaternary ammonium compound stacked on the cathode;

A photoactive layer stacked on the electron transport layer;

A hole transport layer deposited on the photoactive layer; And

And a cathode stacked on the hole transport layer.

Here, as an example of the organic solar cell according to the present invention, Fig. 1 shows the structure of the organic solar cell in a schematic view,

Hereinafter, the organic solar cell according to the present invention will be described in detail.

The conventional invert organic solar cell 10 exhibits a high interface resistance due to the inherent incompatibility between the electron transporting layer 102, which is an inorganic material such as a metal oxide, and the photoactive layer 103, which is an organic material, Therefore, there is a problem that the metal oxide alone has a limitation.

In order to solve the above-mentioned problems, it has been proposed to use a single molecule or a polymer containing a quaternary ammonium compound having a functional group capable of chemical bonding with the surface of a negative electrode instead of an inorganic substance such as a metal oxide conventionally used as an electron transport layer Is used as an electron transporting layer. By using a monomolecular or polymer containing a quaternary ammonium compound in the molecule as an electron transporting layer, the work function of the cathode is controlled and the electron transporting ability is improved.

An organic solar battery 10 according to the present invention includes a substrate 100, a cathode 101, an electron transport layer 102, a photoactive layer 103, a hole transport layer 104 and a cathode 105, (102) is characterized by being composed of a single molecule or a polymer containing a quaternary ammonium compound in the molecule.

In the organic solar cell 10 according to the present invention, the substrate 100 can be used without limitation as long as it supports an organic solar cell and is transparent material capable of emitting light incident from the outside such as sunlight. However, A substrate made of a polymer material such as a glass substrate or a polycarbonate, a polyethylene terephthalate, a polyethylene naphthalate, a polyimide, a polypropylene, and a polyacrylate Can be used.

In the organic solar battery 10 according to the present invention, the cathode 101 is laminated on the substrate 100.

The cathode 101 has electrical conductivity and can be used without limitation as long as it is a transparent material. Preferably, the anode 101 is made of indium tin oxide (ITO), antimony tin oxide (ATO), fluorine tin oxide (FTO) (AZO), gallium-doped zinc oxide (GZO), silver nanoparticles, silver nanowires, and carbon nanotubes (CNT).

The cathode 101 may be deposited by a method such as DC sputtering, chemical vapor deposition (CVD), atomic layer deposition (ALD), and sol-gel coating. Silver nanoparticles, silver nanowires And carbon nanotubes (CNTs) may be coated and used.

The thickness of the cathode 101 is preferably 100 nm to 1,000 nm, but is not limited thereto.

In the organic solar battery 10 according to the present invention, the electron transport layer 102 is stacked on the cathode 101.

The electron transport layer 102 is characterized in that the electron transport layer 102 is made of a single molecule or a polymer containing a quaternary ammonium compound capable of interacting with a hydroxyl group (-OH) existing on the surface of the cathode 101 such as a transparent electrode .

The conventional invert organic solar cell 10 exhibits a high interface resistance due to the inherent incompatibility between the electron transporting layer 102, which is an inorganic material such as a metal oxide, and the photoactive layer 103, which is an organic material, Therefore, there is a problem that the metal oxide alone has a limitation.

In order to solve the above-mentioned problems, it has been proposed to use a single molecule or a polymer containing a quaternary ammonium compound having a functional group capable of chemical bonding with the surface of a negative electrode instead of an inorganic substance such as a metal oxide conventionally used as an electron transport layer Is used as an electron transporting layer. By using a monomolecular or polymer containing a quaternary ammonium compound in the molecule as an electron transporting layer, the work function of the cathode is controlled and the electron transporting ability is improved.

At this time, the monomers containing the quaternary ammonium compound in the molecule may be a compound represented by the general formula (1).

≪ Formula 1 >

(In the formula 1,

R ₁ to R ₄ are each independently a C _{1 ~ 20} linear alkyl, C _{4 -20} branched-chain alkyl, C _{1 ~ 20} linear alkenyl, C _{5 ~ 20} branched chain alkenyl, C _{5 -12} of the aryl, a branched chain alkyl of C _{5 -12} aryl C _{1 -6} straight-chain alkyl or C _{5 -12} aryl C _{4 -6} for the,

X ^- is a halogen ion or a hydroxide ion (OH ^- ).

As a specific example, the monomers containing the quaternary ammonium compound in the molecule may be selected from the group consisting of tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium iodide, But are not limited to, tetraethylammonium iodide, tetrapropylammonium iodide, tetrahexylammonium iodide, diallyldimethylammonium chloride, trimethyl-phenyl-ammonium iodide, phenyl-ammonium iodide, trimethyl- (1-phenyl-ethyl) -ammonium bromide, trimethyl- (1-phenyl- ethyl-ammonium iodide) 1-phenyl-ethyl) -ammonium iodide, allyl-benzyl-diethyl-ammonium bromide and Benzyltrimethylammonium hydroxide, and the like.

Also, the polymer containing the quaternary ammonium compound in the molecule may be poly (diallyldimethylammonium chloride), poly (acrylamide-co-diallyldimethylammonium chloride) (poly (acrylamide-co- bis (2-chloroethyl) ether-alt-1,3-bis [3- (dimethylamino) propyl] urea] quaternarnide (diallyldimethylammonium chloride) and poly [bis 1,3-bis [3- (dimethylamino) propyl] urea] quaternized) and the like.

Furthermore, the thickness of the electron transporting layer made of a single molecule or a polymer containing the quaternary ammonium compound in the molecule may be 0.1 nm to 100 nm, preferably 0.5 nm to 10 nm. If the thickness of the electron transporting layer made of a single molecule or a polymer containing the quaternary ammonium compound in the molecule is less than 0.1 nm, there is a problem that the photoactive layer 103 and the cathode 101 are brought into contact with each other and short- , The electron transfer rate is rather slow and the photoelectric conversion efficiency of the solar cell is reduced.

The electron transport layer 102 may be deposited through a coating process. The coating process may be performed by a spin coating process, a dip coating process, a spray coating process, an inkjet coating process, a screen printing process, a bar coating process, A coating method, a doctor blade coating method, a gravure printing method and the like can be used, but any method capable of coating an organic material can be used without being limited thereto.

In addition, the coating may be performed using an aqueous solution containing a monomolecular or polymer containing 0.05 wt% to 5 wt% of a quaternary ammonium compound in the molecule with respect to the entire aqueous solution, but is not limited thereto.

Furthermore, the aqueous solution may be added with an acidic or basic substance, if necessary, to promote the interaction, but the present invention is not limited thereto.

In the organic solar battery 10 according to the present invention, the photoactive layer 103 is stacked on the electron transporting layer 102.

The photoactive layer 103 is a part that generates light by separating electrons and holes and receives the light. The photoactive layer 103 is a heterojunction in which an electron acceptor and a hole acceptor are mixed, Bulk heterojunction structure.

The hole acceptor may be a thiophene polymer derivative such as poly (3-hexylthiophene) (P3HT), polysiloxane carbazole, poly [[9- (1-octylnonyl) -9H-carbazole-2,7-diyl] -2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]) and the like, PCPDTBT (poly [2,1,3-benzothiadiazole-4,7 di [4,4-bis (2-ethylhexyl) -4H-cyclopenta [2,1-b: 3,4-b '] dithiophene-2,6-diyl] alkyloxybenzo (1,2-b: 4,5-b) dithiophene-2,6-diyl-lower- (alkylthieno (3,4-b) thiophene-2-carboxylate) -2,6-diyl] (PBDTTT) , PTB7 (poly [[4,8-bis [(2-ethylhexyl) oxy] benzo [1,2- b: 4,5- b '] dithiophene-2,6- (9,9'-hexylfluorene) -alt-2 (2-ethylhexyl) carbonyl] thieno [3,4-b] thiophenediyl]]) and the like, PFDTBT (3-dimethyl-5,7-dithien-2-yl-2,1,3-benzothiadiazole)), polyaniline, polyethylene oxide, poly Perth 1) -2,5-phenylene-vinylene, polyindole, polycarbazole, polypyridazine, polyisothianaphthalene, polyphenylene sulfide, polyvinylpyridine, polythiophene, polyfluorene, Derivatives thereof, etc. may be used,

The electron acceptor may be a fullerene derivative such as fullerene, PCBM ([6,6] Phenyl-C61-butyric acid methyl ether), PC ₇₀ BM ([6,6] -phenyl-C71-butyric acid methyl ether), polybenzimidazole ), PTCBI (3,4,9,10-Perylenetetracarboxylic bisbenzimidazole), and the like, but are not limited thereto.

At this time, the photoactive layer 103 may be laminated using a solution in which the above materials are dissolved or dispersed, and may be formed by a spin coating method, a spray coating method, a screen printing method, a bar coating method, a doctor blade coating method, Printing, or the like. However, the method can be used without limitation as long as it can coat the metal oxide.

The thickness of the photoactive layer 103 is preferably 50 nm to 300 nm, but is not limited thereto.

In the organic solar cell 10 according to the present invention, the hole transport layer 104 is stacked on the photoactive layer 103.

The hole transport layer 104 may include a compound capable of transporting holes, as well as a function of blocking electrons, as well as a compound having excellent thin film forming ability. Preferred examples thereof include PEDOT: PSS (poly (3,4-ethylenedioxythiophene)), tungsten oxide (WO ₃ ), nickel oxide (NiO), molybdenum oxide (MoO ₂ , MoO ₃ ) and cerium-doped tungsten oxide (CeWO ₃ ).

The hole transport layer 104 may be formed by a spin coating method, a spray coating method, a screen printing method, a bar coating method, a doctor blade coating method, or the like. The hole transporting layer 104 may be deposited by vacuum evaporation or sputtering It is possible.

The thickness of the hole transport layer 104 is preferably 1 nm to 100 nm, but is not limited thereto.

In the organic solar battery 10 according to the present invention, the anode 105 is stacked on the hole transport layer 104.

The anode 105 may be an electrode material such as a metal, an alloy, an electrically conductive compound, or a mixture thereof having a large work function, but is not limited thereto. For example, metals such as silver (Ag), platinum (Pt), tungsten (W), copper (Cu), molybdenum (Mo), gold (Au), nickel (Ni) and palladium But they are not limited thereto.

At this time, the thickness of the anode 105 is preferably 0.1 탆 to 5 탆, but is not limited thereto.

The present invention

Forming a cathode on the substrate (step 1);

A step (step 2) of forming an electron transport layer made of a single molecule or a polymer containing a quaternary ammonium compound in the molecule on the anode formed in the step 1;

Forming a photoactive layer on the electron transporting layer formed in step 2 (step 3);

Forming a hole transport layer on the photoactive layer formed in Step 3 (Step 4); And

And forming an anode on the hole transporting layer formed in step 4 (step 5).

Hereinafter, a method of manufacturing an organic solar cell according to the present invention will be described in detail for each step.

In the method of manufacturing an organic solar cell according to the present invention, step 1 is a step of forming a cathode on a substrate.

At this time, the substrate of step 1 can be used without limitation as long as it is a transparent material that supports the organic solar cell and allows light incident from the outside such as sunlight to enter. Preferably, the substrate is a glass substrate or polycarbonate, A substrate made of a polymer material such as polyethylene terephthalate, polyethylene naphthalate, polyimide, polypropylene, and polyacrylate can be used.

The negative electrode of step 1 has electrical conductivity and may be any of a transparent material and may be used without limitation. Preferably, indium tin oxide (ITO), antimony tin oxide (ATO), fluorine tin oxide (FTO) (AZO), gallium-doped zinc oxide (GZO), silver nanoparticles, silver nanowires, and carbon nanotubes (CNTs).

The cathode 101 of the step 1 may be deposited by a method such as DC sputtering, chemical vapor deposition (CVD), atomic layer deposition (ALD) and sol-gel coating. Silver nanoparticles, May be coated with nanowires and carbon nanotubes (CNTs).

The thickness of the negative electrode formed in step 1 is preferably 100 to 1,000 nm, but is not limited thereto.

Furthermore, it is preferable that the negative electrode formed in the step 1 is immersed in acetone, alcohol, water or a mixed solution thereof, followed by ultrasonic cleaning and drying to proceed to the next step.

Next, in the method for manufacturing an organic solar cell according to the present invention, Step 2 is a step of forming an electron transport layer made of a single molecule or a polymer containing a quaternary ammonium compound in the molecule on the anode formed in Step 1 above.

The conventional invert organic solar cell has a problem of limitation due to metal oxide because it has a low electron transfer rate due to a high interfacial resistance due to a source incompatibility problem between an electron transport layer which is an inorganic material such as a metal oxide and a photoactive layer which is an organic material have.

In order to solve the above problems, in step 2, a quaternary ammonium compound having a functional group capable of chemical bonding with the surface of the negative electrode is substituted into an inorganic substance such as a metal oxide, which is conventionally used as an electron transport layer, The electron transport layer is formed using a single molecule or a polymer. By using a monomolecular or polymer containing a quaternary ammonium compound in the molecule as an electron transporting layer, the work function of the cathode is controlled and the electron transporting ability is improved.

Further, by using a monomolecular or polymer containing a quaternary ammonium compound in the molecule as the electron transporting layer in the step 2, a low temperature process is possible, which is economical.

Specifically, in the step 2, the electron transporting layer can be formed using a single molecule or a polymer containing a quaternary ammonium compound capable of interacting with a hydroxyl group (-OH) existing on the surface of a negative electrode such as a transparent electrode have.

At this time, the monomolecular molecule containing the quaternary ammonium compound of the step 2 in the molecule may be a compound represented by the general formula (1).

≪ Formula 1 >

(In the formula 1,

R ₁ to R ₄ are each independently a C _{1 ~ 20} linear alkyl, C _{4 -20} branched-chain alkyl, C _{1 ~ 20} linear alkenyl, C _{5 ~ 20} branched chain alkenyl, C _{5 -12} of the aryl, a branched chain alkyl of C _{5 -12} aryl C _{1 -6} straight-chain alkyl or C _{5 -12} aryl C _{4 -6} for the,

X ^- is a halogen ion or a hydroxide ion (OH ^- ).

As a specific example, the monomers containing the quaternary ammonium compound of the step 2 in the molecule may be selected from the group consisting of tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium bromide, Tetraethylammonium iodide, tetrapropylammonium iodide, tetrahexylammonium iodide, diallyldimethylammonium chloride, trimethyl-phenyl-ammonium iodide, tetraethylammonium iodide, phenyl-ethyl-ammonium iodide, trimethyl- (1-phenyl-ethyl) -ammonium bromide, trimethyl- (1-phenyl- ethyl- ammonium iodide trimethyl- (1-phenyl-ethyl) -ammonium iodide, allyl-benzyl-diethyl-ammonium bromide, benzyltrimethylammonium hydroxide, and the like.

The polymer containing the quaternary ammonium compound in Step 2 in the molecule may be selected from the group consisting of poly (diallyldimethylammonium chloride) (poly (diallyldimethylammonium chloride), poly (acrylamide-co-diallyldimethylammonium chloride) bis (2-chloroethyl) ether] -co-diallyldimethylammonium chloride) and poly [bis (2-chloroethyl) ether-alt-1,3-bis [3- (dimethylamino) propyl] urea] quaternary 1,3-bis [3- (dimethylamino) propyl] urea] quaternized).

Further, the thickness of the electron transporting layer formed in the step 2 may be 0.1 nm to 100 nm, preferably 0.5 nm to 10 nm. If the thickness of the electron transporting layer formed in the step 2 is less than 0.1 nm, the photoactive layer and the negative electrode come into contact with each other to cause a short circuit. When the thickness exceeds 100 nm, the electron transporting rate is rather slow, Is reduced.

At this time, it may be formed by coating an aqueous solution containing a monomer or a polymer containing 0.05 wt% to 5 wt% of the quaternary ammonium compound in the molecule with respect to the entire aqueous solution of the step 2. The coating method may be a spin coating method, a dip coating method, a spray coating method, an ink jet coating method, a screen printing method, a bar coating method, a drop casting method, a coating method, a doctor blade coating method, However, the method can be used without limitation as long as it can coat the organic material.

Furthermore, the aqueous solution may be supplemented with an acidic or basic substance, if necessary, to promote the interaction.

Next, in the method of manufacturing an organic solar cell according to the present invention, Step 3 is a step of forming a photoactive layer on the electron transport layer formed in Step 2 above.

At this time, the photoactive layer of step 3 is a part that receives light and generates electrons and holes to generate a current, and the photoactive layer is a heterogeneous junction in which an electron acceptor and a hole acceptor are mixed, And may be formed with a heterojunction structure.

The hole acceptor may be a thiophene polymer derivative such as poly (3-hexylthiophene) (P3HT), polysiloxane carbazole, poly [[9- (1-octylnonyl) -9H-carbazole-2,7-diyl] -2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]) and the like, PCPDTBT (poly [2,1,3-benzothiadiazole-4,7 di [4,4-bis (2-ethylhexyl) -4H-cyclopenta [2,1-b: 3,4-b '] dithiophene-2,6-diyl] alkyloxybenzo (1,2-b: 4,5-b) dithiophene-2,6-diyl-lower- (alkylthieno (3,4-b) thiophene-2-carboxylate) -2,6-diyl] (PBDTTT) , PTB7 (poly [[4,8-bis [(2-ethylhexyl) oxy] benzo [1,2- b: 4,5- b '] dithiophene-2,6- (9,9'-hexylfluorene) -alt-2 (2-ethylhexyl) carbonyl] thieno [3,4-b] thiophenediyl]]) and the like, PFDTBT (3-dimethyl-5,7-dithien-2-yl-2,1,3-benzothiadiazole)), polyaniline, polyethylene oxide, poly Perth 1) -2,5-phenylene-vinylene, polyindole, polycarbazole, polypyridazine, polyisothianaphthalene, polyphenylene sulfide, polyvinylpyridine, polythiophene, polyfluorene, Derivatives thereof, etc. may be used,

The electron acceptor may be a fullerene derivative such as fullerene, PCBM ([6,6] Phenyl-C61-butyric acid methyl ether), PC70BM ([6,6] -phenyl- PTCBI (3,4,9,10-Perylenetetracarboxylic bisbenzimidazole), and the like, but are not limited thereto.

The photoactive layer of step 3 may be laminated using a solution in which the above materials are dissolved or dispersed. As the solvent used in this step, chloroform, chlorobenzene, 1,2-dichlorobenzene, 1,2,4-trichloro But are not limited to, polar solvents such as toluene, toluene, and toluene.

Further, the solution in which the above materials are dispersed may be laminated by a method such as spin coating, spray coating, screen printing, bar coating, doctor blade coating, gravure printing, etc. However, But the present invention is not limited thereto.

The thickness of the photoactive layer formed in step 3 is preferably 50 nm to 300 nm, but is not limited thereto.

Next, in the method of manufacturing an organic solar cell according to the present invention, Step 4 is a step of forming a hole transport layer on the photoactive layer formed in Step 3 above.

At this time, the hole transport layer in the step 4 may include a compound having a capability of transporting holes, as well as a property of blocking electrons, as well as an ability of forming a thin film. Preferred examples thereof include PEDOT: PSS (poly (3,4-ethylenedioxythiophene)), tungsten oxide (WO ₃ ), nickel oxide (NiO), molybdenum oxide (MoO ₂ , MoO ₃ ) and cerium-doped tungsten oxide (CeWO ₃ ).

The hole transport layer in step 4 may be deposited by a spin coating method, a spray coating method, a screen printing method, a bar coating method, a doctor blade coating method, or the like, and may be deposited by vacuum evaporation or sputtering It is possible.

Furthermore, the thickness of the hole transporting layer formed in step 4 is preferably 1 nm to 100 nm, but is not limited thereto.

Next, in the method of manufacturing an organic solar cell according to the present invention, Step 5 is a step of forming an anode on the hole transporting layer formed in Step 4 above.

At this time, the anode of step 5 may be an electrode material such as a metal, an alloy, an electrically conductive compound, or a mixture thereof having a large work function, but is not limited thereto. For example, metals such as silver (Ag), platinum (Pt), tungsten (W), copper (Cu), molybdenum (Mo), gold (Au), nickel (Ni) and palladium But they are not limited thereto.

The thickness of the positive electrode formed in step 5 is preferably 0.1 to 5 占 퐉, but is not limited thereto.

Hereinafter, the present invention will be described in more detail with reference to the following Examples and Experimental Examples.

However, the following examples and experimental examples are intended to illustrate the contents of the present invention, but the scope of the invention is not limited by the examples and the experimental examples.

≪ Example 1 > Preparation of organic solar cell 1

Step 1: A substrate on which a transparent electrode made of ITO (sheet resistance of 15 Ω / sq, thickness: 1,500 Å) was formed as a negative electrode on a glass substrate was immersed in acetone, distilled water and isopropyl alcohol, Lt; / RTI > Thereafter, the surface treatment of the substrate was performed in a UV-ozone apparatus for 15 minutes.

Step 2: A solution prepared by dissolving poly (diallyldimethylammonium chloride) (poly (diallyldimethylammonium chloride)) (PDDAC) in an amount of 0.8 wt% in distilled water was spin-coated on the negative electrode formed in step 1 above, Lt; / RTI > to form an electron transporting layer.

Step 3: In step 2, the substrate on which the electron transporting layer was formed was transferred to a glove box in a dry nitrogen atmosphere with oxygen of 1 ppm or less, and 12.5 mg of P3HT (poly (3-hexylthiophene) 12.5 mg of PC ₇₀ BM ([6,6] -Phenyl-C71-butyric acid methyl ether) (manufactured by Nano-C) as a hole receptor material was dissolved in 1 mL of chlorobenzene to prepare a photoactive layer solution .

Thereafter, the photoactive layer solution was coated on the electron transport layer having the self-assembled layer formed by spin coating and dried at room temperature for 20 minutes. Thereafter, the resultant was heat-treated for 10 minutes on a hot plate adjusted to 160 DEG C to form a photoactive layer having a thickness of 80 nm.

Step 4: To form a hole transport layer having a thickness of a substrate having a photoactive layer in the step 3, the MoO ₃ 10 nm for the photoactive layer under the upper set in a vacuum deposition apparatus, and a high vacuum (10 ^-6 torr).

Step 5: A silver (Ag) thin film having a thickness of 100 nm was formed on the hole transporting layer formed in the step 4 by a vacuum deposition method.

Then, the organic solar cell having the structure of glass substrate / ITO / PDDAC / P3HT: PC ₇₀ BM / MoO ₃ / silver was manufactured through a sealing process.

≪ Example 2 > Preparation of organic solar cell 2

(Acrylamide-co-diallyldimethylammonium chloride) (P (AAm-co-DADMAC)) was added to distilled water in an amount of 0.5% by weight in the step 2 of Example 1, The organic solar cell having the structure of glass substrate / ITO / P (AAm-co-DADMAC / P3HT: PC ₇₀ BM / MoO ₃ / silver) was produced in the same manner as in Example 1 except that the dissolved solution was spin- Respectively.

≪ Example 3 > Preparation of organic solar cell 3

The procedure of Example 1 was repeated except that a solution prepared by dissolving 1.0 wt% of tetrahexylammonium iodide (THAI) in distilled water over the negative electrode was spin-coated in Step 2 of Example 1, / ITO / THAI / P3HT: PC ₇₀ BM / MoO ₃ / silver.

Example 4 Production of Organic Solar Cell 4

The procedure of Example 1 was repeated except that 0.7 wt% of benzyltrimethylammonium hydroxide (BTMAH) in distilled water was spin-coated on the cathode in Step 2 of Example 1 to prepare a glass substrate / ITO / BTMAH / P3HT: PC ₇₀ BM / MoO ₃ / silver.

≪ Example 5 > Preparation of organic solar cell 5

The procedure of Example 1 was repeated, except that 1.0 wt% of tetramethylammonium chloride (TMAC) was dissolved in distilled water over the cathode in Step 2 of Example 1 to prepare a glass substrate / ITO / TMAC / P3HT: PC ₇₀ BM / MoO ₃ / silver.

≪ Example 6 > Preparation of organic solar cell 6

The procedure of Example 1 was repeated, except that 1.0 wt% of tetramethylammonium bromide (TMAB) was dissolved in distilled water over the cathode in Step 2 of Example 1 to prepare a glass substrate / ITO / TMAB / P3HT: PC ₇₀ BM / MoO ₃ / silver.

Example 7 Production of Organic Solar Cell 7

The procedure of Example 1 was repeated except that 1.0 wt% of tetramethylammonium iodide (TMAI) dissolved in distilled water was spin-coated on the cathode in Step 2 of Example 1 to prepare a glass substrate / ITO / TMAI / P3HT: PC ₇₀ BM / MoO ₃ / silver.

≪ Example 8 > Preparation of organic solar cell 8

The procedure of Example 1 was repeated except that 0.7 wt% of tetraethylammonium iodide (TEAI) dissolved in distilled water was spin-coated on the cathode in Step 2 of Example 1 to prepare a glass substrate / ITO / TEAI / P3HT: PC ₇₀ BM / MoO ₃ / silver.

Example 9 Production of Organic Solar Cell 9

The procedure of Example 1 was repeated except that the solution of tetrapropylammonium iodide (TPAI) dissolved in distilled water at a concentration of 0.7 wt% on the anode was spin-coated in Step 2 of Example 1, / ITO / TPAI / P3HT: PC ₇₀ BM / MoO ₃ / silver.

Example 10 Production of Organic Solar Cell 10

The procedure of Example 1 was repeated except that a solution prepared by dissolving 0.7 wt% of diallyldimethylammonium chloride (DADMAC) in distilled water was applied on the anode in Step 2 of Example 1 to prepare a glass substrate / ITO / DADMAC / P3HT: PC ₇₀ BM / MoO ₃ / silver.

Example 11 Preparation of Organic Solar Cell 11

Except that 0.7 wt% of trimethyl-phenyl-ammonium iodide (TMPAI) dissolved in distilled water was spin-coated on the cathode in step 2 of Example 1, An organic solar cell having a structure of glass substrate / ITO / TMPAI / P3HT: PC ₇₀ BM / MoO ₃ / silver was prepared.

Example 12: Production of organic solar cell 12

In Step 2 of Example 1, a solution prepared by dissolving 0.7 wt% of trimethyl- (1-phenyl-ethyl) -ammonium bromide (TMPEAB) in distilled water over the negative electrode was spin- An organic solar cell having a glass substrate / ITO / TMPEAB / P3HT: PC ₇₀ BM / MoO ₃ / silver structure was prepared in the same manner as in Example 1 except for coating.

Example 13 Production of Organic Solar Cell 13

In Step 2 of Example 1, a solution prepared by dissolving trimethyl- (1-phenyl-ethyl-ammonium iodide, TMPEAI) in distilled water in an amount of 0.7 wt% ITO / TMPEAI / P3HT: PC ₇₀ BM / MoO ₃ / silver structure was prepared in the same manner as in Example 1, except that the spin coating was performed.

Example 14 Production of Organic Solar Cell 14

Bis [3- (dimethylamino) propyl] urea] quaternized (poly [bis (2-chloroethyl) The same procedure as in Example 1 was conducted except that 0.5% by weight of a solution obtained by dissolving 0.5% by weight of chloroethyl ether-alt-1,3-bis [3- (dimethylamino) propyl] urea] quaternized, Polyquaternium-2 in distilled water To prepare an organic solar cell having a glass substrate / ITO / Polyquaternium-2 / P3HT: PC ₇₀ BM / MoO ₃ / silver structure.

≪ Comparative Example 1 &

Step 1: A substrate on which ITO (sheet resistance of 15 Ω / sq, sheet resistance: 1,500 Å) transparent electrode was formed as a cathode on top of a glass substrate was immersed in acetone, distilled water and isopropyl alcohol, followed by ultrasonic cleaning for 15 minutes, Lt; / RTI > Thereafter, the surface treatment of the substrate was performed in a UV-ozone apparatus for 15 minutes.

Step 2: A ZnO precursor solution composed of Zinc acetate dihydrate, ethanolamine, and 2-methoxy ethanol was filtered using a 0.20 占 퐉 filter as an electron transport layer on the anode formed in the step 1, and then the anode surface was spin-coated Treated for 1 hour on a hot plate adjusted to 200 DEG C to form an electron transporting layer having a thickness of 30 nm.

Step 3: In step 2, the substrate on which the electron transporting layer was formed was transferred to a glove box in a dry nitrogen atmosphere with oxygen of 1 ppm or less, and 12.5 mg of P3HT (poly (3-hexylthiophene) 12.5 mg of PC ₇₀ BM ([6,6] -Phenyl-C71-butyric acid methyl ether) (manufactured by Nano-C) as a hole receptor material was dissolved in 1 mL of chlorobenzene to prepare a photoactive layer solution .

Thereafter, the photoactive layer solution was coated on the electron transport layer having the self-assembled layer formed by spin coating and dried at room temperature for 20 minutes. Thereafter, the resultant was heat-treated for 10 minutes on a hot plate adjusted to 160 DEG C to form a photoactive layer having a thickness of 80 nm.

Step 4: To form a hole transport layer having a thickness of a substrate having a photoactive layer in the step 3, the MoO ₃ 10 nm for the photoactive layer under the upper set in a vacuum deposition apparatus, and a high vacuum (10 ^-6 torr).

Step 5: A silver (Ag) thin film having a thickness of 100 nm was formed on the hole transporting layer formed in the step 4 by a vacuum deposition method.

Then, the organic solar cell having the structure of glass substrate / ITO / ZnO / P3HT: PC ₇₀ BM / MoO ₃ / silver was manufactured through a sealing process.

Experimental Example 1 Atomic Force Microscopy (AFM) Analysis

In order to confirm the surface shape of the electron transport layer made of a single molecule or a polymer containing the quaternary ammonium compound according to the present invention in the molecule, the ITO performed up to Step 1 of Example 1 and the step 2 of Example 1 were performed The surface of the electron transport layer was observed with an atomic force microscope (AFM). The results are shown in FIG.

As shown in FIG. 2, it was confirmed that a thin film of poly (diallyldimethylammonium chloride) (PDDAC), which is a polymer containing a quaternary ammonium compound in the molecule, was formed on the ITO surface.

<Experimental Example 2> UPS spectrum analysis

In order to confirm the effect of introduction of an electron transport layer made of a single molecule or a polymer containing a quaternary ammonium compound according to the present invention in the molecule, the ITO performed up to step 1 of the above-described example 1 and the step 2 of the above example 1 The electron transport layer was analyzed by UPS spectrum. The results are shown in FIG.

As shown in Fig. 3, it was confirmed that the work function of ITO as the negative electrode was reduced by 0.6 eV by introducing an electron transport layer made of a single molecule or a polymer containing a quaternary ammonium compound in the molecule. Accordingly, the work function of ITO is not greatly different from the LUMO energy level (4.2 eV) of the PC ₇₀ BM, which is a photoactive layer, and it is confirmed that electrons separated by light can be smoothly transferred from the photoactive layer to the cathode .

<Experimental Example 3> Analysis of photoelectric conversion efficiency of organic solar cell

In order to confirm the performance of the organic solar cell according to the present invention, the organic solar cell prepared in Examples 1 to 4 and Comparative Example 1 was measured with a solar simulator (Spectra phsics Co.) 1.5 (1 min, 100 mW / cm ² , 25 캜). The short circuit current density (J _SC ), open circuit voltage (V _OC ), fill factor (FF) and photoelectric conversion efficiency (η) of the solar cell were measured and the results are shown in FIGS. 4 to 7 and Table 1 .

As shown in Figs. 4 to 7 and Table 1, in the case of Comparative Example 1, which is an organic solar cell using a conventional metal oxide as the electron transporting layer, the photoelectric conversion efficiency was about 2.90%.

On the other hand, in Examples 1 to 4, in which an electron transport layer made of a single molecule or a polymer containing a quaternary ammonium compound in a molecule was formed, the photoelectric conversion efficiency was 3.09% to 3.33% And it was confirmed that it improved about 120% or more. In particular, referring to the short-circuit current density of Comparative Example 1 is the case of a 8.377 mA / cm ^2, embodiments can be confirmed that Examples 1 to 4 cases superior to 9.175 mA / cm ² to about 9.485 mA / cm ^2.

As described above, the organic solar cell according to the present invention is a solar cell in which a single molecule or polymer containing a quaternary ammonium compound is introduced into an electron transport layer instead of the metal oxide conventionally used as an electron transport layer, It was confirmed that the electron transfer ability was improved by controlling the work function of the cathode. This improves the photoelectric conversion efficiency of the organic solar cell.

Open-circuit voltage (V) Short circuit current density (mA / cm ² ) Filling factor (%) Photoelectric conversion efficiency (%) Example 1 0.602 9.485 58.28 3.33 Example 2 0.609 9.227 58.26 3.24 Example 3 0.601 9.329 57.91 3.24 Example 4 0.600 9.175 56.25 3.09 Comparative Example 1 0.609 8.377 56.77 2.90

10: Organic solar cell
100: substrate
101: cathode
102: electron transport layer
103: photoactive layer
104: hole transport layer
105: anode

Claims (14)

Board;
A cathode stacked on the substrate;
Poly (diallyldimethylammonium chloride) (poly (diallyldimethylammonium chloride)), poly (acrylamide-co-diallyldimethylammonium chloride) (poly (acrylamide-co (dimethylamino) propyl] urea] quaternized (poly [bis (2-chloroethyl) ether-alt-ldimethylammonium chloride) and poly [bis -1,3-bis [3- (dimethylamino) propyl] urea] quaternized);
A photoactive layer stacked on the electron transport layer;
A hole transport layer deposited on the photoactive layer; And
And a cathode stacked on the hole transport layer.
delete delete delete The method according to claim 1,
Wherein the thickness of the electron transporting layer is 0.1 nm to 100 nm.
The method according to claim 1,
The cathode may be formed of at least one of indium tin oxide (ITO), antimony tin oxide (ATO), fluorine tin oxide (FTO), aluminum doped zinc oxide (AZO), gallium doped zinc oxide (GZO) And carbon nanotubes (CNTs). The organic solar cell according to claim 1, wherein the conductive material is at least one selected from the group consisting of carbon nanotubes (CNTs).
The method according to claim 1,
Wherein the photoactive layer comprises an electron acceptor and a hole acceptor.
8. The method of claim 7,
Wherein the electron acceptor is at least one selected from the group consisting of fullerene, fullerene derivatives, polybenzimidazole (PBI), and PTCBI (3,4,9,10 perylenetetracarboxylic bisbenzimidazole).
8. The method of claim 7,
Wherein the hole acceptor is selected from the group consisting of poly (3-hexylthiophene) (P3HT), polysiloxane carbazole, PCDTBT, PCPDTBT, PBDTTT, PTB7, PFDTBT, polyaniline, polyethylene oxide, poly (1-methoxy- 1) -2,5-phenylene-vinylene, polyindole, polycarbazole, polypyridazine, polyisothianaphthalene, polyphenylene sulfide, polyvinylpyridine, polythiophene, polyfluorene, And derivatives thereof. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt;
The method according to claim 1,
The hole transport layer may be formed of at least one selected from the group consisting of poly (3,4-ethylenedioxythiophene) (PEDOT: PSS), tungsten oxide (WO ₃ ), nickel oxide (NiO), molybdenum oxide (MoO ₂ , MoO ₃ ) And cerium-doped tungsten oxide (CeWO ₃ ).
The method according to claim 1,
Wherein the anode is selected from the group consisting of Ag, Pt, W, Cu, Mo, Au, Ni and Pd Wherein the organic compound is at least one metal.
Forming a cathode on the substrate (step 1);
(Diallyldimethylammonium chloride), poly (acrylamide-co-diallyldimethylammonium chloride) (poly (acrylamide-co-diallyldimethylammonium chloride)) containing a quaternary ammonium compound in the molecule on the negative electrode formed in Step 1, bis (2-chloroethyl) ether] -co-diallyldimethylammonium chloride) and poly [bis (2-chloroethyl) ether-alt-1,3-bis [3- (dimethylamino) propyl] urea] quaternary -tallow-1,3-bis [3- (dimethylamino) propyl] urea] quaternized) (step 2);
Forming a photoactive layer on the electron transporting layer formed in step 2 (step 3);
Forming a hole transport layer on the photoactive layer formed in Step 3 (Step 4); And
And forming an anode on the hole transporting layer formed in step 4 (step 5).
13. The method of claim 12,
The electron transport layer in the step 2 may be a poly (diallyldimethylammonium chloride) (poly (diallyldimethylammonium chloride)) containing 0.05 wt% to 5 wt% of a quaternary ammonium compound in the molecule relative to the entire aqueous solution, 1,3-bis [3- (dimethylamino) propyl] urea] quaternized (poly (acrylamide-co-diallyldimethylammonium chloride)) and poly [bis A method of coating an aqueous solution containing at least one polymer selected from the group consisting of poly [bis (2-chloroethyl) ether-alt-1,3-bis [3- (dimethylamino) propyl] urea] quaternized Wherein the organic solar cell is formed on the substrate.
14. The method of claim 13,
Wherein the coating method is at least one method selected from the group consisting of spin coating, dip coating, inkjet printing, spray coating, screen printing, drop casting, painting, and doctor blade.

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