JP2012114424A - Solar cell and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a solar cell having good time efficiency, material efficiency, and patterning definition, and to provide a solar cell manufactured using that manufacturing method.SOLUTION: The method of manufacturing a solar cell includes a step (S12) for forming a transparent electrode film on a substrate, a step (S13) for forming a hole transport layer on the transparent electrode film, a step (S14) for forming an active layer on the hole transport layer, a step (S15) for forming an electron transport layer on the active layer, and a step (S16) for forming an electrode layer on the electron transport layer. At least one layer of the transparent electrode film, hole transport layer, active layer, and electron transport layer is formed by depositing the mist of a raw material by ultrasonic vibration.

Description

  The present invention relates to a solar cell manufacturing method and a solar cell manufactured using the manufacturing method.

  Conventionally, solar cells, particularly thin-film solar cells such as microcrystalline, silicon, cadtel, and organic, are expected as one of the means for solving next-generation energy problems. Thin film solar cells are manufactured by thinning a semiconductor material, and several methods are known for this manufacturing method.

  For example, Patent Document 1 discloses a method for manufacturing a solar cell in which an organic thin film is formed on a surface of a one-conductivity-type semiconductor on which a grid electrode is formed by dipping, spin coating, spray coating, screen printing, or the like. A method is disclosed.

  In Patent Document 2, after introducing hydrogen onto a silicon substrate, the silicon substrate is heated to 350 ° C. or more and 500 ° C. or less, and a solution containing a thin film raw material is sprayed on the silicon substrate by a spray coating method. A method of manufacturing a thin film for forming a film is disclosed.

JP 58-23486 A JP 2004-266194 A

  However, in the case of a method for manufacturing a solar cell as disclosed in Patent Document 1, there are some problems in practical use from the viewpoint of time efficiency, material efficiency, patterning definition, hybrid film formation, and film structure control.

  For example, the dipping method is a method of immersing a substrate in an organic solution to form a thin film. In this case, the dipped substrate needs to be heat treated and dried, and the time efficiency is very poor.

  The spin coating method is a technique for forming a film by dropping a raw material on a rotating substrate and stretching the raw material with a rotating centrifugal force. In the case of this spin coating method, since it is necessary to perform patterning by photolithography after film formation, time loss due to the photolithography process, cost of resist, etc. are incurred, time efficiency and material efficiency are poor, and substrate formation followability is also high Lack.

  The spray coating method is a technique for forming a film by spraying a raw material on a substrate by spraying. In the case of this spray coating method, since patterning can be performed using a metal mask, time efficiency and material efficiency are good. However, since there is a limit to minimizing the particle size of the raw material to be sprayed, it is difficult to make the raw material reach the edge details when forming a film with complicated patterning. It is difficult to obtain a simple film.

  Further, the ink jet printing method is a technique that can form a film only on a necessary portion using an ink jet apparatus. In the case of the ink jet printing method, since patterning can be performed using a metal mask, the time efficiency and the material efficiency are good. However, it is impossible to form a film in a complicated shape with uneven surfaces, for example. The patterning definition is poor.

  Furthermore, when using the method for producing a thin film as disclosed in Patent Document 2, it is possible to improve the patterning definition, which is a drawback of the spray coating method, but a step of introducing hydrogen into the substrate is required. Therefore, the material cost and time are increased, and the time efficiency and material efficiency are poor.

  The present invention has been made in view of the above problems, and uses a method for manufacturing a solar cell with good time efficiency, material efficiency, patterning definition, hybrid film formation, and film structure control, and its manufacturing method. An object of the present invention is to provide a manufactured solar cell.

  The method for producing a solar cell of the present invention includes a transparent electrode film forming step of forming a transparent electrode film on a substrate, a hole transport layer forming step of forming a hole transport layer on the transparent electrode film, and the hole transport layer An active layer forming step of forming an active layer on the active layer; an electron transport layer forming step of forming an electron transport layer on the active layer; and an electrode layer forming step of forming an electrode layer on the electron transport layer. A method for manufacturing a battery, wherein a thin film is formed by depositing at least one of the transparent electrode film, the hole transport layer, the active layer, and the electron transport layer by a raw material misted by ultrasonic vibration. To do.

  According to the manufacturing method described above, at least one of the transparent electrode film, the hole transport layer, the active layer, and the electron transport layer is formed into a thin film by depositing a raw material misted by ultrasonic vibration. In addition, it is not necessary to ensure a long drying time unlike the dipping method, and time loss due to the photolithography process and the cost of the resist or the like are not required unlike the spin coating method. In addition, since the raw material misted by ultrasonic vibration has a smaller particle size than the raw material sprayed by the spray coating method, the raw material can reach the details of the patterning edge, which is difficult by the spray coating method. Complex patterning is possible. Furthermore, it is possible to form a film in a complicated shape having irregularities on the surface, which is difficult with the ink jet method. Therefore, it is possible to manufacture a solar cell more efficiently than ever in terms of time efficiency, material efficiency, patterning definition, hybrid film formation, and film structure control.

  Moreover, in the method for manufacturing a solar cell of the present invention, when the substrate is heated and the misted raw material is deposited, the raw material may be subjected to heat treatment through the heated substrate.

  According to said manufacturing method, the raw material mist-ized with the heat | fever of the heated board | substrate is heat-processed. Thereby, a chemical reaction by thermal decomposition can be caused in the raw material to form a thin film on the substrate, so that a high-purity thin film can be formed and the coverage is improved.

  Further, in the method for manufacturing a solar cell of the present invention, in the hole transport layer forming step, the misted raw material used when forming the hole transport layer is obtained by diluting a transparent conductive polymer stock solution with water. It may be.

  According to the manufacturing method described above, the material efficiency is further improved because only a small amount of the transparent conductive polymer stock solution is used as it is. Moreover, since a part of raw material is comprised with water, it is safe when handling.

  Moreover, the solar cell of this invention is a solar cell manufactured by the process including said manufacturing method of a solar cell.

  According to the above configuration, at least one of the transparent electrode film, the hole transport layer, the active layer, and the electron transport layer is formed into a thin film by depositing a raw material misted by ultrasonic vibration. It is possible to provide a solar cell that is more efficient in all of time efficiency, material efficiency, patterning definition, hybrid film formation, and film structure control than before.

  The method for producing a solar cell of the present invention includes a transparent electrode film forming step of forming a transparent electrode film on a substrate, a hole transport layer forming step of forming a hole transport layer on the transparent electrode film, and the hole transport. An active layer forming step of forming an active layer on the layer, an electron transport layer forming step of forming an electron transport layer on the active layer, and an electrode layer forming step of forming an electrode layer on the electron transport layer. And at least the active layer is formed into a thin film by depositing a plurality of types of raw materials misted by ultrasonic vibration, and the mist formation is performed for each of the plurality of types of raw materials constituting the active layer. It is characterized by being performed separately.

  According to the above manufacturing method, when the active layer is formed into a thin film by depositing a plurality of types of raw materials misted by ultrasonic vibration, the mist formation is performed separately for each of the plurality of types of raw materials constituting the active layer. Can be done. Therefore, the active layer can be formed into a thin film by depositing a plurality of misted raw materials from different paths. For example, by changing the ratio of raw materials to be deposited as the active layer, an active layer in which a plurality of types of raw materials are mixed at a desired ratio can be formed into a thin film. Further, for example, by changing the timing of misting the raw material deposited as the active layer, an active layer in which a plurality of types of raw materials are stacked in a desired order can be formed into a thin film.

  According to the method for manufacturing a solar cell of the present invention, it is possible to manufacture a solar cell more efficiently in all of time efficiency, material efficiency, patterning definition, hybrid film formation, and film structure control.

It is process drawing which shows the manufacturing method of the solar cell which concerns on embodiment of this invention. It is a figure which shows the structure of the solar cell which concerns on embodiment of this invention. It is a figure which shows the ultrasonic spray mist deposition apparatus which concerns on 1st Embodiment. It is a figure which shows the current-voltage characteristic in an Example. It is a figure which shows the ultrasonic spray mist deposition apparatus which concerns on 2nd Embodiment. (A) It is explanatory drawing of the test body created by the spin coat method. (B) It is explanatory drawing of the test body created by the ultrasonic spray mist deposition apparatus which concerns on 2nd Embodiment. It is explanatory drawing explaining the structure of the planar heterojunction of the active layer produced with the ultrasonic spray mist deposition apparatus which concerns on 2nd Embodiment.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

(Method for manufacturing solar cell)
As shown in FIGS. 1 and 2, the method for manufacturing a solar cell 20 according to the present embodiment includes a substrate placement step (S <b> 11) for placing a substrate 21, and a transparent electrode film for forming a transparent electrode film 22 on the substrate 21. Forming step (S12), hole transport layer forming step (S13) for forming hole transport layer 23 on transparent electrode film 22, active layer forming step (S14) for forming active layer 24 on hole transport layer 23, and The solar cell 20 having the electron transport layer forming step (S15) for forming the electron transport layer 25 on the active layer 24 and the electrode layer forming step (S16) for forming the electrode layer 26 on the electron transport layer 25. In the manufacturing method, at least one of the transparent electrode film 22, the hole transport layer 23, the active layer 24, and the electron transport layer 25 is formed into a thin film by depositing a raw material misted by ultrasonic vibration. .

  The manufacturing method of the solar cell 20 will be specifically described with reference to FIG. First, in the substrate placement step (S11), the substrate 21 made of glass is placed. The substrate 21 is not limited to glass, and may be made of other materials such as plastic.

  Next, in the transparent electrode film forming step (S12), indium tin oxide is applied on the substrate 21 to form the transparent electrode film 22. The transparent electrode film 22 is not limited to indium tin oxide, and other materials may be used.

  Next, in the hole transport layer forming step (S13), using the ultrasonic spray mist deposition apparatus 10 shown in FIG. Thereby, the hole transport layer 23 is formed. A specific film forming method using the ultrasonic spray mist deposition apparatus 10 will be described later with reference to FIG. In addition, the raw material 41 used for the hole transport layer 23 is a transparent conductive polymer stock solution (PEDOT: PSS) diluted with water between the stock solution and 100 times. Therefore, material efficiency is good compared with the case where a transparent conductive polymer stock solution is used as it is. If the transparent conductive polymer stock solution is diluted more than 100 times with water, the transparent conductive polymer becomes too thin and a thin film cannot be formed well. From the viewpoint of material efficiency and thin film formation, it is more effective to dilute the transparent conductive polymer stock solution (PEDOT: PSS) 10 times with water. Note that a thin film formed using a transparent conductive polymer has a transparency exceeding 80% in the visible light region and further in the ultraviolet region, and thus is suitable for forming the hole transport layer 23. Further, it is effective to add a conductivity improver such as dimethyl sulfoxide (DMSO), ethylene glycol, NMP (n-methylpyrrolidone) or the like to the transparent conductive polymer because the conductivity is improved. Furthermore, adding an alcohol such as ethanol to the transparent conductive polymer is effective because the drying speed is improved.

Next, in the active layer forming step (S14), the active layer 24 is formed on the hole transport layer 23. In the active layer 24, poly (3-hexylthiophene) (abbreviation P3HT) is used as a donor material, and [6,6] -Phenyl-C ₆₁ -Butyric Acid Methyl is used as an acceptor material. Ester (phenyl C ₆₁ butyric acid methyl ester) (abbreviation PCBM) is used, and a thin film is formed by spin coating. The donor material and the acceptor material of the active layer 24 are not limited to the above, and other materials may be used. The active layer 24 is bulk-heterojunction by mixing the above donor material and acceptor material.

Next, in the electron transport layer forming step (S15), titanium oxide (Tiox) is laminated on the active layer 24 to form the electron transport layer 25. The electron transport layer 25 is not limited to titanium oxide (Tiox). For example, metal oxides such as molybdenum oxide (MoO ₃ ) and vanadium oxide (V ₂ O ₅ ), lithium fluoride (LiF), barium (Ba), You may be comprised from pigment | dyes, such as calcium (Ca) and Bathocuproine (BCP). The electron transport layer 25 increases the rectification characteristics of the solar cell 20 and increases the fill factor.

  Finally, in the electrode layer forming step (S16), aluminum (Al) is vacuum-deposited on the electron transport layer 25 to form the electrode layer 26, and these are combined.

  According to the above manufacturing method, since the hole transport layer 23 is formed into a thin film by depositing the raw material 41 misted by ultrasonic vibration, it is necessary to ensure a long drying time as in the dipping method. Thus, there is no time loss due to the photolithography process as in the spin coating method, and there is no cost for resist or the like. In addition, since the raw material 41 misted by ultrasonic vibration has a smaller particle size than the raw material sprayed by the spray coating method, the raw material can reach the details of the patterning edge, which is difficult by the spray coating method. Complicated patterning is possible. Furthermore, it is possible to form a film in a complicated shape having irregularities on the surface, which is difficult with the ink jet method. Therefore, it is possible to manufacture the solar cell 20 more efficiently in all of time efficiency, material efficiency, patterning definition, hybrid film formation, and film structure control than before.

  Moreover, according to said manufacturing method, since a small amount is sufficient rather than using a transparent conductive polymer as it is, material efficiency is further favorable. Moreover, since a part of raw material 41 is comprised with water, it is safe also when handling.

  In the process diagram showing the method for manufacturing the solar cell 20 in FIG. 1, the hole transport layer 23 is formed as a thin film using the raw material 41 misted in a gaseous form, but it is not necessary to be limited to this. . That is, at least one of the transparent electrode film 22, the hole transport layer 23, the active layer 24, and the electron transport layer 25 is made of a mist material (which is suitable for each layer regardless of inorganic, organic, and hybrid). Even if the thin film is formed by repeating the deposition and the heat treatment, the same effect is obtained.

(Configuration of solar cell)
As described above, the solar cell 20 manufactured by the manufacturing method shown in FIG. 1 includes a substrate 21, a transparent electrode film 22, a hole transport layer 23, an active layer 24, an electron transport layer 25, and an electrode layer from the top as shown in FIG. 26 are formed in this order. When solar light strikes from the substrate 21 side, electrons and holes are generated in the active layer 24, and the electrons are attracted to the electron transport layer 25 and the holes are attracted to the hole transport layer 23. Thus, by connecting the transparent electrode film 22 side as a positive electrode and the electrode layer 26 side as a negative electrode, electricity flows from the transparent electrode film 22 side to the electrode layer 26 side.

  According to the configuration of the solar cell 20 described above, since the thin film is formed by depositing the raw material 41 misted by ultrasonic vibration, time efficiency, material efficiency, patterning definition, hybrid film formation, An efficient solar cell 20 can be provided in all of the film structure control.

(Configuration of ultrasonic spray mist deposition apparatus 10)
As shown in FIG. 3, the ultrasonic spray mist deposition apparatus 10 according to the present embodiment includes one or a plurality of source gas supply devices 30, source gas ejection nozzles 50, and energy supply devices 60. .

  The raw material gas supply device 30 includes a propagation solution storage unit 32 that stores a propagation solution 42, a raw material storage unit 35 that stores a raw material 41, an ultrasonic transducer 31 disposed at the bottom of the propagation solution storage unit 32, and a raw material The carrier gas supply unit 34 that supplies the carrier gas 44 to the storage unit 35, the source gas communication unit 38 that serves as a passage for transporting the source gas 43 to the source gas ejection nozzle 50, and the dilution gas 45 is supplied to the source gas communication unit 38. A dilution gas supply unit 37. For the propagation solution 42, water is usually used. Examples of the carrier gas 44 and the dilution gas 45 include air and nitrogen, and the flow rate thereof is 4 L / min. The carrier gas 44 and the dilution gas 45 are not limited to air and nitrogen, and other gases may be used, and the flow rates can be set as appropriate. The raw material 41 may be a mixed solution in which a plurality of materials are mixed in advance at a predetermined ratio.

  The raw material storage part 35 has, for example, a rectangular parallelepiped shape, and stores the raw material 41 at the bottom inside thereof. A space is provided between the sea surface of the raw material 41 and the upper inner surface of the raw material container 35 to accommodate a raw material gas 43 described later. That is, the raw material storage unit 35 has a space in the inside thereof that can accommodate the raw material gas 43 even when the raw material 41 is stored. The bottom surface outside the raw material container 35 is immersed in the propagation solution 42 accommodated in the propagation solution container 32, and the ultrasonic waves generated by the vibration of the ultrasonic transducer 31 are transmitted through the propagation solution 42. Propagated to the raw material 41. The propagation solution 42 has a role of cooling the ultrasonic transducer 31 in addition to the role of propagating ultrasonic waves. The ultrasonic vibrator 31 may generate heat due to vibration and have a poor ability. However, since the ultrasonic vibrator 31 is cooled by the propagation solution 42, such a problem does not occur.

  The carrier gas supply unit 34 is provided with a carrier gas flow rate control valve 33, and the carrier gas 44 can be supplied into the raw material storage unit 35 by opening the carrier gas. The dilution gas supply unit 37 is provided with a dilution gas flow rate control valve 36, and the dilution gas 45 can be supplied into the source gas communication unit 38 by opening the dilution gas.

  The source gas ejection nozzle 50 has a housing 51 and a guide member 52 provided inside the housing 51. The casing 51 is based on, for example, a rectangular parallelepiped shape extending in the vertical direction, and the internal space is gradually narrowed from the upper side to the lower side. An opening 53 is formed on the bottom surface of the casing 51, and a guide member 52 projects therefrom. Further, the temperature of the source gas ejection nozzle 50 can be adjusted, for example, by keeping it at a high temperature by a heater (not shown). The guide member 52 is provided along the vertical direction inside the casing 51, and the upper part thereof communicates with the source gas communication unit 38. Further, the lower portion of the guide member 52 protrudes from the opening 53 toward the outside, and is disposed to the vicinity of the surface of the substrate 21 while being kept perpendicular to the surface of the substrate 21. The lower part of the guide member 52 does not necessarily have to be kept perpendicular to the surface of the substrate 21. However, when the source gas 43 is sprayed through the guide member 52, the thin film can be formed more clearly if kept perpendicular. can do.

  The energy supply device 60 has a flat plate shape on which the substrate 21 can be placed, and can adjust the temperature of the substrate 21 by supplying heat to the substrate 21. Further, the energy supply device 60 can move in the horizontal direction, and can horizontally move the substrate 21 with respect to the fixed guide member 52.

(Operation of ultrasonic spray mist deposition apparatus 10)
The ultrasonic spray mist deposition apparatus 10 having the above configuration sprays and thins the raw material 41 misted by ultrasonic vibration on the transparent electrode film 22 formed on the substrate 21 to form a hole transport layer 23. Can be formed.

  Specifically, first, when the ultrasonic transducer 31 is actuated, the generated ultrasonic wave propagates through the propagation solution 42 and propagates to the raw material 41 accommodated in the raw material container 35. As a result, the raw material 41 is vibrated by ultrasonic waves, and the solution particles are subdivided to be misted into gas and released. This is the raw material gas 43 in which the raw material 41 is misted. At this time, the source gas 43 once stays in a space provided inside the source container 35.

  When the raw material 41 is misted and the raw material gas 43 is generated, the carrier gas flow rate control valve 33 provided in the carrier gas supply unit 34 is opened. Then, the carrier gas 44 is supplied into the raw material container 35 with a supply amount corresponding to the opening degree of the carrier gas flow rate control valve 33. Thus, the source gas 43 is conveyed upward toward the source gas communication unit 38 by the carrier gas 44 supplied into the source material storage unit 35. At this time, the raw material gas 43 having a large particle diameter falls downward and is eventually returned to the raw material 41 accommodated in the raw material accommodating portion 35. As a result, only the raw material gas 43 with a small particle diameter is carried to the raw material gas communication unit 38 by the carrier gas 44.

  Next, when the source gas 43 is conveyed to the source gas communication unit 38, the dilution gas flow rate control valve 36 provided in the dilution gas supply unit 37 is opened, and the dilution gas 45 is supplied into the source gas communication unit 38. The Thereby, the source gas 43 is conveyed to the source gas ejection nozzle 50 side through the source gas communication unit 38 by the dilution gas 45 supplied into the source gas communication unit 38. At this time, while passing through the raw material gas communication section 38, the raw material gases 43 having small particle diameters gather to have a large particle diameter. Those having such a large particle diameter can no longer advance in the raw material gas communication section 38 due to their own weight, and return to the raw material 41 stored in the raw material storage section 35 in a reverse direction. Thereby, only the raw material gas 43 having a very small particle diameter is carried by the dilution gas 45 to the raw material gas ejection nozzle 50 side. Even if the dilution gas 45 is not supplied, the source gas 43 is carried to the source gas jet nozzle 50 by the carrier gas 44. However, since the concentration of the source gas 43 can be adjusted by the dilution gas 45, or the concentration can be adjusted by diluting the source gas 43, it is more effective.

  The raw material gas 43 carried to the raw material gas ejection nozzle 50 through the raw material gas communication unit 38 eventually reaches the guide member 52. The source gas 43 flows downward along the planar shape of the guide member 52. At this time, since the source gas ejection nozzle 50 is heated to 80 ° C. by a heater (not shown), the source gas 43 can maintain a certain extremely small particle diameter. Thereafter, the source gas 43 has a uniform concentration in the source gas ejection nozzle 50 and is discharged to the surface of the substrate 21 in a uniform flow by the guide member 52. In this way, the source gas 43 is uniformly sprayed on the surface of the transparent electrode film 22 formed on the substrate 21.

  The substrate 21 is horizontally moved by the energy supply device 60 at a speed of 7.5 to 15 mm / min. Therefore, by adjusting this speed, a transparent conductive polymer thin film having a desired thickness can be uniformly formed on the substrate 21. Further, the substrate 21 is heated by the energy supply device 60. Since the source gas 43 has a very small particle diameter and is mostly due to water, the component water evaporates depending on the temperature of the substrate 21 at the moment when the source gas 43 hits the substrate 21. Thereby, conventionally, when a thin film was formed using a transparent conductive polymer, the transparent electrode film 22 was corroded by the acidic transparent conductive polymer, but in this embodiment, the raw material gas 43 is a very small particle. Because of the diameter, the water does not evaporate due to the temperature of the substrate 21 at the moment when it hits the substrate 21, and the transparent electrode film 22 is not corroded. In addition, the source gas 43 is heat-treated by the heated heat of the substrate 21. As a result, a chemical reaction by thermal decomposition can be caused in the source gas 43 to form a thin film on the substrate 21, so that a high-purity thin film can be formed and the coverage is improved. In addition, the temperature of the board | substrate 21 heated by the energy supply apparatus 60 is between 5 degreeC-200 degreeC. This is because if the temperature is lower than 5 ° C., the moisture of the raw material gas 43 remains on the substrate 21, and if it is higher than 200 ° C., the raw material gas 43 is excessively decomposed and a thin film cannot be formed well. Further, from the above viewpoint, it is more effective to heat the substrate 21 to 150 ° C.

  Further, for the patterning, a metal mask (not shown) is used, and the source gas 43 having a very small particle diameter can reach the details of the edge, so that the patterning definition is very good. Note that the temperature of the source gas ejection nozzle 50 and the temperature of the substrate 21 heated by the energy supply device 60 can be set as appropriate. Further, the moving speed of the substrate 21 horizontally moved by the energy supply device 60 can be set as appropriate in accordance with the film thickness design.

(Examples and comparative examples)
Next, the characteristics of the solar cell 20 according to the present embodiment are evaluated using examples and comparative examples. Here, as Example 1, it evaluates using the solar cell 20 which concerns on this embodiment. That is, the solar cell 20 in which the hole transport layer 23 is formed by spraying the raw material 41 misted by ultrasonic vibration on the transparent electrode film 22 to form a thin film is used. On the other hand, as Comparative Example 1, a solar cell in which a hole transport layer is formed into a thin film by a conventional spin coating method is used. Regarding the configuration and manufacturing method other than the hole transport layer, there is no difference between Example 1 and Comparative Example 1.

  FIG. 4 shows the current-voltage characteristics of the solar cell 20 in Example 1. Table 1 shows the values of the characteristics of the solar cell 20 in Example 1 and the solar cell in Comparative Example 1.

As shown in FIG. 4 and Table 1, the solar cell 20 in Example 1 has a short-circuit current density of 5.28 mA / cm ² , an open-circuit voltage of 0.54 v, and a fill factor of 0.54. 55% has been achieved. On the other hand, the solar cell in Comparative Example 1 had a short-circuit current density of 4.66 mA / cm ² , an open-circuit voltage of 0.54 v, a fill factor of 0.51, and an energy conversion efficiency of 1.27%. From these results, it can be seen that the solar cell 20 in Example 1 has about 20% better characteristics than the solar cell in Comparative Example 1.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings.

In the first embodiment described above, when the active layer 24 is formed on the hole transport layer 23 in the active layer forming step (S14), poly (3-hexylthiophene) (poly (3-helylthiophene) as a donor material is used. )) (abbreviation P3HT) Mochiiri, using _{[6,6] -Phenyl-C 61 -Butyric} acid methyl ester ( phenyl _{C 61} butyric acid methyl ester), (abbreviation PCBM) as an acceptor material, a thin film formed by a spin coating method Explained when to do. On the other hand, in the second embodiment, using the ultrasonic spray mist deposition apparatus 210 shown in FIG. 5, two types of raw materials 241 and 341 that are misted in a gaseous state are sprayed onto the hole transport layer 23. A case where the active layer 24 is formed by forming a thin film will be described. Note that poly (3-hexylthiophene) (abbreviation P3HT) is used for the raw material 241 as a donor material, and [6,6] -Phenyl- as an acceptor material is used for the raw material 341. hereinafter described as using a C ₆₁ -Butyric acid methyl ester (phenyl _{C 61} butyric acid methyl ester), (abbreviation PCBM).

(Configuration of ultrasonic spray mist deposition apparatus 210)
First, the configuration of the ultrasonic spray mist deposition apparatus 210 used in the second embodiment will be described with reference to FIG. Compared with the ultrasonic spray mist deposition apparatus 10 used in the first embodiment, the ultrasonic spray mist deposition apparatus 210 used in the second embodiment is a raw material for accommodating two kinds of raw materials 241 and 341. The difference is that two gas supply devices are provided. In addition, description is abbreviate | omitted about the ultrasonic spray mist deposition apparatus 10 of 1st Embodiment, and the same structure and a role.

  As shown in FIG. 5, the ultrasonic spray mist deposition apparatus 210 according to this embodiment includes two source gas supply devices 230 and 330, a source gas ejection nozzle 250, and an energy supply device 260 as a single unit. There are several.

  As in the first embodiment, the source gas supply device 230 includes a propagation solution storage unit 232 that stores the propagation solution 242, a raw material storage unit 235 that stores the raw material 241, and a superposition disposed at the bottom of the propagation solution storage unit 232. A sonic transducer 231, a carrier gas supply unit 234 that supplies the carrier gas 244 to the source material storage unit 235, and a source gas communication unit 238 that serves as a passage for transporting the source gas 243 mist of the source material 241 to the source gas ejection nozzle 250. And a dilution gas supply unit 237 that supplies the dilution gas 245 to the source gas communication unit 238. The carrier gas supply unit 234 is provided with a carrier gas flow rate control valve 233, and the carrier gas 244 can be supplied into the raw material storage unit 235 by opening the carrier gas. The dilution gas supply unit 237 is provided with a dilution gas flow rate control valve 236. By opening the dilution gas 245, the dilution gas 245 can be supplied into the source gas communication unit 238. As described above, the raw material 241 uses poly (3-hexylthiophene) (abbreviated as P3HT) as a donor material.

Similarly to the raw material gas supply device 230, the raw material gas supply device 330 is also disposed at the bottom of the propagation solution storage portion 332 that stores the propagation solution 342, the raw material storage portion 335 that stores the raw material 341, and the propagation solution storage portion 332. Ultrasonic vibrator 331, carrier gas supply unit 334 for supplying carrier gas 344 to source material storage unit 335, and source gas communication unit serving as a passage for transporting source gas 343 mist of source material 341 to source gas ejection nozzle 250 338 and a dilution gas supply unit 337 that supplies the dilution gas 345 to the source gas communication unit 338. The carrier gas supply unit 334 is provided with a carrier gas flow rate control valve 333, and the carrier gas 344 can be supplied into the raw material storage unit 335 by opening the carrier gas. The dilution gas supply unit 337 is provided with a dilution gas flow rate control valve 336, and the dilution gas 345 can be supplied into the source gas communication unit 338 by opening the dilution gas. Further, as described above, the raw material 341, using a _{[6,6] -Phenyl-C 61 -Butyric} Acid Methyl Ester ( phenyl _{C 61} butyric acid methyl ester), (abbreviation PCBM) as an acceptor material.

  The source gas ejection nozzle 250 has a housing 251 and a guide member 252 provided inside the housing 251. The housing 251 is based on, for example, a rectangular parallelepiped shape extending in the vertical direction, and the internal space is gradually narrowed from the upper side to the lower side. An opening 253 is formed on the bottom surface of the housing 251, and a guide member 252 projects therefrom. Further, the temperature of the source gas ejection nozzle 250 can be adjusted, for example, kept at a high temperature by a heater (not shown). The guide member 252 is provided along the vertical direction inside the housing 251, and the upper part thereof communicates with the source gas communication unit 238 and the source gas communication unit 338. The lower portion of the guide member 252 protrudes from the opening 253 toward the outside, and is disposed to the vicinity of the surface of the substrate 21 while being kept perpendicular to the surface of the substrate 21.

  The energy supply device 60 has a flat plate shape on which the substrate 21 can be placed, and can adjust the temperature of the substrate 21 by supplying heat to the substrate 21. Further, the energy supply device 60 is movable in the horizontal direction, and can horizontally move the substrate 21 with respect to the fixed guide member 252.

(Operation of Ultrasonic Spray Mist Deposition Device 210)
The ultrasonic spray mist deposition apparatus 210 having the above configuration is activated by spraying a thin film by spraying the raw material 241 and the raw material 341 misted by ultrasonic vibration on the hole transport layer 23 formed on the substrate 21. Layer 24 can be formed. In the present embodiment, for example, a case where the raw material 241 and the raw material 341 are mixed at a volume ratio of 1: 1 and the active layer is formed into a thin film by bulk heterojunction will be described. In addition, although the mixing volume ratio of the raw material 241 and the raw material 341 is 1: 1, a desired ratio can be set. Moreover, the ratio at the time of mixing the raw material 241 and the raw material 341 may be defined not only by the volume ratio but also by the weight ratio.

  Specifically, first, when the ultrasonic transducer 231 on the source gas supply device 230 side is operated, the generated ultrasonic wave propagates through the propagation solution 242 and propagates to the raw material 241 stored in the raw material storage unit 235. . As a result, the raw material 241 is vibrated by ultrasonic waves, and the solution particles are subdivided to be misted into gas and released. This is the raw material gas 243 in which the raw material 241 is misted. At this time, the source gas 243 temporarily stays in a space provided inside the source container 235.

  Next, when the raw material 241 is misted and the raw material gas 243 is generated, the carrier gas flow rate control valve 233 provided in the carrier gas supply unit 234 is opened. Then, the carrier gas 244 is supplied into the raw material container 235 with a supply amount corresponding to the opening degree of the carrier gas flow control valve 233. Thus, the source gas 243 is conveyed upward toward the source gas communication unit 238 by the carrier gas 244 supplied into the source material storage unit 235.

  Next, when the source gas 243 is conveyed to the source gas communication unit 238, the dilution gas flow rate control valve 236 provided in the dilution gas supply unit 237 is opened, and the dilution gas 245 is supplied into the source gas communication unit 238. The Thereby, the source gas 243 is conveyed to the source gas ejection nozzle 250 side through the source gas communication unit 238 by the dilution gas 245 supplied into the source gas communication unit 238.

  On the other hand, the ultrasonic vibrator 331 is also operated on the raw material gas supply device 330 side, and the generated ultrasonic wave propagates through the propagation solution 342 and propagates to the raw material 341 stored in the raw material storage unit 335. As a result, the raw material 341 is vibrated by ultrasonic waves, and the solution particles are subdivided to be misted and released in a gaseous state. This is the raw material gas 343 in which the raw material 341 is misted. At this time, the source gas 343 temporarily stays in the space provided inside the source container 335.

  Next, when the raw material 341 is misted and the raw material gas 343 is generated, the carrier gas flow rate control valve 333 provided in the carrier gas supply unit 334 is opened. Then, the carrier gas 344 is supplied into the raw material container 335 with a supply amount corresponding to the opening degree of the carrier gas flow rate control valve 333. Accordingly, the source gas 343 is conveyed upward toward the source gas communication unit 338 by the carrier gas 344 supplied into the source material storage unit 335.

  Next, when the source gas 343 is conveyed to the source gas communication unit 338, the dilution gas flow rate control valve 336 provided in the dilution gas supply unit 337 is opened, and the dilution gas 345 is supplied into the source gas communication unit 338. The Thereby, the source gas 343 is conveyed to the source gas ejection nozzle 250 side through the source gas communication unit 338 by the dilution gas 345 supplied into the source gas communication unit 338.

  Then, the source gas 243 and the source gas 343 carried to the source gas ejection nozzle 250 through the source gas communication unit 238 and the source gas communication unit 338 eventually reach the guide member 252.

  In addition, the mixing volume ratio of the raw material gas 243 and the raw material gas 343 mixed in the raw material gas injection nozzle 250 is set to 1: 1, but this is performed by a computer controlled by a computer (not shown). Operation control of the ultrasonic transducer 231 on the 230 side, opening control of the carrier gas flow rate control valve 233, and opening control of the dilution gas flow rate control valve 236, operation of the ultrasonic transducer 331 on the source gas supply device 330 side By controlling the opening of the carrier gas flow rate control valve 333 and the opening control of the dilution gas flow rate control valve 336, the source gas injection nozzle 250 performs mixing at a desired mixing volume ratio of 1: 1. Is done.

  The mixed source gas 243 and source gas 343 flow downward along the planar shape of the guide member 252. At this time, since the raw material gas ejection nozzle 250 is heated to 80 ° C. by a heater (not shown), the mixed raw material gas 243 and raw material gas 343 can maintain a certain extremely small particle diameter. Thereafter, the mixed source gas 243 and source gas 343 have a uniform concentration with a volume ratio of 1: 1 in the source gas jet nozzle 250 and are discharged to the surface of the substrate 21 in a uniform flow by the guide member 252. Is done. In this way, the raw material 241 and the raw material 341 mixed at a volume ratio of 1: 1 are uniformly sprayed on the surface of the hole transport layer 23 formed on the substrate 21, so that the bulk heterojunction active layer is formed. A thin film is formed.

(Method for preparing active layer specimen)
The operation of the ultrasonic spray mist deposition apparatus 210 has been described above. However, using the ultrasonic spray mist deposition apparatus 210, a solar battery such as a short-circuit current density, an open-circuit voltage, a curve factor, and energy conversion efficiency of the solar battery is used. A method for producing the test body 110 on which the active layer used for finding the mixing volume ratio and mixing weight ratio of the raw material 241 and the raw material 341 that maximize the characteristics will be described.

In the process of manufacturing the solar cell, when the active layer 24 is formed into a thin film, the mixing volume ratio of the raw material 241 and the raw material 341 maximizing the solar cell characteristics may be examined using a specimen. For example, when the mixing volume ratio of the raw material 241 and the raw material 341 is 8: 2, 7: 3, 6: 4, 5: 5, 4: 6, and 3: 7. In order to know which mixing volume ratio maximizes the solar cell characteristics, in order to prepare a test body by the conventional spin coating method, the mixing volume ratio of the raw material 241 and the raw material 341 is previously mixed at a desired ratio. The raw material is dropped on a rotating substrate, and the raw material is stretched by a centrifugal force of rotation to form a film, so that the mixing volume ratio of the raw material 241 and the raw material 341 is as shown in FIG. 8: 2 test body 161, test body 162 having a mixing volume ratio of the raw material 241 and the raw material 341 of 7: 3, test body 163 having a mixing volume ratio of the raw material 241 and the raw material 341 of 6: 4, the raw material 241 and the raw material Specimen 164 having a mixing volume ratio with 341 of 5: 5, Samples 165 having a mixing volume ratio of the material 241 and the raw material 341 of 4: 6, and specimens 166 having a mixing volume ratio of the raw material 241 and the raw material 341 of 3: 7 are prepared one by one. It is necessary to connect the electrodes to the body and examine and compare the solar cell characteristics.
However, a plurality of specimens composed of one kind of mixed volume ratio must be prepared, which is inefficient.
Therefore, a method of depositing an active layer formed at a plurality of mixed volume ratios on one test body 110 by using the ultrasonic spray mist deposition apparatus 210 will be described below.

  Specifically, first, the test body 110 on which the active layer is not deposited is placed on the energy supply device 60. The operation of the ultrasonic transducer 231 on the raw material gas supply device 230 side, the opening control of the carrier gas flow rate control valve 233, and the opening control of the dilution gas flow rate control valve 236 are controlled by a computer (not shown) controlled by programming. The raw material gas injection nozzle 250 is controlled by controlling the operation of the ultrasonic transducer 331 on the raw material gas supply device 330 side, opening control of the carrier gas flow control valve 333, and opening control of the dilution gas flow control valve 336. In FIG. 5, the raw material gas 243 and the raw material gas 343 mixed at a mixing volume ratio of 8: 2 are discharged from the opening 253 to the surface of the test body 110. At this time, as shown in FIG. 6B, when the energy supply device 60 moves by a distance K in the horizontal direction, the mixing volume ratio of the raw material 241 and the raw material 341 is 8 in the region 111 of the test body 110. : An active layer bulk-junctioned at 2 is formed into a thin film.

  Similarly, mixing is performed at a mixing volume ratio of 7: 3 in the source gas ejection nozzle 250 by a computer that is controlled by programming, and the mixed source gas 243 and source gas 343 are discharged from the opening 253 to the surface of the specimen 110. To do. At this time, the energy supply device 60 moves by a distance K in the horizontal direction, so that the active layer formed by bulk heterojunction in the region 112 of the test body 110 with a mixing volume ratio of the raw material 241 and the raw material 341 of 7: 3 is a thin film. It is formed. Similarly, a thin layer is formed in the region 113 of the test body 110 so that an active layer bulk-junctioned at a mixing volume ratio of the raw material 241 and the raw material 341 of 6: 4 is formed. An active layer bulk-junctioned at a mixing volume ratio of 5: 5 is formed into a thin film, and an active layer bulk-junctioned at a region 115 of the test body 110 at a mixing volume ratio of raw material 241 and raw material 341 of 4: 6 A thin film is formed in the region 116 of the test body 110, and an active layer bulk-junctioned with a mixture volume ratio of the raw material 241 and the raw material 341 of 3: 7 is formed.

  As shown in FIG. 6B, the test body 110 thus created is in a state where an active layer formed in a plurality of mixed volume ratios is deposited on one test body 110. Then, an electrode is connected to each of the regions 111 to 116, masking a region unnecessary for investigating the solar cell characteristics, and repeating the procedure of irradiating only the region where the solar cell properties are to be examined, thereby repeating each region 111. The solar cell characteristics at ˜116 can be examined sequentially.

  According to this method, the mixing volume ratio of the raw material 241 and the raw material 341 that maximizes the solar cell characteristics can be efficiently examined as compared with the case where a plurality of specimens with different mixing volume ratios are prepared by spin coating. Can do.

  In the above description, the mixing volume ratio of the raw material 241 and the raw material 341 is described, but it may be defined by the weight ratio of the raw material 241 and the raw material 341. Further, the number of raw materials is not limited to two, but may be three or more. In that case, a raw material gas supply device is added to cope with the problem.

(Planar heterojunction of active layer 24)
Next, a method of forming a thin film by laminating a plurality of types of raw materials as the active layer 24 using the ultrasonic spray mist deposition apparatus 210 will be described.

  First, the substrate 21 on which the hole transport layer 23 is stacked on the uppermost layer is placed on the energy supply device 60. The operation of the ultrasonic transducer 231 on the raw material gas supply device 230 side, the opening control of the carrier gas flow rate control valve 233, and the opening control of the dilution gas flow rate control valve 236 are controlled by a computer (not shown) controlled by programming. The raw material gas injection nozzle 250 is controlled by controlling the operation of the ultrasonic transducer 331 on the raw material gas supply device 330 side, opening control of the carrier gas flow control valve 333, and opening control of the dilution gas flow control valve 336. In this case, only the source gas 343 is discharged from the opening 253 to the surface of the substrate 21. At this time, the energy supply device 60 moves a predetermined distance in the horizontal direction over a predetermined time, so that the misted raw material gas 343 is sprayed and has a predetermined thickness as shown in FIG. The raw material 341 having the above is laminated.

  Subsequently, the operation of the ultrasonic vibrator 231 on the source gas supply device 230 side, the opening control of the carrier gas flow rate control valve 233, and the opening control of the dilution gas flow rate control valve 236 are controlled by a computer that is controlled by programming. By controlling the operation of the ultrasonic vibrator 331 on the source gas supply device 330 side, the opening control of the carrier gas flow rate control valve 333, and the opening control of the dilution gas flow rate control valve 336, the source gas ejection nozzle 250 Only the source gas 243 is discharged from the opening 253 to the surface of the substrate 21. At this time, the energy supply device 60 moves a predetermined distance in the horizontal direction over a predetermined time, so that the mist-formed source gas 243 is sprayed and has a predetermined thickness as shown in FIG. The raw material 241 is stacked.

  By repeating the above procedure, as shown in FIG. 7, a plurality of raw materials 341 and raw materials 241 having a predetermined thickness can be alternately stacked to form a planar heterojunction active layer 24.

  In this method, since the active layer 24 is formed into a thin film using the raw material 341 and the raw material 241 that are misted by ultrasonic vibration, a very thin layer of the raw material 341 and many layers of the raw material 241 are alternately deposited. It becomes possible.

  In the above description, the single source gas ejection nozzle 250 corresponding to the two source gas supply devices 230 and 330 has been described as one. However, the present invention is not limited to this, and the source materials corresponding to the two source gas supply devices 230 and 330, respectively. It is good also as a structure which provided the gas ejection nozzle separately.

(Outline of this embodiment)
As described above, the method for manufacturing the solar cell 20 according to the first embodiment forms the transparent electrode film 22 on the substrate 21 and the hole transport layer 23 on the transparent electrode film 22. A hole transport layer forming step, an active layer forming step of forming an active layer 24 on the hole transport layer 23, an electron transport layer forming step of forming an electron transport layer 25 on the active layer 24, and an electron transport layer 25 An electrode layer forming step of forming an electrode layer 26, comprising: at least one of a transparent electrode film 22, a hole transport layer 23, an active layer 24, and an electron transport layer 25; A thin film is formed by depositing the raw material 41 misted by ultrasonic vibration.

  According to the above manufacturing method, a thin film is formed by depositing at least one of the transparent electrode film 22, the hole transport layer 23, the active layer 24, and the electron transport layer 25 with the raw material misted by ultrasonic vibration. Therefore, it is not necessary to ensure a long drying time as in the dipping method, and time loss due to the photolithography process and the cost of resist and the like are not increased as in the spin coating method. In addition, since the raw material 41 misted by ultrasonic vibration has a smaller particle size than the raw material sprayed by the spray coating method, the raw material can reach the details of the patterning edge, which is difficult by the spray coating method. Complicated patterning is possible. Furthermore, it is possible to form a film in a complicated shape having irregularities on the surface, which is difficult with the ink jet method. Therefore, it is possible to manufacture the solar cell 20 more efficiently in all of time efficiency, material efficiency, patterning definition, hybrid film formation, and film structure control than before.

  Further, in the method for manufacturing the solar cell 20 according to the first embodiment, when the substrate 21 is heated and the misted material 41 is deposited, the material 41 is subjected to heat treatment via the heated substrate 21. ing.

  According to said manufacturing method, the raw material 41 made into mist with the heat | fever of the heated board | substrate 21 is heat-processed. Thereby, a chemical reaction by thermal decomposition can be caused in the raw material 41 to form a thin film on the substrate 21, so that a high-purity thin film can be formed and the covering property is improved.

  Further, in the hole transport layer forming step of the method for manufacturing the solar cell 20 according to the first embodiment, the misted raw material 41 used when forming the hole transport layer 23 is obtained by diluting the transparent conductive polymer stock solution with water. It is a thing.

  According to the manufacturing method described above, the material efficiency is further improved because only a small amount of the transparent conductive polymer stock solution is used as it is. Moreover, since a part of raw material is comprised with water, it is safe when handling.

  Moreover, the solar cell 20 which concerns on 1st Embodiment is manufactured by the process including the manufacturing method of the solar cell 20 which concerns on this embodiment.

  According to the above configuration, at least one layer of the transparent electrode film 22, the hole transport layer 23, the active layer 24, and the electron transport layer 25 is formed into a thin film by depositing the raw material 41 misted by ultrasonic vibration. Therefore, it is possible to provide the solar cell 20 that is more efficient in all of time efficiency, material efficiency, patterning definition, hybrid film formation, and film structure control than before.

  Moreover, the manufacturing method of the solar cell according to the second embodiment includes a transparent electrode film forming step of forming the transparent electrode film 22 on the substrate 21 and a hole transport layer forming of forming the hole transport layer 23 on the transparent electrode film 22. An active layer forming step for forming an active layer 24 on the hole transport layer 23; an electron transport layer forming step for forming an electron transport layer 25 on the active layer 24; and an electrode layer 26 on the electron transport layer 25. Forming at least an active layer 24 by depositing a raw material 241 and a raw material 341 (a plurality of types of raw materials) that have been misted by ultrasonic vibration. Is performed separately for each of the raw material 241 and the raw material 341 constituting the active layer 24.

  According to the above manufacturing method, when the active layer 24 is formed into a thin film by depositing the raw material 241 and the raw material 341 (plural types of raw materials) misted by ultrasonic vibration, This can be performed separately for each of the raw material 241 and the raw material 341 to be configured. For this reason, the active layer 24 can be formed into a thin film from the raw material 241 and the raw material 341 that have been made mist through the separate raw material gas supply device 230 and the raw material gas supply device 330. For example, the active layer 24 in which the raw material 241 and the raw material 341 are mixed at a desired ratio can be formed into a thin film by changing the ratio of the raw material 241 and the raw material 341 deposited as the active layer 24. Further, for example, by changing the timing of misting the raw material 241 and the raw material 341 to be deposited as the active layer 24, the active layer 24 in which the raw material 241 and the raw material 341 are stacked in a desired order can be formed into a thin film.

  The embodiments of the present invention have been described above, but only specific examples have been illustrated, and the present invention is not particularly limited. Specific configurations and the like can be appropriately changed in design. Further, the actions and effects described in the embodiments of the present invention only list the most preferable actions and effects resulting from the present invention, and the actions and effects according to the present invention are described in the embodiments of the present invention. It is not limited to things.

  The present invention can be used for the production of solar cells.

DESCRIPTION OF SYMBOLS 10 Ultrasonic spray mist deposition apparatus 20 Solar cell 21 Substrate 22 Transparent electrode film 23 Hole transport layer 24 Active layer 25 Electron transport layer 26 Electrode layer 30 Raw material gas supply device 41 Raw material 43 Raw material gas 50 Raw material gas ejection nozzle 60 Energy supply device

Claims (5)

A transparent electrode film forming step of forming a transparent electrode film on the substrate;
A hole transport layer forming step of forming a hole transport layer on the transparent electrode film; and
An active layer forming step of forming an active layer on the hole transport layer;
An electron transport layer forming step of forming an electron transport layer on the active layer;
An electrode layer forming step of forming an electrode layer on the electron transport layer;
A method for producing a solar cell having
At least one of the transparent electrode film, the hole transport layer, the active layer, and the electron transport layer is formed into a thin film by depositing a raw material misted by ultrasonic vibration. Manufacturing method.   2. The method of manufacturing a solar cell according to claim 1, wherein when the substrate is heated and the misted material is deposited, the material is subjected to heat treatment through the heated substrate.   The said mist-formed raw material used when forming the said hole transport layer in the said hole transport layer formation process is what diluted the transparent conductive polymer stock solution with water, The feature is 1 or 2. The manufacturing method of the solar cell of description.   The solar cell manufactured by the process including the manufacturing method of the solar cell of Claims 1 thru | or 3. A transparent electrode film forming step of forming a transparent electrode film on the substrate;
A hole transport layer forming step of forming a hole transport layer on the transparent electrode film; and
An active layer forming step of forming an active layer on the hole transport layer;
An electron transport layer forming step of forming an electron transport layer on the active layer;
An electrode layer forming step of forming an electrode layer on the electron transport layer;
A method for producing a solar cell having
At least the active layer is formed into a thin film by depositing a plurality of types of raw materials misted by ultrasonic vibration,
The method of manufacturing a solar cell, wherein the mist formation is performed separately for each of the plurality of types of raw materials constituting the active layer.