Method for manufacturing solar cell

Abstract

The invention relates to a method for manufacturing a solar cell having a self-assembled monomolecular layer (61), comprising the following steps: a) pre-treating a solar cell precursor (60) in a pre-treatment zone; b) coating the pretreated solar cell precursor (60) with a self-assembled monomolecular layer (61) in a coating zone (33); wherein the solar cell precursor (60) is transported in such a manner that one side at least partially contacts the horizontal transport system, so as to pass through the pretreatment zone and the coating zone (33) in sequence, and is subjected to one-sided pretreatment in the pretreatment zone and then subjected to one-sided coating in the coating zone (33).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a solar cell. The solar cell can be a single-junction solar cell or a multi-junction solar cell, and the latter is also called a tandem solar cell. A tandem solar cell includes a plurality of solar cells, which are also called sub-cells, and are arranged in a tandem manner. In this context, two types of tandem solar cells are distinguished: one is a mechanically stacked tandem solar cell, that is, each sub-cell is manufactured independently; the other is a monolithic tandem solar cell, that is, all sub-cells are constructed on the same substrate. Background Art

[0002] Solar cells with SAM (self-assembled monolayer) are known. However, so far, SAM can only be achieved on a laboratory scale and the yield is low. However, there is currently a need to manufacture solar cells with SAM on an industrial scale. Summary of the Invention

[0003] The object of the present invention is to provide a method for manufacturing a solar cell, which can produce solar cells with self-assembled monolayers on an industrial scale.

[0004] According to the present invention, this object is achieved by a method having the features described in claim 1. Advantageous improvements and modifications are given in the dependent claims.

[0005] In this method, the solar cell precursor is transported by a horizontal transport system, passes through the respective regions of the device in sequence, and is subjected to a one-sided processing step. In this process, the focus is on forming a self-assembled monolayer (SAM) on the solar cell precursor, and this layer forms part of the layer structure of the solar cell. This method is a one-sided processing process in the strict sense.

[0006] The present invention relates to a method for manufacturing a solar cell with a self-assembled monolayer, the method comprising the following steps:

[0007] a) Pretreating the solar cell precursor in a pretreatment area;

[0008] b) Coating the pretreated solar cell precursor with a self-assembled monolayer in a coating area, wherein the solar cell precursor is transported in such a way that at least part of one side contacts the horizontal transport system, so as to pass through the pretreatment area and the coating area in sequence, and is subjected to one-sided pretreatment in the pretreatment area and then coating treatment in the coating area.

[0009] The method of the present invention enables batch production of self-assembled monolayers (SAMs) coated on solar cell precursors. The formed SAMs form part of the fabricated solar cell structure. By this method, not only can a single solar cell precursor be coated, but also multiple solar cell precursors can pass through the respective regions of the device successively and / or side by side and be subjected to coating treatment. By integrating multiple process steps in the device, the entire process flow from pretreatment to SAM coating and optional subsequent surface treatment is simplified. The pretreatment process is crucial for achieving good chemical bonding between the SAM molecules and the surface to be coated. The advantages of the method of the present invention lie in its good scalability and strict one-sided treatment of solar cell precursors, thus enabling extremely low material consumption, including the material consumption for SAM precursors. In addition, all process steps are advantageously integrated in the same device. Through the configuration of the device, the sequence of process steps can be flexibly adjusted, so that individual process steps can be omitted or added according to needs.

[0010] This method is used to manufacture single-junction solar cells or multi-junction solar cells. A single-junction solar cell is a single solar cell structure, while a multi-junction solar cell contains multiple sub-cells. Preferably, this method is used for batch manufacturing of multiple solar cells with self-assembled monolayers, wherein multiple solar cell precursors are conveyed in such a way that at least part of one side contacts a horizontal conveying system and pass successively and / or side by side through a pretreatment area and then through a coating area.

[0011] The device for implementing this method is preferably an inline production device comprising a horizontal conveying system. The respective regions of the device are preferably designed as replaceable and / or adjustable device modules, each module having an exclusive function. The horizontal conveying system is preferably designed to be able to convey multiple solar cell precursors successively and / or side by side through the entire device. Preferably, the respective regions of the device can perform full-surface treatment on the solar cell precursors on one side of the solar cell precursors. The treatment is limited to one side.

[0012] In a preferred embodiment, step a) includes pre-cleaning of the solar cell precursors, wherein the solar cell precursors are conveyed through a pre-cleaning area and receive one-sided pre-cleaning in this area. Preferably, the pre-cleaning includes one-sided cleaning of the solar cell precursors with ethanol to achieve good pretreatment effects. Preferably, the solar cell precursors are dried after pre-cleaning to remove the cleaning liquid remaining thereon.

[0013] As an alternative or in addition, step a) preferably includes pre-treatment of the solar cell precursor, wherein the solar cell precursor is conveyed through a pre-treatment zone and undergoes unilateral pre-treatment within this zone. Preferably, the pre-treatment includes subjecting the solar cell precursor to ozone, ultraviolet radiation, O2 and / or N2 plasma on one side. Preferably, the pre-treatment includes subjecting the solar cell precursor to ozone and / or ultraviolet radiation on one side. In this way, good pre-treatment effects can be achieved.

[0014] In a preferred embodiment, in step a), the solar cell precursor is pre-treated by cleaning with ethanol, water or an ethanol / water mixture, and by ozone pre-treatment, so as to achieve good pre-treatment effects.

[0015] The solar cell precursor is treated on one side within each treatment zone, especially with unilateral coating within the coating zone. This does not exclude the possibility that chemicals or treatment processes may inadvertently (e.g., through the conveying rollers of the conveying system) come into contact with the side that should not be treated, especially the side that should not be coated.

[0016] Preferably, in step b), the solar cell precursor is coated on its entire surface unilaterally on the side facing away from the contact horizontal conveying system. Preferably, after the coating step, the solar cell precursor is dried to remove the solvent in the coating material.

[0017] Preferably, the coating material used in step b) for forming the self-assembled monolayer is selected from the following group of compounds: 2PACz ([2-(9H-carbazol-9-yl)ethyl]phosphonic acid), MeO-2PACz ([2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid), Me-4PACz ([4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid), Me-2PACz ([2-(3,6-dimethyl-9H-carbazol-9-yl)ethyl]phosphonic acid), Br-2PACz ([2-(3,6-dibromo-9H-carbazol-9-yl)ethyl]phosphonic acid). Preferably, 2PACz is used as the coating material in step b). The self-assembled monolayer is preferably used as the hole conductor layer in the tandem solar cell.

[0018] In a preferred embodiment, step c) is carried out after step b), i.e., the solar cell precursor coated with the self-assembled monolayer is heat-treated in an annealing zone. During this heat-treatment process, the solar cell precursor is conveyed by the horizontal conveying system in a manner that one side contacts the conveying system, so as to pass through the annealing zone and undergo heat-treatment. In this way, the solvent used in the coating process can be removed.

[0019] In addition, after step b) or step c), step d) can be further performed, that is, post-cleaning the solar cell precursor coated with the self-assembled monolayer in the post-cleaning area. The solar cell precursor is transported by a horizontal transport system in a manner that one side contacts the transport system, passes through the cleaning area, and undergoes single-sided cleaning in the cleaning area. The post-cleaning preferably includes cleaning the solar cell precursor. In this way, the excess substances coated on the solar cell can be removed.

[0020] Preferably, step b) includes coating by means of doctor blade coating, slit nozzle deposition, and / or spraying and / or drop coating. More preferably, spraying and / or slit nozzle deposition system and / or drop coating device are used to achieve single-sided coating.

[0021] In a preferred embodiment, the horizontal transport system includes a plurality of transport rollers that rotate in one direction, so that the solar cell precursor placed on the transport rollers sequentially passes through the pretreatment area, the coating area, and optionally the annealing area and the optional post-cleaning area along the transport direction.

[0022] The manufactured solar cell is preferably a tandem solar cell.

[0023] In a preferred embodiment, the solar cell precursor includes the lower sub-cell of the tandem solar cell, on which a composite layer is provided, and the composite layer is pretreated in step a) and coated in step b).

[0024] Preferably, the lower sub-cell includes a silicon-based absorption layer. The composite layer is preferably a TCO (transparent conductive oxide) layer, and more preferably an ITO (indium tin oxide) layer.

[0025] Preferably, the lower sub-cell of the tandem solar cell has a layer structure arranged in the following order:

[0026] - Conductive layer;

[0027] - Absorption layer, such as a silicon substrate in the form of a p-type or n-type Cz-Si substrate;

[0028] - Back surface passivation layer;

[0029] - Back surface metallization layer, wherein the back surface metallization layer forms a local contact with the absorption layer through the back surface passivation layer;

[0030] Among them, the composite layer coated according to the method of the present invention is provided on the above-mentioned conductive layer.

[0031] Preferably, after step b), and optionally after step c) or d), a perovskite absorption layer is deposited on the self-assembled monolayer, such as Cs 0,05 (MA 0,83 ,FA 0,17 ) 0,95 Pb(I 0,83 ,Br 0,17 )3.

[0032] Preferably, the method further includes a loading step in which a solar cell precursor is loaded into a horizontal conveyor system. This loading step is performed before step a). Preferably, the method further includes an unloading step in which the solar cell precursor is unloaded from the horizontal conveyor system. The unloading step is the last step of the entire method.

[0033] The method is preferably implemented in a specifically designed device that is designed to convey a solar cell precursor through the device in an overall process flow. Preferably, the conveyor system is capable of conveying multiple solar cell precursors sequentially and / or side by side through the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other advantages and features of the method will be further described in connection with the preferred embodiments described below. The drawings are not drawn to scale and are for illustrative and exemplary understanding only.

[0035] The illustrations are as follows:

[0036] Figure 1 : Cross-section of a tandem solar cell that can be manufactured using the method of the present invention; and

[0037] Figure 2 : Schematic diagram of a production device that can be used to implement the method of the present invention. DETAILED DESCRIPTION

[0038] Figure 1 Shows the cross-sectional structure of a tandem solar cell manufactured using the method of the present invention. The solar cell includes the following structural layers in the following order:

[0039] - Front metallization layer 11, such as containing silver;

[0040] - Conductive layer 12, such as an ITO layer;

[0041] - Buffer and electron conductor layer 13, such as an SnO layer;

[0042] - Passivation and hole blocking layer 14, such as a C60 layer;

[0043] - Absorption layer 15, such as a perovskite absorption layer, such as Cs 0.05 (MA 0.83 FA0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3;

[0044] - Hole conductor layer 16, i.e., self-assembled monolayer (SAM), such as 2PACz ([2-(9H-carbazol-9-yl)ethyl]phosphonic acid);

[0045] - Composite layer 17, such as ITO layer;

[0046] - Another conductive layer 21;

[0047] - Another absorption layer 22, such as a silicon substrate in the form of a p-type or n-type Cz-Si substrate;

[0048] - Back surface passivation layer 23;

[0049] - Back surface metallization layer 24, the metallization layer having local contact 25 with another absorption layer 22 through the back surface passivation layer 23.

[0050] The stacked solar cell includes an upper sub-cell 1 comprising layers 11 to 17 and a lower sub-cell 2 comprising layers 22 to 25. Sub-cell 1 has an absorption layer 15 based on a perovskite material, while sub-cell 2 includes an absorption layer 22 based on a silicon material.

[0051] Figure 2 There is shown a device for performing the method of the present invention. To implement the method, the device is provided with a plurality of zones, each zone being designed to process a solar cell precursor 60 separately, and is provided with a horizontal conveying system having conveying rollers 40, the conveying system being arranged and constructed such that the solar cell precursor 60 is conveyed through the respective zones with one side lying flat on the conveying system. A plurality of solar cell precursors are shown being conveyed through different zones of the device. The device is provided with a loading zone 30 in which the solar cell precursor 60 is loaded onto the conveying system such that one side thereof is in contact with the conveying system. A pretreatment zone is connected after the loading zone 30. The pretreatment zone includes a pre-cleaning zone 31 in which the solar cell precursor 60 is first pre-cleaned unilaterally by a cleaning device 41, such as with ethanol, and subsequently dried by a drying device 42; and / or a pretreatment zone 32 in which the solar cell precursor 60 is pretreated unilaterally, for example, with ozone.

[0052] After the pretreatment area 32 is the coating area 33, in which the pretreated solar cell precursor 60 is coated with a self-assembled monolayer 61 on one side by a coating device 43 and optionally dried by another drying device 42. After the coating area 33 is an optional annealing area 34, in which the solar cell precursor 60 coated with the self-assembled monolayer 61 is heat-treated in a heating area 39. After the optional annealing area 34 is an optional post-cleaning area 35, in which the solar cell precursor 60 coated with the self-assembled monolayer 61 is subsequently cleaned by a cleaning device 41 and dried by another drying device 42. After the optional post-cleaning area 35 is an optional drying area 36, in which the solar cell precursor 60 coated with the self-assembled monolayer 61 is dried. After the optional drying area 36 is an unloading area 37, in which the solar cell precursor 60 coated with the self-assembled monolayer 61 is unloaded from the conveying system.

[0053] The method for manufacturing a solar cell 60 having a self-assembled monolayer 61 according to the present invention can be implemented using this device, and the method includes the following steps:

[0054] Step a) Pretreating the solar cell precursor 60 in a pretreatment area, i.e., in the pre-cleaning area 31 and / or the pretreatment area 32; and step b) Coating the pretreated solar cell precursor 60 with a self-assembled monolayer 61 in the coating area 33, wherein the solar cell precursor 60 is conveyed in such a manner that at least a part of one side thereof is in contact with the horizontal conveying system, so as to sequentially pass through the pretreatment area and the coating area 33, and the one side facing away from the conveying system is pretreated on one side in the treatment area and then coated on one side in the coating area 33. Thereafter, the solar cell precursor 60 coated with the self-assembled monolayer 61 can be heat-treated and / or subsequently cleaned. In this way, for example, the hole conductor layer 16 in the stacked solar cell shown below can be manufactured. Figure 1 The hole conductor layer 16 in the stacked solar cell shown.

[0055] List of reference numerals: T Conveying direction 1 Upper sub-cell

[0056] 11 Front surface metallization layer 12 Conductive layer

[0057] 13 Buffer layer

[0058] 14 Electron conductor layer 15 Absorbing layer

[0059] 16 Hole conductor layer 17 Composite layer 2 Lower sub-cell

[0060] 21 Another conductive layer 22 Another absorbing layer 23 Back surface passivation layer 24 Back surface metallization layer 25 Local contact 3 Device

[0061] 30 Loading Area

[0062] 31 Pre - cleaning Area

[0063] 32 Pre - treatment Area

[0064] 33 Coating Area

[0065] 34 Annealing Area

[0066] 35 Post - cleaning Area

[0067] 36 Drying Area

[0068] 37 Unloading Area

[0069] 39 Heating Area

[0070] 40 Conveyor Roll

[0071] 41 Cleaning Device

[0072] 42 Drying Device

[0073] 43 Coating Device 60 Solar Cell Precursor 61 Self - assembled Monolayer

Claims

1. A method for preparing a solar cell with a self-assembled monolayer (61), comprising the following steps: a) Pretreating a solar cell precursor (60) in a pretreatment zone; b) Coating the pretreated solar cell precursor (60) with a self-assembled monolayer (61) in a coating zone (33); wherein the solar cell precursor (60) is conveyed in such a manner that at least one side thereof is at least partially in contact with a horizontal conveying system to sequentially pass through the pretreatment zone and the coating zone (33), and is pretreated on one side in the pretreatment zone and then coated on one side in the coating zone (33).

2. The method according to claim 1, wherein Step a) includes pre-cleaning the solar cell precursor (60), specifically, the solar cell precursor (60) is conveyed through a pre-cleaning zone (31) and undergoes one-sided pre-cleaning, and / or includes pretreating the solar cell precursor (60), specifically, the solar cell precursor (60) is conveyed through a pretreatment zone (32) and undergoes one-sided pretreatment.

3. The method according to claim 2, wherein The pre-cleaning includes one-sided cleaning of the solar cell precursor (60) with ethanol, and / or the pretreatment includes one-sided exposure of the solar cell precursor (60) to ozone, ultraviolet irradiation, O2 and / or N2 plasma.

4. The method according to any one of the preceding claims, characterized in that, Step c) is performed after step b), that is, heat-treating the solar cell precursor (60) coated with the self-assembled monolayer (61) in an annealing zone (34), wherein the solar cell precursor (60) is conveyed by the horizontal conveying system in such a manner that one side thereof is in contact with the conveying system to pass through the annealing zone (34) and undergo heat treatment.

5. The method according to any one of the preceding claims, characterized in that, Step d) is performed, that is, post-cleaning the solar cell precursor (60) coated with the self-assembled monolayer (61) in a post-cleaning zone (35), wherein the solar cell precursor (60) is conveyed in the post-cleaning zone (35) by the horizontal conveying system in such a manner that one side thereof is in contact with the conveying system and undergoes one-sided post-cleaning in the post-cleaning zone (35).

6. The method according to any one of the preceding claims, characterized in that The solar cell precursor (60) is processed on the side facing away from the conveying system.

7. The method according to any one of the preceding claims, characterized in that, Step b) includes doctor blade coating, slot nozzle deposition and / or spraying and / or drop coating.

8. The method according to any one of the preceding claims, characterized in that, The horizontal conveying system is provided with a plurality of conveying rollers (40), and the conveying rollers (40) rotate in a single rotation direction such that the solar cell precursor (60) placed thereon is conveyed in a conveying direction (T) through the pretreatment zone, the coating zone (33), and optionally the annealing zone (34) and the optional post-cleaning zone (35).

9. The method according to any one of the preceding claims, characterized in that The solar cell precursor (60) has a lower sub-cell (2) of the solar cell to be fabricated into a stacked solar cell, and a composite layer (17) is provided on the lower sub-cell. The composite layer is pretreated in step a) and coated in step b), wherein the lower sub-cell (2) preferably has a silicon-based absorption layer (22), and / or the composite layer (17) is preferably a TCO layer, more preferably an ITO layer.

10. The method according to any one of the preceding claims, characterized in that, This method is implemented in a device designed to convey the solar cell precursor (60) through the device by the conveying system throughout the implementation of this method.

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