JP2014157922A - Method for manufacturing solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a solar cell, by which a solar cell having a CIS-based or CZTS-based light absorption layer can be manufactured with high productivity.SOLUTION: In a method for manufacturing a solar cell, at least an electrode layer and a metal precursor film are formed on a substrate, and then subjected to heat treatment in an atmosphere having at least a selenium source to form a CIS-based or CZTS-based light absorption layer. In the method, a long flexible substrate 21 is used as the substrate, the substrate 21 is drawn form a substrate roll 20 in which the substrate 21 is wound in a roll, an electrode layer and a metal precursor film are formed on the surface of the substrate 21 on a conveyance path of the substrate 21, then the substrate 21 is cut off from the substrate roll 20 and bent so that substrate faces are not brought into contact each other, and, while being held with a jig after being bent, the substrate 21 is disposed in an atmosphere having at least a selenium source to be subjected to the heat treatment.

Description

  The present invention relates to a method for manufacturing a solar cell having a CIS-based or CZTS-based light absorption layer.

CIS-based light absorption layer formed of a semiconductor compound such as CuInSe ₂ , CuGaSe ₂ , Cu (In, Ga) Se ₂ , Cu (In, Ga) (S, Se) ₂ , Cu ₂ ZnSnSe ₄ , Cu ₂ A CZTS-based light absorption layer formed of a semiconductor compound such as ZnSn (S, Se) ₄ has been reported to obtain high photoelectric conversion efficiency, and a solar cell having a CIS-based or CZTS-based light absorption layer. Development is underway.

  In Patent Document 1, a CIS-based film is formed at a substrate temperature of 500 ° C. or higher while a long substrate is conveyed in the longitudinal direction, and then Se (selenium) is supplied to the substrate under predetermined conditions. It is disclosed to produce a CIS-based membrane by cooling. And paragraph number 0036 exemplifies a multi-source simultaneous vapor deposition method, a selenization method, a sputtering method, a hybrid sputtering method, and a mechanochemical process method as an example of a method for forming a CIS-based film.

  Thus, as a method for forming a CIS-based or CZTS-based light absorption layer, a multi-source co-evaporation method or a selenization method is widely used.

  In the multi-source co-evaporation method, it can be formed by co-evaporating raw materials containing the constituent elements of the light absorption layer. When a CIS-based or CZTS-based light absorption layer is formed by the multi-source simultaneous vapor deposition method, there is an advantage that the film composition can be controlled by arranging the evaporation source and controlling the evaporation amount. Further, a Roll to Roll process can be applied, which is suitable for manufacturing a solar cell using a flexible substrate. However, there were the following problems. That is, the multi-component simultaneous vapor deposition method has a problem that the film composition and the film thickness distribution are likely to occur in the width direction of the substrate. Although the above distribution can be reduced by increasing the number of vapor deposition sources installed in the width direction, increasing the number of vapor deposition sources leads to an increase in apparatus cost and apparatus maintenance man-hours. In addition, in order to form a high-quality CIS-based or CZTS-based light absorption layer, there is a limit to the film forming speed. Therefore, in order to increase the production amount, it is necessary to increase the size of the film forming apparatus, which causes an increase in apparatus cost. In addition, there is a problem in that troubles such as clogging of the evaporation source crucible and variations in the amount of evaporation are likely to occur, and apparatus maintenance is troublesome.

On the other hand, in the case of a solar cell using a glass substrate, as described in Patent Documents 2 and 3, for example, a selenization method is widely used. In the selenization method, a metal precursor film is formed on the surface of the electrode layer on the substrate by sputtering or the like, and then heat-treated in an atmosphere having a selenium source such as H ₂ Se gas, and CIS or CZTS light An absorption layer is formed. The selenization method has an advantage that the in-plane distribution of the light absorption layer can be reduced as compared to the multi-source simultaneous deposition method because the metal precursor film can be formed by a sputtering method or the like.

  However, the heat treatment of the metal precursor film requires about 60 to 240 minutes including the heating and cooling time. For this reason, when the selenization method is applied to the Roll to Roll process, since the transport must be stopped during the heat treatment of the metal precursor film, the productivity is significantly reduced. If a large heat treatment apparatus is used, heat treatment can be performed while being transported, but the necessary apparatus size becomes large and is not realistic.

JP 2012-15328 A JP 2009-135299 A JP 2009-283560 A

  An object of this invention is to provide the manufacturing method of the solar cell which can manufacture the solar cell which has a CIS type or CZTS type light absorption layer with sufficient productivity.

  In order to achieve the above object, according to the present invention, after forming at least an electrode layer and a metal precursor film on a substrate, a heat treatment is performed in an atmosphere having at least a selenium source to obtain a CIS-based or CZTS-based light. In the method of manufacturing a solar cell for forming an absorption layer, a long flexible substrate is used as the substrate, the substrate is drawn out from a substrate roll obtained by winding the substrate into a roll shape, and the substrate is transported on the transport path. Forming an electrode layer and a metal precursor film on the surface of the substrate, then separating the substrate from the substrate roll, bending the substrate surfaces so as not to contact each other, and holding the jig at least in this state. The heat treatment is performed in an atmosphere having a selenium source.

  In the method for producing a solar cell of the present invention, after the heat treatment, the substrate is held in the jig, and immersed in a solution containing at least one element selected from Cd, Zn, and In. Thus, it is preferable to form a buffer layer containing at least one element selected from Cd, Zn, and In on the light absorption layer.

  In the method for manufacturing a solar cell according to the present invention, a plurality of rolls or holding jigs are used as the jig, and the substrate is bent in a zigzag shape while being held on the rolls or the holding jig, and held by the jig. It is preferable to make it.

  In the method for manufacturing a solar cell according to the present invention, the metal precursor film is a metal film containing at least Cu and In and / or Ga, or a metal film containing at least Cu, Zn, and Sn. Is preferred.

  In the method for producing a solar cell of the present invention, it is preferable that the heat treatment is performed in an atmosphere having at least a selenium source and then performed in an atmosphere having at least a sulfur source.

  According to the present invention, the substrate is pulled out from the substrate roll, and the electrode layer and the metal precursor film are formed on the surface of the substrate on the transport path. Therefore, in the Roll to Roll process, the electrode layer and the metal precursor are formed on the substrate. A film can be formed. Moreover, since the heat treatment of the metal precursor film is performed separately from the substrate roll, the steps after the heat treatment are separated from the Roll to Roll process. For this reason, the metal precursor film can be continuously formed even during the heat treatment of the metal precursor film. Then, the heat treatment of the metal precursor film is performed by bending the substrate on which the metal precursor film is formed so that the substrate surfaces do not come into contact with each other and holding the jig in an atmosphere having at least a selenium source. Therefore, the substrate on which the metal precursor film is formed can be efficiently accommodated in the heat treatment apparatus, and a longer substrate can be heat treated in a large amount with a smaller heat treatment apparatus. Furthermore, since the substrate surfaces are not in contact with each other, the reaction gas can be sufficiently brought into contact with the metal precursor film and heat treatment can be performed, and the yield of products can be increased.

It is the schematic which shows one Embodiment of a solar cell. It is process drawing of one Embodiment of the holding method of a board | substrate. It is process drawing of one Embodiment of the holding method of a board | substrate. It is process drawing of one Embodiment of the holding method of a board | substrate. It is process drawing of other embodiment of the holding method of a board | substrate, Comprising: (a) is a top view, (b) is a side view. It is process drawing of other embodiment of the holding method of a board | substrate. It is process drawing of other embodiment of the holding method of a board | substrate. It is a schematic block diagram of the heat processing apparatus. FIG. 9 is a plan cross-sectional view of the heat treatment apparatus of FIG. 8, and is a schematic view showing a state in which a jig holding substrate is housed inside. FIG. 9 is a plan cross-sectional view of the heat treatment apparatus of FIG. 8, and is a schematic view showing a state in which a jig holding substrate is housed inside. It is the schematic which shows the process of immersing a jig holding substrate in a solution and forming a buffer layer by a solution growth method. It is a figure which shows the solar cell characteristic (current-voltage curve) of the solar cell obtained in the Example.

  First, an embodiment of a solar cell manufactured according to the present invention will be described with reference to FIG.

  A solar cell 10 shown in FIG. 1 is a solar cell having a substrate structure, and a back electrode layer 2, a light absorption layer 3, a buffer layer 4, and a transparent electrode layer 5 are laminated on a substrate 1.

  The substrate 1 is not particularly limited as long as it has flexibility. For example, a plastic film substrate, a metal substrate, etc. are mentioned. Examples of the plastic film substrate include a polyimide film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polyethersulfone film, an acrylic film, and an aramid film. Examples of the metal substrate include a stainless steel thin plate and an aluminum thin plate. In addition, when arrange | positioning the board | substrate 1 in the light-incidence side, the board | substrate 1 needs to be comprised with the material which has transparency.

The substrate 1 may be formed with a barrier layer, an adhesion layer, and the like. The barrier layer is not particularly _{limited, Si 3 N 4, TiN,} CrN, Al 2 O 3, SiO 2 and the like. Although there is no limitation in particular as an adhesion layer, Ti, Cr, W, etc. are mentioned.

  In the back electrode layer 2, it is preferable that at least the layer located on the light absorption layer 3 side contains Mo. According to this, corrosion resistance to Se or the like can be obtained, and corrosion degradation of the back electrode layer 2 can be prevented when the light absorption layer 3 is formed.

  The back electrode layer 2 containing Mo (hereinafter referred to as Mo layer) preferably has a film thickness of 100 to 1000 nm, more preferably 400 to 600 nm. If the Mo layer is thin, the corrosion resistance to Se or the like may be insufficient. If the film thickness of the Mo layer is large, productivity will be deteriorated, for example, it takes time to form. Furthermore, peeling tends to occur easily depending on the stress difference with the substrate.

  The back electrode layer 2 may be a single layer of Mo, or a laminated body of a metal layer (hereinafter also referred to as a low resistance metal layer) containing a conductive material having an electric resistivity lower than that of Mo and a Mo layer. It may be configured.

As the conductive material having an electrical resistivity smaller than that of Mo, a conductive material having an electrical resistivity at 20 ° C. of less than 5.3 × 10 ⁻⁸ Ω · m is preferable. By carrying out like this, the electrical resistivity of the back surface electrode layer 2 can be effectively made smaller than the case where it comprises Mo alone. Specific examples of the conductive material having an electric resistivity lower than that of Mo include Ag, Cu, Au, Al, Mg, W, and alloys thereof, and one or more of these can be preferably used.

  The metal layer constituting the back electrode layer may contain an alkali metal such as Na or K. According to this, Na or the like necessary for increasing the efficiency of the CIS solar cell is supplied from the back electrode layer 2 to the light absorption layer 3.

The light absorption layer 3 is a CIS-based or CZTS-based light absorption layer. In the present invention, the CIS-based light absorption layer is a light absorption layer formed of a semiconductor compound such as CuInSe ₂ , CuGaSe ₂ , Cu (In, Ga) Se ₂ , or Cu (In, Ga) (S, Se) _2. Means. The CZTS-based light absorption layer means a light absorption layer formed of a semiconductor compound such as Cu ₂ ZnSnSe ₄ or Cu ₂ ZnSn (S, Se) ₄ .

  Although the film thickness of the light absorption layer 3 changes with kinds, about 1.5-2.5 micrometers is preferable.

The buffer layer 4 is composed of an n-type transparent conductive film having a wide forbidden band. Preferably, it is a compound containing at least one element selected from Cd, Zn, and In. Specific _{compounds, CdS, ZnO, ZnS, Zn} (OH) 2, ZnInSe 2, ZnMgO, In 2 O 3, In 2 S 3 , and the like.

The transparent electrode layer 5 is made of a transparent conductive material such as ZnO, SnO ₂ , In ₂ O ₃ , or ITO.

  Next, the method for manufacturing the solar cell of the present invention will be described using the method for manufacturing the solar cell shown in FIG. 1 as an example.

  In the present invention, a long flexible substrate is used as the substrate. The substrate may be pretreated as necessary. Pre-treatment includes cleaning with water, 2-propanol, etc., heating the substrate to remove water or organic matter adsorbed on the substrate, heating while applying tension to the substrate, and reducing the residual stress of the substrate. An annealing treatment to reduce is mentioned.

  In the present invention, the substrate is wound into a roll to obtain a substrate roll. Then, the substrate is pulled out from the substrate roll, and a back electrode layer and a metal precursor film are formed on the surface of the substrate on the substrate transport path.

  The back electrode layer and the metal precursor film can be formed by the following methods (1) and (2).

(1) A method of drawing a substrate from a substrate roll and continuously forming a back electrode layer and a metal precursor film on the surface of the substrate on the transport path.
(2) The substrate is pulled out from the substrate roll, a back electrode layer is formed on the substrate surface on the transport path, and the substrate on which the back electrode layer is formed is wound into a roll to obtain a substrate roll. And the method of drawing out the board | substrate with which the back surface electrode layer was formed from a substrate roll, and forming a metal precursor film | membrane on a back surface electrode layer on the conveyance path | route.

  A back surface electrode layer can be formed by methods, such as a sputtering method and a vapor deposition method, using the electrode material containing Mo, for example. In addition, a low-resistance metal layer is formed using an electrode material containing a conductive material selected from Ag, Cu, Au, Al, Mg, W and alloys thereof, and then Mo is contained on the low-resistance metal layer. By forming the Mo layer using the electrode material, a back electrode layer in which the Mo layer is laminated on the low resistance metal layer can be formed. You may make an electrode material contain alkali metals, such as Na and K required for the high efficiency of a CIS type solar cell.

  The method for forming the metal precursor film is not particularly limited. Examples include sputtering, vapor deposition, plating, and nanoparticle printing. Among these, the sputtering method is preferable because a metal film having a small in-plane distribution can be efficiently formed.

  The material of the metal precursor film varies depending on the type of the light absorption layer. In the case of forming a CIS-based light absorption layer, a metal film containing at least Cu and In and / or Ga is formed as a metal precursor film. When a CZTS-based light absorption layer is formed, a metal film including at least Cu, Zn, and Sn is formed as the metal precursor film.

  In the present invention, after the metal precursor film is formed in this way, the substrate is separated from the substrate roll and bent so that the substrate surfaces do not come into contact with each other and held on the jig.

  The substrate may be bent and held by a jig so that the substrate surfaces do not contact each other, and the holding method is not particularly limited.

  One embodiment of a substrate holding method will be described with reference to FIGS.

  As shown in FIG. 2, first, the tip of the substrate 21 drawn out from the substrate roll 20 is fixed to a roll-shaped jig 31. There is no limitation in particular as a fixing method to a jig | tool. For example, the substrate fixing plate may be fixed with a screw or attached to a jig with a heat-resistant tape.

  Next, roll-shaped jigs 32 to 37 are alternately arranged on the upper and lower sides of the substrate 21. In this embodiment, three jigs are arranged on the upper surface side and the lower surface side of the substrate 21, but the number of jigs is not particularly limited.

  Next, the jigs 32 to 37 are moved from the substrate roll 20 toward the substrate 21 in order from the farthest.

  Then, at the portion indicated by arrow A in FIG. 3, the substrate 21 is cut and separated from the substrate roll 20 and fixed to a jig.

  In this way, as shown in FIG. 4, the substrate 21 can be bent and zigzag while being stretched and held on a jig.

  Depending on the length of the substrate 21 and the number of jigs, the substrate 21 may be separated from the substrate roll 20 and held on the jig without cutting the substrate 21.

Another embodiment of the substrate holding method will be described with reference to FIGS.
In this embodiment, a pin-shaped holding jig is used as the jig.

  First, as shown in FIGS. 5 (a) and 5 (b), the both sides in the short direction of the front end portion of the substrate 21 drawn out from the substrate roll 20 are stretched by pin-shaped holding jigs 41 and 41. Fix it.

  Next, the both sides in the short direction of the substrate 21 are fixed while being stretched by the pin-shaped holding jigs 42 to 47 at predetermined intervals from the tip portion.

  Next, the jigs 42 to 47 are alternately moved up and down in order from the far side.

  Then, at the portion indicated by arrow A in FIG. 6, the substrate 21 is cut and separated from the substrate roll 20.

  In this way, as shown in FIG. 7, the substrate 21 can be bent and zigzag while being stretched and held on the jig. The holding jig is not limited to a pin-like one, and any clip-type, vacuum chuck mechanism, electrostatic chuck mechanism, or the like that can hold the substrate with the jig can be preferably used.

  In the state of being held by the jig, the distance between the substrate surfaces is preferably 5 to 100 mm, and more preferably 10 to 20 mm. If the distance between the substrate surfaces is too narrow, the reaction gas is difficult to come into contact with the metal precursor film during heat treatment, and an unreacted portion may be generated, resulting in product defects. Moreover, when the space | interval of a substrate surface is too large, when accommodating the board | substrate hold | maintained at the jig | tool in the heat processing apparatus, since accommodation efficiency falls, production efficiency falls.

  Further, the portion of the metal precursor film that is in contact with the jig cannot be used as a product because the reaction does not proceed during the heat treatment. For this reason, it is preferable to select a jig so that the contact area between the jig and the metal precursor film is reduced.

  Moreover, the waste of material is eliminated by designing the jig size and the contact position between the jig and the metal precursor film so that the part of the metal precursor film that contacts the jig matches the cutting position in the product modularization. be able to.

  Next, the substrate held by the jig is introduced into a heat treatment apparatus to perform heat treatment.

  There is no limitation in particular as a heat processing apparatus. A known heat treatment apparatus used in the selenization method can be used.

  An embodiment of the heat treatment apparatus will be described with reference to FIGS.

  As shown in FIG. 8, the heat treatment apparatus 50 is connected to a reaction gas supply line 51 and an exhaust gas line 52. The reactive gas supply line 51 is connected to a reactive gas supply source (not shown). The exhaust gas line 52 is connected to an exhaust gas system (not shown).

  Referring to FIGS. 9 and 10 together, the heat treatment apparatus 50 is provided with an opening / closing door 53. In the heat treatment apparatus 50, a heater 54 and a transport rail 55 are provided. Although not shown, the heat treatment apparatus 50 is provided with various sensors such as a temperature sensor, a pressure sensor, and a reactive gas concentration sensor, and is configured to monitor the internal conditions and adjust the heat treatment conditions. ing.

  In this heat treatment apparatus, as shown in FIG. 9, the opening / closing door 53 is opened, and a substrate 60 (hereinafter referred to as a jig holding substrate) 60 held on a jig is disposed on a transport rail 55. Then, the jig holding substrate 60 arranged on the transport rail 55 is moved along the direction of arrow B in FIG. After placing a predetermined number of jig holding substrates 60 in the heat treatment apparatus 50, the jig holding substrate 60 can be accommodated in the heat treatment apparatus 50 as shown in FIG.

In the heat treatment of the jig holding substrate 60, a selenium-containing gas such as H ₂ Se gas diluted with an inert gas such as nitrogen gas is introduced from the reaction gas supply line 51 into the heat treatment apparatus 50 and has at least a selenium source. Perform in an atmosphere. Further, after the heat treatment in an atmosphere having at least a source of selenium, the interior of the selenium atmosphere end evacuated by a vacuum pump, then, from the reaction gas supply line 51, H ₂ diluted with an inert gas such as nitrogen gas A sulfur-containing gas such as S may be introduced into the heat treatment apparatus 50 and further heat treatment may be performed in an atmosphere having at least a sulfur source. After performing heat treatment in an atmosphere having a selenium source, further heat treatment is performed in an atmosphere having a sulfur source, whereby a CIS-based or CZTS-based light absorption layer having excellent power generation efficiency can be formed.

  The heat treatment conditions in the atmosphere containing the selenium source and the heat treatment conditions in the atmosphere containing the sulfur source differ depending on the type of the metal precursor film and the type of the light absorption layer to be formed.

  As a specific example of the heat treatment conditions in an atmosphere having a selenium source, for example, the substrate temperature is gradually raised from 100 to 200 ° C. to 350 to 550 ° C., and in that state, preferably 10 to 240 minutes. More preferably, a method of holding for 20 to 120 minutes may be mentioned. Moreover, 1-20 mol% is preferable and, as for the molar concentration of selenium of a selenium containing gas, 2-10 mol% is more preferable.

  As a specific example of the heat treatment conditions in an atmosphere having a sulfur source, for example, the substrate temperature is raised to 500 to 650 ° C., preferably 5 to 120 minutes, more preferably 20 to 120 minutes. preferable. Moreover, 1-30 mol% is preferable and, as for the molar concentration of sulfur of sulfur containing gas, 2-20 mol% is more preferable.

  By performing the heat treatment in this manner, the metal precursor film reacts to form a CIS-based or CZTS-based light absorption layer. Note that the upper limit of the substrate temperature during the heat treatment varies depending on the substrate used.

  Next, the jig holding substrate 60 on which the light absorption layer is formed by heat treatment is taken out from the heat treatment apparatus 50, and a buffer layer containing at least one element selected from Cd, Zn and In is formed on the light absorption layer. .

  The method for forming the buffer layer is not particularly limited, and a conventionally known method can be used. For example, solution growth (CBD), vapor deposition, sputtering, atomic deposition (ALD), ionic layer gas reaction (MOCVD), metal organic chemical vapor deposition (MOCVD) : Metal Organic Chemical Vapor Deposition) and the like. Of these, the solution growth method is preferable. In the solution growth method, by immersing the substrate on which the light absorption layer is formed in a solution containing at least one element selected from Cd, Zn, and In, at least selected from Cd, Zn, and In on the light absorption layer. A buffer layer containing a kind of element can be formed. As described above, the solution growth method has a simple apparatus configuration, can be formed at a low cost, has a high adhesion, and has a surface coating property on the light absorption layer. Moreover, as shown in FIG. 11, since the jig holding substrate 60 can be immersed in the solution 72 in the bathtub 71 without removing the substrate from the jig, the substrate after the heat treatment is used as the jig. It is possible to eliminate the trouble of removing and rewinding. Furthermore, since it can process in large quantities at once, it is excellent in productivity.

  Next, a transparent electrode layer is formed on the buffer layer by a method such as sputtering or vapor deposition. When the buffer layer is formed by dipping in a solution while being held by a jig, a transparent electrode layer forming step is performed after removing the substrate from the jig.

  In this way, the substrate type solar cell 10 shown in FIG. 1 can be manufactured.

  The method for manufacturing the solar cell according to the present invention has been described above by taking the substrate type solar cell as an example. However, the method for manufacturing the solar cell according to the present invention can be applied to a super straight type solar cell or a double-sided light receiving solar cell. It can also be applied to solar cells other than the substrate type such as a battery.

The polyimide film was pulled out from the substrate roll on which the polyimide film having a length of 1000 m was wound, and a Mo film was formed to 500 nm by sputtering on the transport path to form an electrode layer.
Next, a metal precursor film made of a metal film containing Cu, In, and Ga was formed on the electrode layer by a sputtering method to a thickness of 1.5 μm.
Next, the polyimide film on which the metal precursor film was formed was fixed to a jig according to the procedure shown in FIGS.
Next, the polyimide film fixed to the jig is accommodated in a heat treatment apparatus, and H ₂ Se gas diluted to 10% with nitrogen gas is supplied into the apparatus, and the substrate temperature is gradually raised from 200 ° C. to 500 ° C. Then, heat treatment was performed by holding at 500 ° C. for 2 hours to form a light absorption layer made of a semiconductor compound made of Cu (In, Ga) Se ₂ having a thickness of 2.0 μm.
Next, the polyimide film on which the light absorption layer is formed while being fixed to the jig is placed in an aqueous solution containing a metal salt (CdSO ₄ ), a sulfide (thiourea), and a complexing agent (ammonia). A buffer layer made of CdS was formed to a thickness of about 50 nm by a solution growth method by immersion for 10 to 15 minutes at ˜70 ° C.
Next, the polyimide film was removed from the jig, and by sputtering, ZnO: 50-100 nm was formed as a high-resistance buffer layer, and ZnO: Al was formed 200-400 nm as a transparent conductive film.
Thus, the small area sample for the evaluation test of a CIS type solar cell was manufactured.

This solar cell was irradiated with light of AM 1.5 and 100 mW / cm ² by a solar simulator to obtain a current-voltage curve. FIG. 12 shows a current-voltage curve. Further, conversion efficiency (η), short circuit current (Jsc), open circuit voltage (Voc), and fill factor (FF) were determined from the current-voltage curve. The conversion efficiency was 12.3%, the short circuit current was 29.4 mA / cm ² , the open circuit voltage was 0.592 V, and the fill factor was 0.704.

  By the method of the present invention, a solar cell with good power generation characteristics could be manufactured.

1: Substrate 2: Back electrode layer 3: Light absorption layer 4: Buffer layer 5: Transparent electrode layer 10: Solar cell 20: Substrate roll 21: Substrate 31-37, 41-47: Jig 50: Heat treatment device 51: Reaction Gas supply line 52: exhaust gas line 53: open / close door 54: heater 55: transport rail 60: jig holding substrate 71: bathtub 72: solution

Claims (5)

In a method for manufacturing a solar cell in which at least an electrode layer and a metal precursor film are formed on a substrate, and then heat treatment is performed in an atmosphere having at least a selenium source to form a CIS-based or CZTS-based light absorption layer. ,
A long flexible substrate is used as the substrate, the substrate is pulled out from a substrate roll obtained by winding the substrate in a roll shape, and an electrode layer and a metal precursor film are formed on the surface of the substrate on the substrate transport path. Then, the substrate is separated from the substrate roll, bent so that the substrate surfaces do not come into contact with each other, held in a jig, and placed in an atmosphere having at least a selenium source in that state. The manufacturing method of the solar cell characterized by performing.   After the heat treatment, the substrate is held in the jig, immersed in a solution containing at least one element selected from Cd, Zn and In, and selected from Cd, Zn and In by a solution growth method. The method for manufacturing a solar cell according to claim 1, wherein a buffer layer containing at least one element is formed on the light absorption layer.   The sun according to claim 1 or 2, wherein a plurality of rolls or holding jigs are used as the jig, the substrate is bent in a zigzag shape while being stretched by the rolls or holding jigs, and held by the jig. Battery manufacturing method.   The metal precursor film is a metal film containing at least Cu and In and / or Ga, or a metal film containing at least Cu, Zn, and Sn. The manufacturing method of the solar cell of description.   The method for manufacturing a solar cell according to claim 1, wherein the heat treatment is performed in an atmosphere having at least a sulfur source after being performed in an atmosphere having at least a selenium source.