KR102306642B1 - Multijunction Solar Cell and Method for Manufacturing the Same - Google Patents

Abstract

The present invention relates to a multi-junction solar cell, a first solar cell device having a first solar cell layer, a second solar cell device having a second solar cell layer, a first solar cell device, and a second solar cell device It is formed to be bonded therebetween and includes a bonding layer formed in a form in which silver nanowires are dispersed in a transparent silicon compound. According to this multi-junction solar cell and its manufacturing method, by forming lattice-matched solar cell layers on different substrates, respectively, and configuring one multi-junction solar cell through a bonding process, in particular, a triple-junction or more solar cell A significant improvement in efficiency can be expected.

Description

Multijunction Solar Cell and Method for Manufacturing the Same

The present invention relates to a multi-junction solar cell and a method for manufacturing the same, and more particularly, by growing lattice-matched materials on different substrates, bonding them to each other, and minimizing the reduction in performance and reliability of each cell due to lattice mismatch. , to a multi-junction solar cell capable of improving energy efficiency and a method for manufacturing the same.

A solar cell is a core element of photovoltaic power generation, and it is a device that directly converts solar energy into electrical energy using the photovoltaic effect.

A typical solar cell operation consists of generation of an electron-hole pair by sunlight incident on a semiconductor, and the electrons and holes are separated from each other and moved to electrodes at both ends. That is, early solar cells were implemented through the junction of a p-type semiconductor and an n-type semiconductor. However, in recent years, with the advancement of technology, inorganic solar cells made of inorganic materials such as silicon, organic solar cells employing organic materials, etc. have appeared and are being used.

Examples of inorganic solar cells include silicon-based solar cells and chalcogenide and compound semiconductor solar cells such as CIS, CIGS, CdTe, and GaAs.

Examples of organic solar cells include quantum dot solar cells and perovskite solar cells.

The silicon-based solar cell has the advantage of being able to supply a low-cost solar cell because it is easy to obtain materials and inexpensive compared to the compound semiconductor solar cell, but has a disadvantage in that the efficiency is lower than that of the compound semiconductor solar cell. Currently, some Group III-V compound semiconductor multijunction cells have energy efficiencies in excess of 40%, while silicon technology is typically only about 25% efficient. Therefore, there is a need for a technology capable of increasing the efficiency of a solar cell while using silicon as a substrate, and for this purpose, a multi-junction technology can be utilized. In this case, there is a problem in that the carrier life is reduced and the solar cell efficiency is reduced. In order to partially alleviate this, a method of growing a buffer is utilized.

A multi-junction solar cell has been proposed in various ways, such as Korean Patent Registration No. 10-1716149.

On the other hand, according to the NREL announcement, as of 2019, in the case of the hexagonal junction, 39.2% in the non-condensing state and 47.1% in the light-condensing state are known as the maximum efficiency, and the silicon solar cell is known to be 26.1% in the non-condensing state.

Therefore, although a multi-junction technology is required to increase the efficiency of a solar cell, in order to implement a multi-junction solar cell on a single substrate, material parameters are sacrificed due to lattice mismatch, so the overall solar cell efficiency is highly likely to decrease.

The conventional method of implementing a multi-junction solar cell is mainly applying a method of forming cell layers corresponding to different heterogeneous substrates, removing a specific substrate, and then bonding the cells to other substrates. In addition, the adhesion method is mainly welding a solder material, a transparent electrode material (TCO), etc. or a metal material in a transparent resin such as Poly(styrene)-b-poly(2-vinyl pyridine) [PSbP2VP] by self-alignment method. did. However, the metal fusion method may cause damage and deterioration of solar cell elements due to high temperature, and in the case of general transparent resins, yellowing and cracking may occur in terms of long-term reliability due to the visible ray band light absorption edge, which may cause problems. have.

The present invention was devised to solve the above problems, and in order to form a solar cell layer on a heterogeneous substrate so as to broaden the selection of materials for lattice and current matching, each lattice-matched material is grown and then bonding is performed. The purpose of the present invention is to provide a multi-junction solar cell and a method for manufacturing the same, which can improve the efficiency of the solar cell by implementing a multi-junction solar cell with more than double junction while minimizing the reduction in performance and reliability of each cell due to lattice mismatch. have.

In order to achieve the above object, a multi-junction solar cell according to the present invention includes a first solar cell device having a first solar cell layer; a second solar cell device having a second solar cell layer; and a bonding layer formed to be bonded between the first solar cell device and the second solar cell device and in which silver nanowires are dispersed in a transparent silicon compound.

Preferably, the transparent silicon compound contains siloxane, silicate, and silane, but can be thermally cured at a low temperature of 300° C. or less, and is formed of a transparent compound having no light absorption edge in the visible ray band. do.

In addition, transparent conductive oxide (TCO) particles are further added to the bonding layer, the particle diameter of the transparent conductive oxide particles is 100 to 1000 nm, and the content is within 25% by volume of the total volume of the bonding layer. applies.

According to one aspect of the present invention, a first ohmic contact layer formed of a metal material or a transparent electrode material for ohmic contact on the first base substrate, and a metal material or transparent electrode material for ohmic contact on the lower portion of the second base substrate and a second ohmic contact layer formed of, and the bonding layer is applied between the first ohmic contact layer and the second ohmic contact layer.

In addition, in order to achieve the above object, the method for manufacturing a multi-junction solar cell according to the present invention is a. manufacturing a first solar cell device by forming a first solar cell layer on a first base substrate; me. manufacturing a second solar cell device by forming a second solar cell layer on a second base substrate; and c. and forming a bonding layer by bonding and curing between the first solar cell device and the second solar cell device with a liquid transparent silicon compound containing silver nanowires.

The silver nanowire is obtained by continuously reacting an aqueous reducing agent glucose solution and a stabilizer PVP aqueous solution with an aqueous silver nitrate solution, which is a silver precursor. ℃, 20-24 hours hydrothermal synthesis, and apply the prepared by recovering the silver nanowires by a low-speed centrifugation method applying solvent ultrapure water and IPA.

In addition, the liquid transparent silicon compound is prepared by mixing solvent: siloxane: silicate: silane = 8-12: 4: 1: 1 in a molar ratio, and then adding 0.0005 to 0.01 mol % of platinum component based on the total amount, and the solvent is Ethanol (EtOH): Propylene glycol methyl ether (PGME) = 1:1 molar ratio is applied.

According to the multi-junction solar cell and the method for manufacturing the same according to the present invention, each lattice-matched solar cell layer is formed on a different substrate, and a single multi-junction solar cell is formed through a bonding process. The effect of greatly improving the efficiency of the above solar cells can be expected. In addition, it is possible to design and realize a new multi-junction solar cell by giving freedom in substrate selection. Additionally, by growing single or multiple solar cells that not only match current to each other on different substrates, but also match other substrates, and attach them using bonding technology, high-efficiency 5 that is difficult to realize with a single substrate It provides the advantage of realizing a medium or more junction solar cell.

1 is a cross-sectional view showing a multi-junction solar cell according to an embodiment of the present invention;
2 is a view for explaining a process of manufacturing the multi-junction solar cell of FIG. 1,
3 is a view for explaining a process of manufacturing a multi-junction solar cell according to another embodiment of the present invention.

Hereinafter, a multi-junction solar cell and a manufacturing method thereof according to a preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

1 is a cross-sectional view showing a multi-junction solar cell according to an embodiment of the present invention, and FIG. 2 is a view for explaining a process of manufacturing the multi-junction solar cell of FIG. 1 .

1 and 2 , the multi-junction solar cell according to the present invention includes a first solar cell device 110 , a second solar cell device 130 , and a bonding layer 150 .

In the multi-junction solar cell, the second solar cell device 130 made of a GaAs-based compound solar cell is positioned on the bonding layer 150 , and the first solar cell device 110 made of the Si-based solar cell is formed by the bonding layer 150 . The structure is located at the bottom.

In the first solar cell device 110, a Si bottom cell 104 and a back surface layer 106 are sequentially formed under the Si substrate 102, and the Si substrate ( 102) A first ohmic contact layer 108 is formed thereon. Here, the Si substrate 102 corresponds to the first base substrate. Unlike the illustrated example, the first base substrate formed of InP may be applied. In addition, in the first solar cell layer formed on the first base substrate, a material having a band gap lower than that of the substrate is grown to form a heterojunction solar cell and current limitation does not occur.

The Si bottom cell corresponds to the first solar cell layer that converts incident light into electrical energy, and a structure in which a p-type silicon layer and an n-type silicon layer are sequentially stacked may be applied.

The back surface layer 106 may be formed of a metal to be used as an electrode, and may be formed of, for example, aluminum (Al).

The first ohmic contact layer 108 is applied to increase the ohmic contact efficiency when the solar cell devices are bonded to each other with the bonding layer 150 interposed therebetween. In other cases, it may be omitted.

The second solar cell device 130 includes a buffer layer 134 and a GaAs middle cell on the GaAs substrate 132 which is a different material from the Si substrate 102 applied to the first solar cell device 110 . cell) 138 , a tunnel junction 138 , an InGaP top cell 140 , and a surface layer 142 are sequentially stacked, and a GaAs substrate 102 , 132 . A second ohmic contact layer 144 is formed below. Here, the GaAs substrate corresponds to the second base substrate. In addition, the buffer layer 134 is a layer applied to induce lattice matching, and a GaAs middle cell 138 , a tunnel junction 138 , and an InGaP top cell 140 are incident. It corresponds to the second solar cell layer that converts the generated light into electrical energy.

Here, the GaAs middle cell 138 may be formed of p-type GaAs/n-type GaAs, and the InGaP top cell 140 may be formed of p-type InGaP/n-type InGaP sequentially.

The surface layer 142 may include a window layer, an AR coating layer, and an electrode layer sequentially stacked.

The second ohmic contact layer 144 is applied to increase the ohmic contact efficiency when the solar cell devices are bonded to each other with the bonding layer 150 interposed therebetween. In other cases, it may be omitted.

The bonding layer 150 is formed to be bonded between the first solar cell device 110 and the second solar cell device 130, and the silver nanowire 156 is dispersed in the transparent silicon compound 152. .

In the illustrated example, when the first solar cell device 110 and the second solar cell device 130 are to be bonded to each other, first and second ohmic contact layers 108 and 144 are additionally formed to form a bonding layer. (150).

Meanwhile, unlike the illustrated example, as shown in FIG. 3 , unlike in FIG. 2 , the first and second solar cell devices 130 may be inverted so that the solar cells are bonded to each other through the bonding layer 150 . In this case, in the second solar cell device 130 , a sacrificial layer 133 is further formed on the GaAs substrates 102 and 132 , and the second ohmic contact layer is omitted, and the first solar cell For the device 110 , a Si bottom cell layer 104 is disposed on the Si substrate 102 , and a back surface layer 106 is disposed on the bottom surface thereof.

In addition, the bonding layer 150 is formed to be bonded between the Si bottom cell 104 and the buffer layer 134, and then the sacrificial layer is removed, and the surface layer ( 146) can be formed.

As described above, substrates or solar cells or substrates and solar cells may be bonded to each other with respect to the elements disposed to face each other closest to each other on the basis of the bonding layer with respect to the solar cell devices, and as described above, the substrate When they are placed together, they can be joined by applying an ohmic contact layer.

In addition, the first and second base substrates applied to the first solar cell device 110 and the second solar cell device 130 are elements of Group 4, Group 3-5, and Group 2-6 in terms of the periodic rate of elements in addition to those exemplified. Combination of and Mo, SiO ₂ It can be applied to a material made of any one or more of the materials. In addition, the first solar cell layer and the second solar cell layer may be formed of a single or multi-junction solar cell.

On the other hand, the transparent silicon compound 152 applied to the bonding layer 150 does not have a light absorption edge in the visible ray band, so a material having excellent light resistance and yellowing resistance is applied. The transparent silicon compound 152 applied to the bonding layer 150 contains siloxane, silicate, and silane, but can be thermally cured at a low temperature of 300° C. or less, and has a light absorption edge in the visible ray band. Apply a clear compound without When the required thermal curing temperature of the transparent silicon compound 152 exceeds 300° C., deterioration and damage of the solar cell may occur.

Preferably, the transparent silicone compound 152 is composed of an alkyl-based organic group, oxygen and a catalyst material for curing in the -Si-O- backbone chain, and a material having only a single bond is applied, and siloxane (siloxane) any one of PDMS (polydimethysiloxane) and PMHS (polymethylhydrosiloxane) is applied, for silicate, any one of TMOS (tetramethylorthosilicate) and TEOS (tetraethylorthosilicate) is applied, and silane is MTMS (methyltrimethoxysilane) , any one of TEES (triethoxyethylsilane) is applied.

In addition, the silver nanowire 156 applied to the bonding layer 150 has a diameter of 100 to 500 nm, and a length of 300 μm to 10 mm is applied. When the diameter of the silver nanowire 156 is less than 100 nm, the current density is limited, and when it is more than 500 nm, a problem of breaking may occur due to inflexibility, and when the length is less than 300 μm, electrical connection between the solar cells in the bonding layer 150 is impossible. can

Here, the content of the silver nanowire 156 applied to the bonding layer 150 has an electrical conductivity of 1×10 ⁵ S/m or more, preferably 1×10 ⁵ S/m to 1×10 ⁸ S/m, and , It is applied so that the light transmittance in the visible light band is 90% or more. When the electrical conductivity of the bonding layer 150 containing the silver nanowires 156 is ^{less than 1×10 5} S/m, a current density limitation phenomenon may occur, and when the light transmittance is less than 90%, the solar cell efficiency is reduced.

In addition, transparent conductive oxide (TCO) particles 154 may be added to the bonding layer 150 . The particle diameter of the transparent electrically conductive oxide particles 154 added to the bonding layer 150 is 100 to 1000 nm in the sub-micron range. In addition, the added content of the transparent conductive oxide (TCO) particles 154 applied to the bonding layer 150 is applied within 25% by volume of the total volume of the bonding layer 150 . Alternatively, the amount of transparent conductive oxide (TCO) particles 154 applied to the bonding layer 150 may be applied within 25% by weight based on the total weight of the bonding layer 150 . When the particle diameter of the transparent conductive oxide (TCO) particles 154 is less than 100 nm, electrical conductivity and optical transmittance at the interface between the particles and the transparent material may be reduced due to too many particle numbers, and if it exceeds 1000 nm, bonding Since the thickness of the layer 150 is too thick, the adhesive state may be poor. In addition, when the amount of the transparent electrically conductive oxide particles 154 added is more than 25% by volume, fluidity when bonding the bonding layer 150 is lowered, so that the bonding process may be poorly treated.

Here, the transparent electrically conductive oxide is selected from the group consisting of indium tin oxide (ITO), aluminum doped tin oxide (ATO), indium doped zinc oxide (IZO), aluminum doped zinc oxide (AZO), and fluorine doped tin oxide (FTO). Any one or more substances that are applied are applied.

On the other hand, in the illustrated example, a double junction structure has been exemplified to avoid the complexity of the description, and in the case of multiple junctions of triple junction or more, the multi-junction solar cell further includes a third base substrate to an n-th base substrate, each When the solar cell layer is deposited or grown on the base substrate of the n-th base substrate, and the n-th base substrate is included, n-1 bonding layers 150 are formed.

In this multi-junction solar cell, a first solar cell layer is formed on a first base substrate to manufacture the first solar cell device 110 , and a second solar cell layer is separately formed on a second base substrate to form a second solar cell layer. The battery device 130 is manufactured.

Next, the bonding layer 150 is formed by bonding and curing the liquid transparent silicon compound 152 containing the silver nanowires 156 between the first solar cell device 110 and the second solar cell device 130 .

On the other hand, in this manufacturing process, the silver nanowire 156 is produced by continuously reacting an aqueous reducing agent glucose solution and a stabilizer polyvinylpyrrolidone (PVP) aqueous solution with an aqueous silver nitrate solution, which is a silver precursor. After slowly reacting the ion precursor NaCl aqueous solution, hydrothermal synthesis at 140-180° C. for 20-24 hours, and the low-speed centrifugation method using solvent ultrapure water and IPA (isopropyl alcohol) to recover the silver nanowires 156 and apply the prepared ones.

The hydrothermal synthesis conditions during the manufacturing process of the silver nanowire 156 are formed of silver nanoparticles or silver particles when the temperature is less than 140° C. or more than 180° C., silver nanoparticles when it is less than 20 hours, and aggregation of the silver nanowires 156 when it is more than 24 hours. phenomenon occurs.

In addition, the liquid transparent silicon compound 152 is prepared by mixing solvent: siloxane: silicate: silane = 8 to 12: 4: 1: 1 in a molar ratio and then adding 0.0005 to 0.01 mol % of platinum component based on the total amount. . The solvent is ethanol (EtOH): propylene glycol methyl ether (PGME) = 1:1 molar ratio is applied. Among silicon precursors (siloxane, silicate, silane), siloxane is essential, and a 2:1 molar ratio of siloxane to non-siloxane (a silicon precursor not siloxane) is applied. When the molar ratio of siloxane to non-siloxane exceeds 2, there is a risk of hardness degradation, and when the molar ratio is less than 2, cracks and peeling problems may occur. EtOH and PGME applied as solvents act as polymerization initiators while dissolving or dispersing silicon precursors (siloxane, silicate, silane) into a viscous material at an appropriate level. If the amount of the solvent is less than 8 or more than 12, the viscosity is high or low, and the fairness is deteriorated.

Platinum components include chloroplatinate (H₂PtCl), Platinum(II) acetylacetonate, Potassium hexachloroplatinate(IV), and Palladium(II) nitrate hydrate. It is too fast and there is a problem of curing even before the bonding process.

- Bonding process after synthesizing a liquid transparent silicon compound containing silver nanowires

After dispersing the silver nanowires 156 in the liquid transparent silicon compound 152 to prepare the liquid transparent silicon compound 152 containing 5 to 15% by weight of the silver nanowires 156, immersion coating, spin coating, etc. After placement, heat curing at 150~250℃ for 1 hour or longer to bond heterogeneous solar cells . When the silver nanowire 156 is less than 5% by weight, the electrical conductivity is lowered, and when it is 15% by weight or more, a problem in that the light transmittance is lowered may occur. When the thermosetting temperature is less than 150 ℃, curing failure occurs, and when the curing temperature is more than 250 ℃, deformation of the silver nanowire 156 and peeling of the bonding layer 150 are concerned, and when the curing time is less than 1 hour, curing is poor This can happen.

In addition, the transparent electrically conductive oxide to be further dispersed in the liquid transparent silicon compound 152 may be used by exfoliating the thin film implemented through immersion coating method, spin coating method, vacuum deposition method, etc. and powdered or hydrothermal synthesis method, co-precipitation method, heat The powder may be directly implemented through a spraying method or the like.

As an example, ITO particles through thermal spraying may be applied, and the preparation example is as follows. After mixing ethanol with ultrapure water, indium oxide (In ₂ O ₃ ) is dissolved, and hydrochloric acid is added to adjust the pH to 2.0 to prepare an aqueous indium chloride solution, and tin chloride (SnCl ₂ ) is dissolved in ultrapure water to dissolve tin chloride aqueous solution After preparing the solution to be applied to the thermal spray method by mixing each aqueous solution so that the molar ratio of indium chloride and tin chloride is 0.027: 0.003, respectively, apply to thermal spray equipment to which 24MHz ultrasonic piezoelectric body is applied and maintain 700℃ ITO spherical particles of sub-micron particle size are realized by thermal spraying on a glass substrate.

- The manufacturing method of the multi-junction solar cell proposed in the present invention will be described in detail through the following manufacturing examples.

[Production Example 1] (InGaP/GaAs double junction solar cell implementation)

An AlAs sacrificial layer 133 is formed on the GaAs substrate 132 using a crystal growth method applied by MOCVD, an InGaP n, p layer (InGaP top cell) 140 is formed, and then a tunnel junction structure 138 is formed. ), a GaAs n, p layer (GaAs middle cell) 136 is formed, and then a buffer layer 136 is formed to manufacture the second solar cell device 130 which is an upper layer solar cell.

[Production Example 2] (Si solar cell implementation)

Implemented a typical monocrystalline silicon solar cell. Specifically, texturing is performed on both sides of the p-type silicon substrate by anisotropic liquid-phase etching, n-doping is performed by diffusing phosphorus on the upper surface, and the electrode and back surface field are printed on the upper surface, and the electrode and back surface field are printed and heat treated. manufactured through

[Production Example 3] (Silver nanowire implementation)

8.75mL 0.133M glucos aqueous solution was added to 26.25mL 0.02M AgNO3 aqueous solution being stirred, stirred for 10 minutes, 8.75mL 0.005M PVP aqueous solution was added, stirred for 20 minutes, 26.25mL 0.04M NaCl aqueous solution was added dropwise after 20 minutes After stirring for a minute, take 70 mL, put it in a 100 mL Teflon-lined autoclave, perform hydrothermal synthesis at 160°C, 22 hours, and transfer the completed liquid to low speed (2500 rpm), 60 minutes with ultrapure water 3 times and IPA 3 times in the order of silver nanowire (156) is recovered by centrifugation and the silver nanowires 156 are dispersed in IPA at a level of 20% by weight.

[Preparation Example 4] (Liquid transparent silicone compound)

49.96 mL PGME was mixed with 29.18 mL EtOH, 28.95 mL Mn 550 PDMS, 7.13 mL MTMS, 10.41 TEOS were added, stirred for 10 minutes, 0.12 g chloroplatinic acid (H₂PtCl) was added, and stirred for 30 minutes.

[Preparation Example 5] (Silver nanowires, liquid transparent silicon compound containing transparent electrically conductive oxide)

5.76 mL of a solution containing 20 wt% silver nanowires 156 and 1g ITO spherical particles were added to 10g liquid transparent silicone compound 152 and stirred with a vacuum stirrer to prepare a liquid transparent silicone compound containing 10% by weight silver nanowires.

[Production Example 6] (InGaP/GaAs solar cell bonding on top of Si solar cell)

Between the upper part of the Si solar cell and the upper part of InGaP/GaAs, a silver nanowire 156 and a liquid transparent silicon compound 152 containing a transparent electrically conductive oxide were coated to a level of 5 μm or less by spin coating, followed by heat treatment at 175° C. for 1 hour. thermosetting adhesive.

[Preparation Example 7] (GaAs substrate removal and surface layer formation)

After removing the GaAs substrate from the entire solar cell layer by removing the AlAs sacrificial layer between the GaAs substrate and the InGaP cell layer by laser irradiation, a window layer, AR coating layer, and electrode layer are successively formed on the InGaP n layer to complete the solar cell. .

[Production Example 8] (Example of implementation of multi-junction solar cell without substrate separation)

A buffer layer for lattice matching is formed on a GaAs substrate using a crystal growth method applied by MOCVD, a GaAs p, n layer is formed, a tunnel junction structure is formed, and an InGaP p, n layer is formed. After forming a surface layer, thinning the GaAs substrate, forming a second ohmic contact layer on the lower surface of the substrate to complete the upper layer solar cell, and forming an ohmic contact layer on the upper layer of the silicon solar cell mentioned in Preparation Example 2 to form the lower layer solar cell After the cell is completed, a bonding layer is formed between each of the first and second ohmic contact layers as in Preparation Example 6 to implement a multi-junction solar cell.

Such a multi-junction solar cell can improve the efficiency of a multi-junction solar cell with a triple junction or higher while minimizing the reduction in performance and reliability of each cell due to lattice mismatch by growing a lattice-matched material on a heterogeneous substrate and then bonding the substrate. have. Specifically, it is possible to avoid element damage and deterioration due to heating during the bonding process, and it is possible to maintain long-term solar cell efficiency by maintaining light transmittance by suppressing long-term yellowing, etc. The long-term reliability of the solar cell can be secured by suppressing cracking and peeling of the junction due to the surrounding thermal environment.

That is, in the present invention, damage and deterioration of the solar cell element according to the high-temperature process that occurred in the existing technology, and the efficiency decrease accompanying the yellowing phenomenon due to the use of a resin containing a visible light absorption edge, cracking, peeling, etc. In order to solve reliability problems, silver nanowires with high current density and excellent electrical conductivity and transparent electrode materials with excellent light transmittance and electrical conductivity are applied to secure electrical conductivity, and a transparent silicon compound with almost no visible light absorption edge is applied to transmit light. It is possible to alleviate thermal stress that may occur during the bonding process and actual use of solar cells by applying silver nanowires and transparent electrode materials to a low-temperature curing liquid material that can perform adhesion at low temperatures in the form of a composite.

110: first solar cell device
130: second solar cell device
150: bonding layer

Claims (16)

delete delete a first solar cell device having a first solar cell layer;
a second solar cell device having a second solar cell layer;
a bonding layer formed to be bonded between the first solar cell device and the second solar cell device and in which silver nanowires are dispersed in a transparent silicon compound;
The transparent silicon compound contains siloxane, silicate, and silane, but can be thermally cured at a low temperature of 300° C. or less and is formed of a transparent compound having no light absorption edge in the visible light band,
The transparent silicone compound is a material that consists only of an alkyl-based organic group, oxygen and a catalyst material for curing in a -Si-O- backbone chain and has only a single bond, and the siloxane is Any one of polydimethysiloxane (PDMS) and polymethylhydrosiloxane (PMHS) is applied, any one of tetramethylorthosilicate (TMOS) and tetraethylorthosilicate (TEOS) is applied to the silicate, and the silane is methyltrimethoxysilane (MTMS), TEES (triethoxyethylsilane) Multi-junction solar cell, characterized in that any one is applied. delete a first solar cell device having a first solar cell layer;
a second solar cell device having a second solar cell layer;
a bonding layer formed to be bonded between the first solar cell device and the second solar cell device and in which silver nanowires are dispersed in a transparent silicon compound;
The bonding layer has an electrical conductivity of 1×10 ⁵ S/m to 1×10 ⁸ S/m and a multi-junction solar cell, characterized in that it contains the silver nanowire so that the visible light band transmittance is 90% or more . a first solar cell device having a first solar cell layer;
a second solar cell device having a second solar cell layer;
a bonding layer formed to be bonded between the first solar cell device and the second solar cell device and in which silver nanowires are dispersed in a transparent silicon compound;
Transparent conductive oxide (TCO) particles are added to the bonding layer, the particle diameter of the transparent conductive oxide particles is 100 to 1000 nm, and the content is within 25% by volume of the total volume of the bonding layer A multi-junction solar cell with The method of claim 6, wherein the transparent electrically conductive oxide is ITO (Indium Tin Oxide), ATO (Aluminum doped Tin Oxide), IZO (Indium doped Zinc Oxide), AZO (Aluminum doped Zinc Oxide), FTO (Fluorine doped Tin Oxide) A multi-junction solar cell, characterized in that it is made of any one or more materials selected from the group consisting of. delete delete delete delete delete delete go. manufacturing a first solar cell device by forming a first solar cell layer on a first base substrate;
me. manufacturing a second solar cell device by forming a second solar cell layer on a second base substrate; and
all. and forming a bonding layer between the first solar cell device and the second solar cell device by bonding and curing with a liquid transparent silicon compound containing silver nanowires;
The silver nanowire is obtained by continuously reacting an aqueous reducing agent glucose solution and a stabilizer PVP aqueous solution with an aqueous silver nitrate solution, which is a silver precursor. A method of manufacturing a multi-junction solar cell, characterized in that it is subjected to hydrothermal synthesis at ℃, 20 to 24 hours, and the silver nanowire is recovered and prepared by a low-speed centrifugal separation method using solvent ultrapure water and IPA. go. manufacturing a first solar cell device by forming a first solar cell layer on a first base substrate;
me. manufacturing a second solar cell device by forming a second solar cell layer on a second base substrate; and
all. and forming a bonding layer between the first solar cell device and the second solar cell device by bonding and curing with a liquid transparent silicon compound containing silver nanowires;
The liquid transparent silicone compound is prepared by mixing solvent: siloxane: silicate: silane = 8-12: 4: 1: 1 in a molar ratio, and then adding 0.0005 to 0.01 mol % of platinum component relative to the total amount, and the solvent is ethanol ( EtOH): Propylene glycol methyl ether (PGME) = 1:1 A method for manufacturing a multi-junction solar cell, characterized in that the mixture is applied in a molar ratio. go. manufacturing a first solar cell device by forming a first solar cell layer on a first base substrate;
me. manufacturing a second solar cell device by forming a second solar cell layer on a second base substrate; and
all. and forming a bonding layer between the first solar cell device and the second solar cell device by bonding and curing with a liquid transparent silicon compound containing silver nanowires;
The multi-step is to disperse the silver nanowires in the liquid transparent silicon compound to prepare a liquid transparent silicon compound containing 5 to 15 wt% silver nanowires, and then apply any one coating method of immersion coating and spin coating to the bonding site. A method of manufacturing a multi-junction solar cell, characterized in that the heat curing is carried out at 150 to 250° C. for at least 1 hour.

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