Full evaporation type perovskite-crystalline silicon laminated solar cell and preparation method thereof

Abstract

The invention relates to a full evaporation type perovskite-crystalline silicon laminated solar cell and a preparation method thereof, and belongs to the technical field of photovoltaic devices. The preparation method comprises the following steps: S1, evaporating a hole transport layer on one side of a crystalline silicon substrate; the material of the hole transport layer is subjected to pre-melting treatment before evaporation; s2, sequentially evaporating a perovskite layer, an electron transport layer, a hole barrier layer, an anti-reflection layer and a top electrode layer on the surface of the hole transport layer; and S3, evaporating a bottom electrode layer on the other side of the crystalline silicon substrate to obtain the full-evaporation type perovskite-crystalline silicon laminated solar cell. According to the preparation method, pre-melting and evaporation are combined, the problem that evaporation is difficult when self-assembled molecules serve as hole transport materials is solved, in addition, the proportion of perovskite components is regulated and controlled by adjusting the evaporation rate proportion, the problem of band gap adaptation with a crystalline silicon substrate is solved, and finally full-evaporation preparation of the perovskite-crystalline silicon laminated solar cell is achieved. And the prepared device is excellent in performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic devices, and in particular relates to a fully evaporated perovskite-crystalline silicon stacked solar cell and a preparation method thereof. Background Art

[0002] As the global demand for clean energy continues to increase, solar energy, as an important form of renewable energy, has received widespread attention. Although traditional single-junction silicon-based solar cells have made significant progress in commercialization, their efficiency improvement faces bottlenecks. In order to further improve the conversion efficiency and reduce the cost of power generation, scientists have begun to explore multi-junction or multi-bandgap stacked solar cell technology, among which perovskite-crystalline silicon stacked solar cells have become a research hotspot due to their high theoretical efficiency and potential cost-effectiveness. Perovskite materials have excellent optoelectronic properties, such as wide spectral absorption, high extinction coefficient, and long carrier diffusion length, which makes them very suitable for use as light-absorbing layers for high-efficiency photovoltaic devices. However, the traditional solution method for preparing perovskite films has problems such as poor uniformity and difficulty in compatibility with high-quality crystalline silicon substrates, which limits its application in stacked structures. As an alternative process, evaporation method evaporates perovskite precursor materials onto substrates through physical vapor deposition (PVD) technology to form uniform and dense films, providing a new way to solve the above problems.

[0003] At present, some process layers are prepared by evaporation, but it is still inevitable to use other processes such as solvent method, magnetron sputtering method, etc. to prepare the process layers. This will lead to incompatibility between perovskite cells and crystalline silicon solar preparation processes, increase the production cost in the preparation process of stacked devices, and is not conducive to the industrial development of perovskite-crystalline silicon stacked photovoltaic devices. Summary of the invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the perovskite layer and related process layer parts in the perovskite-crystalline silicon tandem solar cell in the prior art. These layers still cannot avoid being prepared by methods such as solvent method and magnetron sputtering method, which leads to problems such as poor process compatibility of the preparation.

[0005] In order to solve the above technical problems, the present invention provides a fully evaporated perovskite-crystalline silicon tandem solar cell and a preparation method thereof. By combining pre-melting and evaporation operations, the problem of difficulty in evaporating self-assembled molecules as hole transport materials is solved. In addition, by adjusting the evaporation rate ratio to control the proportion of perovskite components, the problem of band gap adaptation with the crystalline silicon substrate is solved, and finally the fully evaporated preparation of the perovskite-crystalline silicon tandem solar cell is realized, and the prepared perovskite-crystalline silicon tandem solar cell has high conversion efficiency and good stability.

[0006] The first object of the present invention is to provide a method for preparing a fully evaporated perovskite-crystalline silicon tandem solar cell, comprising the following steps:

[0007] S1, evaporating a hole transport layer on one side of a crystalline silicon substrate; the material of the hole transport layer is pre-melted before evaporation;

[0008] S2, sequentially evaporating a perovskite layer, an electron transport layer, a hole blocking layer, an anti-reflection layer and a top electrode layer on the surface of the hole transport layer;

[0009] S3, vapor-depositing a bottom electrode layer on the other side of the crystalline silicon substrate to obtain the fully vapor-deposited perovskite-crystalline silicon stacked solar cell.

[0010] In one embodiment of the present invention, in S1, the pre-melting process is performed by using a vapor deposition machine with a current of 41A-49A for 5min-20min. Pre-melting ensures the subsequent stable vapor deposition, and the material rate during the vapor deposition process will be very stable. If the pre-melting process is not performed, the air pressure in the cavity will fluctuate violently, the rate will be extremely unstable, and the material will easily decompose.

[0011] In one embodiment of the present invention, in S1, the material of the hole transport layer is selected from one or more of [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid (Me-2PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz) and [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), and the evaporation rate is For example, it can be wait.

[0012] In one embodiment of the present invention, in S2, the material of the perovskite layer includes an inorganic salt and an organic salt;

[0013] The inorganic salt is selected from one or more of lead iodide (PbI2), lead chloride (PbCl2), lead bromide (PbBr2), cesium iodide (CsI) and cesium bromide (CsBr); the evaporation rate of the inorganic salt is For example, it can be wait;

[0014] The organic salt is selected from formamidine hydroiodide (FAI) and / or methylamine hydrochloride (MACl); the evaporation rate of the organic salt is For example, it can be wait;

[0015] The amount of the inorganic salt and the organic salt meets the general formula MA x FA 1-y Cs y PbB z Cl t I 3-z-t ; Among them, 0≤x≤0.1, 0≤y≤0.1, 0≤z≤0.2, 0≤t≤0.2.

[0016] In one embodiment of the present invention, in S2, after the perovskite layer is evaporated, an annealing step is also included, and the annealing temperature is 120°C-170°C, for example, it can be 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, etc.; the time is 10min-30min, for example, it can be 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min, 20min, 21min, 22min, 23min, 24min, 25min, 26min, 27min, 28min, 29min, 30min, etc.

[0017] Further, the evaporation method of the perovskite layer is selected from a sequential two-step method or a one-step co-evaporation method;

[0018] When the perovskite layer is evaporated by a sequential two-step method, the main evaporation rate of the inorganic salt is The main evaporation rate of organic salt is The annealing temperature is 140℃-170℃, and the time is 10min-20min;

[0019] When the perovskite layer is evaporated by one-step co-evaporation, the main evaporation rate of the inorganic salt is The main evaporation rate of organic salt is The annealing temperature is 120°C-160°C, and the time is 15min-30min.

[0020] The main evaporation rate refers to the evaporation rate of the material with a larger amount.

[0021] In one embodiment of the present invention, in S2, the material of the electron transport layer is selected from fullerene (C60) and / or 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), and the evaporation rate is For example, it can be wait.

[0022] In one embodiment of the present invention, in S2, the material of the hole blocking layer is selected from 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) and / or 4,7-diphenyl-1,10-phenanthroline (Bphen), and the evaporation rate is For example, it can be wait.

[0023] In one embodiment of the present invention, in S2, the material of the anti-reflection layer is selected from magnesium fluoride (MgF2) and / or zinc sulfide (ZnS), and the evaporation rate is For example, it can be wait.

[0024] In one embodiment of the present invention, in S2 and S3, the materials of the top electrode layer and the bottom electrode layer are independently selected from one or more of silver (Ag), gold (Au) and copper (Cu).

[0025] In one embodiment of the present invention, in S2 and S3, the thickness of the bottom electrode layer is 100nm-300nm, for example, 100nm, 150nm, 200nm, 250nm, 300nm, etc.;

[0026] The thickness of the hole transport layer is 2nm-50nm, for example, 2nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, etc.;

[0027] The thickness of the perovskite layer is 500nm-800nm, for example, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, etc.;

[0028] The thickness of the electron transport layer is 5nm-20nm, for example, 5nm, 10nm, 15nm, 20nm, etc.;

[0029] The thickness of the hole blocking layer is 5nm-15nm, for example, 5nm, 10nm, 15nm, etc.;

[0030] The thickness of the anti-reflection layer is 5nm-20nm, for example, 5nm, 10nm, 15nm, 20nm, etc.;

[0031] The thickness of the top electrode layer is 50 nm-200 nm, for example, 50 nm, 100 nm, 150 nm, 200 nm, etc.

[0032] The second object of the present invention is to provide a fully evaporated perovskite-crystalline silicon tandem solar cell prepared by the method described.

[0033] The technical solution of the present invention has the following advantages over the prior art:

[0034] (1) The preparation method described in the present invention optimizes the evaporation process of the hole transport layer and optimizes the ratio of the perovskite components to obtain a full evaporation preparation method adapted to the crystalline silicon substrate, thereby opening up a full dry preparation process suitable for preparing the perovskite solar cell part in the perovskite-crystalline silicon tandem solar cell, achieving compatibility between the preparation processes of the perovskite solar cell and the crystalline silicon solar cell. The stacked device finally prepared has high conversion efficiency and good stability.

[0035] (2) The preparation method described in the present invention solves the decomposition problem of the hole transport layer material during evaporation by means of precise pre-melting, thereby achieving stable evaporation of such hole transport layer material.

[0036] (3) The preparation method described in the present invention optimizes the evaporation process of the perovskite layer and its component ratio to adapt to the crystalline silicon substrate, thereby achieving a reasonable match between the band gaps of the silicon cell and the perovskite cell, so that the prepared perovskite-crystalline silicon stacked solar cell can fully and efficiently absorb light in various bands, so that the device has a high light conversion efficiency.

[0037] (4) The preparation method of the present invention solves the evaporation process of the hole transport layer and the perovskite layer. The synergistic cooperation of the two processes achieves energy level matching between the layers and achieves more favorable carrier transport. In addition, the solution of the two-layer evaporation process achieves process compatibility between the perovskite top cell and the crystalline silicon bottom cell, reduces the preparation cost of the perovskite-crystalline silicon stacked solar cell, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0039] Figure 1 It is a schematic structural diagram of a fully evaporated perovskite-crystalline silicon tandem solar cell of the present invention;

[0040] Figure 2 This is a cross-sectional SEM image of the fully evaporated perovskite-crystalline silicon tandem solar cell in Test Example 1 of the present invention;

[0041] Figure 3 This is the energy level diagram of the fully evaporated perovskite-crystalline silicon tandem solar cell in Test Example 2 of the present invention. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. It should be understood that the specific embodiments are only used to explain the present invention, but the embodiments are not intended to limit the present invention.

[0043] In the present invention, unless otherwise explained, technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the art to which the present invention belongs.

[0044] In the present invention, unless otherwise stated, the term "and / or" used in the present invention includes any and all combinations of one or more of the associated listed items.

[0045] In the present invention, unless otherwise stated, the experimental methods used in the embodiments of the present invention are conventional methods unless otherwise stated, and the materials, reagents, etc. used are all commercially available unless otherwise stated.

[0046] In the present invention, unless otherwise stated, when the terms "comprise" and / or "include" are used in the specification of the present invention, it indicates the existence of the described features, integers, steps, operations, raw materials or components, but does not exclude the existence or addition of one or more other features, integers, steps, operations, raw materials, components or their combinations.

[0047] Example 1

[0048] Reference Figure 1 As shown, the fully evaporated perovskite-crystalline silicon tandem solar cell and the preparation method thereof of this embodiment specifically include the following steps:

[0049] S1, the crystalline silicon substrate after sputtering ITO was cleaned in an ultrasonic bath with deionized water and ethanol for 15 min each;

[0050] S2, move the processed crystalline silicon substrate to the evaporation chamber, first pre-melt 2PACz at a current of 45.2A for 15min, then cool to room temperature, and then 2PACz was evaporated at a rate of 1000 to obtain a hole transport layer with a thickness of 15 nm;

[0051] S3, continue to co-evaporate PbI2, PbCl2 and CsI on the hole transport layer to form an inorganic salt layer with a total thickness of about 300nm. The evaporation rate of PbI2 is The evaporation rate of PbCl2 is The evaporation rate of CsI is Then, FAI was evaporated at a rate of 1.5 to form an organic salt layer with a thickness of about 350 nm; finally, the perovskite layer was obtained by annealing at 150°C for 15 min.

[0052] S4, on the perovskite layer C60 was evaporated at a rate of 100 to form an electron transport layer with a thickness of 10 nm;

[0053] S5, on the electron transport layer BCP was evaporated at a rate of 100 nm to form a hole blocking layer with a thickness of 10 nm;

[0054] S6, in the hole blocking layer MgF2 was evaporated at a rate of 100 to form an anti-reflection layer with a thickness of 10 nm;

[0055] S7, evaporating a Ag top electrode layer with a thickness of about 100 nm on the anti-reflection layer to complete the preparation of the process layer used on the top;

[0056] S8. A Ag bottom electrode layer with a thickness of about 200 nm is evaporated on the bottom of the crystalline silicon substrate to prepare a fully evaporated perovskite-crystalline silicon stacked solar cell.

[0057] Example 2

[0058] The method is basically the same as Example 1, except that the preparation of the perovskite layer specifically includes the following steps:

[0059] Continue to co-evaporate PbI2, PbBr2, FAI and MACl on the hole transport layer, with a total thickness of about 650nm. The evaporation rate of PbI2 is The evaporation rate of PbBr2 is The evaporation rate of FAI is The evaporation rate of MACl is Then the perovskite layer was obtained by annealing at 140°C for 20 minutes, and finally a fully evaporated perovskite-crystalline silicon stacked solar cell was successfully prepared.

[0060] Example 3

[0061] The method is basically the same as Example 1, except that the hole transport layer material is replaced with Me-4PACz, and finally a fully evaporated perovskite-crystalline silicon tandem solar cell is successfully prepared.

[0062] Comparative Example 1

[0063] The same as Example 1, except that the evaporation rate of CsI is adjusted to

[0064] Compared with Example 1, the power conversion efficiency of the prepared fully evaporated perovskite-crystalline silicon tandem solar cell is slightly lower, which is caused by the change in the perovskite composition. The change in the perovskite composition causes the energy level of the perovskite layer to change, resulting in a mismatch in the energy levels of the layers around the perovskite layer. The mismatch in energy levels causes the power conversion efficiency of the tandem device to decrease.

[0065] Test Example 1

[0066] The cross section of the fully evaporated perovskite-crystalline silicon tandem solar cell of Example 1 was characterized by SEM. Figure 2 As shown. Figure 2 As can be seen from the figure, the perovskite layer can be well covered on the surface of the crystalline silicon substrate, and the perovskite layer has an excellent shape-keeping effect. Compared with the current more mature wet or dry + wet perovskite layer preparation process, the perovskite layer with the participation of the wet method is more difficult to maintain its shape, while the perovskite layer prepared by the dry method has a good shape-keeping effect, can grow on the surface of large velvet crystalline silicon, and is not affected by the substrate, and the operability becomes stronger.

[0067] Test Example 2

[0068] The layers in the fully evaporated perovskite-crystalline silicon tandem solar cell of Example 1 were characterized by ultraviolet photoelectron spectroscopy (UPS). The calculated energy level values ​​and related energy level diagrams are shown in FIG. Figure 3 As shown. Figure 3 It can be seen that the valence band and conduction band of the material 2PACz itself can achieve good hole transport and electron blocking effects with the surrounding layers, and the transmission of holes from the perovskite layer to the electron transport layer C60 is also well blocked. Therefore, the evaporated hole transport layer and the perovskite layer achieve good energy level matching with the surrounding layers, which is beneficial to the transmission of carriers in the perovskite-crystalline silicon stacked solar cells, thereby making the device have excellent power conversion efficiency.

[0069] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for preparing a fully evaporated perovskite-crystalline silicon tandem solar cell, characterized in that: The following steps are involved: S1, evaporating a hole transport layer on one side of a crystalline silicon substrate; the material of the hole transport layer is pre-melted before evaporation; S2, sequentially evaporating a perovskite layer, an electron transport layer, a hole blocking layer, an anti-reflection layer and a top electrode layer on the surface of the hole transport layer; S3, vapor-depositing a bottom electrode layer on the other side of the crystalline silicon substrate to obtain the fully vapor-deposited perovskite-crystalline silicon stacked solar cell.

2. The method for preparing a fully evaporated perovskite-crystalline silicon tandem solar cell according to claim 1, characterized in that: In S1, the pre-melting process is performed by using a vapor deposition machine with a current of 41A-49A for 5min-20min.

3. The method for preparing a fully evaporated perovskite-crystalline silicon tandem solar cell according to claim 1, characterized in that: In S1, the material of the hole transport layer is selected from one or more of [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid, [2-(9H-carbazole-9-yl)ethyl]phosphonic acid and [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, and the evaporation rate is 4. The method for preparing a fully evaporated perovskite-crystalline silicon tandem solar cell according to claim 1, characterized in that: In S2, the material of the perovskite layer includes an inorganic salt and an organic salt; The inorganic salt is selected from one or more of lead iodide, lead chloride, lead bromide, cesium iodide and cesium bromide; the evaporation rate of the inorganic salt is The organic salt is selected from formamidine hydroiodide and / or methylamine hydrochloride; the evaporation rate of the organic salt is The amount of the inorganic salt and the organic salt meets the general formula MA x FA 1-y Cs y PbB z Cl t I 3-z-t ; Among them, 0≤x≤0.1, 0≤y≤0.1, 0≤z≤0.2, 0≤t≤0.

2.

5. The method for preparing a fully evaporated perovskite-crystalline silicon tandem solar cell according to claim 1, characterized in that: In S2, after the perovskite layer is evaporated, an annealing step is also included, wherein the annealing temperature is 120° C.-170° C. and the time is 10 min-30 min.

6. The method for preparing a fully evaporated perovskite-crystalline silicon tandem solar cell according to claim 1, characterized in that: In S2, the material of the electron transport layer is selected from fullerene and / or 1,3,5-tri(1-phenyl-1H-benzimidazol-2-yl)benzene, and the evaporation rate is 7. The method for preparing a fully evaporated perovskite-crystalline silicon tandem solar cell according to claim 1, characterized in that: In S2, the material of the hole blocking layer is selected from 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline and / or 4,7-diphenyl-1,10-phenanthroline, and the evaporation rate is 8. The method for preparing a fully evaporated perovskite-crystalline silicon tandem solar cell according to claim 1, characterized in that: In S2, the material of the anti-reflection layer is selected from magnesium fluoride and / or zinc sulfide, and the evaporation rate is 9. The method for preparing a fully evaporated perovskite-crystalline silicon tandem solar cell according to claim 1, characterized in that: In S2 and S3, the materials of the top electrode layer and the bottom electrode layer are independently selected from one or more of silver, gold and copper.

10. A fully evaporated perovskite-crystalline silicon tandem solar cell prepared by the method according to any one of claims 1 to 9.

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