Manufacturing process of a solar cell

Abstract

Methods for manufacturing a solar cell, comprising the steps: (a) Producing a silicon substrate (4) having one major surface and another major surface, (b) Nebulizing a solution (14) containing a metal element, (c) Spraying the nebulized solution onto a major surface of the silicon substrate under non-vacuum conditions to form a passivation film (5) made of a metal oxide film on a major surface of the silicon substrate, (d) Manufacturing a solar cell structure using the silicon substrate with the passivation film formed on it, and (e) Performing a light irradiation process in which an interface between the passivation film and the silicon substrate is irradiated with a given light (21), wherein step (d) comprises: (d-1) a step of forming one electrode and another electrode on a major surface side and another major surface side of the silicon substrate, and step (d-1) comprises a firing operation for firing at a given firing temperature, and the step (e) is carried out after the step (d), wherein where the light provided in step (e) is light whose photon energy is 1.1 eV or more, artificial solar light with AM of 1.5 or ultraviolet light with a wavelength of 365 nm.

Description

Technical area

[0001] The present invention relates to a method for manufacturing a solar cell and, more particularly, to a method for forming a passivation film on a silicon substrate. State of the art

[0002] In the field of crystalline silicon solar cells, silicon substrates have been reduced in thickness to reduce the amount of silicon consumed and improve the conversion efficiency of silicon substrates. Unfortunately, thinner silicon substrates have significantly lower conversion efficiency. One reason for this is that a large number of defects in the front surface of the silicon substrate exhibit conductivity, which primarily causes a reduction in the lifetime of minority carriers (e.g., electrons in a p-type substrate) generated by light irradiation. Thus, reducing the loss of minority carriers may potentially improve the conversion efficiency of solar cells.

[0003] To control the reduction in carrier lifetime, a passivation film is generally formed on the surface of a silicon substrate. An aluminum oxide film, one of a variety of passivation films, has attracted attention due to its superior passivation effect (lifetime regulating function) on p-type silicon substrates.

[0004] Aluminum oxide films have negative fixed charges and are known to produce the passivation effect resulting from the field effect caused by the fixed charges. That is, if a passivation film made of the aluminum oxide film with negative fixed charges is formed on the front surface of the p-type silicon substrate, the diffusion of electrons, which are minority carriers, into the substrate surface can be regulated, thereby preventing carrier loss.

[0005] For example, WO 2015 / 004767 A1 discloses, as a method for manufacturing a solar cell, a method in which a misting method is used as a method for forming the aluminum oxide film, which is the passivation film, on the p-type silicon substrate. This manufacturing method achieves the effect of forming a passivation film without damaging a silicon substrate with a high degree of production efficiency and a lower manufacturing cost by forming the passivation film by the misting method.

[0006] Further related techniques can be found in WO 2015 / 004767 A1, which is directed to a method for producing a solar cell, in US 2013 / 0101867 A1, which describes a method for producing a metal oxide layer, and in US 2014 / 0242741 A1, which describes a material for producing a passivation layer for a semiconductor substrate. Summary of the inventionProblems to be solved by the invention

[0007] However, when the passivation film is formed by the nebulization method, there is a problem that the film quality may be lower than in the case where the passivation film is formed by an ALD (Atomic Layer Deposition) method, Plasma-CVD (Chemical Vapor Deposition) method, or the like.

[0008] In the present invention, an object is to solve a problem as described above and to provide a method for manufacturing a solar cell that enables the formation of a passivation film with high film quality without damaging a substrate, while at the same time achieving a high degree of production efficiency at a lower manufacturing cost. Means to solve the problems

[0009] The above object is achieved by a method for producing a solar cell as defined by the appended independent claim 1. The respective dependent claims describe optional features and preferred embodiments.

[0010] A method for manufacturing a solar cell according to the present invention comprises the steps of: (a) preparing a silicon substrate (4) having one main surface and another main surface, (b) misting a solution (14) containing a metal element, (c) spraying the misted solution onto a main surface of the silicon substrate under non-vacuum to form a passivation film (5) made of a metal oxide film on a main surface of the silicon substrate, (d) manufacturing a solar cell structure using the silicon substrate having the passivation film formed thereon, and (e) performing light irradiation processing in which an interface between the passivation film and the silicon substrate is formed with a givengiven) light (21), wherein the step (d) comprises: (d-1) a step of forming an electrode and another electrode on one main surface side and another main surface side of the silicon substrate, and the step (d-1) comprises a firing processing for firing at a given firing temperature, and the step (e) is performed after the step (d), wherein the light provided in the step (e) comprises a light whose photon energy is 1.1 eV or more, artificial solar light with AM of 1.5 or ultraviolet light with a wavelength of 365 nm. Effects of the invention

[0011] According to the method for manufacturing a solar cell of the present invention, a passivation film made of a metal oxide film is formed on a main surface of the silicon substrate by performing steps (b) and (c), whereby a passivation film can be formed without damaging a silicon substrate, with a high degree of production efficiency at a lower manufacturing cost.

[0012] Furthermore, the present invention according to claim 1 enables obtaining a high-quality passivation film that improves a lifetime by the light irradiation processing according to step (e).

[0013] These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. Short description of the characters Fig. 1 is a sectional view showing a solar cell structure fabricated in one embodiment. Fig. 2 is an explanatory diagram showing a configuration of a film forming apparatus for implementing a film forming method of a passivation film in an embodiment. Fig. 3 is a sectional view showing a situation of light irradiation processing by ultraviolet light of Embodiment 1. Fig. 4 is a graph showing the effect of a method for manufacturing a solar cell of Embodiment 1. Fig. 5 is a graph showing the effect of a method for manufacturing a solar cell of Embodiment 2. Description of the embodiments (solar cell structure)

[0014] Fig. 1 is a sectional view showing a solar cell structure manufactured by a method for manufacturing a solar cell according to the present embodiment (Embodiment 1, Embodiment 2).

[0015] As shown in Fig. 1, a silicon layer 3 (hereinafter referred to as "n-type silicon layer 3") having n-type conductivity is formed on the surface (the other main surface) of a silicon substrate 4 (hereinafter referred to as "p-type silicon substrate 4") having p-type conductivity. In addition, in Fig. 1, the solar cell is shown in such a way that the front side of the p-type silicon substrate 4 is an upper surface and the back side is a lower surface.

[0016] A transparent front-surface passivation film 2 is formed on the front surface of the n-type silicon layer 3. For example, a silicon oxide film, a silicon nitride film, an aluminum oxide film, or a laminated film including these films can be considered as the front-surface passivation film 2. Then, a front-surface electrode 1, which penetrates through a portion of the front-surface passivation film 2, is selectively formed on the front surface of the n-type silicon layer 3, thereby electrically connecting the front surface electrode 1 to the n-type silicon layer 3.

[0017] Furthermore, a backside passivation film 5 is formed on the backside (one main surface) of the p-type silicon substrate 4. An aluminum oxide film or a laminated film of an aluminum oxide film and a silicon nitride film is used as the backside passivation film 5. Furthermore, a backside electrode 6 penetrates a part of the backside passivation film 5 and is formed directly on the backside of the p-type silicon substrate 4 and over the backside of the backside passivation film 5. Accordingly, the backside electrode 6 is electrically connected to the p-type silicon substrate 4.

[0018] In the Fig. 1, the light incident from the front passivation film 2 side reaches a pn junction between the n-type silicon layer 3 and the p-type silicon substrate 4 to generate carriers, so that current is generated, and then, the generated electricity is extracted through the electrodes 1 and 6.

[0019] As described above, the passivation films 2 and 5 are formed to regulate the reduction of carrier lifetime. That is, a large number of defects (such as lattice defects) occur in the front surface of the n-type silicon layer 3 or the back surface of the p-type silicon substrate 4, and thus minority carriers generated by light irradiation are recombined by the defects. Therefore, the front-side passivation film 2 and the back-side passivation film 5 are formed on the front surface of the n-type silicon layer 3 and the back surface of the p-type silicon substrate 4 to regulate the recombination of carriers, thereby improving the carrier lifetime.

[0020] The present invention relates to improving the film quality of the backside passivation film 5 formed on the backside of the p-type silicon substrate 4. Hereinafter, the present invention will be described in detail with reference to the figures illustrating embodiments thereof. <Ausführungsform 1>

[0021] Fig. 2 is an explanatory diagram showing a schematic configuration of a film forming apparatus for implementing a film forming method of a backside passivation film 5 according to the present embodiment (Embodiment 1, Embodiment 2).

[0022] As in Fig. 2, the film forming apparatus used in the film forming method of the present embodiment includes a reaction vessel 11, a heater 13 for heating the reaction vessel 11, a solution vessel 15 for containing a (material) solution 14, and a mist forming apparatus 16 for misting the solution 14 in the solution vessel 15.

[0023] In such a configuration, a solution 14, which has been nebulized by a mist generator 16, is sprayed onto the back surface of the p-type silicon substrate 4 in the reaction vessel 11 through a channel L1, whereby the back surface passivation film 5 made of the aluminum oxide film can be formed on the back surface of the p-type silicon substrate 4. In this case, the p-type silicon substrate 4 is arranged on the heater 13 in the reaction vessel 11 in such a manner that the back surface is an upper surface and the front surface is a lower surface.

[0024] That is, while the p-type silicon substrate 4 is placed on the heating element 13, mist (the liquid solution 14 having a small particle diameter) is supplied into the reaction vessel 11 at atmospheric pressure, and then the backside passivation film 5 is formed on the backside of the p-type silicon substrate 4 as a result of a given reaction.

[0025] The heater 13, which is, for example, a heating device, can heat the p-type silicon substrate 4 disposed on the heater 13. During film formation, the heater 13 is heated by an external controller (not shown) until the heater reaches a temperature required to form the backside passivation film 5 composed of the aluminum oxide film.

[0026] The solution container 15 is filled with the solution 14, which serves as a raw material solution for forming the backside passivation film 5. The solution 14 contains aluminum (Al) elements as a metal source.

[0027] For example, an ultrasonic atomizing device can be used as the mist-forming device 16. The mist-forming device 16, which is the ultrasonic atomizing device, applies ultrasonic waves to the solution 14 in the solution tank 15, thereby atomizing the solution 14 in the solution tank 15. The atomized solution 14 flows through a channel L1 to be supplied to the back side (top surface) of the p-type silicon substrate 4 in the reaction tank 11.

[0028] The nebulized solution 14 is supplied into the reaction tank 11, and then the solution 14 undergoes a reaction on the backside of the p-type silicon substrate 4, which is subjected to heating under atmospheric pressure, thereby forming the backside passivation film 5 on the backside of the p-type silicon substrate 4. The unreacted solution 14 in the reaction tank 11 is discharged (continuously) from the reaction tank 11 via the channel L2. (Manufacturing process)

[0029] Next, a method for manufacturing a solar cell (particularly, a method for forming the backside passivation film 5 (the aluminum oxide film)) of Embodiment 1 will be described.

[0030] First, a given impurity is introduced into a silicon substrate using crystalline silicon as a constituent material to produce a p-type silicon substrate 4 having p-type conductivity. Then, the p-type silicon substrate 4 is placed on the heater 13 in the reaction vessel 11. At this time, the p-type silicon substrate 4 is placed on the heater 13 in such a manner that the back surface is an upper surface and the front surface is a lower surface, and the interior of the reaction vessel 11 is adjusted to atmospheric pressure. In this way, the p-type silicon substrate 4 having a back surface and a front surface (one main surface and the other main surface) is manufactured.

[0031] The heater 13 heats the p-type silicon substrate 4 arranged on the heater 13 until a film forming temperature of the backside passivation film 5 made of aluminum oxide film is reached, and keeps the p-type silicon substrate 4 at the film forming temperature.

[0032] Meanwhile, in the solution tank 15, the solution 14 is nebulized by the mist-forming device 16. The nebulized solution 14 (the solution 14 with a small particle diameter) flows through the channel L1, undergoes flow rectification, and is supplied to the reaction tank 11. The solution 14 contains aluminum as the metal source. In this way, the solution 14 (the raw material solution), which contains aluminum and is a metal element, is nebulized.

[0033] The atomized solution 14, which has undergone flow alignment, is supplied to the back surface of the p-type silicon substrate 4 under application of heat under atmospheric pressure. The supplied solution 14 is sprayed onto the back surface of the p-type silicon substrate 4 under application of heat, and then the back surface passivation film 5 made of the aluminum oxide film is formed on the back surface of the p-type silicon substrate 4. As described above, the back surface passivation film 5, which is made of the aluminum oxide and is a metal oxide film, is formed on the back surface of the p-type silicon substrate 4 by spraying the atomized solution 14 onto the back surface of the p-type silicon substrate 4 under atmospheric pressure (under non-vacuum).

[0034] Afterwards, the Fig. The solar cell structure shown in Figure 1 is fabricated using the p-type silicon substrate 4 including the backside passivation film 5 (the aluminum oxide film) formed thereon. Generally, the backside passivation film 5 is formed after the formation of the frontside passivation film 2 and the n-type silicon layer 3, and thereafter, the frontside electrode 1 and the backside electrode 6 are formed. Additionally, the order of film formation of the frontside passivation film 2 and the backside passivation film 5 can be reversed.

[0035] Fig. 3 is a sectional view showing a situation of light irradiation processing by ultraviolet light 21 of Embodiment 1. As in Fig. As shown in Fig. 3, light irradiation processing in which a solar cell is irradiated for 30 seconds with ultraviolet light 21 having a wavelength of 365 nm (given light) from above the front surface of the solar cell structure (above the front surface of the p-type silicon substrate 4) is performed in such a manner that the front surface of the p-type silicon substrate 4 is an upper surface. As described above, the ultraviolet light 21 from above the front surface of the solar cell structure is passed through a front surface passivation film 2 and an n-type silicon layer 3, and light irradiation processing in which an interface between the p-type silicon substrate 4 and the passivation film 5 is irradiated with the ultraviolet light 21 is performed, thereby completing a solar cell of Embodiment 1.

[0036] As described above, the method for forming the back passivation film 5 (the aluminum oxide film) in the method for manufacturing a solar cell of Embodiment 1 uses the mist method (the method of forming a film by spraying the liquid solution 14 under atmospheric pressure) to form the back passivation film 5 on the back surface of the p-type silicon substrate 4.

[0037] The backside passivation film 5 made of an aluminum oxide film is not formed by supplying the evaporated raw material to the p-type silicon substrate 4 by, for example, CVD or ALD. Alternatively, in Embodiment 1, the backside passivation film 5 is formed by spraying the atomized liquid solution 14 onto the p-type silicon substrate 4. As described above, the solution 14 includes aluminum elements. Thus, the backside passivation film 5 made of an aluminum oxide film can be formed on the backside of the p-type silicon substrate 4 using a material that is safe and easy to handle, instead of using a material such as TMA (trimethyl aluminum), which is expensive and difficult to handle.

[0038] Furthermore, Embodiment 1, which is film formation processing under atmospheric pressure, eliminates the need for vacuum processing and the like, thereby enabling a reduction in manufacturing costs. In addition, in Embodiment 1, the atomized solution 14 is sprayed onto the p-type silicon substrate 4 to perform film formation processing. Therefore, during film formation processing, the p-type silicon substrate 4 is not damaged by plasma irradiation or the like.

[0039] The back surface passivation film 5 is formed by the nebulization method at a speed of 10 to 15 nm / min, which is five or more times faster than the speed at which the aluminum oxide film is formed by, for example, the ALD method. Accordingly, using the method for forming a back surface passivation film 5 of Embodiment 1 can also improve production efficiency.

[0040] In addition, in Embodiment 1, light irradiation processing is performed in which an interface between the back surface passivation film 5 and the p-type silicon substrate 4 is irradiated with ultraviolet light 21.

[0041] Fig. 4 is a graph showing the effect of the above-mentioned light irradiation processing of Embodiment 1. Fig. Figure 4 shows the results of the following lifetime measurement. That is, a lifetime after the formation of a film (before light irradiation processing) of the back surface passivation film 5 is measured, and then, light irradiation processing, in which a solar cell is irradiated with ultraviolet light 21 having a wavelength of 365 nm for 30 seconds, is performed, and the lifetime is measured again. Fig. 4 indicates an effective lifetime, which is determined by taking the lifetime after film formation (before light irradiation) as a normalized value “1”.

[0042] As in Fig. As shown in Figure 4, it is found that the effective lifetime after light irradiation can be increased to approximately "2.3." As described above, it is found that the light irradiation processing greatly improves a passivation effect (a function of regulating a reduction in lifetime) of the backside passivation film 5 formed by the solar cell manufacturing method in Embodiment 1.

[0043] As described above, in the method for manufacturing a solar cell of Embodiment 1, the passivation film 5 made of the aluminum oxide film is formed by spraying the atomized (material) solution 14 of aluminum onto the back surface of the p-type silicon substrate 4, whereby the back surface passivation film 5 can be formed without damaging a substrate with a high degree of production efficiency at a lower manufacturing cost.

[0044] Furthermore, a passivation film 5 with high film quality, which greatly improves an effective lifetime, can be obtained upon completion of a solar cell by the ultraviolet light irradiation processing 21 performed after the formation of the backside passivation film 5.

[0045] Furthermore, it is possible to achieve an improvement in the film quality of the passivation film 5 in a relatively short time (30 seconds in an example of Fig. 4) by light irradiation using the ultraviolet light 21 for the light irradiation processing.

[0046] In addition, while the Fig. 4 indicates an example in which the p-type silicon substrate is irradiated with ultraviolet light 21 for 30 seconds, it is preferable to set a light irradiation time to 1 second or more, thereby surely achieving an improvement in the effective lifetime of the back surface passivation film 5. <Ausführungsform 2>

[0047] Baking processing at the time of forming a front electrode 1 and a back electrode 6 is an important process in completing the solar cell. For example, when forming the front electrode 1 and the back electrode 6, an electrode material containing a metal as the main component is applied, and then baking processing is performed.

[0048] In Embodiment 1, a method of performing light irradiation processing after forming the backside passivation film 5 was described without considering the presence or absence of firing processing at the time of electrode formation. That is, Embodiment 1 is a method for manufacturing a solar cell in which the following steps (1) and (2) are generally performed.

[0049] (1) A p-type silicon substrate 4 is prepared, an aluminum-containing solution 14 is nebulized, and the nebulized solution 14 is sprayed onto the back surface of the p-type silicon substrate 4 under non-vacuum to form a passivation film 5 made of aluminum oxide film on the back surface of the p-type silicon substrate 4.

[0050] (2) A light irradiation processing in which an interface between the backside passivation film 5 and the p-type silicon substrate 4 is irradiated with ultraviolet light (21) is performed.

[0051] However, the above-mentioned burning processing is an essentially important processing in forming the front electrode 1 and the back electrode 6 that constitute a solar cell. That is, a process step of obtaining the Fig. 1 includes the step of forming the front-side electrode 1 (the other electrode) and the back-side electrode 6 (one electrode) on one side of the front side and one side of the back side of the p-type silicon substrate 4, and this step includes the firing processing for firing the p-type silicon substrate 4 at a given firing temperature.

[0052] Embodiment 2 is a method for manufacturing a solar cell in which light irradiation processing is performed taking into account an influence of firing processing at the time of forming the front-side electrode 1 and the back-side electrode 6, and Embodiment 2 is generally carried out by the following steps (1), (3) and (2).

[0053] (1) As in Embodiment 1, a p-type silicon substrate 4 is prepared, an aluminum-containing solution 14 is nebulized, and the nebulized solution 14 is sprayed onto the back surface of the p-type silicon substrate 4 under non-vacuum to form a passivation film 5 made of the aluminum oxide film on the back surface of the p-type silicon substrate 4.

[0054] (3) The front electrode 1 and the back electrode 6 are formed to form a solar cell structure as shown in Fig. 1. Firing is performed at a firing temperature of 500°C or higher to form the front electrode 1 and the back electrode 6.

[0055] (2)' After the firing processing of step (3), a light irradiation processing is performed in which an interface between the p-type silicon substrate 4 and the backside passivation film 5 is irradiated by the ultraviolet light 21.

[0056] Fig. 5 is a graph showing the effect of a method for manufacturing a solar cell of Embodiment 2. Fig. 5 shows the results of the following lifetime measurement. That is, a lifetime value after film formation (before light irradiation) of the backside passivation film 5 is measured, and then firing processing, which is a heat treatment under atmospheric pressure with a firing temperature of 800°C and a firing time of 10 seconds, is performed, and the lifetime after firing (processing) is measured. After that, as in Embodiment 1, light irradiation processing is performed, in which a solar cell is irradiated with ultraviolet light 21 having a wavelength of 365 nm for 30 seconds, and the lifetime is measured. Fig. 5 indicates an effective lifetime, which is determined by taking the lifetime after film formation (before light irradiation) as a normalized value “1”.

[0057] As in Fig.As shown in Figure 5, it is found that the effective lifetime is increased to approximately "2.0" after light irradiation. That is, the effective lifetime immediately after firing is reduced from "1.0" to approximately "0.5", but subsequent light irradiation processing increases the effective lifetime to "2.0", which greatly exceeds the "1.0" before firing.

[0058] As described above, in the method for manufacturing a solar cell of Embodiment 2, the effective lifetime to indicate the film quality of the back surface passivation film 5 formed in the step (1) is temporarily lowered by performing the firing processing (step (3)), which is essentially important in the manufacturing process of a solar cell, for forming the front electrode 1 and the back electrode 6, but by the light irradiation processing of the step (2)' performed thereafter, the film quality of the back surface passivation film 5 can be greatly improved from the quality before the step (2)' is performed.

[0059] At this time, it is also possible to achieve an improvement in the film quality of the backside passivation film 5 even in the situation that the firing processing is carried out at a firing temperature of 800°C, which is a firing temperature of 500°C or higher. <andere>

[0060] In addition, an example of using ultraviolet light 21 as the light (given light) to be used for light irradiation processing is described in Embodiment 1 and Embodiment 2 described above; however, a different type of light may be used. For example, it is possible to use light whose photon energy is 1.1 eV or more (a wavelength of 1100 nm or less), that is, light that a crystalline silicon in the p-type silicon substrate 4 can absorb, to implement light irradiation in an interface between the p-type silicon substrate 4 and the backside passivation film 5, instead of the ultraviolet light 21.

[0061] It is also possible to achieve an improvement in the film quality of the backside passivation film 5 when, as described above, the light irradiation processing using light that the crystalline silicon can absorb and whose photon energy is 1.1 eV or more (a wavelength is 1100 nm or less) is employed as the light irradiation processing in the method for manufacturing a solar cell of Embodiment 1 or Embodiment 2.

[0062] Furthermore, it is possible to achieve an improvement in the film quality of the backside passivation film 5 at a relatively low cost by using solar light or artificial solar light having AM of 1.5 as the light to be used for the light irradiation processing in the method for manufacturing a solar cell of Embodiment 1 or Embodiment 2.

[0063] Moreover, when an execution order of the firing processing (step (3)) and the light irradiation processing (step (2)') is reversed in the method for manufacturing a solar cell of Embodiment 2, it cannot be expected that a great improvement in the film quality of the backside passivation film 5 can be achieved unlike Embodiment 2, but it is of course possible to achieve the effect of improving the film quality of the backside passivation film 5 compared to a conventional manufacturing method in which the light irradiation processing is not performed. List of reference symbols: 4 p-type silicon substrate 5 Backside passivation film 11 reaction vessels 13 Heating 14 (Raw material) Solution 15 solution containers 16 Fog generation device 21 ultraviolet light L1, L2 channel< / andere>

Claims

[1] A method for producing a solar cell, comprising the steps of: (a) producing a silicon substrate (4) having one main surface and another main surface, (b) nebulising a solution (14) comprising a metal element, (c) spraying the atomized solution onto a main surface of the silicon substrate under non-vacuum to form a passivation film (5) made of a metal oxide film on a main surface of the silicon substrate, (d) manufacturing a solar cell structure using the silicon substrate having the passivation film formed thereon, and (e) performing a light irradiation process in which an interface between the passivation film and the silicon substrate is irradiated with a given light (21), wherein step (d) comprises: (d-1) a step of forming an electrode and another electrode on one main surface side and another main surface side of the silicon substrate, and the step (d-1) comprises a firing process for firing at a given firing temperature, and step (e) is carried out after step (d), wherein wherein the light provided in step (e) comprises a light whose photon energy is 1.1 eV or more, artificial solar light with AM of 1.5 or ultraviolet light with a wavelength of 365 nm. [2] A method for producing a solar cell according to claim 1, wherein the metal element is aluminum, and the metal oxide film is aluminum oxide. [3] A method for manufacturing a solar cell according to claim 1, wherein the silicon substrate is a silicon substrate in which crystalline silicon, which is a constituent material, has p-type conductivity. [4] A method for manufacturing a solar cell according to claim 1, wherein the light provided in step (e) comprises light whose photon energy is 1.1 eV or more. [5] A method of manufacturing a solar cell according to claim 1, wherein the light provided in step (e) comprises artificial solar light having AM of 1.

5. [6] A method for producing a solar cell according to claim 1, wherein the light provided in step (e) is ultraviolet light having a wavelength of 365 nm. [7] A method for producing a solar cell according to claim 6, wherein the irradiation time of the ultraviolet light is 1 second or more. [8] A method for producing a solar cell according to claim 1, wherein the given firing temperature in step (d-1) is 500 °C or higher.

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