KR20230061631A - A photo-rechargeable battery having a photochromic layer - Google Patents

Abstract

The present invention relates to a solar battery-integrated device, comprising: a first electrode; a second electrode facing the first electrode; an electrolyte positioned between the first electrode and the second electrode; a light absorption and storage layer made of a perovskite material formed on the first electrode; and a photochromic material layer provided between the first electrode and the light absorption and storage layer and including a photochromic material that selectively performs functions of an electron transport layer and a hole transport layer.

Description

Solar battery-integrated device having a photochromic material layer {A PHOTO-RECHARGEABLE BATTERY HAVING A PHOTOCHROMIC LAYER}

The present invention relates to a solar cell-battery integrated device, and more particularly, to a solar cell-battery integrated device having a structure in which a solar cell and a battery are integrated with improved efficiency.

In accordance with the recent need for high-capacity small battery technology, the use of secondary batteries with high energy density is increasing, and accordingly, various researches for improving the performance of secondary batteries are being developed. It is inconvenient to periodically charge such a secondary battery for a predetermined time to supply power.

For this reason, Korean Patent No. 10-2003-0081250 discloses a photovoltaic rechargeable battery in which a photovoltaic panel and a rechargeable battery are integrated. However, since the photovoltaic panel and the rechargeable battery are individually configured, and the photovoltaic panel and the rechargeable battery are not substantially integrated, miniaturization is difficult and efficiency is reduced.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a solar cell battery-integrated device capable of miniaturization and improving efficiency.

In order to solve the above problem, a solar cell battery-integrated device according to an embodiment of the present invention includes a second electrode facing the first electrode; an electrolyte positioned between the first electrode and the second electrode; a light absorption and storage layer made of a perovskite material formed on the first electrode; and a photochromic material layer provided between the first electrode and the light absorption and storage layer and including a photochromic material that selectively performs functions of an electron transport layer and a hole transport layer.

In an embodiment, the electrolyte is provided with any one of a solid electrolyte and a liquid electrolyte, and when the electrolyte is a liquid electrolyte, the electrolyte further includes a separator separating the first electrode and the second electrode.

In another embodiment, the photochromic material includes at least two isomers that are reversibly converted to each other by light and heat, and the LUMO energy level of the first isomer is a work function of the first electrode to the light absorption and storage layer , and the HOMO energy level of the second isomer is located between the HOMO energy level of the light absorption and storage layer and the work function of the first electrode.

Also in the embodiment, the LUMO energy level of the first isomer is located between -4.7eV and -3.9eV, and the HOMO energy level of the second isomer is located between -5.4eV and -4.7eV.

In another embodiment, the first isomer functions as an electron transport layer, and the second isomer functions as a hole transport layer.

In another embodiment, one surface of the photochromic material layer is provided adjacent to the first electrode, and a rear surface is provided adjacent to the light absorption and storage layer.

In another embodiment, the photochromic material is spiropyrane, spironaphthoxazines, naphthopyrans, fulgides, diarylethenes, diarylethenes, It may be selected from the group consisting of dihydropyridine and azobenzene derivatives.

According to the present invention, the solar cell-battery-integrated device can generate electric power when light is irradiated, and can store the electric power itself, making it possible to reduce the weight and size.

According to the present invention, the photochromic material layer is provided between the first electrode and the light absorption and storage layer, so that the performance of the solar cell and battery integrated device can be improved.

1A and 1B are views for explaining a solar cell-battery integrated device according to an embodiment of the present invention.
FIG. 2 is a view for explaining the structure of the light absorption and storage layer shown in FIG. 1A.
3A and 3B are cross-sectional views illustrating problems in the case where the hole transport layer is provided between the light absorption and storage layer and the first electrode and the case where the sperm transport layer is provided between the light absorption and storage layer and the first electrode.
FIG. 4 is a diagram for explaining energy levels of the photochromic material layer shown in FIG. 1A.
FIG. 5 is an example of the photochromic material layer shown in FIG. 1A, and is a view for explaining spiropyran-based isomers.
FIG. 6 is a view for explaining the characteristics of the SP type and H-PMC type spiropyran system shown in FIG. 5.
FIG. 7 is a diagram for explaining an operation process of the photochromic material layer shown in FIG. 1A.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. In the accompanying drawings, there may be components that are shown to have a specific pattern or have a predetermined thickness, but this is for convenience of description or distinction, so even if they have a specific pattern and predetermined thickness, the present invention is a feature of the illustrated components It is not limited to only

1A and 1B are views for explaining a solar cell-battery integrated device according to an embodiment of the present invention.

In the solar battery-integrated device of the present invention, the electrolyte 140 is provided as a liquid electrolyte or a solid electrolyte. The electrolyte 150 in FIG. 1A is a liquid electrolyte and includes a separator 140 to pass positive ions and block electrons. Meanwhile, the electrolyte 150 in FIG. 1B is a solid electrolyte, and the solid electrolyte includes both the function of the liquid electrolyte and the function of the separator 140 in FIG. 1A.

Referring to FIG. 1A , the solar cell-battery integrated device 100 includes a substrate 110, a first electrode 120, a second electrode 130, a separator 140, an electrolyte 150, and a photochromic material layer 160. ), and a light absorption storage layer 170. Here, the electrolyte 150 is a liquid electrolyte.

Referring to FIG. 1B, the solar battery-integrated device 100 includes a substrate 110, a first electrode 120, a second electrode 130, an electrolyte 150, a photochromic material layer 160, and light absorption. A storage layer 170 is included. Here, the electrolyte 150 is a solid electrolyte and also includes a function of a separator.

Hereinafter, a solar cell battery-integrated device having a liquid electrolyte as an electrolyte will be described with reference to FIG. 1A, and a description of FIG. 1B is omitted because it overlaps with the description of FIG. 1A.

The substrate 110 supports the entire device and transmits light.

A first electrode 120, a hole electron transport layer 160, a light absorption and storage layer 170, a separator 140, and a second electrode 130 are sequentially stacked on the substrate 110, and the first electrode 120 ) and the second electrode 130, the electrolyte 150 is interposed.

The substrate 110 includes a material capable of transmitting light. The light transmitted through the substrate 110 is provided to the light absorption and storage layer 170 .

The substrate 110 includes any one material of glass, plastic, and plastic film capable of transmitting light.

In this case, the plastic film may be formed of a material having high chemical stability, mechanical strength, transparency, and flexibility. Plastic films include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polystyrene (PS), polypropylene (PP), polyimide (PI), polyethylene sulfonate (PES), and polyocene. It may include at least one material of simethylene (POM), polyether ether ketone (PEEK), polyether sulfone (PES), and polyetherimide (PEI).

The first electrode 120 is formed on the substrate 110 and participates in electron transfer of the light absorption and storage layer 170 .

The first electrode 120 includes a transparent conductive metal oxide so that light transmitted through the substrate 110 reaches the light absorption and storage layer 170 .

Transparent conductive metal oxides include indium tin oxide (ITO), fluorine doped tin oxide (FTO), aluminum doped zink oxide (AZO), and indium zinc oxide (IZO). , ZnO-Ga2O3, ZnOAl2O3 and antimony tin oxide (ATO).

The second electrode 130 may be a positive electrode or a negative electrode of a rechargeable secondary battery. When the charging electrode is a positive electrode, lithium metal or oxides containing lithium (LiCoO2, LiNiCoMnO2, LiMnO2, LiFeO4) capable of providing positive ions are used as the second electrode 130. It may include, and may include graphite (graphite) in the case of a negative electrode.

The separator 140 physically separates the first electrode 120 and the second electrode 130, allows positive ions to pass through, and blocks the movement of electrons.

The electrolyte 150 allows positive ions to move between the light absorption storage layer 170 and the second electrode 130 . The electrolyte may be provided with any one of a known liquid electrolyte, a gel polymer electrolyte, and a solid electrolyte. When the electrolyte 150 is a solid electrolyte, the separator 140 may be omitted.

Meanwhile, the electrolyte may include light scattering particles. The light-scattering particles include a transparent material, scatter light that is not absorbed by the light absorption and storage layer 170 and transmits and reaches the electrolyte 150, and returns a part of the scattered light to the light absorption and storage layer 170, thereby returning the solar cell to the solar cell. Efficiency of the battery-integrated device may be increased.

The light absorption storage layer 170 absorbs light to generate unpaired electron pairs, provides electrons to the second electrode 130 through a conducting wire, and stores positive ions provided from the second electrode 130 through the electrolyte cell 150. Alternatively, it serves to provide positive ions to the second electrode 130 through the electrolyte 150.

The light absorption and storage layer 170 includes a photoactive material, a conductive material, and a binder.

The conductive material is graphite, vapor grown carbon fibers, Ketjen black, Denka black, acetylene black, carbon black, carbon nanotube, multi-walled carbon nanotube -Walled Carbon Nanotube) and mesoporous carbon (Ordered Mesoporous Carbon).

The binder is polyvinyl acetate, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polyvinylidene fluoride (PVDF), polyhexafluoropropylene-polyvinylidene fluoride copolymer , polyethyl acrylate, polytetrafluoroethylene, polyvinyl chloride, polyacrylonitrile and carboxylmethylcellulose (CMC), thermoplastic polyester resins, and mixtures thereof.

The photoactive material of the light absorption and storage layer 170 may include a perovskite material having a cation storage function and a photoelectric conversion function.

The perovskite material can be represented by ABX ₃ , A is at least one of methylammonium, formamidinium, phenylamine, phenylmethylamine, phenylethylamine and cesium, B is any one of Pb and Sn, X may consist of any one of I, Br and Cl. Although the perovskite material has been described as an example, it is not limited thereto.

FIG. 2 is a view for explaining the structure of the light absorption and storage layer shown in FIG. 1A.

Referring to FIG. 2 , when the light absorption and storage layer 170 has a layered structure, positive ions passing through the separator 140 may be stored/released between layers of the photoelectrode 130 . When the light absorption and storage layer 170 includes a three-dimensional perovskite material, the perovskite material can be formed by arranging the first electrode 120 in a layered structure and overlapping the two-dimensional structure again. there is. In addition, if the functional group 171 capable of electrostatically attractive bonding with cations is included in the layered structure of the light absorption storage layer 170 as in the present embodiment, the storage efficiency of the cations of the light absorption storage layer 170 is further increased. can

In general, in the case of a solar cell, a separate battery is required to store the power generated by photocharging because it has power generation capability but no storage capability. In the case of the present invention, the light absorption and storage layer not only absorbs light to cause a photoelectric effect, but also has a storage capability through storage and release of positive ions, so that a separate battery is not required.

Figure 3a is a view for explaining the problem when a hole transport layer is provided between the light absorption storage layer and the first electrode, Figure 3b is a view for explaining the problem when the electron transport layer is provided between the light absorption storage layer and the first electrode It is a drawing for explanation.

A hole transport layer (HTL), an electron transport layer (ETL), and the like are mainly used in solar cells, light emitting diodes, and the like to improve the mobility of electrons or holes in one direction. In the case of a solar cell or light emitting diode, since electrons or holes move only in one direction, the mobility of electrons or holes can be improved by using a hole transport layer (HTL) or an electron transport layer (ETL).

However, in the case of a solar battery-integrated device in which a solar cell and a battery are integrated, since electrons move in different directions during charging and discharging, the hole transport layer (HTL) or the electron transport layer (ETL) is formed between the first electrode 120 and the first electrode 120. It is difficult to intervene between the light absorption and storage layers 170 .

In detail, referring to FIG. 3A, a problem in the case where a hole transport layer is provided between the light absorption storage layer and the first electrode will be described. 3A and 3B, the first electrode 120 is FTO, and the light absorption and storage layer 170 is perovskite.

When the hole transport layer (HTL) is provided between the light absorption and storage layer 170 and the first electrode 120, the hole transport capability from the light absorption and storage layer 170 to the first electrode 120 during the discharge process is Enhanced by the transport layer (HTL). However, the ability to transport electrons from the light absorption and storage layer 170 to the first electrode 120 during the charging process is reduced by the hole transport layer (HTL).

As a result, the hole transport layer (HTL) cannot be interposed between the light absorption and storage layer and the first electrode.

Referring to FIG. 3B, a problem in the case where an electron transport layer is provided between the light absorption and storage layer and the first electrode will be described.

When the electron transport layer (ETL) is provided between the light absorption and storage layer 170 and the first electrode 120, the electron transport capability from the light absorption and storage layer 170 to the first electrode 120 during the light charging process is enhanced by the electron transport layer (ETL). However, the hole transport capability from the light absorption and storage layer 170 to the first electrode 120 during the discharge process is reduced by the electron transport layer ETL.

As a result, an electron transport layer (ETL) cannot be interposed between the light absorption and storage layer and the first electrode.

In order to solve the above problems, the present invention provides a photochromic material layer 160 that selectively performs the functions of a hole transport layer and an electron transport layer by heat and light, the light absorption storage layer 170 and the first electrode 120 ) placed between them. At this time, one surface of the photochromic material layer 160 is provided adjacent to the first electrode 120 and the rear surface is provided adjacent to the light absorption and storage layer 170 .

In the present invention, "photochromic material" refers to inorganic, organic, and glass materials that change into isomers having different colors, LUMO (lowest unoccupied molecular orbital) energy levels, and HOMO (highest unoccupied molecular orbital) energy levels by light. It means any substance among the substances in the system.

For example, photochromic materials include spiropyranes, spironaphthoxazines, naphthopyrans, pools, including at least two isomers that are reversibly converted to each other by light and heat. It may be selected from the group consisting of fulgides, diarylethenes, dihydropyridine and azobenzene derivatives.

FIG. 4 is a diagram for explaining energy levels of the photochromic material layer shown in FIG. 1A.

Referring to FIG. 4, it is necessary to consider the work function of the first electrode 120 and the LUMO energy level and HOMO energy level of the first and second isomers constituting the light absorption and storage layer 170 in relation to the photochromic material layer there is

The light absorption and storage layer 170 includes a perovskite material. For example, a specific perovskite known to have a LUMO energy level of -5.4 eV and a HOMO energy level of -3.9 eV can be used.

Also, when the first electrode 120 is formed of, for example, FTO, it is known that a generally known work function of FTO has an energy level of -4.7Ev.

In the case of a photochromic material, the LUMO energy level of the first isomer is located between the work function of the first electrode 120 and the LUMO energy level of the light absorption and storage layer 170, and the HOMO energy level of the second isomer is light absorption and storage A photochromic material may be selected that lies between the HOMO energy level of layer 170 and the work function of the first electrode.

Specifically, the first electrode 120 is formed of FTO having a work function of -4.7eV, and the light absorption and storage layer 170 has a LUMO energy level of -3.9eV and a HOMO energy level of -4.7eV. If the material is included, the photochromic material may be selected as follows.

As shown in (a) of FIG. 4, the LUMO energy level of the first isomer is located between -4.7eV and -3.9eV, and at the same time, as shown in (b) of FIG. 4, the HOMO energy level of the second isomer is -5.4eV to A photochromic material located between -4.7 eV may be selected.

As shown in (a) of FIG. 4, since the LUMO energy level is sequentially lowered in the order of perovskite, first isomer, and FTO, the first isomer may function as an electron transport layer (ETL). And, as shown in (b) of FIG. 4, since the HOMO energy level sequentially increases in the order of perovskite, second isomer, and FTO, the second isomer may function as a hole transport layer (HTL).

According to the present invention, between the first electrode 120 and the light absorption and storage layer 170, a photochromic material layer made of a photochromic material having a first isomer and a second isomer that are reversibly converted to each other by light and heat By interposing the photochromic material layer to selectively perform the function of the electron transport layer and the function of the hole transport layer, the performance of the solar cell-battery-integrated device can be improved during discharge and charge.

FIG. 5 is an example of the photochromic material layer shown in FIG. 1A, and is a view for explaining spiropyran-based isomers, and FIG. 6 is an SP-type and H-PMC-type spiropyran shown in FIG. It is a drawing for explaining the characteristics of the system.

5 and 6, the H-PMC type spiropyran as shown in FIG. 5 (b) is a colorless closed SP type spiropyran as shown in FIG. 5 (a) when visible light is irradiated. (Spiropyran), and when heat is applied to the SP type spiropyran as shown in FIG. 5 (a), it is converted into H-PMC type spiropyran as shown in FIG. 5 (b) . That is, transformations between isomers are mutually reversible.

The LUMO energy level of Spiropyran of the SP form (a) as shown in FIG. 6 (a) is -2.8eV and the HOMO energy level is -5.3eV. As shown in (b) of FIG. 6, the LUMO energy level of Spiropyran in the form of H-PMC is -4.0eV and the HOMO energy level is -6.1eV.

Referring to (a) of FIG. 6, in the case of SP type spiropyran, the HOMO energy level increases in the order of perovskite, SP type spiropyran, and FTO, so FTO and perovskite Spiropyran in the form of SP interposed between the two layers may function as a hole transport layer (HTL).

When heat is applied to Spiropyran in the SP form, it is converted to Spiropyran in the form of H-PMC (protonated PMC form). When spiropyran in the form of SP is dispersed in silica, when heat is applied, the intermolecular hydrogen bonds between the oxide anion generated by the cleavage of the CO bond and the partially uncondensed Si-OH and OH bonds of the silica converted to H-PMC form by

Referring to (b) of FIG. 6, since the LUMO energy level is lowered in the order of perovskite, H-PMC type spiropyran, and FTO, H-PMC type interposed between FTO and perovskite Spiropyran of (Spiropyran) can perform the function of the hole transport layer (HTL).

As a result, when heat is applied to spiropyran, it is converted into a hole transport layer, and when light is irradiated, it is converted into an electron transport layer. Therefore, one spiropyran disposed between the first electrode 120 and the light absorption storage layer 170 The material layer may selectively function as a hole transport layer and an electron transport layer by heat and light.

FIG. 7 is a diagram for explaining an operation process of the photochromic material layer shown in FIG. 1A.

Regarding the charging process of the solar battery-integrated device, again referring to FIG. 7 (a), the light absorption and storage layer 170 absorbs light to generate unpaired electron pairs, and transfers electrons to the second electrode through the conducting wire. (130). At the same time, the light absorption storage layer 170 emits lithium cations (Li+) and supplies the released lithium cations (Li+) to the second electrode 130 through the electrolyte 50. Lithium cations (Li+) supplied to the second electrode 130 are reduced to lithium (Li). Although the cation is described as lithium cation (Li+) in FIG. 7, it is not limited thereto. During the charging process, electrons moving from the light absorption and storage layer 170 to the first electrode 120 are converted into isomers whose energy levels are converted by at least one of heat or light to perform the function of the electron transport layer. It can move smoothly through the layer 160 .

Referring to (b) of FIG. 7 describing the discharging process of the solar battery-integrated device, the light absorption and storage layer 170 absorbs electrons provided from the second electrode 120 through the conducting wire during discharging and at the same time , Lithium cations (Li+) released from the second electrode 120 and passing through the electrolyte 150 are absorbed and stored. Electrons moving from the first electrode 120 to the light absorption and storage layer 170 during the discharge process are a photochromic material layer composed of isomers whose energy levels are converted to perform the function of the hole transport layer by at least one of light and heat ( 160), you can move smoothly. Meanwhile, for conversion between isomers of the light absorbing material, sunlight may be used or artificial light or heat may be applied.

According to the present invention, the solar cell-battery-integrated device can generate electric power when light is irradiated, and can store the electric power itself, making it possible to reduce the weight and size.

According to the present invention, the photochromic material layer 160 is provided between the first electrode 120 and the light absorption and storage layer 170 in the solar cell battery integrated device, thereby improving the performance of the solar cell battery integrated device. .

Although the embodiments of the present invention have been described above, those skilled in the art can add, change, delete, or add components within the scope not departing from the spirit of the present invention described in the claims. Various modifications and changes may be made to the present invention, which will also be included within the scope of the present invention.

100: solar battery integrated device
110: substrate
120: first electrode
130: second electrode
140: separator
150: electrolyte
160: photochromic material layer
170: light absorption storage layer

Claims (6)

a first electrode;
a second electrode facing the first electrode;
an electrolyte positioned between the first electrode and the second electrode;
a light absorption and storage layer made of a perovskite material formed on the first electrode; and
A photochromic material layer including a photochromic material provided between the first electrode and the light absorption and storage layer and selectively performing functions of an electron transport layer and a hole transport layer. A solar cell battery integrated device. According to claim 1,
The electrolyte is provided with any one of a solid electrolyte and a liquid electrolyte,
When the electrolyte is a liquid electrolyte, the solar battery-integrated device further comprises a separator separating the first electrode and the second electrode. According to claim 1,
The photochromic material includes at least two isomers that are reversibly converted to each other,
The lowest unoccupied molecular orbital (LUMO) energy level of the first isomer is located between the work function of the first electrode and the LUMO energy level of the light absorption and storage layer,
The solar battery integrated device, characterized in that the highest occupied molecular orbital (HOMO) energy level of the second isomer is located between the HOMO energy level of the light absorption and storage layer and the work function of the first electrode. According to claim 3,
The first isomer performs the function of an electron transport layer,
The second isomer is a solar cell battery integrated device, characterized in that performing the function of the hole transport layer. According to claim 1,
A solar battery integrated device, characterized in that one side of the photochromic material layer is provided adjacent to the first electrode, and a rear side is provided adjacent to the light absorption and storage layer. According to claim 3,
The photochromic material is
Spiropyranes, spironaphthoxazines, naphthopyrans, fulgides, diarylethenes, dihydropyridines and azobenzenes Solar cell battery integrated device, characterized in that selected from the group consisting of derivatives).

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