KR102277729B1 - A solar cell comprising light wavelength conversion layer - Google Patents

Abstract

The present invention relates to a solar cell including a light wavelength conversion layer, and to a manufacturing method thereof. According to the solar cell, through a light wavelength conversion layer, the output change is small according to the change of the incident light, the light efficiency is excellent, and high-efficiency power generation is possible in an indoor environment as well as outdoors.

Description

A solar cell comprising light wavelength conversion layer

The present invention relates to a solar cell including a light wavelength conversion layer, and more particularly, to a solar cell that exhibits excellent performance indoors as well as outdoors by introducing a light wavelength conversion layer that changes the wavelength of incident light.

A solar cell is a device that converts light energy into electrical energy. The photoactive layer included in the solar cell has a characteristic of using both an organic semiconductor and an inorganic semiconductor. Since the organic semiconductor and the inorganic semiconductor can be solution-processed, an organic solar cell can be manufactured through a simple method, which can be applied in the field of flexible organic electronic devices, and thus is spotlighted as a next-generation power source.

The structure of a solar cell generally includes a photoactive layer, a charge transport layer and an electrode. The photoactive layer has photoelectric properties to convert light energy into electrical energy. The charge transport layer moves the charges generated in the photoactive layer to the electrode. The electrode receives the transferred charge and moves it to an external circuit. In particular, since the charge transport layer serves to extract and move the charges generated in the photoactive layer to the electrode, it is essential to improve the efficiency of the solar cell.

The charge transport layer includes an electron transport layer that extracts or moves electrons to the cathode and a hole transport layer that extracts or moves holes to the anode. The electron transport layer is generally an ion-binding metal capable of forming a film through a thermal deposition process, for example, barium fluoride (BaF ₂ ), lithium fluoride (LiF), etc. are mainly used, and the film is formed through a sol-gel process. Formable zinc oxide (ZnO) and titanium dioxide (TiO ₂ ) are being introduced as solution processes. The hole transport layer is generally a transition metal capable of forming a film through a thermal evaporation process, for example, molybdenum oxide (MoO ₃ ), vanadium pentoxide (V ₂ O ₅ ), tungsten oxide (WO ₃ ), etc. are mainly used, and solution PEDOT:PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) polymer, which can form a film through the process, is mainly used.

A solar cell incorporating a charge transport layer is easy to control the optical properties of the material used, and it can be generated from various light sources such as incandescent lamps, fluorescent lamps, and LEDs (light emitting diodes). In particular, since solar cells incorporating a charge transport layer can generate electricity not only outdoors, but also indoors, the field of application for indoor power generation is further expanding in line with the 4th industrial revolution, such as smart factories and Internet of Things sensors. However, the materials previously used in solar cells incorporating the charge transport layer showed photoelectric conversion characteristics through absorption characteristics suitable for optical limitations, but did not show the maximum photoelectric conversion characteristics in an environment where the incident angle of light was changed or the amount of light was reduced. Therefore, in order to manufacture a high-output solar cell that can be used both outdoors as well as indoors, a strategy that maximizes light efficiency is required.

Regarding this, referring to Korean Patent Registration No. 10-2029229, a photovoltaic module having improved reliability and photostability is disclosed by coating a solution containing a quantum dot complex on a surface on which sunlight is incident from a photovoltaic module.

In order to solve the above problems, the present inventors introduced an inorganic semiconductor compound to form a light wavelength conversion layer.

An object of the present invention is to provide a solar cell having a small output change according to a change in incident light through the light wavelength conversion layer and excellent light efficiency.

Another object of the present invention is to provide a solar cell capable of high-efficiency power generation in an indoor environment as well as outdoors through the light wavelength conversion layer.

Another object of the present invention is to provide a solar cell having improved power conversion efficiency (PCE) through the light wavelength conversion layer.

The problem to be solved by the present invention is not limited to the above-mentioned problems, and the problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the present specification.

The solar cell according to the present invention includes a light-receiving electrode and a photoactive layer sequentially stacked, and a light wavelength conversion layer between the light-receiving electrode and the photoactive layer, wherein the light wavelength conversion layer contains an inorganic semiconductor compound, and the inorganic The semiconductor compound converts light of a first wavelength into light of a second wavelength, the light of the first wavelength is light of a wavelength having a peak of 250 nm or more and less than 450 nm, and the light of the second wavelength is 550 nm or more It may be light of a wavelength having a peak less than 850 nm.

The solar cell according to the present invention includes a light-receiving electrode and a photoactive layer sequentially stacked, and a light wavelength conversion layer between the light-receiving electrode and the photoactive layer, wherein the light wavelength conversion layer contains an inorganic semiconductor compound, and the inorganic The semiconductor compound may be at least one selected from the group consisting of a group IV element, a group II-VI semiconductor compound, a group III-V semiconductor compound, and a group IV-IV semiconductor compound.

The solar cell according to the present invention changes the wavelength of the light incident to the solar cell through the light wavelength conversion layer, so that the output is small even when the incident light changes (outdoor light and indoor light) and the light efficiency is excellent.

In addition, the solar cell according to the present invention is capable of high-efficiency power generation in an indoor environment as well as outdoors.

In addition, the solar cell according to the present invention may improve the photoelectric conversion efficiency (PCE) through the light wavelength conversion layer.

Effects of the present invention are not limited to the above-described effects, and effects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the present specification.

1 shows an example of an organic solar cell including a light wavelength conversion layer. Figure 1 (a) is a structure in which the optical wavelength conversion layer is located between the charge transport layer and the photoactive layer. Figure 1 (b) is a structure in which the optical wavelength conversion layer is located between the electrode and the charge transport layer. Figure 1 (c) is a structure in which the multilayer optical wavelength conversion layer is positioned between the electrode and the photoactive layer. 1( d ) is a structure in which a single-layer optical wavelength conversion layer is disposed between an electrode and a photoactive layer.
2 shows an optical wavelength conversion composition according to a preparation example of the present invention.
3 is a result of evaluating the characteristics of the light wavelength conversion composition and the comparative group according to a preparation example of the present invention using an ultraviolet hand lamp (UV hand lamp, VL-4L) that generates light in the λ = 365 nm region. it has been shown (a) an optical wavelength conversion composition; (b) control group (alcohol)
4 shows the results of evaluating the characteristics of the light wavelength conversion composition and the comparative group according to a preparation example of the present invention using an LED lamp (Oriel VeraSol Solar Simulator) that generates light in a λ = 400 to 780 nm region. . (a) an optical wavelength conversion composition; (b) control group (alcohol)
5 shows the results of evaluating the characteristics of the thin film formed through the light wavelength conversion layer and the comparative group according to a manufacturing example of the present invention using an LED lamp (Oriel VeraSol Solar Simulator). (a) an optical wavelength conversion layer; (b) Comparative group (alcohol thin film)
6 shows a composite composition formed according to a volume ratio and a ZnO composition according to a preparation example of the present invention. (a) a ZnO composition; (b) composite composition
Figure 7 (a) is a ZnO composition (represented as a pure charge transport layer solution in the figure) and a composite composition (represented as a light wavelength conversion charge transport layer solution in the figure) according to a preparation example of the present invention UV hand lamp (UV hand lamp, VL-4L) shows the results of property evaluation. 7 (b) is a ZnO composition (represented as a pure charge transport layer solution in the drawing) and a composite composition (represented as a light wavelength conversion charge transport layer solution in the drawing) according to a preparation example of the present invention LED lamp (Oriel VeraSol Solar Simulator) The results of characteristic evaluation using
8 shows the results of evaluating the characteristics of the thin film formed through the light wavelength conversion layer and the comparative group according to a manufacturing example of the present invention using an LED lamp (Oriel VeraSol Solar Simulator). (a) a light wavelength conversion layer (formed by the composite composition); (b) Comparative group (ZnO layer)
9 shows a dried state after forming the optical wavelength conversion layer according to an embodiment of the present invention.
10 shows a dried state after forming an electron transport layer according to an embodiment of the present invention.
11 shows the results of evaluating the optical properties of the optical wavelength conversion layer and the ZnO layer according to a manufacturing example of the present invention. (a) results of ultraviolet-visible spectroscopic analysis; (b) Results of luminescence spectroscopic analysis
12 shows current-voltage characteristics (a) and external quantum efficiency (EQE) behavior (b) of organic solar cells according to an embodiment and a comparative example of the present invention.
13 shows current-voltage characteristics (a) and external quantum efficiency (EQE) behavior (b) of large-area organic solar cells according to an embodiment and a comparative example of the present invention.
14 shows the results of ultraviolet-visible spectroscopic analysis of the photoactive layer thin film, the photoactive layer thin film stacked on the electron transport layer, and the photoactive layer thin film stacked on the light wavelength conversion layer according to an embodiment of the present invention.
15 shows the results of emission spectroscopic analysis of the photoactive layer thin film, the photoactive layer thin film stacked on the electron transport layer, and the photoactive layer thin film stacked on the light wavelength conversion layer according to an embodiment of the present invention. (a) λ _ex =430 nm; (b) λ _ex =530 nm; (c) λ _ex =630 nm
16 shows internal quantum efficiency (IQE) behavior and reflectance of organic solar cells according to an embodiment and a comparative example of the present invention.
17 shows the results of analysis through a field emission scanning electron microscope (Field Emission Scanning Electron Microscope) for the light wavelength conversion layer of an embodiment of the present invention and the electron transport layer of a comparative embodiment of the present invention. (a) an optical wavelength conversion layer; (b) electron transport layer
18 shows the analysis results through atomic force microscopy (Atomic Force Microscopy) for the light wavelength conversion layer of an embodiment of the present invention and the electron transport layer of a comparative embodiment of the present invention. (a) an optical wavelength conversion layer; (b) electron transport layer
19 is an atomic force microscope (Atomic Force Microscopy) for the lamination of the photoactive layer on the light wavelength conversion layer of an embodiment of the present invention and the photoactive layer on the electron transport layer of a comparative example It shows the analysis results. . (a) a light wavelength conversion layer/photoactive layer; (b) electron transport layer/photoactive layer
20 shows long-term stability evaluation results of organic solar cells according to Examples and Comparative Examples of the present invention. (a) change in photoelectric conversion efficiency (PCE) with time; (b) change in open circuit voltage (V _oc ) with time; (c) change in short-circuit density current (J _sc ) with time; (d) change of fill factor (FF) with time

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

The present invention can provide a solar cell exhibiting excellent performance indoors as well as outdoors by introducing a light wavelength conversion layer that changes the wavelength of incident light.

As used herein, the term “solar cell” refers to a device that generates electricity using light energy of the sun. The solar cell includes a silicon solar cell and a non-silicon solar cell, and the non-silicon solar cell may include an inorganic thin-film solar cell, an organic solar cell, a quantum dot solar cell, and a perovskite. In addition, the solar cell includes a tandem solar cell having a multi-junction structure. In the present specification, the present invention is described as an organic solar cell for convenience of description, but this is only an example and may be used as the above-described various solar cells.

As used herein, the term “light-receiving electrode” may refer to an electrode that receives light first when all types of light including sunlight strike the solar cell. In the present specification, the light-receiving electrode may be used as a first electrode, and the opposite electrode of the light-receiving electrode may be used as a second electrode.

As used herein, the term “light wavelength conversion layer” may include a first light wavelength conversion layer and a second light wavelength conversion layer. In the present specification, the optical wavelength conversion layer located between the light-receiving electrode and the photoactive layer may be used as the first optical wavelength conversion layer, and the optical wavelength conversion layer located between the opposite electrode of the light-receiving electrode and the photoactive layer is used as the second optical wavelength conversion layer. Can be used.

As used herein, the term "charge transport layer" is a layer that smoothly transports holes or electrons in the solar cell. When transporting holes, the hole transport layer can be used as an electron transport layer. .

As used herein, the term “room temperature” may mean a temperature between about 10 °C and 30 °C.

As used herein, the term "substitution" means that one or more hydrogen atoms in a compound are replaced with other atoms or substituents, unless otherwise specified.

As used herein, the term “substituted or unsubstituted” may mean that one or two or more hydrogen atoms are substituted or not substituted with other atoms or substituents unless otherwise specified.

As used herein, the term “substituent” may be expressed as J. In addition, the substituent J is halogen (chloro (Cl), iodine (I), bromo (Br), fluoro (F)), an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, consisting of a hydroxy group It may be one or more selected from the group, but is not limited thereto. In addition, each of the substituents exemplified above may again be unsubstituted or substituted with a substituent selected from these substituent groups.

The term "alkyl group" as used herein, unless otherwise specified, has 1 to 20 carbon atoms, or 1 to 16 carbon atoms, or 1 to 12 carbon atoms, or 1 to 8 carbon atoms, or a straight or branched chain having 1 to 6 carbon atoms. acyclic; a cyclic form having 3 to 20 carbon atoms, or 3 to 16 carbon atoms, or 3 to 12 carbon atoms, or 3 to 8 carbon atoms, or 3 to 6 carbon atoms; Or it may mean a saturated hydrocarbon to which they are bound.

The term "alkenyl group" as used herein, unless otherwise specified, has 2 to 20 carbon atoms, or 2 to 16 carbon atoms, or 2 to 12 carbon atoms, or 2 to 8 carbon atoms, or 2 carbon atoms, unless otherwise specified. to 6 straight-chain, branched acyclic; a cyclic type having 3 to 20 carbon atoms, or 3 to 16 carbon atoms, or 3 to 12 carbon atoms, or 3 to 8 carbon atoms, or 3 to 6 carbon atoms having one or more double bonds; Or it may mean an unsaturated hydrocarbon to which they are bonded.

The term "alkynyl group" as used herein, unless otherwise specified, has 2 to 20 carbon atoms, or 2 to 16 carbon atoms, or 2 to 12 carbon atoms, or 2 to 8 carbon atoms, or 2 carbon atoms, unless otherwise specified. to 6 straight-chain, branched acyclic; a cyclic type having 3 to 20 carbon atoms, or 3 to 16 carbon atoms, or 3 to 12 carbon atoms, or 3 to 8 carbon atoms, or 3 to 6 carbon atoms having one or more triple bonds; Or it may mean an unsaturated hydrocarbon to which they are bonded.

As used herein, the term "aryl group" may mean an aromatic ring in which one hydrogen is removed from an aromatic hydrocarbon ring, unless otherwise specified, and may be a single ring or a polycyclic ring.

As used herein, the term "heteroaryl group" may mean an aromatic ring containing one or more heteroatoms (eg, N, O, S, etc.) as atoms forming a ring, unless otherwise stated. , may be a single ring or a polycyclic ring.

A solar cell according to an embodiment of the present invention includes a light-receiving electrode and a photoactive layer sequentially stacked, and a light wavelength conversion layer between the light-receiving electrode and the photoactive layer, wherein the light wavelength conversion layer includes an inorganic semiconductor compound. can In this case, the optical wavelength conversion layer may form a multilayer.

In the solar cell according to an embodiment of the present invention, the light wavelength conversion layer is positioned between the light-receiving electrode and the photoactive layer to convert the wavelength of incident light to increase the light efficiency that can be utilized in the photoactive layer, so it can exhibit excellent performance.

The solar cell according to an embodiment of the present invention may include a charge transport layer between the light receiving electrode and the photoactive layer. In this case, the charge transport layer may be a hole transport layer or an electron transport layer, but is preferably an electron transport layer.

The positional relationship between the light wavelength conversion layer and the charge transport layer is not particularly limited as long as it is positioned between the light receiving electrode and the photoactive layer. For example, the structure of the solar cell according to an embodiment of the present invention may include a light-receiving electrode/charge transport layer/light wavelength conversion layer/photoactive layer, and includes a light-receiving electrode/light wavelength conversion layer/charge transport layer/photoactive layer. can do. In addition, the optical wavelength conversion layer and the charge transport layer may each form a multilayer, and the stacked structure of the optical wavelength conversion layer and the charge transport layer may be a unit structure to form a multilayer structure. For example, the structure of the solar cell according to an embodiment of the present invention may include a light-receiving electrode/charge transport layer (1)/charge transport layer (2)/light wavelength conversion layer/photoactive layer, and a light-receiving electrode/charge transport layer/ It may include a light wavelength conversion layer (1) / light wavelength conversion layer (2) / photoactive layer, light receiving electrode / charge transport layer (1) / charge transport layer (2) / light wavelength conversion layer (1) / light wavelength conversion layer (2)/photoactive layer. In addition, for example, the structure of the solar cell according to an embodiment of the present invention is light-receiving electrode / charge transport layer (1) / light wavelength conversion layer (1) / charge transport layer (2) / light wavelength conversion layer (2) / photoactive layer, and may include a light-receiving electrode/light wavelength conversion layer (1)/charge transport layer (1)/light wavelength conversion layer (2)/charge transport layer (2)/photoactive layer.

The solar cell according to an embodiment of the present invention may further include a second electrode, which is an electrode opposite to the light-receiving electrode, on the photoactive layer, and in this case, at least one of a charge transport layer and a light wavelength conversion layer may be included between them. . That is, a photoactive layer may be included between the light-receiving electrode and the second electrode, and a light wavelength conversion layer may be further included between the photoactive layer and the second electrode. In this case, the term “on” may mean being laminated on an object while physically in contact, or may mean being laminated with other materials interposed therebetween without physical contact. The positional relationship between the charge transport layer and the light wavelength conversion layer located between the photoactive layer and the opposite electrode of the photoreceptor electrode is not particularly limited, and a multilayer structure may be formed, respectively, or a multilayer structure may be formed by forming a stacked structure thereof as a unit structure. have. For example, the structure of the solar cell according to an embodiment of the present invention may include a light-receiving electrode/charge transport layer/light wavelength conversion layer (1)/photoactive layer/light wavelength conversion layer (2)/second electrode.

The solar cell according to an embodiment of the present invention may include a charge transport layer between the photoactive layer and the second electrode. In this case, the charge transport layer may be a hole transport layer or an electron transport layer. If the light wavelength conversion layer and the charge transport layer are positioned between the photoactive layer and the second electrode, their positional relationship is not particularly limited.

The solar cell according to an embodiment of the present invention may include a transparent substrate on one surface of the light-receiving electrode. In this case, it is preferable that the transparent substrate be positioned on the opposite side to the photoactive layer with respect to the light-receiving electrode.

1A to 1D respectively show a solar cell according to an embodiment of the present invention. 1A and 1B show a structure including a charge transport layer in a solar cell. 1A shows a transparent substrate 110 , a first electrode 120 , a first charge transport layer 130 , a first optical wavelength conversion layer 130 - 1 , a photoactive layer 140 , and a second optical wavelength conversion layer 150 . -1), the second charge transport layer 150 and the second electrode 160 are stacked in this order. 1b shows a transparent substrate 110, a first electrode 120, a first optical wavelength conversion layer 130-1, a first charge transport layer 130, a photoactive layer 140, a second charge transport layer 150, A solar cell in which the second light wavelength conversion layer 150 - 1 and the second electrode 160 are stacked in this order is shown. 1C and 1D show a structure in which a charge transport layer is not included in a solar cell. 1c is a transparent substrate 110, a first electrode 120, the first optical wavelength conversion layer (1, 130-1), the first optical wavelength conversion layer (2, 130-2), the photoactive layer 140, A solar cell in which the second light wavelength conversion layer 1,150-1, the second light wavelength conversion layer 2, 150-2, and the second electrode 160 are stacked in this order is shown. 1D shows the transparent substrate 110, the first electrode 120, the first optical wavelength conversion layer 130-1, the photoactive layer 140, the second optical wavelength conversion layer 150-1, and the second electrode ( 160) shows the solar cells stacked in that order.

The light wavelength conversion layer of the solar cell according to an embodiment of the present invention may include an inorganic semiconductor compound.

The inorganic semiconductor compound may refer to a semiconductor that converts light of a specific wavelength (light of a first wavelength) into light of another wavelength (light of a second wavelength). Here, the conversion of light of a specific wavelength into light of another wavelength means that light having a peak of a specific wavelength (light of a first wavelength) has a peak of a wavelength other than the specific wavelength (light of a second wavelength). of light). In addition, the light of the second wavelength may be light having a peak of one wavelength, or light having a peak of each of the two wavelengths.

The light of the first wavelength is light of a wavelength having a peak of 250 nm or more and less than 450 nm, or light of a wavelength having a peak of 275 nm or more and less than 400 nm, or light of a wavelength having a peak of 300 nm or more and less than 375 nm can

The light of the second wavelength is light of a wavelength having a peak of 550 nm or more and less than 850 nm, or light of a wavelength having a peak of 575 nm or more and less than 800 nm, or light of a wavelength having a peak of 585 nm or more and less than 775 nm can

In addition, the light of the second wavelength is light of a wavelength having a peak of 550 nm or more and less than 650 nm, or light of a wavelength having a peak of 575 nm or more and less than 625 nm, or a wavelength having a peak of 585 nm or more and less than 615 nm. can be light. In addition, the light of the second wavelength is light of a wavelength having a peak of 650 nm or more and less than 850 nm, or light of a wavelength having a peak of 700 nm or more and less than 800 nm, or a wavelength having a peak of 725 nm or more and less than 775 nm may be the light of In addition, the light of the second wavelength may be light having peaks of two wavelengths as described above, and the light of the second wavelength is light of a wavelength having a peak of 550 nm or more and less than 650 nm and 650 nm or more and 850 nm. It may be light of a wavelength having a peak less than nm. In addition, the light of the second wavelength may be light of a wavelength having a peak of 575 nm or more and 625 nm or less and light of a wavelength having a peak of 700 nm or more and less than 800 nm. In addition, the light of the second wavelength may be light of a wavelength having a peak of 585 nm or more and 615 nm or less and light of a wavelength having a peak of 725 nm or more and less than 775 nm.

The inorganic semiconductor compound may refer to a semiconductor in the form of a compound made of two or more chemical elements. The inorganic semiconductor compound includes a group IV element on the periodic table (eg, C, Si, Ge, Sn, Pb, etc.), a group II-VI semiconductor compound (ZnO, CdO, ZnS, CdS, ZnSe, CdSe, ZnTe, CdTe, Hg _1-x Cd _x Te, etc.), group III-V semiconductor compounds (eg, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, Ga _1-x Al _x As, InGaAsP, etc.) and IV At least one selected from the group consisting of -IV group semiconductor compounds (such as SiC) may be selected.

The inorganic semiconductor compound used in the present invention may include a semiconductor compound in the form of quantum dots. For example, the semiconductor compound in the form of a quantum dot is one selected from the group consisting of a quantum dot of a group IV element on the periodic table, a quantum dot of a group II-VI semiconductor compound, a quantum dot of a group III-V semiconductor compound, and a quantum dot of a group IV-IV semiconductor compound. The above may be selected.

Quantum dots of group IV elements include, for example, carbon quantum dots, graphene quantum dots, silicon quantum dots, and the like. Quantum dots of group II-VI semiconductor compounds include, for example, zinc oxide quantum dots, cadmium oxide quantum dots, zinc sulfide quantum dots, cadmium sulfide quantum dots, zinc selenide quantum dots, cadmium selenide quantum dots, zinc tellunide quantum dots, cadmium telluride quantum dots, etc. have. Quantum dots of group III-V semiconductor compounds include, for example, gallium nitride quantum dots, gallium phosphide quantum dots, gallium arsenide quantum dots, gallium antimonide quantum dots, indium nitride quantum dots, indium phosphide quantum dots, indium arsenide quantum dots, indium antimonide quantum dots, etc. have. The group IV-IV semiconductor compound quantum dots include, for example, silicon carbide quantum dots. In addition, the semiconductor compound in the form of quantum dots is not limited to the above types.

In the structure of the solar cell according to an embodiment of the present invention, the light wavelength conversion layer located between the light-receiving electrode and the photoactive layer includes an inorganic semiconductor and It may include at least one or more from the group consisting of a conductive polymer and a metal oxide.

In this case, the conductive polymer that may be included in the light wavelength conversion layer may include a polymerization unit represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ and R ₂ may each independently be represented by Formula 2 below.

[Formula 2]

In Formula 2, p may be an integer between 0 and 10.

In Formula 2, M may be represented by Formula 2-1 or Formula 2-2.

[Formula 2-1]

In Formula 2-1, R ₃ and R ₄ are each independently an alkyl group having 1 to 10 carbon atoms substituted or unsubstituted with a hydroxyl group or a sulfonic acid group, an alkenyl group having 2 to 10 carbon atoms substituted or unsubstituted with a hydroxyl group or a sulfonic acid group and an alkynyl group having 2 to 10 carbon atoms that is unsubstituted or substituted with a hydroxyl group or a sulfonic acid group.

[Formula 2-2]

In Formula 2-2, R ₅ , R ₆ and R ₇ are each independently an alkyl group having 1 to 10 carbon atoms substituted or unsubstituted with a hydroxyl group or a sulfonic acid group, 2 to 10 carbon atoms substituted or unsubstituted with a hydroxyl group or a sulfonic acid group It may be selected from the group consisting of an alkynyl group having 2 to 10 carbon atoms that is unsubstituted or substituted with an alkenyl group, a hydroxyl group, or a sulfonic acid group. In addition, in Formula 2-2, the nitrogen cation and the halogen ion may or may not bind.

In Formula 1, In Formula 1, Ar is a single bond; or a unit structure represented by the following Chemical Formulas 3 to 6; can be one of

[Formula 3]

In Formula 3, R ₈ and R ₉ are each independently a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, and a substituted or unsubstituted C2 to C20 alkyl group It may be selected from the group consisting of a nyl group. In this case, the carbon number may be 2 to 16, or 3 to 16, or 4 to 12, or 6 to 10. In addition, R _8, and alkyl, alkenyl, alkynyl R ₉ group is preferably an acyclic straight or branched independently. Also, R ₈ and R ₉ may have the same structure.

[Formula 4]

In Formula 4, Q ₁ may be an oxygen atom or a sulfur atom. In this case, Q ₁ is preferably a sulfur atom.

[Formula 5]

In Formula 5, Q ₂ may be an oxygen atom or a sulfur atom. In this case, Q ₂ is preferably an oxygen atom.

[Formula 6]

Formulas 1 to 6 may be substituted with a substituent J.

-(diethanolamino)hexyl)fluorene]), PFN-Br(Poly [(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] dibromide) 등 PFN계열 화합물일 수 있으며, 상기 화학식 1로 나타낼 수 있으면 특별히 제한되는 것은 아니다.The conductive polymer that may be included in the light wavelength conversion layer is, for example, PFN (Poly [(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2, 7-(9,9-dioctylfluorene)]), PFN-OH (Poly[9,9-bis(6

-(diethanolamino)hexyl)fluorene]), PFN-Br(Poly [(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-( 9,9-dioctylfluorene)] dibromide) may be a PFN-based compound, and is not particularly limited as long as it can be represented by Formula 1 above.

The metal oxide that may be included in the light wavelength conversion layer may be at least one metal oxide selected from the group consisting of Zn, Ba, Li, and Ti.

The metal oxide that may be included in the light wavelength conversion layer may be, for example, ZnO, BaO, Li ₂ O, TiO 2 , and the like, but is not particularly limited.

The light wavelength conversion layer of the solar cell according to an embodiment of the present invention is 1 to 10 ⁴ g/cm ³ , or 10 to 10 ⁴ g/cm ³ , or 10 ² to 10 ⁴ g/cm ³ , or 10- ^The inorganic semiconductor compound may be included in a content range of 3 to 10 ⁴ g/cm ^{3 .} By including the inorganic semiconductor compound in the above content, it is possible to effectively convert the wavelength of the light incident on the light-receiving electrode into a wavelength that the photoactive layer can easily utilize.

When the light wavelength conversion layer is positioned between the photoactive layer and the photoactive layer in the structure of the solar cell according to an embodiment of the present invention, another light wavelength conversion layer may be included between the photoactive layer and the opposite electrode of the photoactive layer. In this case, another light wavelength conversion layer positioned between the photoactive layer and the opposite electrode of the light-receiving electrode may include a hole-transporting material forming a hole-transporting layer to be described below. The hole transport material is not particularly limited as long as it can transport holes, and a known material may be used.

The light wavelength conversion layer of the solar cell according to an embodiment of the present invention is between the light-receiving electrode and the photoactive layer, and is at an interval of 0.5 to 220 nm, or 0.5 to 200 nm, or 0.5 to 190 nm, from the surface of the light receiving electrode, or 0.5 to 180 nm spacing, or 0.5 to 170 nm spacing, or 0.5 to 160 nm spacing, or 0.5 to 150 nm spacing. In this case, the interval means from the bottom to 1/2 of the total thickness of the light wavelength conversion layer from the surface of the light receiving electrode. In addition, the surface of the light-receiving electrode in the interval means a surface on which a light wavelength conversion layer, a photoactive layer, etc. are to be laminated. The photoactive layer and the surface of the light-receiving electrode are

The light wavelength conversion layer of the solar cell according to an embodiment of the present invention may be formed to a thickness of 1 to 300 nm. Specifically, it may have a thickness of about 1 to 100 nm in a small-area solar cell, and preferably a thickness of 1 to 50 nm. In a large-area solar cell, it can be formed to a thickness of up to 300 nm. As used herein, the term small-area solar cell means a solar cell having a photoactive area of 0.001 or more and 0.1 cm ² or less, and a large-area solar cell means a ^{solar cell having a photoactive area of more than 0.1 and 10 cm 2} or less. . In the present specification, unless otherwise specified, it corresponds to a small-area solar cell.

In the structure of the solar cell according to an embodiment of the present invention, a charge transport layer may be positioned between the photoactive layer and the photoactive layer or between the photoactive layer and the opposite electrode of the photoactive electrode.

The charge transport layer may include an electron transfer layer (ETL) and a hole transport layer (HTL), and the electron transport layer may transport electrons formed in the electrode and the hole transport layer may transport holes formed in the electrode.

-spirobi[fluorene]), mCPPO1(9-(3-(9H -Carbazol-9-yl)phenyl)-3-(diphenylphosphoryl)-9H-carbazole), TPBI(1,3,5-Tris(1-phenyl-1H-benzimidazol-2-yl)benzene), PFN(Poly [(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)]), PFN-OH(Poly[9,9-bis(6

-(diethanolamino)hexyl)fluorene]), PFN-Br(Poly [(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] dibromide), ZnO, BaO, Li₂O, TiO₂ 등일 수 있으며 이에 제한되는 것은 아니다. 만약, 전자수송층을 형성하기 위해서 무기 금속 산화물 전구체를 용매에 용해시켜 ZnO, BaO, Li₂O, TiO₂ 등과 같은 금속 산화물로 전이시킬 수 있다. 이 때, 사용할 수 있는 무기 금속 산화물 전구체는 아연 전구체, 바륨 전구체, 리튬 전구체, 티타늄 전구체 등일 수 있다. 예를 들면, 아세트산 아연, 아세트산 바륨, 아세트산 리튬, 아세트산 티타늄, 아연 이소프로폭사이드, 바륨 이소프로폭사이드, 리튬 이소프로폭사이드, 티타늄 이소프로폭사이드 등일 수 있다.The electron transport layer may include an electron transport material. The electron transport material is not particularly limited as long as the electron transport layer is positioned in the solar cell to smoothly transfer electrons formed in the electrode to the photoactive layer, and a known material may be used. Known electron transport materials include, for example, TBCPF (9,9-di(4,4'-bis(3,6-Di-tert-butyl-9H-carbazole)-phenyl)-9H-fluorene), SPPO13 ( 2,7-bis(diphenylphosphoryl)-9,9

-spirobi[fluorene]), mCPPO1(9-(3-(9H-Carbazol-9-yl)phenyl)-3-(diphenylphosphoryl)-9H-carbazole), TPBI(1,3,5-Tris(1-phenyl) -1H-benzimidazol-2-yl)benzene), PFN(Poly [(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-( 9,9-dioctylfluorene)]), PFN-OH (Poly[9,9-bis(6

-(diethanolamino)hexyl)fluorene]), PFN-Br(Poly [(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-( 9,9-dioctylfluorene)] dibromide), ZnO, BaO, Li ₂ O, TiO _{2 and the} like, but is not limited thereto. If, in order to form an electron transport layer, an inorganic metal oxide precursor may be dissolved in a solvent and transferred to a metal oxide such as _{ZnO, BaO, Li 2} O, TiO _{2 .} In this case, the usable inorganic metal oxide precursor may be a zinc precursor, a barium precursor, a lithium precursor, a titanium precursor, or the like. For example, it may be zinc acetate, barium acetate, lithium acetate, titanium acetate, zinc isopropoxide, barium isopropoxide, lithium isopropoxide, titanium isopropoxide, and the like.

The hole transport layer may include a hole transport material. The hole transport material is not particularly limited as long as the hole transport layer is positioned in the solar cell to smoothly transfer the holes formed in the electrode to the photoactive layer, and a known material may be used. Known hole transport materials include, for example, polypyrrole, polyfuran, polythiophene, polyselenophene, PEDOT:PSS (poly (3,4-ethylene dioxythiophene):polystyrene sulfonate), PEDOT (poly (3,4-ethylene) dioxythiophene)), PEDOS (poly(3,4-ethylene dioxy selenophene), WO ₃ , V ₂ O ₃ , NiO, MoO _{3 ,} etc., but is not limited thereto. If, in order to form a hole transport layer, an inorganic metal oxide precursor can be dissolved in a solvent to _{be converted into a metal oxide such as WO 3} , V ₂ O ₃ , NiO, MoO ₃ etc. In this case, the usable inorganic metal oxide precursor is a molybdenum precursor, a tungsten precursor, a vanadium precursor, a nickel precursor, It may be a molybdenum precursor, etc. For example, molybdenum diacetylacetonate dioxide, ammonium heptamolybdate tetrahydrate, nickel(II) acetylacetonate, nickel acetate ( nickel(II) acetate), vanadium acetate, tungsten(V, IV) ethoxide, phosphomolybdic acid, and phosphotungstic acid.

The charge transport layer may be formed using a known method. For example, it is applied uniformly through a solution process such as spin-coating, inkjet-printing, bar-coating, and slot-die coating to form a thin film. It may be formed, and may be formed using a physical vapor deposition method (PVD), a chemical vapor deposition method (CVD), an atomic layer deposition method (ALD), or a thermal evaporation method.

The light-receiving electrode (or first electrode) of the solar cell according to the present invention may be formed on a transparent substrate by physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), or thermal vapor deposition. The transparent substrate, as used herein, is light-transmitting glass, quartz, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polycarbonate (PC), polystyrene (PS), poly It may be formed of at least one selected from the group consisting of oxyethylene (POM), acrylonitrile-styrene resin (AS resin), and triacetyl cellulose (TAC).

The light-receiving electrode may be formed of a metal oxide thin film having light transmittance. The metal oxide thin film is, for example, an indium tin oxide (ITO) film, a tin fluoride (FTO) film, an indium zinc oxide (IZO) film, an aluminum doped oxide (AZO) film, a zinc oxide (ZnO) film, and an IZTO film. It may be at least one selected from the group consisting of (indium zinc tin oxide) film.

The opposite electrode (or second electrode) of the light-receiving electrode of the solar cell according to the present invention may be formed using a physical vapor deposition method (PVD), a chemical vapor deposition method (CVD), an atomic layer deposition method (ALD), or a thermal evaporation method. For example, it is deposited inside a thermal evaporator with a high vacuum of ^{about 5×10 -7 torr.} The second electrode is preferably a material having high oxidation stability against exposure to air, and Cu, Ag, Au, W, Ni, Al, and Ti may be used, and may be appropriately selected in consideration of the structure of the solar cell to be manufactured. .

The photoactive layer of the solar cell according to the present invention may include an inorganic material using crystalline silicon or the like, and may be formed in the form of a thin film of an organic material. For example, in an organic solar cell, the photoactive layer may be formed using a photoactive composition prepared by mixing an electron donor material and an electron acceptor material. Specifically, it may be formed based on a bulk-heterojunction structure in which the electron donor material and the electron acceptor material are mixed, but is not limited thereto.

Electron donor materials that can be used in the present invention include PTB7 (CAS No. 1266549-31-8), PTB7-Th (CAS No. 1469791-66-9), PBDB-T (CAS No. 145929-80-4), It may be at least one selected from the group consisting of PBDB-T-2F (CAS No. 1802013-83-7) and ternary copolymers represented by the following Chemical Formulas 7 to 10 (Korea Patent Application No. 10-2020-0052656) see No.).

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

In Formulas 7 to 10, n is an integer between 1 and 10,000.

The electron acceptor material that can be used in the present invention includes at least one or more from the group consisting of fullerene derivatives and non-fullerene derivatives. Fullerene derivatives include PC ₆₁ BM (CAS No. 160848-22-6), PC ₇₁ BM (CAS No. 609771-63-3), and the like, and non-fullerene derivatives include ITIC (CAS No. 16694293-06-4). , ITIC-M (or IT-M or m-ITIC) (CAS No. 2047352-80-5), ITIC-Th (CAS No. 1889344-13-1), IDIC (CAS No. 1883441-92-6) , IT-4F (or ITIC-4F) (CAS No. 2097998-59-7), ITIC-4Cl (CAS No. 2253663-81-7), ITIC-2F (CAS No. 2097998-59-7), BTP -4F (CAS No. 2304444-49-1), BTP-4Cl, Y6-BO-4Cl, IEICO-4F (CAS: 2089044-02-8), IEICO-4Cl, and the like. However, the present invention is not limited thereto and may include any electron acceptor material used in the art.

A mixing ratio (w/w) of the electron donor material and the electron acceptor material may be 1:0.5 to 1:2, 1:0.75 to 1:1.5, and 1:0.9 to 1:1.2.

The present invention can provide a method of manufacturing a solar cell that exhibits excellent performance indoors as well as outdoors by introducing a light wavelength conversion layer that changes the wavelength of incident light.

When the terms used in the method for manufacturing a solar cell according to the present invention overlap with the above-described contents, the above-described contents may be followed. Hereinafter, content different from the description described above will be mainly described.

The method for manufacturing a solar cell according to an embodiment of the present invention may include forming a light-receiving electrode (or a first electrode), forming a light wavelength conversion layer with the prepared light wavelength conversion composition, and then forming a photoactive layer. In this case, the optical wavelength conversion composition may be prepared using a commercially available material.

The optical wavelength conversion composition may be prepared by dispersing the inorganic semiconductor compound in the first solvent to obtain an inorganic semiconductor dispersion.

In this case, the first solvent may be a polar solvent, which is a solvent having polar molecules. For example, water, a compound containing a hydroxyl group (e.g., methanol, ethanol, 2-methoxyethanol, 2-ethoxyethanol, propanol, 2-propanol, butanol, pentanol, hexanol and mixtures thereof, etc.) ), a compound containing a carboxyl group (eg, formic acid, acetic acid, and mixtures thereof, etc.), a compound containing a ketone group (eg, acetone, etc.) and a compound containing an amine group (eg, N, N- dimethylformamine, N,N-dimethylacetamine, ethanolamine, and mixtures thereof) may be at least one selected from the group consisting of). In addition, the first solvent may be in the form of an anhydride. Considering the stability of the inorganic semiconductor dispersion, the first solvent may be at least one of water or a compound containing a hydroxyl group. A mixture of each compound exemplified in the first solvent means a mixture of two or more compounds. For example, a mixture of methanol, ethanol, 2-methoxyethanol, and 2-propanol in a compound containing a hydroxyl group may be the first solvent. In addition, the first solvent may mean a mixture of one or more compounds in each compound. For example, a mixture obtained by selecting 2-methoxyethanol from a mixture containing a hydroxyl group and selecting ethanolamine from a compound containing an amine group may be the first solvent.

In the inorganic semiconductor dispersion, the concentration of the inorganic semiconductor compound may be 0.05 to 20 mg/mL. When the concentration of the inorganic semiconductor compound is lower than 0.05 mg/mL, the effect of optical wavelength conversion is insignificant, and when the concentration of the inorganic semiconductor compound is higher than 20 mg/mL, the photoelectric conversion efficiency decreases. Considering the better light conversion effect, the concentration of the inorganic semiconductor compound may be 0.1 to 10 mg/mL

The optical wavelength conversion composition may be prepared as a composite composition in which an inorganic semiconductor compound is dispersed in a first solvent and then a conductive polymer, a metal oxide, or a combination thereof dispersed in a second solvent is mixed.

In this case, the second solvent may be a polar solvent, which is a solvent composed of polar molecules like the first solvent. The description of the second solvent is the same as the description of the first solvent.

The composite composition is prepared by mixing an inorganic semiconductor dispersion in which an inorganic semiconductor compound is dispersed in a first solvent and a conductive dispersion in which a conductive polymer, a metal oxide, or a combination thereof are dispersed in a second solvent from 1:0.01 (v/v) to 1:10 (v). /v) ratio, preferably 1:1 (v/v) to 1:5 (v/v) can be formed by mixing. In this case, when the conductive dispersion is less than 0.01 volume by volume relative to 100 volume ratio of the inorganic semiconductor dispersion, the optical wavelength conversion effect is insignificant, and when the conductive dispersion is larger than 10 volume ratio, the photoelectric conversion efficiency may decrease.

Solution processes such as spin-coating, inkjet-printing, bar-coating, and slot-die coating in the solar cell manufacturing method according to an embodiment of the present invention Since it can be uniformly applied to form a thin film, it can be applied even when manufacturing small-area unit cells to large-area and modular solar cells, so it can be applied not only to outdoor applications such as BIPVs and AIPVs, but also to smart factories, It has the advantage that it can greatly contribute to indoor applications such as IoT sensors. The spin coating may be applied at a speed of 1,000 rpm to 5,000 rpm, and the slot die coating may apply a dispersion or various compositions at a discharge rate of 0.1 to 1.0 mL/min and a speed of 0.1 to 1.0 m/min.

The method for manufacturing a solar cell according to the present invention may be according to the structure of the solar cell according to an example of the present invention described above. That is, a solar cell may be manufactured by sequentially applying or depositing each dispersion or composition capable of forming each layer of the solar cell structure.

In the method for manufacturing a solar cell according to the present invention, the light receiving electrode (first electrode), the charge transport layer, the photoactive layer, and the light receiving electrode and the opposite electrode (second electrode) can be formed using methods and materials already known in the art. have.

In the method for manufacturing a solar cell according to the present invention, heat treatment is performed before and after the step of forming each layer (a light-receiving electrode (first electrode), a charge transport layer, a photoactive layer, a light wavelength conversion layer, and an electrode opposite to the light-receiving electrode (second electrode)). can be performed. The heat treatment temperature is about 40 °C to 300 °C, and in order to maximize the light wavelength effect without reducing the efficiency of the solar cell, it is preferably about 60 °C to 250 °C. In particular, it is preferable to heat-treat at a temperature between about 80° C. and 200° C. before and after forming the optical wavelength conversion layer.

In the solar cell according to the present invention, the thickness of each layer (light-receiving electrode (first electrode), charge transport layer, photoactive layer, and the light-receiving electrode and the opposite electrode (second electrode)) excluding the light wavelength conversion layer is optimized within the range that is optimized. The light receiving electrode (first electrode) is about 100 to 250 nm, the electron transporting layer is 10 to 70 nm, the photoactive layer is 50 to 200 nm, the hole transporting layer is 1 to 15 nm, and the opposite electrode of the light receiving electrode (second electrode) ) may be about 50 to 150 nm.

In the above, the configuration and features of the present invention have been described based on the embodiments according to the present invention, but the present invention is not limited thereto, and it is understood that various changes or modifications can be made within the spirit and scope of the present invention. It is apparent to those skilled in the art that such changes or modifications are intended to fall within the scope of the appended claims.

<Preparation Example 1A> Preparation and evaluation of optical wavelength conversion composition

In order to manufacture the organic solar cell according to the present invention, a light wavelength conversion composition including graphene quantum dots having light wavelength characteristics was prepared. The light wavelength conversion composition containing the graphene quantum dots used in this preparation example absorbs light of a wavelength having a peak of 300 nm or more and less than 375 nm, and light of a wavelength having a peak of 585 nm or more and less than 615 nm and 725 nm It has a light emission characteristic of light of a wavelength having a peak of more than 775 nm.

To prepare the optical wavelength conversion composition, a 5 mL vial was prepared by vacuum and nitrogen substitution. In addition, 2-methoxy ethanol (2-methoxy ethanol), 2-propanol anhydrous (2-propanol anhydrous, CAS No. 67-63-0), methanol anhydrous (methanol anhydrous, CAS No. 67-56-1) and Ethanol anhydrous (ethanol anhydrous, CAS No. 64-17-5) containing alcohol (alcohol) was prepared by putting it in a vial. Then, the graphene quantum dots were added to the vial containing the alcohol so that the concentration of the graphene quantum dots was 0.5 to 5 mg/mL and stirred at room temperature. When sufficiently dissolved, the vial containing the dark brown clear solution was sealed using a para film. After that, stirred and stored in a roll-mixer at room temperature for 1 hour, filled with distilled water in a sonicator, and fixed so that distilled water reaches 2/3 of the vial and sonicated for 30 minutes did. Thereafter, as shown in FIG. 2 , a light wavelength conversion composition as a clear dark brown solution was obtained.

The properties of the obtained light wavelength conversion composition were evaluated using an ultraviolet hand lamp (VL-4L) emitting light in the λ = 365 nm region. A control group was the alcohol used in the preparation of the optical wavelength conversion composition. Characteristic evaluation results by the ultraviolet hand lamp are shown in Figs. 3 (a) and 3 (b). As shown in FIG. 3( a ), the prepared light wavelength conversion composition exhibited strong light emitting characteristics of bright yellow, and it was found that there was a light wavelength conversion property through this. In addition, as shown in FIG. 3(b) , in the comparison group, light emission in the visible region did not occur, and thus a transparent solution was obtained.

In addition, the properties of the obtained light wavelength conversion composition were evaluated using an LED lamp (Oriel VeraSol Solar Simulator). The comparative group was the alcohol used in the preparation of the optical wavelength conversion composition as described above. LED lamps, which are mainly used as indoor light sources, generate light in the λ = 400-780 nm region. Characteristic evaluation results by the LED lamp are shown in Figs. 4 (a) and 4 (b). As shown in FIG. 4( a ), the prepared light wavelength conversion composition exhibited a bright yellow strong luminescence property, and it was found that there was a light wavelength conversion property through this. In addition, as shown in FIG. 4(b) , in the comparative group, light emission in the visible region did not occur, and thus a transparent solution was obtained.

<Production Example 1B> Preparation and evaluation of the optical wavelength conversion layer

An optical wavelength conversion layer was formed by spin coating the optical wavelength conversion composition prepared in Preparation Example 1A on ITO glass.

The characteristics of the light wavelength conversion layer formed by the LED lamp used in Preparation Example 1A were evaluated. As a control group, the alcohol used in the preparation of the optical wavelength conversion composition in Preparation Example 1A was spin-coated on ITO glass as a coating thin film. Characteristic evaluation results by the LED lamp are shown in Figs. 5 (a) and 5 (b). As shown in FIG. 5( a ), the prepared light wavelength conversion layer showed light emitting properties. In addition, as shown in FIG. 5( b ), the comparative group did not generate a characteristic light emitting phenomenon and thus appeared as a transparent layer.

<Preparation Example 2A> Preparation and evaluation of the composite composition

In order to form an optical wavelength conversion layer capable of simultaneously performing optical wavelength conversion and charge transport in the solar cell according to the present invention, a ZnO composition, which is a conductive dispersion, was first prepared.

To prepare the ZnO composition, a 5 mL vial was prepared by vacuum and nitrogen substitution. In addition, zinc acetate dehydrate (CAS No. 5970-45-6), 2-methoxyethanol and ethanolamine (ethanolamine, ACS reagent, CAS No. 141-43-5) was placed in the vial, and stirred for about 12 hours at a speed of 200 rpm on a hot-plate set at a temperature of 60 °C. At this time, zinc acetate dihydrate is converted to ZnO, and the mechanism for this was referred to Vaccum 2004, 77, 57-62. Thereafter, a ZnO precursor was formed through a sol-gel process, and a ZnO composition as a clear solution was obtained as shown in FIG. 6(a).

The ZnO composition and the optical wavelength conversion composition prepared in Preparation Example 1A were mixed in a ratio of 1:1 (v/v), 1:2 (v/v) and 1:5 (v/v) in FIG. 6(b) ), a complex composition was obtained as a clear dark brown solution.

The obtained composite using an ultraviolet hand lamp (VL-4L) that generates light in the λ = 365 nm region and an LED lamp (Oriel VeraSol Solar Simulator) that generates light in the λ = 400-780 nm region The properties of the composition were evaluated. A control group was used as the ZnO composition. The characteristic evaluation result by the ultraviolet hand lamp is shown in FIG. 7(a), and the characteristic evaluation result by the LED lamp is shown in FIG. 7(b). Since the ZnO composition is also used to form the charge transport layer, the ZnO composition is indicated as a pure charge transport layer solution in FIG. 7 . Since the composite composition performs the roles of optical wavelength conversion and charge transport at the same time, it is indicated as an optical wavelength conversion charge transport layer solution in FIG. 7 . As shown in FIGS. 7(a) and 7(b), the composite composition showed strong light emitting characteristics of bright yellow, and it was confirmed that there was a light wavelength conversion characteristic through this. In addition, in the comparative group, light emission in the visible region did not occur, and thus a transparent solution was obtained.

<Preparation Example 2B> Preparation and evaluation of the optical wavelength conversion layer

A light wavelength conversion layer was formed by spin coating the composite composition prepared in Preparation Example 2A on ITO glass.

The characteristics of the light wavelength conversion layer formed by the LED lamp used in Preparation Example 2A were evaluated. As a control group, the ZnO composition in Preparation Example 2A was spin-coated on ITO glass as a ZnO layer. The characteristic evaluation result of the light wavelength conversion layer by the LED lamp is shown in Fig. 8(a), and the characteristic evaluation result of the ZnO layer is shown in Fig. 8(b). As shown in FIG. 8( a ), the prepared light wavelength conversion layer showed light emitting properties. In addition, as shown in FIG. 8(b), in the comparison group, light emission in the visible region did not occur, and thus a transparent layer appeared.

1. Manufacture of inverted organic solar cell

<Example 1>

In order to manufacture a reverse structure organic solar cell including a light wavelength conversion layer, a transparent substrate; light-receiving electrode (first electrode); a first optical wavelength conversion layer; photoactive layer; hole transport layer; The structure of the second electrode was introduced. At this time, the light wavelength conversion layer was formed of a composite composition.

1.1: Preparation of conductive dispersion

A ZnO precursor was prepared as a conductive dispersion. A ZnO precursor was obtained in the same manner as in Preparation Example 2A for forming the ZnO precursor.

1.2: Preparation of optical wavelength conversion composition

In the same manner as in Preparation Example 1A, a dark brown clear solution, a light wavelength conversion composition, was obtained. The obtained dark brown, clear light wavelength conversion layer composition was stirred and stored in a roll-mixer at room temperature.

1.3: Preparation of Composite Composition

A composite composition was prepared by mixing the conductive dispersion prepared in step 1.1 and the optical wavelength conversion composition prepared in step 1.2. At this time, the conductive dispersion and the optical wavelength conversion composition were mixed in a volume ratio of 1:2.

1.4: Manufacturing of inverted organic solar cell (1) | Preparation and pretreatment

Wet the patterned ITO glass through sonication in an ultrasonic cleaner in the order of acetone (CAS: 67-64-1), neutral detergent, 2-propanol and distilled water. went through a cleaning process. After sonicating for each step, it was rinsed with distilled water, and moisture was removed with _{nitrogen (N 2 ) gas.} After the wet cleaning process, the ITO glass was dried on a hot plate at a temperature of 120° C. for 10 minutes. The surface of the dried ITO glass was modified to be hydrophilic through UV-ozone treatment in a UV-ozone cleaner device.

1.5: Manufacturing of inverted organic solar cell (2) | First light wavelength conversion layer coating

The composite composition prepared in step 1.3 was spin-coated to a thickness of 10 nm on the modified ITO glass in the atmosphere. At this time, it was observed with the naked eye that the formed light wavelength conversion layer was dried while drawing a circle from the center outward. Spin coating was carried out until the shape of circular gathering disappeared, and was performed for about 30 seconds. As shown in FIG. 9 , it can be confirmed that the first optical wavelength conversion layer is formed of a transparent thin film.

1.6: Manufacturing of inverted organic solar cell (3) | Photoactive composition preparation and photoactive layer coating

A photoactive composition was prepared by mixing an electron donor material P(Cl-Cl) (BDD=0.2) and an electron acceptor material IT-4F in a 1:1 (w/w) ratio to form a bulk heterojunction structure. The electron donor material, P(Cl-Cl) (BDD=0.2) is the same as in Chemical Formula 10 shown below, and n in Chemical Formula 10 is an integer between 1 and 10,000 (refer to Korean Patent Application No. 10-2020-0052656) ). IT-4F, which is the electron acceptor material, is as shown in Chemical Formula 11 below.

[Formula 10]

[Formula 11]

1,8-diiodooctane (1,8-diiodooctane, CAS No. 24772-63-2) chlorobenzene anhydrous (CAS No. 108-90-7) in 0.5 to 1.0 volume ratio based on 1.0 volume ratio Prepare a solvent containing a, based on the 1.0 weight ratio of the solvent, 0.5 to 1.5 weight ratio of the mixed composition of P (Cl-Cl) (BDD = 0.2) and IT-4F to the solvent to obtain a photoactive composition .

Before coating the photoactive composition on the thin film on which the light wavelength conversion layer is formed, the photoactive composition was activated in the atmosphere at a temperature of 90 °C and then activated again at a temperature of 90 °C. Thereafter, a thin film having a thickness of 80 to 120 nm was formed on the thin film on which the optical wavelength conversion layer was formed by using spin coating. The formed thin film (photoactive layer) was heat-treated on a hot plate at 100° C. to 160° C. for 15 minutes.

1.7: Manufacturing of inverted organic solar cells (4) | Hole transport layer coating and second electrode formation

In order to coat the hole transport layer on the photoactive layer formed in step 1.6 and form a second electrode, the laminate formed in step 1.6 was transferred to a high vacuum ( ^{less than 10 -6} torr) vacuum chamber using a cryo-pump. moved to Thereafter, molybdenum trioxide (MoO ₃ , CAS No. 1313-27-5) was thermally deposited at a rate of 0.1 to 0.5 Å/s to a thickness of 1 to 10 nm to form a hole transport layer. Thereafter, silver (argentum, Ag, CAS No. 7440-22-4) is thermally deposited at a rate of 0.1 to 3.0 Å/s to a thickness of 10 to 100 nm to form a second electrode on the hole transport layer, thereby forming an inverse structure. A solar cell (photoactive area 0.04 cm ² ) was prepared.

<Example 2>

In order to manufacture a reverse structure organic solar cell including a light wavelength conversion layer, a transparent substrate; light-receiving electrode (first electrode); electron transport layer; a first optical wavelength conversion layer; photoactive layer; hole transport layer; The structure of the second electrode was introduced.

2.1: Preparation of conductive dispersion

As in step 1.1 above, a ZnO precursor as a conductive dispersion was obtained.

2.2: Preparation of optical wavelength conversion composition

A light wavelength conversion composition was obtained in the same manner as in step 1.2 above.

2.3: Manufacturing of inverted organic solar cell (1) | Preparation and pretreatment

A modified ITO glass was prepared in the same manner as in step 1.4.

2.4: Manufacturing of inverted organic solar cells (2) | Electron transport layer coating

The ZnO precursor prepared in step 2.1 was diluted in 2-methoxyethanol at a ratio of 1:1 to 1:5 on the ITO glass that had undergone the pretreatment process, and spin-coated to a thickness of 30 to 40 nm in the air. to form a thin film. Thereafter, it was fired by heating on a hot plate at a temperature of 150° C. to 200° C. for 30 minutes to 1 hour. At this time, the formed thin film appeared as a transparent layer as shown in FIG.

2.5: Manufacturing of inverted organic solar cells (3) | First light wavelength conversion layer coating

In order to form the first optical wavelength conversion layer on the thin film on which the electron transport layer is formed, the optical wavelength conversion composition prepared in step 2.2 was spin-coated to a thickness of 10 nm on the thin film on which the electron transport layer was formed in the atmosphere. At this time, it was observed with the naked eye that the formed light wavelength conversion layer was dried while drawing a circle from the center outward. The spin coating was performed until the shape of circular gathering disappeared to form the first optical wavelength conversion layer.

2.6: Manufacturing of inverted organic solar cells (4) | Photoactive layer coating, hole transport layer coating and second electrode formation

In the same manner as in steps 1.6 and 1.7, an inverse structure organic solar cell (photoactive area 0.04 cm ² ) was prepared by forming a hole suit layer and a second electrode after coating the photoactive layer.

<Example 3>

In order to manufacture a reverse structure organic solar cell including a light wavelength conversion layer, a transparent substrate; light-receiving electrode (first electrode); a first optical wavelength conversion layer; electron transport layer; photoactive layer; hole transport layer; The structure of the second electrode was introduced.

3.1: Preparation of conductive dispersion

As in step 1.1 above, a ZnO precursor as a conductive dispersion was obtained.

3.2: Preparation of optical wavelength conversion composition

A light wavelength conversion composition was obtained in the same manner as in step 1.2 above.

3.3: Manufacturing of inverted organic solar cell (1) | Preparation and pretreatment

A modified ITO glass was prepared in the same manner as in step 1.4.

3.4: Manufacturing of inverted organic solar cells (2) | First light wavelength conversion layer coating

In order to form the first optical wavelength conversion layer on the ITO glass subjected to the pretreatment process, the optical wavelength conversion composition prepared in step 3.2 was spin-coated to a thickness of 10 nm on the ITO glass subjected to the pretreatment process in the air. At this time, it was observed with the naked eye that the formed light wavelength conversion layer was dried while drawing a circle from the center outward. The spin coating was performed until the shape of circular gathering disappeared to form the first optical wavelength conversion layer.

3.5: Manufacturing of inverted organic solar cell (3) | Electron transport layer coating

In order to form an electron transport layer on the thin film on which the light wavelength conversion layer is formed, the ZnO precursor prepared in step 3.1 is diluted in 2-methoxy ethanol at a ratio of 1:1 to 1:5, and the atmosphere A thin film was formed by spin coating in a thickness of 30 to 40 nm. Thereafter, it was fired by heating on a hot plate at a temperature of 150° C. to 200° C. for 30 minutes to 1 hour.

3.6: Fabrication of inverted organic solar cells (4) | Photoactive layer coating, hole transport layer coating and second electrode formation

In the same manner as in steps 1.6 and 1.7, an inverse structure organic solar cell (photoactive area 0.04 cm ² ) was prepared by forming a hole suit layer and a second electrode after coating the photoactive layer.

<Example 4>

In order to manufacture a reverse structure organic solar cell including a light wavelength conversion layer, a transparent substrate; light-receiving electrode (first electrode); a first optical wavelength conversion layer; photoactive layer; a second optical wavelength conversion layer; The structure of the second electrode was introduced. At this time, the light wavelength conversion layer positioned between the first electrode and the photoactive layer was formed of a composite composition.

4.1: Preparation of conductive dispersions

As in step 1.1 above, a ZnO precursor as a conductive dispersion was obtained.

4.2: Preparation of optical wavelength conversion composition

A light wavelength conversion composition was obtained in the same manner as in step 1.2 above.

4.3: Preparation of hole transport materials

A 5 mL vial was prepared by vacuum and nitrogen substitution, and PEDOT:PSS was added thereto. In addition, the solvent was placed in the vial and stirred on a hot-plate. Thereafter, a PEDOT:PSS solution, which is a hole transport composition, was obtained, and the obtained PEDOT:PSS solution was stored in the atmosphere.

4.4: Preparation of Composite Compositions

A composite composition was prepared by mixing the conductive dispersion prepared in step 4.1 and the optical wavelength conversion composition prepared in step 4.2. At this time, the conductive dispersion and the optical wavelength conversion composition were mixed in a volume ratio of 1:2.

4.5: Manufacturing of inverted organic solar cell (1) | Preparation and pretreatment

A modified ITO glass was prepared in the same manner as in step 1.4.

4.6: Manufacturing of inverted organic solar cells (2) | First light wavelength conversion layer coating

In order to form the first optical wavelength conversion layer on the ITO glass subjected to the pretreatment process, the composite composition prepared in step 4.4 was spin-coated to a thickness of 10 nm on the ITO glass subjected to the pretreatment process in the air. At this time, it was observed with the naked eye that the formed light wavelength conversion layer was dried while drawing a circle from the center outward. The spin coating was performed until the shape of circular gathering disappeared to form the first optical wavelength conversion layer.

4.7: Manufacturing of inverted organic solar cells (3) | Photoactive composition preparation and photoactive layer coating

After preparing the photoactive composition in the same manner as in step 1.6, a photoactive layer was formed.

4.8: Fabrication of inverted organic solar cells (4) | Second light wavelength conversion layer coating

The hole transport material prepared in step 4.3 and the optical wavelength conversion composition prepared in step 4.2 were mixed, and a second light wavelength conversion layer was formed by coating in the atmosphere on the thin film on which the photoactive layer was formed. It was spin-coated to a thickness of 10 nm on the thin film on which the photoactive layer was formed. At this time, it was observed with the naked eye that the formed light wavelength conversion layer was dried while drawing a circle from the center outward. The spin coating was performed until the shape of circular gathering disappeared to form a second light wavelength conversion layer.

4.9: Fabrication of inverted organic solar cells (5) | Second electrode formation

In the same manner as in step 1.7, a second electrode was formed to prepare ^{an inverted organic solar cell (photoactive area 0.04 cm 2 ).}

<Example 5>

In order to manufacture a reverse structure organic solar cell including a light wavelength conversion layer, a transparent substrate; light-receiving electrode (first electrode); a first optical wavelength conversion layer; electron transport layer; photoactive layer; hole transport layer; a second optical wavelength conversion layer; The structure of the second electrode was introduced.

5.1: Preparation of conductive dispersion

As in step 1.1 above, a ZnO precursor as a conductive dispersion was obtained.

5.2: Preparation of Optical Wavelength Conversion Composition

A light wavelength conversion composition was obtained in the same manner as in step 1.2 above.

5.3: Preparation of hole transport materials

In the same manner as in step 4.3, a PEDOT:PSS solution, which is a hole transport material, was obtained.

5.4: Manufacturing of inverted organic solar cell (1) | Preparation and pretreatment

A modified ITO glass was prepared in the same manner as in step 1.4.

5.5: Manufacturing of inverted organic solar cells (2) | First light wavelength conversion layer coating

In order to form the first optical wavelength conversion layer on the ITO glass that has undergone the pretreatment process, the optical wavelength conversion composition prepared in step 5.2 was spin-coated to a thickness of 10 nm on the ITO glass that had undergone the pretreatment process in the air. At this time, it was observed with the naked eye that the formed light wavelength conversion layer was dried while drawing a circle from the center outward. The spin coating was performed until the shape of circular gathering disappeared to form the first optical wavelength conversion layer.

5.6: Manufacturing of inverted organic solar cells (3) | Electron transport layer coating

In order to form an electron transport layer on the thin film on which the optical wavelength conversion layer is formed, the ZnO precursor prepared in step 5.1 is diluted in 2-methoxy ethanol at a ratio of 1:1 to 1:5, and the atmosphere A thin film was formed by spin coating in a thickness of 30 to 40 nm. Thereafter, it was fired by heating on a hot plate at a temperature of 150° C. to 200° C. for 30 minutes to 1 hour.

5.7: Fabrication of inverted organic solar cells (4) | Photoactive composition preparation and photoactive layer coating

After preparing the photoactive composition in the same manner as in step 1.6, a photoactive layer was formed on the thin film on which the electron transport layer was formed.

5.8: Fabrication of inverted organic solar cells (5) | hole transport layer coating

In order to form a hole transport layer on the thin film on which the photoactive layer is formed, the PEDOT:PSS solution prepared in step 5.3 was spin-coated in the air to form a thin film.

5.8: Fabrication of inverted organic solar cells (6) | Second light wavelength conversion layer coating

In order to form a second optical wavelength conversion layer on the thin film on which the hole transport layer is formed, the optical wavelength conversion composition prepared in step 5.2 was spin-coated to a thickness of 10 nm on the thin film on which the hole transport layer was formed in the atmosphere. At this time, it was observed with the naked eye that the formed light wavelength conversion layer was dried while drawing a circle from the center outward. The spin coating was performed until the shape of circular gathering disappeared to form a second light wavelength conversion layer.

5.9: Fabrication of inverted organic solar cells (7) | Second electrode formation

In the same manner as in step 1.7, a second electrode was formed to prepare ^{an inverted organic solar cell (photoactive area 0.04 cm 2 ).}

<Comparative Example 1>

A general inverted organic solar cell (photoactive area 0.04 cm ² ) without a light wavelength conversion layer was prepared. That is, a transparent substrate; light-receiving electrode (first electrode); electron transport layer; photoactive layer; hole transport layer; The structure of the second electrode was introduced.

In this case, the ITO glass modified in the same manner as in step 1.4 was used for the transparent substrate and the first electrode. In addition, the electron transport layer was formed by coating a ZnO precursor on the modified ITO glass in the same manner as in step 2.4. In addition, the photoactive layer was formed by preparing the photoactive composition in the same manner as in step 1.6, and then coating it on the electron transport layer. In addition, the hole transport layer and the second electrode were _{formed by depositing MoO 3} on the photoactive layer and depositing silver (Ag) thereon in the same manner as in step 1.7.

<Comparative Example 2>

transparent substrate; light-receiving electrode (first electrode); electron transport layer; photoactive layer; a second optical wavelength conversion layer; An inverted organic solar cell (photoactive area 0.04 cm ² ) to which the structure of the second electrode was introduced was prepared.

In this case, the ITO glass modified in the same manner as in step 1.4 was used for the transparent substrate and the first electrode. In addition, the electron transport layer was formed by coating a ZnO precursor on the modified ITO glass in the same manner as in step 2.4. In addition, the photoactive layer was formed by preparing the photoactive composition in the same manner as in step 1.6, and then coating it on the electron transport layer. In addition, the light wavelength conversion layer was formed by mixing the hole transport material and the light wavelength conversion composition in the same manner as in step 4.8, and then coating it on the photoactive layer. In addition, the second electrode was formed by depositing silver (Ag) in the same manner as in step 1.7.

<Comparative Example 3>

transparent substrate; light-receiving electrode (first electrode); electron transport layer; photoactive layer; a second optical wavelength conversion layer; hole transport layer; An inverted organic solar cell (photoactive area 0.04 cm ² ) to which the structure of the second electrode was introduced was prepared.

In this case, the ITO glass modified in the same manner as in step 1.4 was used for the transparent substrate and the first electrode. In addition, the electron transport layer was formed by coating a ZnO precursor on the modified ITO glass in the same manner as in step 2.4. In addition, the photoactive layer was formed by preparing the photoactive composition in the same manner as in step 1.6, and then coating it on the electron transport layer. In addition, the light wavelength conversion layer was formed by coating the light wavelength conversion composition prepared in step 1.2 on the photoactive layer. In addition, the hole transport layer and the second electrode were _{formed by depositing MoO 3} on the photoactive layer and depositing silver (Ag) thereon in the same manner as in step 1.7.

<Comparative Example 4>

transparent substrate; light-receiving electrode (first electrode); electron transport layer; photoactive layer; hole transport layer; a second optical wavelength conversion layer; An inverted organic solar cell (photoactive area 0.04 cm ² ) to which the structure of the second electrode was introduced was prepared.

In this case, the ITO glass modified in the same manner as in step 1.4 was used for the transparent substrate and the first electrode. In addition, the electron transport layer was formed by coating a ZnO precursor on the modified ITO glass in the same manner as in step 2.4. In addition, the photoactive layer was formed by preparing the photoactive composition in the same manner as in step 1.6, and then coating it on the electron transport layer. In addition, the hole transport layer was formed by introducing PEDOT:PSS on the photoactive layer in the same manner as in step 5.8. In addition, the optical wavelength conversion layer was formed by coating the optical wavelength conversion composition prepared in step 1.2 on the hole transport layer. In addition, the second electrode was formed by depositing silver (Ag) in the same manner as in step 1.7.

Table 1 shows the structure of the prepared organic solar cell. For ease of distinction, in Table 1 below, the first optical wavelength conversion layer and the second optical wavelength conversion layer are described in parallel as the optical wavelength conversion layer.

division Structure of organic solar cell Example 1 1st electrode/light wavelength conversion layer (ZnO mixture)/photoactive layer/hole transport layer/second electrode Example 2 First electrode/electron transport layer/light wavelength conversion layer/photoactive layer/hole transport layer/second electrode Example 3 First electrode/light wavelength conversion layer/electron transport layer/photoactive layer/hole transport layer/second electrode Example 4 1st electrode/optical wavelength conversion layer (ZnO mixture)/photoactive layer/optical wavelength conversion layer (MoO3 mixture)/second electrode Example 5 First electrode / light wavelength conversion layer / electron transport layer / photoactive layer / hole transport layer / light wavelength conversion layer / second electrode Comparative Example 1 1st electrode/electron transport layer/photoactive layer/hole transport layer/second electrode Comparative Example 2 1st electrode/electron transport layer/photoactive layer/optical wavelength conversion layer (PEDOT:PSS mixture)/second electrode Comparative Example 3 1st electrode/electron transport layer/photoactive layer/light wavelength conversion layer/hole transport layer/second electrode Comparative Example 4 First electrode/electron transport layer/photoactive layer/hole transport layer/light wavelength conversion layer/second electrode

2. Manufacturing of large-area inverted organic solar cells

<Example 6>

An organic solar cell was manufactured in the same manner as in Example 1, but by changing the pattern formed on the ITO glass, a large-area inverted organic solar cell having a photoactive area of ^{1.0 cm 2} 25 times larger than the ^{existing area of 0.04 cm 2} was produced. At this time, the optical wavelength conversion layer was formed to a thickness of 30 to 50 nm, the photoactive layer was formed to have a thickness of 100 to 130 nm, and the hole transport layer to have a thickness of 3 to 12 nm at a rate of 0.5 Å/s.

<Example 7>

An organic solar cell was manufactured in the same manner as in Comparative Example 2, but by changing the pattern formed on the ITO glass, a large-area inverted organic solar having a photoactive area of ^{1.0 cm 2} 25 times larger than the ^{existing area of 0.04 cm 2} A battery was manufactured.

<Comparative Example 5>

An organic solar cell was manufactured in the same manner as in Comparative Example 1, but by changing the pattern formed on the ITO glass, a large-area inverted organic solar having a photoactive area of ^{1.0 cm 2} 25 times larger than the ^{conventional area of 0.04 cm 2} A battery was manufactured.

<Comparative Example 6>

An organic solar cell was manufactured in the same manner as in Comparative Example 4, but by changing the pattern formed on the ITO glass, a large-area inverted organic solar having a photoactive area of ^{1.0 cm 2} 25 times larger than the ^{conventional area of 0.04 cm 2} A battery was manufactured.

3. Characterization test and results

<Test Example 1> Evaluation of optical properties of the optical wavelength conversion layer formed of the composite composition

The light wavelength conversion layer and the ZnO layer formed in Preparation Example 2B were subjected to UV-vis spectroscopy (Agilent 8453) analysis and photoluminescence spectroscopy (Perkin Elmer LS55) analysis. For the measurement, the same ITO glass used in Preparation Example 2B was set as a blank, and optical properties of the optical wavelength conversion layer and the ZnO layer were measured. The results of the optical characteristic analysis are shown in FIGS. 11(a) and 11(b). For this Test Example 1, [Materials Chemistry Frontiers, 2020, 4, 421-436] and [Chemical Communications, 2012, 48, 3686-3699] were referred to.

The results of ultraviolet-visible spectroscopic analysis are shown in FIG. 11(a). Referring to FIG. 11( a ), it can be seen that the wavelength conversion layer absorbs more light of λ=300-375 nm than the ZnO layer. In the λ=430 nm region, which is the absorption region of graphene quantum dots, the result of emission spectroscopy through excitation is shown in FIG. 11(b). Referring to FIG. 11(b), the light wavelength conversion layer showed higher light emission characteristics than the ZnO layer in the λ=550 to 650 nm and λ=650 to 850 nm regions.

11 (a) and 11 (b), the graphene quantum dots in the optical wavelength conversion layer absorb light in the short wavelength region and emit light in the long wavelength region, resulting in an effective optical wavelength conversion action as described above. appears to have appeared.

<Test Example 2> Evaluation of outdoor environment (1 sun) characteristics of organic solar cells

^{The organic solar cells (photoactive area 0.04 cm 2} ) prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were characterized through a solar simulator (New port Oriel, 100 mW/cm ² ), and the results are as follows Table 2 shows.

Specifically, the solar simulator was characterized with an air mass (AM) 1.5 G filter. In addition, the solar simulator was intensity-calibrated at ^{100 mW/cm 2} using an AIST-certified silicon reference device. The current-voltage behaviors of the above examples and comparative examples were measured using a Keithley 2400 SMU.

Through this test example, short circuit current density (J _sc ), open circuit voltage (V _oc ), fill factor (FF) and photoelectric conversion efficiency, which are factors for evaluating characteristics of an organic solar cell (power conversion efficiency, PCE) was measured. At this time, the fill factor (FF) was calculated as [voltage (V _max ) × current density (J _max )] / [(open voltage (V _oc ) × short circuit current density (J _sc )] at the maximum power point. , the photoelectric conversion efficiency (PCE) was calculated as [short-circuit current density (J _sc ) × open-circuit voltage (V _oc ) * fill factor (FF)] / P _in (=100 mW/cm ² ). Quantum efficiency, EQE) behavior was measured using a Polaronix K3100 IPCE measurement system (McScience Inc.).

organic solar cell J _sc (mA/cm ² ) V _oc (V) FF(%) PCE (%) Example 1 22.6 0.858 72.1 14.0 Example 2 21.6 0.858 72.2 13.5 Example 3 20.8 0.858 72.5 12.9 Example 4 21.5 0.858 72.0 13.3 Example 5 20.5 0.858 71.7 12.6 Comparative Example 1 20.2 0.878 70.5 12.5 Comparative Example 2 20.4 0.858 69.5 12.2 Comparative Example 3 20.4 0.858 68.5 12.0 Comparative Example 4 19.6 0.858 68.6 11.6

Looking at the results shown in Table 2, the characteristics of the organic solar cells prepared in Examples 1 to 5 and Comparative Examples 1 to 4 can be confirmed. _{The short-circuit current density (J sc} ) of the organic solar cell (first electrode; electron transport layer; photoactive layer; hole transport layer; second electrode structure) prepared according to Comparative Example 1 was 20.0 mA/cm ² , open circuit voltage (V _oc ) was 0.878 V, and the fill factor (FF) was 70.5%, and the calculated photoelectric conversion efficiency (PCE) was 12.5%.

The organic solar cell manufactured according to Example 1 in which the light wavelength conversion layer is located between the light receiving electrode (first electrode) and the photoactive layer (first electrode; light wavelength conversion layer; photoactive layer; hole transport layer; structure of the second electrode) , an organic solar cell manufactured according to Example 2 (first electrode; electron transport layer; light wavelength conversion layer; photoactive layer; hole transport layer; structure of the second electrode), an organic solar cell manufactured according to Example 3 (first Electrode; light wavelength conversion layer; electron transport layer; photoactive layer; hole transport layer; structure of second electrode), organic solar cell prepared according to Example 4 (first electrode; light wavelength conversion layer; photoactive layer; light wavelength conversion layer) ; second electrode) and the short-circuit current density (J) of the organic solar cell (first electrode; light wavelength conversion layer; electron transport layer; photoactive layer; hole transport layer; light wavelength conversion layer; second electrode) manufactured according to Example 5 _{sc ) and fill factor (FF) were greater than the short-circuit current density (J sc} ) and fill factor (FF) of the organic solar cell prepared according to Comparative Example 1, and showed better photoelectric conversion efficiency (PCE). In particular, the organic solar cell prepared according to Example 1, in which the light wavelength conversion layer serves as an electron transport layer, showed the highest photoelectric conversion efficiency (PCE) among Examples. This shows that it is possible to obtain a better organic solar cell by forming a light wavelength conversion layer that performs the role of electron transport rather than separately having an electron transport layer and a light wavelength conversion layer in the organic solar cell. The current-voltage characteristics of the organic solar cell prepared according to Example 1 and the organic solar cell prepared according to Comparative Example 1 are shown in FIG. 12(a), and their external quantum efficiency ( EQE) behavior. 12 (a) and 12 (b), the short-circuit current density of the organic solar cell prepared according to Example 1 is significantly improved compared to the short-circuit current density of the organic solar cell prepared according to Comparative Example 1 You can check what has been done.

The organic solar cell (first electrode; electron transport layer; photoactive layer; light wavelength conversion layer; second electrode) prepared according to Comparative Example 2 in which the light wavelength conversion layer is positioned between the photoactive layer and the opposite electrode (second electrode) of the light receiving electrode electrode structure), the organic solar cell (first electrode; electron transport layer; photoactive layer; light wavelength conversion layer; hole transport layer; structure of the second electrode) prepared according to Comparative Example 3 and Comparative Example 4 The photoelectric conversion efficiency (PCE) of the organic solar cell (first electrode; electron transport layer; photoactive layer; hole transport layer; light wavelength conversion layer; structure of the second electrode) is the photoelectric conversion efficiency (PCE) of Comparative Example 1 that does not include the light wavelength conversion layer. It showed a lower result than the conversion efficiency (PCE). These results show that when the light wavelength conversion layer is introduced, an organic solar cell with better performance can be manufactured when the light wavelength conversion layer is located in a specific position between the first electrode and the photoactive layer.

The organic solar cell manufactured according to Example 4 has a structure in which the hole transport layer is substituted with a light wavelength conversion layer containing _{MoO 3 in the organic solar cell manufactured according to Example 1.} As a result, the organic solar cell manufactured according to Example 4 showed superior characteristics compared to Comparative Examples 1 to 4, but showed a lowered characteristic compared to the organic solar cell manufactured according to Example 1. Also, similarly, the organic solar cell manufactured according to Example 5 has a structure in which a light wavelength conversion layer is inserted between the second electrode and the hole transport layer in the organic solar cell manufactured according to Example 3, Compared to the organic solar cell manufactured according to the method, the characteristics were lowered. In other words, when the light wavelength conversion layer is introduced, even if the light wavelength conversion layer is located between the first electrode and the photoactive layer, the performance is rather reduced when the light wavelength conversion layer is introduced between the photoactive layer and the second electrode.

<Test Example 3> Evaluation of outdoor environment (1 sun) characteristics of large-area organic solar cells

The characteristics of the large-area organic solar cells (photoactive area 1.00 cm ² ) prepared in Example 6 and Comparative Example 5 were analyzed, and the results are shown in Table 3 below.

organic solar cell J _sc (mA/cm ² ) V _oc (V) FF(%) PCE (%) Example 6 21.9 0.899 59.5 11.7 Comparative Example 5 20.9 0.878 58.0 10.6

Looking at the results shown in Table 3, the characteristics of the organic solar cells prepared in Example 6 and Comparative Example 5 can be confirmed. _{The short-circuit current density (J sc} ) of the large-area organic solar cell prepared according to Example 6 was 21.9 mA/cm ² , the open-circuit voltage (V _oc ) was 0.899 V, and the fill factor (FF) was 59.5%, thus The calculated photoelectric conversion efficiency (PCE) was found to be 11.7%. _{The short-circuit current density (J sc} ) of the large-area organic solar cell prepared according to Comparative Example 5 was 20.9 mA/cm ² , the open-circuit voltage (V _oc ) was 0.878 V, and the fill factor (FF) was 58.0%, Accordingly, the calculated photoelectric conversion efficiency (PCE) was found to be 10.6%.

The large-area organic solar cell (photoactive area 1.00 cm ² ) manufactured according to Example 6 has a larger area than the organic solar cells prepared according to Examples 1 to 5 having a photoactive area of 0.04 cm ^{2 , so that the overall fill factor (FF)} ) was reduced. However, the characteristics of the large-area organic solar cell prepared according to Example 6 including the light wavelength conversion layer between the first electrode and the photoactive layer were similar to those of the large-area organic solar cell prepared according to Comparative Example 5 without the light wavelength conversion layer inserted between the first electrode and the photoactive layer. It shows superior characteristics compared to the characteristics of solar cells. The current-voltage characteristics of the large-area organic solar cell prepared according to Example 6 and the large-area organic solar cell prepared according to Comparative Example 5 are shown in FIG. 13(a), and their External quantum efficiency (EQE) behavior was shown. 13(a) and 13(b), the short-circuit current density of the large-area organic solar cell prepared according to Example 6 is the short-circuit current density of the large-area organic solar cell prepared according to Comparative Example 5. It can be seen that there is a marked improvement compared to

<Test Example 4> Evaluation of indoor environment (1,000 lux and 200 lux) characteristics of organic solar cells

^{The organic solar cells (photoactive area 0.04 cm 2} ) prepared in Examples 1 and 3 and Comparative Examples 1 and 4 were characterized through an indoor solar simulator (Yamashita denso, 5000 K LEDs lamps), and as a result, the is shown in Table 4 below.

Specifically, the incident light quantity was calculated using a light quantity meter (delta-ohm, HD2102.1 and software). At 1,000 lux, the amount of light was about 320.3 μW/cm ² and at 200 lux, about 62.8 μW/cm ^{2 .}

Through this test example, short circuit cyrrent density (J _se ), open circuit voltage (V _oc ), fill factor (FF) and photoelectric conversion efficiency, which are factors for evaluating the characteristics of an organic solar cell (power conversion efficiency, PCE) was measured.

organic solar cell J _sc (μA/cm ² ) V _oc (V) FF(%) PCE (%) Example 1
(200 lux) 23.3 0.660 71.9 17.6 Example 3
(200 lux) 22.7 0.660 62.7 17.9 Comparative Example 1
(200 lux) 21.9 0.663 54.2 12.5 Comparative Example 4
(200 lux) 20.7 0.616 50.3 10.2 Example 1
(1,000 lux) 116.7 0.728 73.7 19.6 Example 3
(1,000 lux) 112.3 0.725 70.3 17.9 Comparative Example 1
(1,000 lux) 109.2 0.737 68.5 17.2 Comparative Example 4
(1,000 lux) 108.7 0.724 64.7 15.9

Referring to the results shown in Table 4, the characteristics of the organic solar cells prepared in Examples 1 and 3 and Comparative Examples 1 and 4 in an indoor environment can be confirmed. _{The short-circuit current density (J sc} ) of the organic solar cell (first electrode; electron transport layer; photoactive layer; hole transport layer; structure of the second electrode) prepared according to Comparative Example 1 at 200 lux was 21.9 μA/cm ² , open The voltage (V _oc ) was 0.663 V, the fill factor (FF) was 54.2%, and the calculated photoelectric conversion efficiency (PCE) was 12.5%. _{In addition, the short-circuit current density (J sc} ) of the organic solar cell prepared according to Comparative Example 1 at 1,000 lux was 109.2 μA/cm ² , the open-circuit voltage (V _oc ) was 0.737 V, and the fill factor (FF) was 68.5%. and the calculated photoelectric conversion efficiency (PCE) was found to be 17.2%.

The organic solar cell (first electrode; light wavelength conversion layer; photoactive layer; hole transport layer; second electrode structure) and Example 3 prepared according to Example 1 in which the light wavelength conversion layer was positioned between the first electrode and the photoactive layer The short-circuit current density (Jsc) and fill factor (FF) of the organic solar cell (first electrode; light wavelength conversion layer; electron transport layer; photoactive layer; hole transport layer; structure of the second electrode) prepared according to In a lux environment, the short-circuit current density (Jsc) and fill factor (FF) of the organic solar cell prepared according to Comparative Example 1 were larger and exhibited better photoelectric conversion efficiency (PCE).

In addition , the organic solar cell (first electrode; electron transport layer; photoactive layer; hole transport layer; light wavelength conversion layer; second electrode) prepared according to Comparative Example 4 in which the light wavelength conversion layer is located between the photoactive layer and the second electrode structure) showed a lower result than the photoelectric conversion efficiency (PCE) of Comparative Example 1 not including the optical wavelength conversion layer in 200 lux and 1,000 lux environments.

This result is the same as the result according to the characteristics evaluated in the outdoor environment, and when the light wavelength conversion layer of the organic solar cell is located between the first electrode and the photoactive layer, relatively excellent characteristics are obtained not only in the outdoor environment but also in the indoor environment. it can be seen that

<Test Example 5> Evaluation of indoor environment (200 lux and 1,000 lux) characteristics of large-area organic solar cells

^{The large-area organic solar cells (photoactive area 1.00 cm 2} ) prepared according to Examples 6 and 7 and Comparative Examples 5 and 6 were characterized, and the results are shown in Table 5 below.

organic solar cell J _sc (μA/cm ² ) V _oc (V) FF(%) PCE (%) Example 6
(200 lux) 22.7 0.647 63.2 14.8 Example 7
(200 lux) 21.9 0.657 61.3 14.0 Comparative Example 5
(200 lux) 22.1 0.657 50.6 11.7 Comparative Example 6
(200 lux) 19.9 0.616 50.1 9.8 Example 6
(1,000 lux) 111.1 0.710 69.5 17.1 Example 7
(1,000 lux) 109.8 0.712 67.1 16.3 Comparative Example 5
(1,000 lux) 107.9 0.725 64.1 15.7 Comparative Example 6
(1,000 lux) 108.2 0.713 62.9 15.1

Referring to the results shown in Table 5, the characteristics of the large-area organic solar cells prepared according to Examples 6 and 7 and Comparative Examples 5 and 6 can be confirmed. The large-area organic solar cells prepared according to Examples 6 and 7 in which the light wavelength conversion layer was positioned between the first electrode and the photoactive layer were manufactured according to Comparative Example 5 without including the light wavelength conversion layer at 200 lux and 1,000 lux It exhibited better performance than the large-area organic solar cell and the large-area organic solar cell prepared according to Comparative Example 6 in which the light wavelength conversion layer was located between the photoactive layer and the second electrode.

<Test Example 6> Evaluation of optical properties of organic solar cells incorporating a light wavelength conversion layer

After forming a light wavelength conversion layer with the photoactive layer thin film, the photoactive layer thin film laminated on the electron transport layer, and the composite composition, UV-vis spectroscopy (Agilent 8453) analysis and light emission of the photoactive layer thin film laminated thereon Spectroscopy (photoluminescence spectroscopy, Perkin Elmer LS55) analysis was performed. The results of the ultraviolet-visible spectroscopic analysis and the emission spectroscopic analysis are shown in FIGS. 14 and 15 .

The photoactive layer thin film was formed using the photoactive composition prepared in step 1.6. In addition, the photoactive layer thin film laminated on the electron transport layer was formed using the photoactive composition prepared in step 1.6 and the ZnO precursor prepared in step 1.1. In addition, after forming the light wavelength conversion layer with the electron transport composite composition, the photoactive layer thin film laminated thereon was formed using the photoactive composition prepared in step 1.6 and the composite composition prepared in step 1.3.

14 is a photoactive layer thin film, a photoactive layer thin film laminated on an electron transport layer, and a photoactive layer thin film laminated thereon after forming a light wavelength conversion layer with a composite composition shows the results of ultraviolet-visible spectroscopic analysis. Referring to FIG. 14 , it can be seen that the absorbance of the photoactive layer thin film stacked on the light wavelength conversion layer is generally increased compared to the absorbance of the photoactive layer thin film stacked on the photoactive layer thin film and the electron transport layer. Specifically, it can be seen that the absorbance of the photoactive layer thin film stacked on the light wavelength conversion layer is relatively small in the λ=300-350 nm region, but is increased at λ=350-900 nm. This result means that when the photoactive layer is laminated on the light wavelength conversion layer, the amount of light that can be utilized in the photoactive layer is increased, and as a result, some of the light incident to the organic solar cell is reduced by the light wavelength conversion layer of the photoactive layer. It means that it can be converted into a light absorption region.

15 shows the results of emission spectroscopy analysis of the photoactive layer thin film, the photoactive layer thin film laminated on the electron transport layer, and the photoactive layer thin film laminated thereon after forming the light wavelength conversion layer with the composite composition. Specifically, FIG. 15(a) shows emission spectral characteristics measured after exciting through light of λ=430 nm, which is the absorption peak wavelength of graphene quantum dots included in the light wavelength conversion layer. Also, FIG. 15(b) shows emission spectroscopy measured after exciting through light of λ=530 nm, which is the absorption peak wavelength of P(Cl-Cl) (BDD=0.2), which is an electron donor material included in the photoactive layer. The characteristics are shown, and FIG. 15( c ) shows the emission spectral characteristics measured after exciting with light of λ = 630 nm, which is the absorption peak wavelength of IT-4F, an electron accepting material included in the photoactive layer. The measurement results of emission spectral characteristics measured at λ = 430 nm, 530 nm and 630 nm are shown in Table 6 below.

thin film structure Light-emitting properties compared to the photoactive layer λ _ex = 430 nm λ _{ex =} 530 nm λ _{ex =} 630 nm photoactive layer thin film 100.00 100.00 100.00 Electron transport layer/photoactive layer thin film 111.36 111.67 114.79 Light wavelength conversion layer/light active layer thin film 116.58 115.45 118.95

Looking at the results shown in Table 6, it can be seen that the light emitting characteristics of the photoactive layer thin film laminated on the light wavelength conversion layer increased compared to the light emitting characteristics of the photoactive layer thin film and the photoactive layer thin film laminated on the electron transport layer. In particular, the measured luminescence properties significantly increased after exciting through light of λ = 430 nm, which is the absorption region of graphene quantum dots, and λ = 630 nm, which is the absorption region of IT-4F, an electron acceptor material. This result appears to be due to the effective optical wavelength conversion to the light absorption region of IT-4F, an electron accepting material, by the graphene quantum dots.

<Test Example 7> Evaluation of internal quantum efficiency (IQE) behavior and reflectance of organic solar cells

In Example 1 and Comparative Example 1, internal quantum efficiency (IQE, Mcscience) behavior and reflectance (Mcscience) were measured for the thin film formed up to the photoactive layer, and the results are shown in FIG. 16 .

Referring to FIG. 16 , the internal quantum efficiency (IQE) of the thin film formed from Example 1 to the photoactive layer was overall higher than the internal quantum efficiency (IQE) of the thin film formed from Comparative Example 1 to the photoactive layer. Referring to FIGS. 16 and 12 ( b ), it can be seen that the optical efficiency of the organic solar cell or thin film including the optical wavelength conversion layer is improved compared to the organic solar cell or the thin film that does not include the optical wavelength conversion layer. In addition, the reflectance of the thin film formed from Example 1 to the photoactive layer was decreased than that of the thin film formed from Comparative Example 1 to the photoactive layer at λ=350 to 700 nm.

<Test Example 8> Evaluation of resistance characteristics of organic solar cells in outdoor environments (1 sun) and indoor environments (200 lux and 1,000 lux)

The organic solar cells prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were measured for series resistance ( R _s ) and shunt resistance ( R _sh ) in an outdoor environment (1 sun). In addition, the organic solar cells prepared in Examples 1 and 6 and Comparative Examples 1 and 5 were subjected to series resistance ( R _s ), shunt resistance ( R _sh ) in an indoor environment (200 lux and 1,000 lux). was measured. The series resistance ( R _s ) and the shunt resistance ( R _sh ) are the inverse of the slope of _{the open-circuit voltage (V oc} ) and the short-circuit current density (J _sc ) of the current-voltage curve analyzed in Test Examples 2 to 5 above. It was calculated, and it was calculated by forming an equivalent circuit in the prepared organic solar cell. As in Test Examples 2 and 3, the series resistance ( R _s ) and the shunt resistance ( R _sh ) measured in an outdoor environment (1 sun) are shown in Table 7 below. In addition, as in Test Examples 4 and 5, the series resistance ( R _s ) and the shunt resistance ( R _sh ) measured in an indoor environment (200 lux and 1,000 lux) are shown in Table 8 below. The mechanism was referred to in [ACS Applied Materials & Interfaces, 2018, 10, 3885-3894].

organic solar cell PCE (%) R _s (Ω cm ² ) R _sh (Ω cm ² ) Example 1 14.0 3.1 2,127 Example 2 13.5 3.9 2,034 Example 3 12.9 3.9 1,966 Example 4 13.3 3.8 1,805 Example 5 12.6 4.3 991 Comparative Example 1 12.5 4.0 874 Comparative Example 2 12.2 4.5 1,034 Comparative Example 3 12.0 6.6 870 Comparative Example 4 11.6 7.1 1,229 Example 6
(Large area) 11.7 11.5 1,423 Comparative Example 5
(Large area) 10.6 11.8 985

organic solar cell PCE (%) R _s (Ω cm ² ) R _sh (Ω cm ² ) Example 1
(200 lux) 17.6 2,128 104,971 Comparative Example 1
(200 lux) 12.5 3,392 90,180 Example 6
(Large area, 200 lux) 14.8 2,278 115,394 Comparative Example 5
(Large area, 200 lux) 11.7 2,993 74,364 Example 1
(1,000 lux) 19.6 399 132,511 Comparative Example
(1,000 lux) 17.2 414 125,269 Example 6
(Large area, 1,000 lux) 17.1 317 238,211 Comparative Example 5
(Large area, 1,000 lux) 15.7 432 110,708

Looking at the results shown in Table 7, the organic solar cells prepared according to Examples 1 to 6 in which the light wavelength conversion layer is located between the first electrode and the photoactive layer are generally organic solar cells prepared according to Comparative Examples 1 to 5 It was found to have a low series resistance ( R _s ) and a high shunt resistance ( R _{sh ) compared to the battery.} In general, the series resistance ( R _s ), the series resistance of a circuit, tends to move more smoothly when the value is low, and the shunt resistance ( R _sh ), the parallel resistance of the circuit, tends to decrease the recombination of charges when the value is high. There is this. Excellent performance means low series resistance ( R _s ) and high shunt resistance ( R _sh ) values, and Examples 1 to 6 generally have low series resistance ( R _s ) and high shunt resistance ( R _sh ). It shows that the utilization of electric charge can be maximized.

Referring to the results shown in Table 8, the organic solar cells prepared according to Examples 1 and 6, in which the light wavelength conversion layer was located between the first electrode and the photoactive layer, were compared to the organic solar cells prepared according to Comparative Examples 1 and 5. It was found to have a low series resistance ( R _s ) and a high shunt resistance ( R _{sh ) compared to them.} In particular, in an indoor environment, since the amount of light is absolutely insufficient, effective utilization of the generated electric charge is important. The organic solar cells manufactured according to Examples 1 and 6 have a relatively low series resistance ( R _s ) and a high shunt resistance ( R _sh ). This indicates that the utilization of the generated charge can be maximized.

<Test Example 9> Evaluation of thin film shape characteristics of organic solar cells

In order to confirm the thin film shape characteristics of the light wavelength conversion layer formed in Example 1 and the electron transport layer formed in Comparative Example 1, a field emission scanning electron microscope (FE-SEM, SU8010, Hitachi) ), were analyzed through atomic force microscopy (AFM, Park system, XE-150), and the results are shown in FIGS. 17 and 18, respectively.

The composite composition prepared to form the light wavelength conversion layer in Example 1 was spin-coated on ITO glass to form a light wavelength conversion layer thin film, and the ZnO precursor prepared to form the electron transport layer in Comparative Example 1 was applied to ITO glass. A thin film of the electron transport layer was formed by spin coating on it.

Fig. 17 (a) shows the shape of the electron transport layer thin film with a field emission scanning electron microscope, and Fig. 18 (a) shows the shape of the electron transport layer thin film with an atomic force microscope. As shown in FIGS. 17(a) and 18(a), the electron transport layer thin film exhibited a uniform crystal structure and uniform thin film shape, and a root mean square roughness (RMS roughness) of 2.57 nm.

Fig. 17 (b) shows the shape of the optical wavelength conversion layer thin film with a field emission scanning electron microscope, and Fig. 18 (b) shows the shape of the optical wavelength conversion layer thin film with an atomic force microscope. As shown in FIGS. 17(b) and 18(b), the optical wavelength conversion layer thin film exhibited a relatively small and uniform crystal structure and uniform thin film shape, and showed a relatively low root-mean-square roughness of 1.35 nm.

Additionally, after forming the photoactive layer on the electron transport layer thin film, the surface shape characteristics were evaluated with an atomic force microscope, and the results are shown in FIG. 19( a ). As shown in FIG. 19( a ), the photoactive layer formed on the electron transport layer thin film had large agglomerations expressed in dark and bright colors, and showed a root mean square roughness of 1.36 nm. In addition, after forming the photoactive layer on the light wavelength conversion layer thin film, the surface shape characteristics were evaluated by an atomic force microscope, and the result is shown in FIG. 19(b). As shown in FIG. 19(b), a relatively uniformly spread shape was observed, and a relatively low root-mean-square roughness of 1.03 nm was observed. From these results, it can be seen that the thin film on which the optical wavelength conversion layer is formed has a more uniform surface.

<Test Example 10> Long-term stability evaluation of organic solar cells

In order to evaluate the long-term stability of the organic solar cells prepared according to Example 1 and Comparative Example 1, each organic solar cell was evaluated while being stored for about 1,200 hr. The long-term stability evaluation result for 1,200 hr is shown in FIG. 20, specifically, the photoelectric conversion efficiency (PCE) in FIG. 20(a), the open-circuit voltage (V _oc ) in FIG. 20(b), and the short circuit in FIG. 20(c). The current density (J _sc ) and the fill factor (FF) are shown in FIG. 20(d). Referring to FIG. 20( a ), the photoelectric conversion efficiency (PCE) of the organic solar cell prepared according to Comparative Example 1 decreased from 12.5% initially to 8.9% after about 1,200 hr, indicating a reduction rate of about 28.8%. On the other hand, the photoelectric conversion efficiency (PCE) of the organic solar cell prepared according to Example 1 decreased from 14.0% initially to 13.2% after about 1,200 hr, indicating a decrease rate of about 5.7%. That is, the organic solar cell prepared according to Example 1 exhibited relatively excellent long-term stability. In particular, referring to FIGS. 20(b) to 20(d) , it can be seen that the difference in the reduction rate of the photoelectric conversion efficiency PCE is caused by a change in the fill factor FF.

In the present invention, as described above, a method for manufacturing an organic solar cell including a light wavelength conversion layer has been described through the Examples, Comparative Examples, and Test Examples, but it is not necessary to specifically limit it, and it is not necessary to satisfy the above examples. Any manufacturing method may be used.

110: transparent substrate 140: photoactive layer
120: first electrode 150: second charge transport layer
130: first charge transport layer 160: second electrode

Claims (19)

It includes a sequentially stacked light-receiving electrode and a photoactive layer,
and a light wavelength conversion layer between the light-receiving electrode and the photoactive layer,
The light wavelength conversion layer includes an inorganic semiconductor compound,
The inorganic semiconductor compound converts light of a first wavelength into light of a second wavelength,
The light of the first wavelength is light of a wavelength having a peak of 250 nm or more and less than 450 nm,
The light of the second wavelength is light of a wavelength having a peak of 550 nm or more and less than 850 nm,
The photoactive layer is formed based on a bulk-heterojunction structure in which an electron donor material and an electron acceptor material are mixed,
The electron donor material is at least one solar cell selected from the group consisting of ternary copolymers represented by the following Chemical Formulas 7 to 10:
[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

In Formulas 7 to 10, n is an integer between 1 and 10,000.
According to claim 1,
The light of the second wavelength is light of a wavelength having a peak of 550 nm or more and less than 650 nm and light of a wavelength having a peak of 650 nm or more and less than 850 nm.
According to claim 1,
A solar cell further comprising an electron transport layer between the light receiving electrode and the photoactive layer.
According to claim 1,
The light wavelength conversion layer is a solar cell further comprising at least one or more from the group consisting of a conductive polymer and a metal oxide.
5. The method of claim 4,
A solar cell in which the conductive polymer includes a polymerization unit represented by the following Chemical Formula 1, and the metal oxide is at least one metal oxide selected from the group consisting of Zn, Ba Li and Ti:
[Formula 1]

In Formula 1, R ₁ and R ₂ are each independently represented by Formula 2 below,
[Formula 2]

In Formula 2, p is an integer between 0 and 10, and Formula M is represented by Formula 2-1 or Formula 2-2 below,
[Formula 2-1]

In Formula 2-1, R ₃ and R ₄ are each independently an alkyl group having 1 to 10 carbon atoms substituted or unsubstituted with a hydroxyl group or a sulfonic acid group, an alkenyl group having 2 to 10 carbon atoms substituted or unsubstituted with a hydroxyl group or a sulfonic acid group and an alkynyl group having 2 to 10 carbon atoms that is unsubstituted or substituted with a hydroxyl group or a sulfonic acid group,
[Formula 2-2]

In Formula 2-2, R ₅ , R ₆ and R ₇ are each independently an alkyl group having 1 to 10 carbon atoms substituted or unsubstituted with a hydroxyl group or a sulfonic acid group, 2 to 10 carbon atoms substituted or unsubstituted with a hydroxyl group or a sulfonic acid group is selected from the group consisting of an alkynyl group having 2 to 10 carbon atoms that is unsubstituted or substituted with an alkenyl group, a hydroxyl group or a sulfonic acid group, and the nitrogen cation is not bonded or bonded to a halogen ion;
In Formula 1, Ar is a single bond; or a unit structure represented by the following Chemical Formulas 3 to 6; is one of
[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

In Formula 3, R ₈ and R ₉ are each independently a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, and a substituted or unsubstituted C2 to C20 alkyl group selected from the group consisting of nyl groups,
In Formula 4, Q ₁ is an oxygen atom or a sulfur atom,
In Formula 5, Q ₂ is an oxygen atom or a sulfur atom.
According to claim 1,
The light wavelength conversion layer is a solar cell located 0.5 to 220 nm apart from the surface of the light receiving electrode.
According to claim 1,
Further comprising a second electrode opposite to the light-receiving electrode,
A photoactive layer is included between the light-receiving electrode and the second electrode,
A solar cell further comprising the light wavelength conversion layer between the photoactive layer and the second electrode.
It includes a sequentially stacked light-receiving electrode and a photoactive layer,
and a light wavelength conversion layer between the light-receiving electrode and the photoactive layer,
The light wavelength conversion layer includes an inorganic semiconductor compound,
The inorganic semiconductor compound is at least one selected from the group consisting of a group IV element, a group II-VI semiconductor compound, a group III-V semiconductor compound, and a group IV-IV semiconductor compound,
The photoactive layer is formed based on a bulk-heterojunction structure in which an electron donor material and an electron acceptor material are mixed,
The electron donor material is at least one solar cell selected from the group consisting of ternary copolymers represented by the following Chemical Formulas 7 to 10:
[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

In Formulas 7 to 10, n is an integer between 1 and 10,000.
9. The method of claim 8,
The inorganic semiconductor compound is a solar cell comprising a semiconductor compound in the form of quantum dots.
10. The method of claim 9,
A semiconductor compound in the form of a quantum dot,
Carbon quantum dots, graphene quantum dots, silicon quantum dots, zinc oxide quantum dots, cadmium oxide quantum dots, zinc sulfide quantum dots, cadmium sulfide quantum dots, zinc selenide quantum dots, cadmium selenide quantum dots, zinc tellunide quantum dots, cadmium tellunide quantum dots, gallium nitride quantum dots, At least one solar cell selected from the group consisting of gallium phosphide quantum dots, gallium arsenide quantum dots, gallium antimonide quantum dots, indium nitride quantum dots, indium phosphide quantum dots, indium arsenide quantum dots, indium antimonide quantum dots, and silicon carbide quantum dots.
9. The method of claim 8,
A solar cell in which the content of the inorganic semiconductor compound in the light wavelength conversion layer is 1 to 10 ⁴ g/cm ^{3 at room temperature.}
9. The method of claim 8,
The thickness of the light wavelength conversion layer is in the range of 1 to 300 nm solar cell.
9. The method of claim 8,
Further comprising a second electrode opposite to the light-receiving electrode,
A photoactive layer is included between the light-receiving electrode and the second electrode,
A solar cell further comprising the light wavelength conversion layer between the photoactive layer and the second electrode.
9. The method of claim 1 or 8,
The light-receiving electrode is formed of a metal oxide thin film,
The metal oxide thin film is an ITO (indium tin oxide) film, FTO (tin fluoride oxide) film, IZO (indium zinc oxide) film, AZO (aluminum doped oxide) film, ZnO (zinc oxide) film and IZTO (indium zinc tin oxide) film A solar cell formed of at least one selected from the group consisting of oxide) films.
delete According to claim 1,
The mixing ratio (w/w) of the electron donor material and the electron acceptor material is 1:0.5 to 1:2.
According to claim 1,
The electron acceptor material is a solar cell comprising at least one or more from the group consisting of fullerene derivatives and non-fullerene derivatives.
12. The method of claim 11,
Electron donor materials include PTB7 (CAS No. 1266549-31-8), PTB7-Th (CAS No. 1469791-66-9), PBDB-T (CAS No. 145929-80-4) and PBDB-T-2F ( CAS No. 1802013-83-7) at least one solar cell selected from the group consisting of.
9. The method of claim 1 or 8,
A solar cell with a photoactive area of 0.001 to 10 cm ^{2 .}

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