KR20160020121A - Perovskite solar cell and method of manufacturing the same - Google Patents

Abstract

An organic-inorganic hybrid perovskite solar cell is provided. The organic-inorganic hybrid perovskite solar cell of the present invention comprises an anode, a cathode, a photoactive layer disposed between the anode and the cathode, and a hole extraction layer disposed between the photoactive layer and the anode, wherein the photoactive layer includes an organic-inorganic hybrid perovskite and wherein the hole extraction layer has conductivity of 0.01 S/cm or more based on a thickness of 100 nm, is a self-assembled hole extraction layer including a conductive polymer and a fluorine-based material, and has a first surface disposed at the cathode and a second surface disposed at the photoactive layer, wherein a difference between absolutes values of a work function of the second surface and a high occupied molecular orbital (HOMO) level of the organic-inorganic hybrid perovskite may be no more than 0.1 eV. Accordingly, the self-assembled hole extraction layer is used to reduce an energy gap in an interface between the hole extraction layer and the photoactive layer, thereby providing a solar cell having improved photovoltaic conversion efficiency.

Description

The present invention relates to a perovskite solar cell and a method of manufacturing the same.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell, and more particularly, to an organic hybrid perovskite solar cell and a manufacturing method thereof.

At present, as interest in renewable energy is increasing worldwide, hybrid or perovskite solar cells, which have various advantages as future energy and report the usable efficiency, are attracting attention.

Hybrid Perovskite solar cell refers to a solar cell produced by combining inorganic and organic materials and using a material that has a perovskite crystal structure and is easily chemically synthesized. At this time, perovskite is a material of special structure which shows superconducting phenomenon together with non-conductor, semiconductor, conductor properties.

Such organic / inorganic hybrid perovskite solar cells are capable of manufacturing flexible thin film devices and manufacturing at a lower cost than inorganic solar cell devices. In addition, since it reports a higher efficiency than an organic solar cell, it has an advantage that it can be variously applied to various flexible devices to be industrialized in the future.

Conventional organic / inorganic hybrid perovskite solar cells may include a negative electrode, an electron extraction layer, an organic hybrid perovskite photoactive layer, a hole extraction layer, and a positive electrode. The light irradiated to the organic / inorganic hybrid perovskite solar cell is separated into electrons and holes in the photoactive layer, holes are extracted to the positive electrode through the hole extraction layer, and electrons are extracted to the negative electrode through the electron extraction layer.

However, as in Korean Patent Laid-Open No. 10-2014-0035285 (Apr. 31, 2014), when a mesoporous oxide semiconductor is used as an electron extraction layer in a conventional organic / inorganic hybrid perovskite solar cell, There is a problem that it can not be made.

In addition, when the conductive polymer is used as the hole extracting layer, the photoelectric conversion efficiency is unsatisfactory due to the energy gap at the interface between the hole extracting layer and the photoactive layer.

SUMMARY OF THE INVENTION The present invention provides a hybrid organic perovskite solar cell using a self-organized hole extraction layer (SOHEL), and a method of manufacturing the same.

According to an aspect of the present invention, there is provided an organic / inorganic hybrid perovskite solar cell. Wherein the organic / inorganic hybrid perovskite solar cell comprises a positive electrode, a negative electrode, a photoactive layer positioned between the positive electrode and the negative electrode, and a hole extraction layer located between the photoactive layer and the positive electrode, Wherein the hole extraction layer has a conductivity of 0.01 S / cm or more on the basis of 100 nm thickness, the hole extraction layer is a self-assembled hole extraction layer including a conductive polymer and a fluorine-based material, Layer has a first surface disposed on the anode side and a second surface disposed on the side of the photoactive layer, wherein a work function of the second surface and a HOMO (High Occupied Molecular Orbital) level of the organic / inorganic hybrid perovskite May be less than or equal to 0.1 eV.

And a buffer layer including a metal oxide, between the hole extracting layer and the hole extracting layer and between the hole extracting layer and the photoactive layer. At this time, MoO _3, NiO _x, or AgO _x .

Further, in the hole extracting layer, the conductive polymer and the fluorine-based substance may be uniformly mixed with each other.

The conductive polymer may be a polythiophene, a polyaniline, a polypyrrole, a polystyrene, a polyethylene dioxythiophene, a polyacetylene, a polyphenylene, a polyphenylvinylene, a polycarbazole, a copolymer containing two or more different repeating units thereof, Or a blend of two or more thereof.

Wherein the conductive polymer comprises a self-doped conducting polymer doped with at least one of an ionic group and a polymeric acid, the ionic group comprising an anionic group and a counter cationic group for the anionic group And the anionic group is selected from the group consisting of PO ₃ ^2- , SO ₃ ^- , COO ^- , I ^- , CH ₃ COO ^- and BO ₂ ^2- , and the cation group includes at least one of a metal ion and an organic ion , wherein the metal ion is ^{Na +, K +, Li +} , Mg +2, Zn ^+2, and is selected from the group consisting of Al ^+3, the organic ions are ^{_{H +, CH 3 (CH 2}} ) n NH 3 + (n is an integer of 0 to 50), NH ₄ ⁺ , NH ₂ ⁺ , NHSO ₂ CF ₃ ⁺ CHO ⁺ , C ₂ H ₅ OH ⁺ , CH ₃ OH ⁺ and RCHO ⁺ (R is CH ₃ (CH ₂ ) _n -; n is an integer from 0 to 50).

Further, the fluorine-based material may be an ionomer represented by the following Formula 1:

≪ Formula 1 >

In Formula 1,

0 < m? 10,000,000, 0? N <10,000,000, 0? A? 20, 0? B? 20;

A, B, A 'and B' are each independently selected from the group consisting of C, Si, Ge, Sn, and Pb;

Each of R ₁ , R ₂ , R ₃ , R ₄ , R ₁ ', R ₂ ', R ₃ 'and R ₄ ' is independently hydrogen, halogen, a nitro group, a substituted or unsubstituted amino group, unsubstituted C ₁ -C ₃₀ alkyl group, a substituted or unsubstituted C ₁ -C ₃₀ heteroaryl group, a substituted or unsubstituted C ₁ -C ₃₀ alkoxy group, a substituted or unsubstituted C ₁ -C ₃₀ heterocyclic alkoxy group, a substituted or unsubstituted C ₆ -C ₃₀ aryl group, a substituted or unsubstituted C ₆ -C aryl group, a substituted or unsubstituted aryloxy-substituted C ₆ -C _30, substituted or unsubstituted C _{2 30} - for C ₃₀ heteroaryl group, a substituted or unsubstituted C ₂ -C ₃₀ heteroarylalkyl group, a substituted or unsubstituted C ₂ -C ₃₀ heteroaryloxy group, a substituted or unsubstituted C ₅ -C ₂₀ in the bicyclo alkyl group, a substituted or unsubstituted C ₂ -C ₃₀ heterocycloalkyl group, a substituted or unsubstituted C ₁ -C ₃₀ alkyl ester group, a substituted or unsubstituted C ₁ -C ₃₀ heteroalkyl of S. Encircling, is selected from substituted or unsubstituted aryl ester group of the unsubstituted C ₆ -C ₃₀ and, a heteroaryl group consisting of ester group of a substituted or unsubstituted C ₂ -C _30, However, R _1, R _2, R _3, And R &lt; ₄ &gt; is an ionic group or an ionic group;

The X and X 'are each independently selected from a simple bond, O, S, substituted or unsubstituted C ₁ -C ₃₀ alkylene group, a substituted or unsubstituted C ₁ -C ₃₀ heteroalkylene group, substituted or unsubstituted C ₆ - C ₃₀ aryl group, a substituted or unsubstituted C ₆ -C ₃₀ aryl alkyl group, a substituted or unsubstituted C ₂ -C ₃₀ heteroaryl group, a substituted or unsubstituted heteroaryl group of C ₂ -C ₃₀ alkylene group of , A substituted or unsubstituted C ₅ -C ₂₀ cycloalkylene group, a substituted or unsubstituted C ₅ -C ₃₀ heterocycloalkylene group, a substituted or unsubstituted C ₆ -C ₃₀ aryl ester group, And an unsubstituted C ₂ -C ₃₀ heteroaryl ester group,

Provided that when n is 0, at least one of R ₁ , R ₂ , R ₃ , and R ₄ is a hydrophobic functional group containing a halogen element or includes a hydrophobic functional group.

The hole extraction layer may further include a carbon-based nanostructure. The carbon nanostructure may include a carbon nanotube, a graphene quantum dot, or a carbon dot.

Also, the organic or inorganic hybrid perovskite material may be CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbCl ₃ , CH ₃ NH ₃ PbBr ₃ , CH ₃ NH ₃ PbI _3-x Cl _x , CH ₃ NH ₃ Pb ( _{I 1-x Br x) 3} , HC (NH 2) 2 PbI 3, CH 3 NH 3 Sn 1-x Pb x I 3, HC (NH 2) 2 PbI y Br 3-y, (C 4 H 9 NH ₃ ) ₂ MI ₄ (M = Ge, Sn, Pb) or (CH ₃ NH ₃ ) _x (HC (NH ₂ ) ₂ ) _1-x PbI ₃ .

In addition, the absolute value of the HOMO level of the organic / inorganic hybrid perovskite material may be at least 5.1 eV.

The hole extracting layer may include a first layer including the conductive polymer and disposed on the anode side, and a second layer including the fluorine-based substance and disposed on the photoactive layer side.

According to another aspect of the present invention, there is provided a method of manufacturing a hybrid organic-inorganic hybrid solar cell. The method for manufacturing an organic / inorganic hybrid perovskite solar cell includes the steps of forming a positive electrode on a substrate, forming a hole extraction layer on the positive electrode, forming an organic hybrid perovskite on the hole extraction layer Forming a photoactive layer and a cathode on the photoactive layer, wherein the hole extraction layer has a conductivity of 0.01 S / cm or more on a thickness of 100 nm, and the hole extraction layer comprises a conductive polymer and a fluorine- Wherein the hole extraction layer has a first surface disposed on the anode side and a second surface disposed on the side of the photoactive layer, and the work function of the second surface and the organic / inorganic hybrid layer The difference between the absolute value of the HOMO (High Occupied Molecular Orbital) level of the Lobskyite may be 0.1 eV or less.

Further, after the step of forming the hole extraction layer, the surface of the hole extraction layer may be treated with UV-ozone or oxygen plasma.

The method may further include forming a buffer layer including a metal oxide on the anode, between the step of forming the anode and the step of forming the hole extraction layer.

The method may further include forming a buffer layer including a metal oxide on the hole extraction layer between the step of forming the hole extraction layer and the step of forming the photoactive layer.

According to the present invention, by using the self-assembled hole extraction layer, it is possible to reduce the energy gap at the interface between the hole extracting layer and the photoactive layer, thereby providing a solar cell having improved photoelectric conversion efficiency.

In addition, since the self-assembled hole extraction layer is flexible, the organic / inorganic hybrid perovskite solar cell can be manufactured as a flexible device having excellent photoelectric conversion efficiency and long life.

The technical effects of the present invention are not limited to those mentioned above, and other technical effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a cross-sectional view of an organic / inorganic hybrid perovskite solar cell according to an embodiment of the present invention.
2A is a cross-sectional view of another embodiment of the hole extracting layer.
2B is a cross-sectional view of another embodiment of the hole extracting layer.
3 is a graph showing the characteristics of the solar cell according to the comparative example and the example 1. Fig.
4 is a graph showing work function characteristics of the hole extraction layer according to the weight ratio of PFI and PEDOT: PSS.
FIGS. 5 and 6 are graphs showing voltage-current characteristics of the solar cell according to the comparative example and the example 1. FIG.
7 is a graph showing the voltage-current characteristics of the solar cell according to the second embodiment.
8 is an image and a graph showing a morphology of a hole extracting layer of a solar cell according to a comparative example.
9 is an image and a graph showing the morphology of the hole extracting layer of the solar cell according to the first embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. Rather, the intention is not to limit the invention to the particular forms disclosed, but rather, the invention includes all modifications, equivalents and substitutions that are consistent with the spirit of the invention as defined by the claims.

It will be appreciated that when an element such as a layer, region or substrate is referred to as being present on another element "on," it may be directly on the other element or there may be an intermediate element in between .

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers and / or regions, such elements, components, regions, layers and / And should not be limited by these terms.

1 is a cross-sectional view of an organic / inorganic hybrid perovskite solar cell according to an embodiment of the present invention.

1, an organic / inorganic hybrid perovskite solar cell according to an embodiment of the present invention includes an anode 200, a hole extraction layer 300, a photoactive layer 400, The layer 500 and the cathode 600 are sequentially stacked. The hole extracting layer 300 at this time is disposed on the side of the anode 200 to be in contact with the anode 200 and on the side of the photoactive layer 400 to be in contact with the photoactive layer 400, And a surface 302.

The substrate 100 may be a substrate used in a conventional semiconductor process. For example, the substrate 100 may be formed of a material selected from the group consisting of silicon, silicon oxide, metal foil (e.g., copper foil, aluminum foil, stainless steel, etc.), metal oxide, &Lt; / RTI &gt;

The metal foil may be made of a material having a high melting point and not acting as a catalyst capable of forming graphene.

Examples of the metal oxide include aluminum oxide, molybdenum oxide, indium tin oxide, and the like. Examples of the polymer substrate include polytetrafluoroethylene (PES), polyethersulphone (PES), polyacrylate (PAR) Polyetherimide (PEI), polyethylenenaphthalate (PEN), polyethyleneterephthalate (PET), polyphenylene sulfide (PPS), polyallylate, polyimide but are not limited to, polyimide, polycarbonate (PC), cellulose triacetate (TAC), and cellulose acetate propinonate (CAP).

For example, the substrate 100 may be a polymer substrate as described above, but is not limited thereto.

On the other hand, in order to realize a solar cell with a flexible element, it is preferable to use the substrate 100 as a flexible substrate.

The anode 200 may be formed on the substrate 100. The anode 200 may be formed by providing a material for forming an anode by a vapor deposition method, a sputtering method, or the like.

The anode 200 may be selected from a material having a relatively high work function to facilitate hole extraction. In this case, the anode 200 may be a reflective electrode or a transmissive electrode.

Examples of such an anode forming material include transparent and highly conductive indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO ₂ ), zinc oxide (ZnO), metal oxide / metal / Graphene, and carbon nano tube may be used.

(Mg), aluminum (Al), Ag, ITO, Ag / IZO, Al-Li, Ca, Mg- -Ag) or the like, the anode 200 may be formed as a reflective electrode.

In addition, the anode 200 may include two different materials. For example, the anode can be formed into a two-layer structure including two different materials, and various modifications are possible.

The hole extracting layer 300 may be formed on the anode 200. That is, the hole extraction layer 300 is located between the photoactive layer 400 and the anode 200.

The hole extracting layer 300 may include a conductive polymer and a fluorine-based material.

The hole extraction layer 300 may be formed by spin coating, dip coating, thermal deposition, or spray deposition.

The hole extraction layer 300 may be formed by self-assembly of a conductive polymer and a fluorine-based material.

The hole extracting layer 300 has a conductivity of 0.001 S / cm or more on the basis of 100 nm thickness.

The difference between the work function of the second surface 302 of the hole extracting layer 300 and the absolute value of the HOMO (High Occupied Molecular Orbital) level of the organic / inorganic hybrid perovskite may be 0.1 eV or less. This increases the work function of the hole extraction layer 300 by the fluorine-based material, thereby reducing the energy gap at the interface between the hole extraction layer 300 and the photoactive layer 400, thereby improving the photoelectric conversion efficiency.

Meanwhile, the hole extracting layer 300 may be a single film in which the conductive polymer and the fluorine-based substance are uniformly mixed with each other.

In another example, the concentration of the fluorine-based material in the second surface 302 of the hole extraction layer 300 may be greater than the concentration of the fluorine-based material in the first surface 301 of the hole extraction layer 300. For example, the hole extracting layer 300 may be a single film having a concentration gradient in which the concentration of the fluorine-based substance increases in the direction of the photoactive layer 400. As a result, the concentration of the fluorine-based material on the second surface 302, which is in contact with the photoactive layer 400, of the hole extracting layer 300 becomes relatively high and the absolute value of the work function of the second surface 302 and the photo- The absolute value difference of the HOMO level of the organic / inorganic hybrid perovskite of the nonlinear element can be further reduced.

The conductive polymer may be at least one selected from the group consisting of polythiophene, polyaniline, polypyrrole, polystyrene, polyethylene dioxythiophene, polyacetylene, polyphenylene, polyphenylvinylene, polycarbazole, , Derivatives thereof, or blends of two or more thereof.

The copolymer at this time includes a copolymer in which all the different repeating units of the conductive polymers are included in the main chain, and one of the different repeating units of the conductive polymers is a graft type copolymer included in the side chain. In addition, the copolymer may be a random copolymer, an alternative copolymer, or a block copolymer.

Also, the conductive polymer may include a self-doped conductive polymer doped with at least one of an ionic group and a polymeric acid. The ionic group at this time may include an anionic group and a counter cation group for the anionic group.

The anionic group may be selected from the group consisting of PO ₃ ^2- , SO ₃ ^- , COO ^- , I ^- , CH ₃ COO ^- and BO ₂ ^2- , and the cation group may include at least one of a metal ion and an organic ion have. Wherein the metal ion is selected from the group consisting of Na ⁺ , K ⁺ , Li ⁺ , Mg ⁺² , Zn ⁺² and Al ⁺³ and the organic ion is selected from the group consisting of H ⁺ , CH ₃ (CH ₂ ) _n NH ₃ ⁺ Is an integer of 0 to 50), NH ₄ ⁺ , NH ₂ ⁺ , NHSO ₂ CF ₃ ⁺ CHO ⁺ , C ₂ H ₅ OH ⁺ , CH ₃ OH ⁺ and RCHO ⁺ (R is CH ₃ (CH ₂ ) _n -; n is an integer from 0 to 50).

The fluorine-based material may be an ionomer represented by the following formula (1).

&Lt; Formula 1 >

In Formula 1,

0 < m? 10,000,000, 0? N <10,000,000, 0? A? 20, 0? B? 20;

A, B, A 'and B' are each independently selected from the group consisting of C, Si, Ge, Sn, and Pb;

Each of R ₁ , R ₂ , R ₃ , R ₄ , R ₁ ', R ₂ ', R ₃ 'and R ₄ ' is independently hydrogen, halogen, a nitro group, a substituted or unsubstituted amino group, unsubstituted C ₁ -C ₃₀ alkyl group, a substituted or unsubstituted C ₁ -C ₃₀ heteroaryl group, a substituted or unsubstituted C ₁ -C ₃₀ alkoxy group, a substituted or unsubstituted C ₁ -C ₃₀ heterocyclic alkoxy group, a substituted or unsubstituted C ₆ -C ₃₀ aryl group, a substituted or unsubstituted C ₆ -C aryl group, a substituted or unsubstituted aryloxy-substituted C ₆ -C _30, substituted or unsubstituted C _{2 30} - for C ₃₀ heteroaryl group, a substituted or unsubstituted C ₂ -C ₃₀ heteroarylalkyl group, a substituted or unsubstituted C ₂ -C ₃₀ heteroaryloxy group, a substituted or unsubstituted C ₅ -C ₂₀ in the bicyclo alkyl group, a substituted or unsubstituted C ₂ -C ₃₀ heterocycloalkyl group, a substituted or unsubstituted C ₁ -C ₃₀ alkyl ester group, a substituted or unsubstituted C ₁ -C ₃₀ heteroalkyl of S. Encircling, is selected from substituted or unsubstituted aryl ester group of the unsubstituted C ₆ -C ₃₀ and, a heteroaryl group consisting of ester group of a substituted or unsubstituted C ₂ -C _30, However, R _1, R _2, R _3, And R &lt; ₄ &gt; is an ionic group or an ionic group;

The X and X 'are each independently selected from a simple bond, O, S, substituted or unsubstituted C ₁ -C ₃₀ alkylene group, a substituted or unsubstituted C ₁ -C ₃₀ heteroalkylene group, substituted or unsubstituted C ₆ - C ₃₀ aryl group, a substituted or unsubstituted C ₆ -C ₃₀ aryl alkyl group, a substituted or unsubstituted C ₂ -C ₃₀ heteroaryl group, a substituted or unsubstituted heteroaryl group of C ₂ -C ₃₀ alkylene group of , A substituted or unsubstituted C ₅ -C ₂₀ cycloalkylene group, a substituted or unsubstituted C ₅ -C ₃₀ heterocycloalkylene group, a substituted or unsubstituted C ₆ -C ₃₀ aryl ester group, And an unsubstituted C ₂ -C ₃₀ heteroaryl ester group,

Provided that when n is 0, at least one of R ₁ , R ₂ , R ₃ , and R ₄ is a hydrophobic functional group containing a halogen element or includes a hydrophobic functional group.

The fluorine-based material may be a low molecular weight material, a polymer material, or a crosslinker containing fluorine atoms.

Accordingly, the hole extracting layer 300 includes a conductive polymer and a fluorine ionomer. The hole extracting layer 300 is advantageous in that it can be manufactured as a perovskite flexible device.

Meanwhile, the hole extraction layer 300 may further include a carbon-based nanostructure.

For example, the carbon nanostructure may include a carbon nanotube (CNT), a grapheme quantum dot, or a carbon dot.

The carbon nanotubes can improve the extraction of the photocurrent by improving the conductivity and can improve the work function of the hole extraction layer through doping such as nitrogen (N-) or boron (B-). As a result, short-circuit current, open-circuit voltage, and fill factor can be improved by such carbon nanotubes.

In addition, the photon currents can be improved by the surface plasmon effect of graphene quantum dots and carbon dots. The graphene quantum dots and carbon dots are nanoseconds of several tens to several nanometers in size, absorbing light of a wavelength that is not absorbed by a photoactive material, and transferring energy to a photoactive material by a surface plasmon effect, The light absorption amount and the short-circuit current can be improved.

The photoactive layer 400 may be formed on the hole extracting layer 300. The photoactive layer 400 may include an organic hybrid perovskite.

For example, the organic-based hybrid perovskite material may be CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbCl ₃ , CH ₃ NH ₃ PbBr ₃ , CH ₃ NH ₃ PbI _3-x Cl _x , CH ₃ NH ₃ Pb _{(I 1-x Br x)} 3, HC (NH 2) 2 PbI 3, CH 3 NH 3 Sn 1-x Pb x I 3, HC (NH 2) 2 PbI y Br 3-y, (C 4 H 9 NH ₃ ) ₂ MI ₄ (M = Ge, Sn, Pb) or (CH ₃ NH ₃ ) _x (HC (NH ₂ ) ₂ ) _1-x PbI ₃ .

The photoactive layer 400 may be formed by a spin coating method, a dip coating method, a thermal evaporation method, or a spray evaporation method.

It is preferable that the absolute value of the HOMO level of the organic / inorganic hybrid perovskite material is at least 5.1 eV.

An electron extraction layer 500 may be formed on the photoactive layer 400. The electron extraction layer 500 may be formed by a spin coating method, a dip coating method, a thermal evaporation method, or a spray evaporation method.

The electron extraction layer 500 may serve to assist electrons generated in the photoactive layer 400 to be transported to the cathode. For example, the electron extraction layer 500 may include materials such as LiF and Alq3. Such an electron extraction layer 500 may be omitted in some cases.

The cathode 600 may be formed on the electron extraction layer 500. The cathode 600 may be formed, for example, by thermal evaporation.

The cathode 600 may use a metal, an alloy, an electrically conductive compound, and a combination thereof having a relatively low work function. Specific examples thereof include lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium- .

Other embodiments of the hole extracting layer will be described with reference to FIGS. 2A and 2B.

2A is a cross-sectional view of another embodiment of the hole extracting layer.

2A, the hole extracting layer 300 includes a first layer 310 including a conductive polymer and disposed on an anode (200 in FIG. 1) and a first layer 310 including a fluorine-based substance and having a photoactive layer (400 in FIG. 1) And a second layer 320 disposed on the first layer.

The first layer 310 having conductivity suitable for transferring holes to the positive electrode 200 and the second layer 310 controlling the surface work function so as to conform to the HOMO level and Ohmic contact or Ohmic contact of the photoactive layer 400 (320) perform optimal functions to enhance hole extraction efficiency.

2B is a cross-sectional view of another embodiment of the hole extracting layer.

2A, the hole extracting layer 300 includes a first layer 310 including a conductive polymer and disposed on an anode (200 in FIG. 1) and a first layer 310 including a fluorine-based substance and having a photoactive layer (400 in FIG. 1) And a second layer 320 disposed on the second layer 320 between the first layer 310 and the second layer 320. The conductive polymer contained in the first layer 310 and the second layer 320 included in the second layer 320 An intermediate layer 330 including a fluorine-based material may be interposed.

At this time, the intermediate layer 330, which is the interface between the first layer 310 and the second layer 320, may be made to be gradual so that the components constituting the first layer 310 and the second layer 320 exist in a gradual manner, The function of the extraction layer 300 can be maximized.

On the other hand, a buffer layer (not shown) may be further disposed between the anode and the hole extracting layer or between the hole extracting layer and the photoactive layer.

Such a buffer layer may comprise a metal oxide. For example, such a buffer layer may comprise MoO _3, NiO _x, or AgO _x .

Accordingly, the work function of the hole extracting layer is increased by the buffer layer, thereby reducing the energy gap at the interface between the hole extracting layer and the photoactive layer, increasing the work function and the short-circuit current, and rectification, The fill factor FF rises and acts as an optical space so that the amount of light absorbed by the light absorbing layer increases and the shortcircuit current Jsc can rise.

Therefore, by inserting this buffer layer between the positive electrode and the hole extracting layer or between the hole extracting layer and the photoactive layer, the photoelectric conversion efficiency can be improved.

A method of manufacturing an organic / inorganic hybrid perovskite solar cell according to an embodiment of the present invention will be described.

Referring to the structure of FIG. 1, first, a substrate 100 is prepared.

Then, the anode 200 can be formed on the substrate 100. [ The anode 200 may be formed using a deposition method or a sputtering method.

Then, a hole extracting layer 300 may be formed on the anode 200. [ The hole extraction layer 300 may be formed by spin coating, dip coating, thermal deposition, or spray deposition.

The hole extraction layer 300 has a conductivity of 0.01 S / cm or more on the basis of 100 nm thickness, and the hole extraction layer 300 is a self-assembled hole extraction layer 300 including a conductive polymer and a fluorine-based material.

The hole extracting layer 300 has a first surface 301 disposed on the anode 200 side and a second surface 302 disposed on the photoactive layer 400 side, 302 and the absolute value of the HOMO (High Occupied Molecular Orbital) level of the organic / inorganic hybrid perovskite may be 0.1 eV or less.

On the other hand, after the hole extraction layer 300 is formed, the surface of the hole extraction layer 300 may be treated with UV ozone or oxygen plasma. Therefore, the work function of the hole extracting layer 300 can be further increased through UV ozone or oxygen plasma treatment, and the surface of the hole extracting layer 300 can be made hydrophilic.

Accordingly, when the perovskite photoactive layer 400 is coated on the hole extracting layer 300 whose surface is hydrophilized, the photoelectric conversion efficiency of the solar cell is increased and the thin film is easily formed.

Next, a photoactive layer 400 including an organic hybrid perovskite may be formed on the hole extracting layer 300.

The photoactive layer 400 may be formed by a spin coating method, a dip coating method, a thermal evaporation method, or a spray evaporation method.

Next, an electron extraction layer 500 may be formed on the photoactive layer 400. The electron extraction layer 500 may be formed by a spin coating method, a dip coating method, a thermal evaporation method, or a spray evaporation method.

The cathode 600 may then be formed on such an electron extraction layer 500. The cathode 600 may be formed by a thermal evaporation method.

The method may further include the step of forming a buffer layer (not shown) including a metal oxide on the anode 200 between the step of forming the anode 200 and the step of forming the hole extraction layer 300 can do.

Further, the method may further include forming a buffer layer (not shown) including a metal oxide on the hole extraction layer between the step of forming the hole extraction layer and the step of forming the photoactive layer.

Such a buffer layer can be formed by a spin coating method, a dip coating method, a thermal evaporation method, or a spray evaporation method.

Example 1

An organic / inorganic hybrid perovskite solar cell according to an embodiment of the present invention was manufactured.

First, an ITO substrate (glass substrate coated with ITO anode) was prepared. Then, a solution of PEDOT: PSS (CLEVIOS PH manufactured by Heraeus Co., Ltd.) and the following polymer 1 was spin-coated on the ITO anode, followed by heat treatment at 150 ° C. for 10 minutes To form a hole extraction layer having a thickness of 30 nm.

After the heat treatment, a first layer containing 50% or more of a conductive polymer is formed in the lower part of the hole extraction layer, and a second layer containing 50% or more of the polymer 1 is formed in the upper part. That is, the first layer and the second layer are self-assembled.

The weight ratio of the hole extracting layer including the first layer and the second layer is PEDOT: PSS: Polymer 1 of 1: 2.5: 0.73 and the work function of 5.4 eV.

A solution (463 mg: 1 ml) containing PbI 2 and dimethylformamide was spin-coated on the hole extracting layer and heat-treated at 70 ° C. for 10 minutes. Then, a solution containing CH ₃ NH ₃ I and IPA (20 mg: 1 ml ) Was spin-coated and heat-treated at 100 ° C for 10 minutes to form a 280 nm-thick CH ₃ NH ₃ PbI ₃ perovskite photoactive layer.

The HOMO level of the CH ₃ NH ₃ PbI ₃ perovskite photoactive layer is -5.4 eV and the work function of the surface of the second layer of the hole extraction layer is -5.4 eV.

Subsequently, a solution of PCBM (nano-C Inc.) and chloroform (10.36 mg: 1 ml) was spin-coated on the photoactive layer and aluminum of 100 nm in thickness was deposited thereon to form a negative electrode, A perovskite solar cell device was fabricated

<Polymer 1>

(Of the polymer 1, x = 1300, y = 200, z = 1)

Example 2

A hybrid organic perovskite solar cell device was fabricated using the same method as in Example 1 except that the ITO-coated glass substrate was a PET substrate.

Comparative Example

PEDOT: PSS (HELEAUS CLEVIOS PH) solution of Example 1 was spin-coated on the ITO anode and heat-treated at 150 ° C for 10 minutes to form a 30 nm-thick single layer hole-extracting layer (work function: 4.9 eV) was formed on the surface of the solar cell, and the same method as in Example 1 was used to fabricate an organic hybrid perovskite solar cell device. That is, the hole extraction layer at this time is a PEDOT: PSS layer.

Experimental Example

3 is a graph showing the characteristics of the solar cell according to the comparative example and the example 1. Fig.

Referring to FIG. 3, the work function of the hole extraction layer (PFI / PEDOT: PSS = 0.209) is increased by 0.5 eV as compared to the conventional PEDOT: PSS by ultraviolet photoelectron spectroscopy (UPS) analysis.

4 is a graph showing work function characteristics of the hole extraction layer according to the weight ratio of PFI and PEDOT: PSS.

Table 1 below is a graph showing the results shown in Fig.

PFI / PEDOT: PSS Work function (eV) 0 4.86 0.027 5.11 0.053 5.21 0.105 5.32 0.209 5.39 0.417 5.46 0.833 5.48

Referring to FIG. 4 and Table 1, as the PFI / PEDOT: PSS value increases, that is, as the PFI concentration ratio increases, the work function value of the hole extraction layer increases. Therefore, it can be seen that the work function value increases as the concentration ratio of the fluorine-based material increases.

FIGS. 5 and 6 are graphs showing voltage-current characteristics of the solar cell according to the comparative example and the example 1. FIG.

7 is a graph showing the voltage-current characteristics of the solar cell according to the second embodiment. The image embedded in FIG. 7 indicates that the solar cell according to the second embodiment is bent and is a flexible solar cell.

Table 2 below is a table summarizing the results of the evaluation of the voltage-current density characteristics of Figs. 5 to 7. Fig.

Voltage-current density characteristic evaluation, the light source is a xenon lamp (Xenon lamp) using the (solar condition (AM1.5) of the xenon lamp is also corrected using a standard solar cell device) in the light of 100mW / cm ² Were irradiated to each organic solar cell element.

On the other hand, the photoelectric conversion efficiency (PCE) (%) was calculated from the short-circuit current (J _SC ), open-circuit voltage (V _OC ) and fill factor (FF) calculated from the measured voltage-current graph.

V _oc (V) J _sc (mA / cm ² ) FF (%) PCE (%) Comparative Example 0.835 14.1 68.5 8.1 Example 1 0.982 16.7 70.5 11.7 Example 2 1.040 15.5 49.9 8.0

From FIG. 5 to FIG. 7 and Table 2, it can be confirmed that the organic-inorganic hybrid perovskite solar cell device of Example 1 has superior characteristics to the organic / inorganic hybrid perovskite solar cell device of Comparative Example.

Also, Example 2, in which a hybrid organic perovskite solar cell device was fabricated using a PET substrate to fabricate a flexible device, also shows excellent characteristics.

8 is an image and a graph showing a morphology of a hole extracting layer of a solar cell according to a comparative example. 9 is an image and a graph showing the morphology of the hole extracting layer of the solar cell according to the first embodiment.

8 and 9, the morphology of the hole extracting layer of the solar cell according to Example 1 is similar to that of the comparative morphology.

According to the present invention, by using the self-assembled hole extraction layer, it is possible to reduce the energy gap at the interface between the hole extracting layer and the photoactive layer, thereby providing a solar cell having improved photoelectric conversion efficiency.

In addition, since the self-assembled hole extraction layer is flexible, the organic / inorganic hybrid perovskite solar cell can be manufactured as a flexible device having excellent photoelectric conversion efficiency and long life.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

100: substrate 200: anode
300: hole extraction layer 301: first side
302: second side 310: first side
320: second layer 330: middle layer
400: photoactive layer 500: electron extraction layer
600: cathode

Claims (16)

A positive electrode, a negative electrode, a photoactive layer positioned between the positive electrode and the negative electrode, and a hole extraction layer located between the photoactive layer and the positive electrode,
Wherein the photoactive layer comprises an organic hybrid perovskite,
The hole extraction layer has a conductivity of 0.01 S / cm or more on the basis of 100 nm thickness,
Wherein the hole extraction layer is a self-assembled hole extraction layer including a conductive polymer and a fluorine-
Wherein the hole extracting layer has a first surface disposed on the anode side and a second surface disposed on the photoactive layer side,
Wherein the difference between the work function of the second surface and the absolute value of the HOMO (High Occupied Molecular Orbital) level of the organic / inorganic hybrid perovskite is 0.1 eV or less. The method according to claim 1,
Between the positive electrode and the hole extracting layer or between the hole extracting layer and the photoactive layer,
A hybrid organic perovskite solar cell comprising a buffer layer containing a metal oxide. 3. The method of claim 2,
The buffer layer may comprise MoO _3, NiO _x, or AgO _x . Hybrid perovskite solar cells with or without organic inclusion. The method according to claim 1,
Wherein the hole extracting layer is formed by uniformly mixing the conductive polymer and the fluorine-based material with each other. The method according to claim 1,
Wherein the conductive polymer is selected from the group consisting of polythiophene, polyaniline, polypyrrole, polystyrene, polyethylene dioxythiophene, polyacetylene, polyphenylene, polyphenylvinylene, polycarbazole, a copolymer containing two or more different repeating units thereof, Or an organic or inorganic hybrid perovskite solar cell comprising at least two of the blends. The method according to claim 1,
The conductive polymer includes a self-doped conductive polymer doped with at least one of an ionic group and a polymeric acid,
Said ionic group comprising an anionic group and a counter cationic group for said anionic group,
The anionic group is selected from the group consisting of PO ₃ ^2- , SO ₃ ^- , COO ^- , I ^- , CH ₃ COO ^- and BO ₂ ^2- ,
The cationic group includes at least one of a metal ion and an organic ion,
Wherein the metal ion is selected from the group consisting of Na ⁺ , K ⁺ , Li ⁺ , Mg ⁺² , Zn ⁺² and Al ⁺³ and the organic ion is selected from the group consisting of H ⁺ , CH ₃ (CH ₂ ) _n NH ₃ ⁺ Is an integer of 0 to 50), NH ₄ ⁺ , NH ₂ ⁺ , NHSO ₂ CF ₃ ⁺ Wherein the organic hybrid perovskite is selected from the group consisting of CHO ⁺ , C ₂ H ₅ OH ⁺ , CH ₃ OH ⁺ and RCHO ⁺ (R is CH ₃ (CH ₂ ) _n - and n is an integer from 0 to 50) Solar cells. The method according to claim 1,
Wherein the fluorine-based material is an ionomer represented by the following formula (1): < EMI ID =
&Lt; Formula 1 &gt;

In Formula 1,
0 < m? 10,000,000, 0? N <10,000,000, 0? A? 20, 0? B? 20;
A, B, A 'and B' are each independently selected from the group consisting of C, Si, Ge, Sn, and Pb;
Each of R ₁ , R ₂ , R ₃ , R ₄ , R ₁ ', R ₂ ', R ₃ 'and R ₄ ' is independently hydrogen, halogen, a nitro group, a substituted or unsubstituted amino group, unsubstituted C ₁ -C ₃₀ alkyl group, a substituted or unsubstituted C ₁ -C ₃₀ heteroaryl group, a substituted or unsubstituted C ₁ -C ₃₀ alkoxy group, a substituted or unsubstituted C ₁ -C ₃₀ heterocyclic alkoxy group, a substituted or unsubstituted C ₆ -C ₃₀ aryl group, a substituted or unsubstituted C ₆ -C aryl group, a substituted or unsubstituted aryloxy-substituted C ₆ -C _30, substituted or unsubstituted C _{2 30} - for C ₃₀ heteroaryl group, a substituted or unsubstituted C ₂ -C ₃₀ heteroarylalkyl group, a substituted or unsubstituted C ₂ -C ₃₀ heteroaryloxy group, a substituted or unsubstituted C ₅ -C ₂₀ in the bicyclo alkyl group, a substituted or unsubstituted C ₂ -C ₃₀ heterocycloalkyl group, a substituted or unsubstituted C ₁ -C ₃₀ alkyl ester group, a substituted or unsubstituted C ₁ -C ₃₀ heteroalkyl of S. Encircling, is selected from substituted or unsubstituted aryl ester group of the unsubstituted C ₆ -C ₃₀ and, a heteroaryl group consisting of ester group of a substituted or unsubstituted C ₂ -C _30, However, R _1, R _2, R _3, And R &lt; ₄ &gt; is an ionic group or an ionic group;
The X and X 'are each independently selected from a simple bond, O, S, substituted or unsubstituted C ₁ -C ₃₀ alkylene group, a substituted or unsubstituted C ₁ -C ₃₀ heteroalkylene group, substituted or unsubstituted C ₆ - C ₃₀ aryl group, a substituted or unsubstituted C ₆ -C ₃₀ aryl alkyl group, a substituted or unsubstituted C ₂ -C ₃₀ heteroaryl group, a substituted or unsubstituted heteroaryl group of C ₂ -C ₃₀ alkylene group of , A substituted or unsubstituted C ₅ -C ₂₀ cycloalkylene group, a substituted or unsubstituted C ₅ -C ₃₀ heterocycloalkylene group, a substituted or unsubstituted C ₆ -C ₃₀ aryl ester group, And an unsubstituted C ₂ -C ₃₀ heteroaryl ester group,
Provided that when n is 0, at least one of R ₁ , R ₂ , R ₃ , and R ₄ is a hydrophobic functional group containing a halogen element or includes a hydrophobic functional group. The method according to claim 1,
Wherein the hole extraction layer further comprises a carbon nanostructure. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; 9. The method of claim 8,
Wherein the carbon-based nanostructure comprises carbon nanotubes, graphene quantum dots, or carbon dots. The method according to claim 1,
The organic-inorganic hybrid perovskite material is _{CH 3 NH 3 PbI 3, CH} 3 NH 3 PbCl 3, CH 3 NH 3 PbBr 3, CH 3 NH 3 PbI 3-x Cl x, CH 3 NH 3 Pb (I 1 _{-x Br x) 3, HC (} NH 2) 2 PbI 3, CH 3 NH 3 Sn 1-x Pb x I 3, HC (NH 2) 2 PbI y Br 3-y, (C 4 H 9 NH 3) _{2 MI 4 (M = Ge,} Sn, Pb) or _{(CH 3 NH 3) x (} HC (NH 2) 2) inorganic containing _1-x PbI ₃ perovskite hybrid solar cells. The method according to claim 1,
Wherein the absolute value of the HOMO level of the organic / inorganic hybrid perovskite material is at least 5.1 eV. The method according to claim 1,
Wherein the hole extraction layer comprises an organic hybrid perovskite solar cell including the conductive polymer and including a first layer disposed on the anode side and a second layer disposed on the side of the photoactive layer, . Forming an anode on the substrate;
Forming a hole extraction layer on the anode;
Forming a photoactive layer including an organic hybrid perovskite on the hole extraction layer; And
And forming a negative electrode on the photoactive layer,
The hole extraction layer has a conductivity of 0.01 S / cm or more on the basis of 100 nm thickness,
Wherein the hole extraction layer is a self-assembled hole extraction layer including a conductive polymer and a fluorine-
Wherein the hole extracting layer has a first surface disposed on the anode side and a second surface disposed on the photoactive layer side,
Wherein the difference between the work function of the second surface and the absolute value of the HOMO (High Occupied Molecular Orbital) level of the organic / inorganic hybrid perovskite is 0.1 eV or less. 14. The method of claim 13,
After the step of forming the hole extracting layer,
Treating the surface of the hole extracting layer with UV-ozone or oxygen plasma. 14. The method of claim 13,
Between the step of forming the anode and the step of forming the hole extraction layer,
Further comprising forming a buffer layer containing a metal oxide on the anode. &Lt; RTI ID = 0.0 &gt; 21. &lt; / RTI &gt; 14. The method of claim 13,
Between the step of forming the hole extracting layer and the step of forming the photoactive layer,
And forming a buffer layer including a metal oxide on the hole extraction layer. The method of manufacturing a hybrid organic perovskite solar cell according to claim 1,

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