WO2013038535A1 - Photoelectric conversion device - Google Patents

Abstract

A photoelectric conversion device (1) which is provided with: a photoelectric conversion layer (130) that performs conversion between light and electrical energy; and a pair of electrodes (110, 120) that are provided on one surface of the photoelectric conversion layer. One electrode (110) and the other electrode (120) are arranged abreast of each other. An organic semiconductor (15) of a p-layer, which is composed of a hole transport material, is provided on the electrode (110), and an organic semiconductor (16) of an n-layer, which is composed of an electron transport material, is provided on the electrode (120). The electrode (110) functions as a p-type electrode, and the electrode (120) functions as an n-type electrode.

Description

Photoelectric conversion device

The present invention relates to a photoelectric conversion device.

A photoelectric conversion device is a device that converts light into electrical energy and a device that converts electrical energy into light. Examples of the former include solar cells, and examples of the latter include light emitting diodes.

Today, the need for solar power supply as a clean energy is recognized again. There are various types of solar cells such as Si solar cells, compound solar cells, and organic semiconductor thin film solar cells.

The Si solar cell will be described by taking a single crystal Si solar cell as an example. A p-type single crystal wafer is converted into a pn junction by changing the surface layer of the wafer to an n-type semiconductor by vapor phase diffusion or implantation of n-type impurity ions. A pin junction is created. Then, a solar cell having a sandwich structure is manufactured by forming the front electrode and the back electrode.

There are various types of compound solar cells, but they have the advantages of high energy conversion efficiency, low light degradation due to secular change, excellent radiation resistance, wide light absorption wavelength range, and large light absorption coefficient. A chalcopyrite solar cell will be described as an example. This is a solar cell provided with a CIGS layer made of a chalcopyrite compound (Cu (In + Ga) Se ₂ ) containing elements of Group I, Group III and Group VI as constituent components as a p-type light absorption layer (for example, Patent Documents). 1).

This solar cell with a CIGS layer generally prevents a back electrode layer, which is a positive electrode made of a Mo metal layer, on a glass substrate such as a soda lime glass (SLG) substrate, and Na unevenness caused by the SLG substrate. For forming a multilayer structure including a Na dip layer, a CIGS light absorption layer, an n-type buffer layer, and an outermost surface layer formed of a transparent electrode layer as a negative electrode.
Here, the n-type buffer layer is made of CdS, ZnO, InS or the like, and the transparent electrode layer is made of ZnOAl or the like.

In this multilayer laminated structure, when irradiation light enters from the light receiving portion on the surface, a pair of electrons and holes are excited in the vicinity of the pn junction of the multilayer laminated structure by the irradiation light having energy greater than the band gap. Occurs. The excited electrons and holes reach the pn junction by diffusion, and the electrons are collected in the n region and the holes are separated in the p region due to the internal electric field of the junction. As a result, the n region is negatively charged, the p region is positively charged, and a potential difference is generated between the electrodes provided in each region. Using this potential difference as an electromotive force, a photocurrent is obtained when the electrodes are connected by a conductive wire.

The CIGS light absorbing layer is obtained by the following process. That is, the substrate itself provided with the In layer and the Cu—Ga layer as a precursor is accommodated in the annealing chamber and preheated. Thereafter, the precursor is converted into a CIGS layer by raising the temperature of the chamber to a temperature range of 500 to 520 ° C. while introducing H ₂ Se gas through a gas introducing tube inserted into the annealing chamber.

On the other hand, organic semiconductor thin film solar cells are attracting attention as solar cells suitable for mass production because they can be formed by a coating method. The organic solar cell has a so-called bulk heterojunction structure in which an organic donor material and an organic acceptor material are mixed. Among them, an organic thin-film solar cell capable of forming a cathode on a flexible substrate by coating and a low-temperature process has been developed (for example, Patent Document 2).

According to Patent Document 2, an organic semiconductor thin film solar cell has a structure in which an anode, a photoelectric conversion layer having a bulk heterojunction structure, and a cathode are sequentially laminated on one surface of a substrate, and a silver oxide and a reducing agent By forming a laminated structure in which an electron transport layer doped with an organic metal is applied in the vicinity of the cathode, not only the cathode is formed at a low temperature, but also the bonding between the organic metal doped layer and the cathode is improved. It is said.

Japanese Patent Laid-Open No. 2006-196771 JP 2011-124468 A

However, in the conventional structure, it is necessary to provide a pair of electrodes across a region that becomes a pn junction. For this reason, the light irradiation side electrode is required to have good light transmittance and low electrical resistance. For this reason, the light irradiation side electrode needs to be formed by vapor deposition or plating of an expensive rare metal. In addition, the process steps are complicated accordingly.

Therefore, an object of the present invention is to provide a photoelectric conversion device that does not require optical transparency as an electrode material.

In order to achieve the above object, a photoelectric conversion device of the present invention is a photoelectric conversion device comprising a photoelectric conversion layer that converts light and electric energy, and a pair of electrodes provided on one side of the photoelectric conversion layer. One electrode and the other electrode are provided side by side, a p-layer organic semiconductor made of a hole transport material is provided on the one electrode, and an electron transport is provided on the other electrode. An n-layer organic semiconductor made of a material is provided, the one electrode functions as a p-type electrode, and the other electrode functions as an n-type electrode.
In the present invention, the p-layer organic semiconductor and the n-layer organic semiconductor are preferably covered with a transparent protective layer.

Conventionally, a p-layer organic semiconductor is laminated on one electrode and an n-layer organic semiconductor is laminated thereon to form a pn junction, and a transparent electrode is formed on the n-layer organic semiconductor as the other electrode. Although the photoelectric conversion device is configured by sequentially stacking, according to the present invention, one electrode functioning as a p-type electrode and the other electrode functioning as an n-type electrode are formed on the same surface. Therefore, the transparent electrode material conventionally required as the electrode material becomes unnecessary. The present invention can be manufactured on a flexible substrate such as a glass substrate. In addition, since an organic semiconductor can be provided over the electrode by coating, the manufacturing process is not complicated, and the organic semiconductor can be manufactured at low cost.

It is sectional drawing of the photoelectric conversion device which concerns on embodiment of this invention. It is sectional drawing of the photoelectric conversion device which concerns on the 1st modification of embodiment of this invention. It is a top view which shows the electrode structure in the photoelectric conversion device shown in FIG. FIG. 4 is an enlarged view of a region A in FIG. 3. It is sectional drawing of the photoelectric conversion device which concerns on the 2nd modification of embodiment of this invention. It is a perspective view which shows the electrode structure in the photoelectric conversion device shown in FIG. It is an enlarged view of the area | region of the code | symbol A shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In particular, the photoelectric conversion device will be described assuming that a solar cell converts light into electric energy. However, the present invention can also be applied to a device that converts electric energy into light energy.

FIG. 1 is a cross-sectional view of a photoelectric conversion device 1 according to a first embodiment of the present invention. As shown in FIG. 1, the photoelectric conversion device 1 according to the embodiment of the present invention includes a pair of electrodes 110 and 120 arranged side by side, and a photoelectric conversion layer 130 that covers the electrodes 110 and 120. I have.

The photoelectric conversion layer 130 is provided on one electrode 110, the other electrode 120 disposed side by side on the same plane with a predetermined distance from the one electrode 110, and the positive electrode provided on the one electrode 110. It is composed of a p-layer organic semiconductor 15 made of a hole transport material and an n-layer organic semiconductor 16 made of an electron transport material provided on the other electrode 120. The p-layer organic semiconductor 15 and the n-layer organic semiconductor 16 are arranged adjacent to each other in the lateral direction to form a pn junction. The p-layer organic semiconductor 15 and the n-layer organic semiconductor 16 including the pn junction are formed. A protective layer 17 is provided so as to cover the entire surface.

The p-layer organic semiconductor 15 is formed of a hole transport material. As a hole transport material, in addition to triphenylamine (TAPC) represented by the chemical formula (1), TPD and other aromatic amines which are dimers of triphenylamine represented by the chemical formula (2), the chemical formula (3) Α-NPD represented by formula (4), (DTP) DPPD represented by formula (4), m-MTDATA represented by formula (5), HTM1 represented by formula (6), 2-TNATA represented by formula (7), TPTE1 represented by the chemical formula (8), TCTA represented by the chemical formula (9), NTPA represented by the chemical formula (10), spiro TAD represented by the chemical formula (11), TFREL represented by the chemical formula (12), and the like are used.

The n-layer organic semiconductor 16 is formed of an electron transport material. Examples of the electron transport material include Alq ₃ represented by the chemical formula (13), BCP represented by the chemical formula (14), an oxadiazole derivative represented by the chemical formula (15), and an oxadiazole dimer represented by the chemical formula (16). And Starbust Oxadiazole represented by Chemical Formula (17), Triazole Derivative represented by Chemical Formula (18), Phenylxoxaline Derivative represented by Chemical Formula (19), Silole Derivative represented by Chemical Formula (20), and the like.

The protective layer 17 is formed of, for example, resin or the like as long as it is a material that transmits irradiation light such as sunlight.

A method for manufacturing the photoelectric conversion device 1 shown in FIG. First, a pair of electrodes 110 and 120 are formed on the same surface. Here, the same surface may be either a virtual surface or a substrate surface, but when formed on the substrate surface, it may be a flat substrate or a flexible substrate that can be bent. An appropriate method such as vapor deposition, sputtering, or plating is used to form the electrode. Photolithographic techniques may be used as necessary. One electrode 1110 and the other electrode 120 are formed by the same process.

Thereafter, a hole transport material to be the p-layer organic semiconductor 15 is applied to a predetermined portion, for example, one electrode 110. For the application, for example, a printing method using an inkjet printer can be applied.

Next, an electron transport material to be the n-layer organic semiconductor 16 is applied between the p layer and the p layer, for example, the other electrode 120. As in the case of the p-layer organic semiconductor 15, a printing technique using an inkjet printer can be used for coating.

Thereby, a pn junction is formed by the p-layer organic semiconductor 15 and the n-layer organic semiconductor 16. The n-layer organic semiconductor 16 may be applied, and then the p-layer organic semiconductor 15 may be applied.

Thereafter, the photoelectric conversion device 1 is manufactured by forming the protective layer 17 by painting or the like. Note that the method is not limited to the above-described method as long as the photoelectric conversion device 1 illustrated in FIG. 1 is manufactured.

According to the photoelectric conversion device 1 according to the present embodiment, the electrodes for the photoelectric conversion device are alternately arranged planes in which one electrode functioning as a p-type electrode and the other electrode functioning as an n-type electrode are formed side by side. It has an electrode structure. Therefore, it is not necessary to provide a p-layer organic semiconductor on one electrode and an n-layer organic semiconductor on the other electrode to form a pn junction in layers and to provide a transparent electrode on the organic semiconductor. . Therefore, in the present invention, it is not necessary to use a transparent electrode material as the electrode material. The photoelectric conversion device 1 can be manufactured on a flexible substrate such as a glass substrate or the like. Since an organic semiconductor can be provided on the electrode by coating, the manufacturing process is not complicated, and the organic semiconductor can be manufactured at low cost.

[First Modification of Embodiment]
FIG. 2 is a cross-sectional view of a photoelectric conversion device 1A according to a first modification of the embodiment of the present invention. As shown in FIG. 2, the photoelectric conversion device 1 </ b> A includes an insulating base material 11, one electrode 13 and the other electrode 14 as photoelectric conversion device electrodes 12 formed side by side on the base material 11, A p-layer organic semiconductor 15 made of a hole transport material provided on one electrode 13, an n-layer organic semiconductor 16 made of an electron transport material provided on the other electrode 14, and a p-layer organic semiconductor 15 And a protective layer 17 provided so as to cover the n-layer organic semiconductor 16. The p-layer organic semiconductor 15 and the n-layer organic semiconductor 16 form a pn junction.

Thus, the p-layer organic semiconductor 15 and the n-layer organic semiconductor 16 are formed side by side on the photoelectric conversion device electrode 12. Also, one electrode 13 and the other electrode 14 constituting the photoelectric conversion device electrode 12 are formed side by side on the surface of the base material 11, similarly to the organic semiconductor 15 and the organic semiconductor 16. Therefore, it is not necessary to provide an electrode on the light incident surface as in Patent Document 2, and it is not necessary to use a rare metal for the transparent electrode provided on the light irradiation side of Patent Document 2 as a material. Therefore, as will be described later, the photoelectric conversion device electrode 12 may use Cu, Al, or the like.

The base material 11 may be various types such as a glass substrate, a resin substrate, and a printed circuit board. When a resin substrate or the like is used as the base material 11, the mounting surface of the photoelectric conversion device may not be a flat surface but may be a curved surface.

One electrode 13 and the other electrode 14 will be described. 3 is a plan view of the electrode for the photoelectric conversion device 1A shown in FIG. 2, and FIG. 4 is an enlarged view of a portion A in FIG. As shown in FIG. 3, one electrode 13 and the other electrode 14 are configured as comb electrodes. The comb-tooth electrode has a structure in which a plurality of electrode fingers 13a and 14a arranged in a comb-like shape in parallel at an appropriate interval are electrically connected at one end by connection electrodes 13b and 14b. One connection electrode 13b and the other connection electrode 14b are arranged opposite to each other, and the electrode fingers 13a and 14a are arranged within the space between each other, whereby the electrode finger 13a of one electrode and the other electrode The electrode fingers 14a are alternately arranged.

That is, an interdigital electrode is formed by one electrode 13 and the other electrode 14. The interdigital electrode is composed of comb electrodes interleaved with each other, and the electrode fingers 13a and electrode fingers 14a of the comb electrodes are alternately arranged.

One electrode 13 and the other electrode 14 are respectively connected to electrode electrodes 13a, 14a and one end of the connection electrodes 13b, 14b, and one end of the connection electrodes 13b, 14b, and a connection terminal for external wiring And lead-out electrodes 13c and 14c extending to 13d and 14d.

In the case shown in FIG. 3, the electrode fingers 13 a and 14 a are formed to extend left and right, and the electrode fingers 13 a and the electrode fingers 14 a are alternately spaced at predetermined intervals in a direction substantially perpendicular to the extending direction. The same number is lined up. The left end of each electrode finger 13a is connected to the connection electrode 14b, and the lead-out electrode 13c extends from the lower end of the connection electrode 14b to the connection terminal 13d with the external wiring along the aforementioned extending direction. On the other hand, the right end of each electrode finger 14a is connected to the connection electrode 14b, and a connection terminal 14d for external wiring is formed at the lower end of the connection electrode 14b. In other words, depending on the position of the connection terminal with the external wiring, the lead electrode may not be necessary.

Organic semiconductors 15 and 16 are provided on such an electrode structure. A p-layer organic semiconductor 15 is formed on at least the electrode finger 13 a of one electrode 13, and an n-layer organic semiconductor 16 is formed on at least the electrode finger 14 a of the other electrode 14. Therefore, the electrode finger 13a of one electrode 13 functions as a p-type electrode, and the electrode finger 14a of the other electrode 14 functions as an n-type electrode.

A method for manufacturing the photoelectric conversion device 1A shown in FIG. First, a base material 11 is prepared, and one electrode 13 and the other electrode 14 are formed on the base material 11 at a predetermined interval. An appropriate method such as vapor deposition, sputtering, or plating is used for electrode formation. Photolithographic techniques may be used as necessary. One electrode 13 and the other electrode 14 are formed by the same process.

Thereafter, a hole transport material to be the p-layer organic semiconductor 15 is applied to a predetermined portion, for example, one electrode 13. For the application, for example, a printing method using an inkjet printer can be applied.

Next, an electron transport material to be the n-layer organic semiconductor 16 is applied between the p layer and the p layer, for example, the other electrode 14. As in the case of the p-layer organic semiconductor 15, a printing technique using an inkjet printer can be used for the application.

Thereby, a pn junction is formed by the p-layer organic semiconductor 15 and the n-layer organic semiconductor 16. The n-layer organic semiconductor 16 may be applied, and then the p-layer organic semiconductor 15 may be applied.

Thereafter, the protective layer 17 is formed by painting or the like to produce the photoelectric conversion device 1A. Note that the method is not limited to the above-described method as long as the photoelectric conversion device 1A illustrated in FIG. 2 is manufactured.

Also in this photoelectric conversion device 1A, like the above-described photoelectric conversion device 1, an alternating array in which one electrode functioning as a p-type electrode and the other electrode functioning as an n-type electrode are formed side by side on a substrate. It has a planar electrode structure. Therefore, it is not necessary to provide a p-layer organic semiconductor on one electrode and an n-layer organic semiconductor on the other electrode to form a pn junction and provide an electrode on the organic semiconductor. Therefore, it is not necessary to use a transparent electrode material as the electrode material.

[Second Modification of Embodiment]
FIG. 5 is a cross-sectional view of a photoelectric conversion device 1B according to a second modification of the embodiment of the present invention, and FIG. 6 is a perspective view of the photoelectric conversion device 1B.

The photoelectric conversion device 1B includes an insulating base material 11 ′, an electrode 12 ′ provided on the upper surface of the base material 11 ′, a photoelectric conversion layer 130 that covers the electrode 12 ′, and a protective layer that covers the upper surface of the photoelectric conversion layer 130. 17. In FIG. 6, the display of the photoelectric conversion layer 130 and the protective layer 17 is omitted.

The base material 11 ′ is formed in a sheet shape and has flexibility. For example, what was formed as a flexible substrate by PET etc. is used. In this embodiment, as shown in FIG. 6, the base material 11 ′ has a rectangular outline. Hereinafter, for convenience of explanation, the short side is referred to as the first side 11A ′, and the long side is referred to as the second side 11B ′.

The electrode 12 ′ will be described with reference to FIG. The electrode 12 'extends along the first side 11A' of the base material 11 'and further has a plurality of warps 12A' arranged at a predetermined pitch in the extending direction of the second side 11B ', and the base material 11'. And a plurality of weft yarns 12B ′ disposed at a predetermined pitch in the extending direction of the first side 11A ′. The warp yarns 12A 'and the weft yarns 12B' are woven so as to intersect each other. That is, the electrode 12 'is formed in a plain weave net shape.

As the warp yarn 12A ′ extending along the first side 11A ′, three kinds of wires are used. Specifically, the first metal wire 121 ′, the second metal wire 122 ′, and the first insulating wire 123 ′ are used.
As shown in FIG. 6, the first metal wire 121 ′ and the second metal wire 122 ′ are alternately arranged, and the first metal wire 121 ′ and the second metal wire 122 ′ are arranged between the first metal wire 121 ′ and the second metal wire 122 ′. An insulating wire 123 'is provided. In addition, although the space | interval of 1st metal wire 121 'and 2nd metal wire 122' is equivalent to the diameter of the cross section of 1st insulated wire 123 'pinched | interposed between them, it is easy to understand a structure in drawing. Therefore, a gap is provided between the members.

As the first metal wire 121 ′ and the second metal wire 122 ′, for example, a copper wire, a stainless wire, a wire obtained by performing metal plating on the surface of a chemical fiber, or the like can be used. One end 121E ′ of each first metal wire 121 ′ is connected to the first bus bar 121A ′ as shown in FIG. Each second metal wire 122 'has an end 122E' located on the other end 121F 'side of the first metal wire 121' connected to the second bus bar 122A '.

The first insulating wire 123 ′ is made of a flexible insulating resin such as nylon resin, silicone resin, urethane resin, epoxy resin, polycarbonate resin, vinyl resin, or the like.

The second insulating wire is used as the weft 12B 'extending along the second side 11B'. Similar to the first insulating wire 123 ', the second insulating wire is made of a flexible insulating resin such as nylon resin, silicone resin, urethane resin, epoxy resin, polycarbonate resin, or vinyl resin.

The first metal wire 121 ′, the second metal wire 122 ′, the first insulating wire 123 ′, and the second insulating wire are set to a thickness of about 20 μm to 30 μm.

Next, the photoelectric conversion layer 130 will be described.
FIG. 7 is a schematic enlarged view of a circle B region in FIG. The photoelectric conversion layer 130 is provided on one electrode, that is, the p-layer organic semiconductor 15 made of a hole transport material provided on the first metal wire 121 ′ and the second metal wire 122 ′ as the other electrode. And an n-layer organic semiconductor 16 made of an electron transport material. Therefore, one first metal wire 121 ′ functions as a p-type electrode, and the other second metal wire 122 ′ functions as an n-type electrode. The p-layer organic semiconductor 15 and the n-layer organic semiconductor 16 form a pn junction.

As described above, the first metal wire 121 ′ and the second metal wire 122 ′ constituting the photoelectric conversion device electrode 12 ′ are formed on the base material 11 ′, and the first metal wire 121 ′ and the second metal wire 121 ′ are further formed. A p-layer organic semiconductor 13A ′ and an n-layer organic semiconductor 13B ′ are formed on the same surface so as to cover the metal wire 122 ′. Therefore, the surface on which light is incident can be the protective layer 17 instead of the photoelectric conversion device electrode 12 side.

The protective layer 17 is provided so as to cover the p-layer organic semiconductor 15 and the n-layer organic semiconductor 16. The protective layer 17 is formed of, for example, a resin or the like as long as it is a material that transmits irradiation light such as sunlight.

A method for manufacturing the photoelectric conversion device 1B shown in FIG. First, the base material 11 ′ is prepared. Next, the first metal wire 121 ′, the second metal wire 122 ′, the first insulating wire 123 ′, and the second insulating wire are prepared and plain woven. An electrode 12 ′ formed by plain weaving is fixed on the substrate 11 with, for example, an adhesive. Thereafter, a hole transport material to be the p-layer organic semiconductor 15 is applied on a predetermined portion, for example, on the first metal wire 121 ′ as one electrode. For the application, for example, a printing method using an inkjet printer can be applied.

Next, an electron transport material to be the n-layer organic semiconductor 16 is applied between the p layer and the p layer, for example, on the second metal wire 122 ′ as the other electrode. As in the case of the p-layer organic semiconductor 15, a printing technique using an inkjet printer can be used for coating.

Thereby, a pn junction is formed by the p-layer organic semiconductor 15 and the n-layer organic semiconductor 16. The n-layer organic semiconductor 16 may be applied, and then the p-layer organic semiconductor 15 may be applied.

Thereafter, the protective layer 17 is formed by painting or the like to produce the photoelectric conversion device 1B. Note that the method is not limited to the above method as long as the photoelectric conversion device 1B illustrated in FIG. 5 is manufactured.

As described above, according to the present invention, the first metal wire 121 ′ and the second metal wire 122 ′ constituting the photoelectric conversion device electrode 12 ′ are formed on the base material 11 ′, and the first metal wire 121 is further formed. A p-layer organic semiconductor 15 and an n-layer organic semiconductor 16 are formed on the base material 11 'so as to cover' and the second metal wire 122 '. Therefore, the surface on which light is incident can be the protective layer 17 instead of the photoelectric conversion device electrode 12 ′ side. Therefore, it is not necessary to configure the electrode with a transparent electrode, and it is not necessary to use a rare metal for the transparent electrode as a material. Therefore, Cu, Al, etc. can be used for electrode 12 'for photoelectric conversion devices.
Further, in the photoelectric conversion device 1B, since the electrode 12 'is formed of a flexible net, it can be attached to a curved surface after being formed in a flat shape.

Although the embodiments of the present invention have been described above, the present invention can be implemented with appropriate modifications within the scope of the present invention.
In the configuration of FIG. 5 described above, the configuration in which one first insulating wire 123 ′ is provided between the first metal wire 121 ′ and the second metal wire 122 ′ is described, but a plurality of the first insulating wire 123 ′ may be provided.
Further, the photoelectric conversion device 1B may be configured by omitting the base material 11 '.

1, 1A, 1B: Photoelectric conversion devices 110, 120: Electrodes 11, 11 ': Base material 12, 12': Electrode conversion device electrodes 12A ': Warp yarn 12B': Weft yarn 121 ': First metal wire 122': First 2 metal wires 123 ′: first insulating wire 13: one electrode 14: other electrodes 13a, 14a: electrode fingers 13b, 14b: connection electrodes 13c: routing electrodes 13d, 14d: connection terminals 15 to the external wiring 15: p Layer organic semiconductor 16: n layer organic semiconductor 17: protective layer

Claims (2)

A photoelectric conversion device comprising a photoelectric conversion layer for converting light and electric energy, and a pair of electrodes provided on one side of the photoelectric conversion layer,
One electrode and the other electrode are provided side by side,
A p-layer organic semiconductor made of a hole transport material is provided on the one electrode,
An n-layer organic semiconductor made of an electron transport material is provided on the other electrode,
The photoelectric conversion device, wherein the one electrode functions as a p-type electrode and the other electrode functions as an n-type electrode. The photoelectric conversion device according to claim 1, wherein the organic semiconductor of the p layer and the organic semiconductor of the n layer are covered with a transparent protective layer.

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