Transparent electrode, preparation method thereof and perovskite / silicon heterojunction laminated cell

Abstract

The invention provides a transparent electrode, a preparation method thereof and a perovskite / silicon heterojunction laminated cell, and belongs to the technical field of solar cells. The transparent electrode comprises a TCO barrier layer and a TCO leading functional layer arranged on the TCO barrier layer; the magnetron sputtering power adopted for preparing the TCO barrier layer is first power, the magnetron sputtering power adopted for preparing the TCO leading functional layer is second power, and the second power is higher than the first power; the TCO barrier layer is made of ITO, and the TCO leading function layer is made of IZO. According to the transparent electrode, different magnetron sputtering powers and different materials are adopted to prepare the corresponding TCO barrier layer and the TCO leading functional layer, so that the overall structure effectively reduces the electrical and optical loss of the cell and improves the efficiency of the cell.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cells, and in particular relates to a transparent electrode and a preparation method thereof, and a perovskite / silicon heterojunction stacked cell. Background Art

[0002] Since perovskite is used as the window layer in the perovskite / silicon heterojunction stacked cell, the top cell needs to be a semi-transparent cell. In the semi-transparent perovskite solar cell, the top transparent electrode plays a key role, mainly including light transmission and electron collection. Light transmission: The top transparent electrode has high transparency and can transmit sunlight through the electrode to the semi-transparent perovskite layer, thereby providing energy to the photovoltaic cell; Electron collection: During the photoelectric conversion process, light excites electrons in the semi-transparent perovskite layer to jump from the valence band to the conduction band, and the electrons in the conduction band are collected into the circuit through the top transparent electrode.

[0003] At present, the top transparent electrode is generally made of a transparent conductive oxide film (TCO film), including indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide (AZO), tungsten-doped indium oxide (IWO) or cerium-doped indium oxide (ICO) and other films. The preparation methods of the top transparent electrode include magnetron sputtering, evaporation, electron beam, reactive plasma deposition (RPD) or atomic layer deposition (ALD). However, they are all single-layer TCO films prepared on the surface of the contact layer using a single preparation method.

[0004] For example, patent application document CN114373781A discloses a perovskite / silicon tandem solar cell and its preparation method, and Examples 1-3 all sputter a layer of ITO film on the tin oxide contact layer as a transparent conductive film. For another example, patent application document CN 115347071A discloses a silicon / perovskite three-terminal tandem solar cell structure and its preparation method, and Example 1 uses a magnetron sputtering method to prepare a layer of AZO on the molybdenum oxide contact layer, and Examples 2 and 3 use a magnetron sputtering method to prepare a layer of IZO on the tin oxide contact layer. Summary of the invention

[0005] The present invention is based on the inventors' discovery and understanding of the following facts and problems: if the TCO layer is prepared at high power, the perovskite layer is easily damaged during the coating process, causing a significant decrease in battery efficiency. Therefore, related technologies use low power to prepare a single-layer TCO layer, which cannot simultaneously meet the functional layer's requirements for low resistivity, high transmittance, and excellent interface composite, resulting in an insufficient efficiency of the stacked battery.

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the embodiments of the present invention provide a transparent electrode and a preparation method thereof and a perovskite / silicon heterojunction stacked cell.

[0007] An embodiment of the present invention provides a transparent electrode for a perovskite / silicon heterojunction stacked cell, comprising a TCO barrier layer and a TCO dominant functional layer arranged on the TCO barrier layer; the magnetron sputtering power used to prepare the TCO barrier layer is a first power, and the magnetron sputtering power used to prepare the TCO dominant functional layer is a second power, and the second power is higher than the first power; the TCO barrier layer adopts ITO, and the TCO dominant functional layer adopts IZO.

[0008] The advantages and technical effects brought by the transparent electrode of the embodiment of the present invention are as follows:

[0009] (1) In the transparent electrode of the embodiment of the present invention, the TCO barrier layer can prevent high-power magnetron sputtering from damaging the perovskite functional layer; at the same time, the TCO dominant functional layer is obtained by magnetron sputtering under high power conditions, so it can improve the light transmittance of the transparent electrode, reduce the resistivity of the transparent electrode, and improve its electronic conductivity, which is conducive to the formation of a high short-circuit current density of the final laminated battery product. It can be seen that the TCO barrier layer and the TCO dominant functional layer effectively improve the battery efficiency through the mutual cooperation of different magnetron sputtering powers.

[0010] (2) In the transparent electrode of the embodiment of the present invention, the material of the TCO barrier layer is different from the material used in the TCO dominant functional layer. Compared with IZO, ITO has better light transmittance, which is conducive to the absorption of light by the TCO barrier layer. At the same time, ITO prepared at low power has better interface modification. Although IZO is not as light transmittance as ITO, it has better conductivity. As the top layer of the stacked battery, conductivity plays a leading role. Therefore, the TCO dominant functional layer using IZO material has lower resistivity and higher electronic conductivity, which is conducive to the formation of high short-circuit current density of the final stacked battery product. It can be seen that the photoelectric performance of the transparent electrode is better through the combination of different materials of the TCO barrier layer and the TCO dominant functional layer.

[0011] (3) Compared with the single-layer TCO transparent electrode in the related art, the transparent electrode of the embodiment of the present invention has a higher fill factor (FF) and open circuit voltage (Voc), indicating that its interface recombination is more excellent.

[0012] In some embodiments, the first power is 30-35W.

[0013] In some embodiments, the first power is 35W.

[0014] In some embodiments, the second power is 80-85W.

[0015] In some embodiments, the second power is 80W.

[0016] In some embodiments, the TCO barrier layer has a thickness of 8-12 nm.

[0017] In some embodiments, the thickness of the TCO dominant functional layer is 88-92 nm.

[0018] In addition, an embodiment of the present invention further provides a method for preparing a transparent electrode for a perovskite / silicon heterojunction stacked cell, comprising the following steps:

[0019] S1, using ITO as a target material, performing magnetron sputtering on a substrate at the first power to obtain the TCO barrier layer;

[0020] S2. Using IZO as a target material, magnetron sputtering is performed on the TCO barrier layer at the second power to obtain the TCO dominant functional layer.

[0021] The advantages and technical effects brought by the preparation method of the embodiment of the present invention are:

[0022] (1) The preparation method of the embodiment of the present invention adopts magnetron sputtering to prepare transparent electrodes. The coating adhesion, density and uniformity in a vacuum environment are better. In addition, the magnetron sputtering equipment is simple, easy to control, has a large coating area, and has the advantages of high speed, low temperature and low damage.

[0023] (2) In the preparation method of the embodiment of the present invention, in step S1, the ITO target is first magnetron sputtered at low power, and the formed TCO barrier layer can effectively prevent the magnetron sputtering process in step S2 from damaging the perovskite functional layer. In addition, since the TCO barrier layer is made of ITO material, its light transmittance is high, which is conducive to light absorption;

[0024] (3) In the preparation method of the embodiment of the present invention, in step S2, the IZO target is subjected to high-power magnetron sputtering, and the formed TCO-dominant functional layer has high electronic conductivity. Therefore, the overall structure of the transparent electrode effectively reduces the electrical and optical losses of the battery and improves the battery efficiency.

[0025] (4) The transparent electrode prepared by the preparation method of the embodiment of the present invention has a higher fill factor (FF) and open circuit voltage (Voc) than the single-layer TCO transparent electrode in the related art, indicating that its interface recombination is more excellent.

[0026] In addition, an embodiment of the present invention further provides a perovskite / silicon heterojunction stacked cell, comprising the transparent electrode of the embodiment of the present invention as claimed in the claims, or comprising a transparent electrode obtained by the preparation method of the embodiment of the present invention.

[0027] The advantages and technical effects of the perovskite / silicon heterojunction stacked cell of the embodiment of the present invention are as follows:

[0028] Due to the use of a transparent electrode with high light transmittance, high electronic conductivity and excellent interface recombination, the efficiency of the perovskite / silicon heterojunction stacked cell of the embodiment of the present invention is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a graph of the photoelectric conversion efficiency of the perovskite / silicon heterojunction stacked cells of Example 1, Comparative Example 1, Comparative Example 3 and Comparative Example 4. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0031] An embodiment of the present invention provides a transparent electrode for a perovskite / silicon heterojunction stacked cell, comprising a TCO barrier layer and a TCO dominant functional layer arranged on the TCO barrier layer; the magnetron sputtering power used to prepare the TCO barrier layer is a first power, and the magnetron sputtering power used to prepare the TCO dominant functional layer is a second power, and the second power is higher than the first power; the TCO barrier layer adopts ITO, and the TCO dominant functional layer adopts IZO.

[0032] The transparent electrode of the embodiment of the present invention adopts a double-layer structure formed by a TCO barrier layer and a TCO dominant functional layer. The TCO barrier layer can effectively prevent the high-power magnetron sputtering from damaging the perovskite functional layer during the preparation of the TCO dominant functional layer, thereby improving the battery efficiency. At the same time, the TCO barrier layer located below has high requirements for high light transmittance, so ITO is used to improve its light transmittance. The TCO dominant functional layer is the dominant transparent electrode material layer, and the requirements for low resistivity are greater than high transmittance. Therefore, IZO with better electronic conductivity is required to improve the short-circuit current density. The overall structure of the transparent electrode of the embodiment of the present invention effectively reduces the electrical and optical losses of the battery, and improves the short-circuit current density and fill factor of the battery.

[0033] In some embodiments, the first power is 30-35 W. When the first power is too low, the target material may be difficult to ignite, affecting the preparation of the TCO barrier layer. When the first power is too high, it is not conducive to reducing the damage to the perovskite functional layer during the magnetron sputtering process.

[0034] In some embodiments, the second power is 80-85 W. When the second power is too low, it is not conducive to improving the light transmittance and electronic conductivity of the TCO dominant functional layer. When the second power is too high, even with the presence of the TCO barrier layer, it is not conducive to reducing the damage to the perovskite functional layer during the magnetron sputtering process.

[0035] In some embodiments, the thickness of the TCO barrier layer is 8-12 nm. The function of the TCO barrier layer is mainly to prevent the high-power magnetron sputtering from damaging the perovskite functional layer during the preparation of the TCO dominant functional layer, so a thin TCO barrier layer is sufficient. When the thickness of the TCO barrier layer is too thin, the blocking effect of the TCO barrier layer is limited, which is not conducive to improving the protection effect. When the thickness of the TCO barrier layer is too thick, under the condition that the thickness of the transparent electrode is certain, the thickness of the TCO dominant functional layer will be too thin, which is not conducive to improving the electronic conductivity of the transparent electrode, and thus not conducive to improving the short-circuit current density.

[0036] In some embodiments, the thickness of the TCO dominant functional layer is 88-92nm. The TCO dominant functional layer is the dominant transparent electrode material layer, so the thickness of the TCO dominant functional layer is much greater than the thickness of the TCO barrier layer. When the thickness of the TCO dominant functional layer is too thin, it is not conducive to improving the electronic conductivity of the transparent electrode, and then it is not conducive to improving the short-circuit current density. When the thickness of the TCO dominant functional layer is too thick, under the condition of a certain thickness of the transparent electrode, the thickness of the corresponding TCO barrier layer will be too thin, and the blocking effect of the TCO barrier layer is limited, which is not conducive to improving the protection effect.

[0037] In addition, an embodiment of the present invention further provides a method for preparing a transparent electrode for a perovskite / silicon heterojunction stacked cell, comprising the following steps:

[0038] S1, using ITO as a target material, performing magnetron sputtering on a substrate at the first power to obtain the TCO barrier layer;

[0039] S2. Using IZO as a target material, magnetron sputtering is performed on the TCO barrier layer at the second power to obtain the TCO dominant functional layer.

[0040] It should be noted that the substrate in step S1 refers to a contact layer such as tin oxide, or may be C 60 The electron transport layer needs to be set according to the structure of the battery to be prepared.

[0041] In some embodiments, the pressure in step S1 and step S2 is 1.8-2.2 Pa. The greater the pressure, the lower the vacuum degree, which means that the TCO plasma concentration in the magnetron sputtering chamber is lower. When the pressure in the magnetron sputtering chamber is too small, it is necessary to set a larger magnetron sputtering power to increase the TCO plasma concentration, which is not conducive to controlling the magnetron sputtering power within the preferred range. When the pressure in the magnetron sputtering chamber is too high, it is necessary to set a smaller magnetron sputtering power to reduce the TCO plasma concentration, which is not conducive to controlling the magnetron sputtering power within the preferred range.

[0042] In addition, an embodiment of the present invention further provides a perovskite / silicon heterojunction stacked cell, comprising the transparent electrode of the embodiment of the present invention as claimed in the claims, or comprising a transparent electrode obtained by the preparation method of the embodiment of the present invention.

[0043] Due to the use of transparent electrodes with high light transmittance, high electronic conductivity and excellent interface recombination, the efficiency of perovskite / silicon heterojunction stacked cells can be significantly improved.

[0044] The present invention is described in detail below with reference to the embodiments and the accompanying drawings.

[0045] Example 1

[0046] The method for preparing a transparent electrode and a perovskite / silicon heterojunction stacked cell comprises the following steps:

[0047] (1) Sequentially prepare a perovskite top cell structure on a silicon bottom cell;

[0048] (2) using an ITO target with a target spacing of 19 cm, a 10 nm thick ITO film, i.e., a TCO barrier layer, was prepared on the SnO2 layer by magnetron sputtering at a pressure of 2 Pa and a first power of 35 W;

[0049] (3) Using an IZO target with a target spacing of 19 cm, a 90 nm thick IZO film, i.e., a TCO dominant functional layer, was prepared on the TCO barrier layer by magnetron sputtering at a pressure of 2 Pa and a second power of 80 W;

[0050] (4) Prepare Ag gate lines on the TCO dominant functional layer.

[0051] Example 2

[0052] The preparation method of this embodiment is the same as that of Embodiment 1, except that the first power is 30W and the second power is 85W.

[0053] Example 3

[0054] The preparation method of this embodiment is the same as that of Embodiment 1, except that the first power is 100W.

[0055] Comparative Example 1

[0056] The preparation method of this comparative example is the same as that of Example 1, except that ITO is used as the target material when preparing the TCO dominant functional layer.

[0057] Comparative Example 2

[0058] The preparation method of this comparative example is the same as that of Example 1, except that IZO is used as a target material when preparing the TCO barrier layer.

[0059] Comparative Example 3

[0060] The method for preparing a transparent electrode and a perovskite / silicon heterojunction stacked cell comprises the following steps:

[0061] (1) Sequentially prepare a perovskite top cell structure on a silicon bottom cell;

[0062] (2) Using an ITO target with a target spacing of 19 cm, a 100 nm thick ITO film was prepared on the SnO2 layer by magnetron sputtering at a pressure of 2 Pa and a power of 35 W;

[0063] (3) Prepare Ag gate lines on the ITO film.

[0064] Comparative Example 4

[0065] The method for preparing a transparent electrode and a perovskite / silicon heterojunction stacked cell comprises the following steps:

[0066] (1) Sequentially prepare a perovskite top cell structure on a silicon bottom cell;

[0067] (2) Using an ITO target with a target spacing of 19 cm, a 100 nm thick ITO film was prepared on the SnO2 layer by magnetron sputtering at a pressure of 2 Pa and a power of 80 W;

[0068] (3) Prepare Ag gate lines on the ITO film.

[0069] The photoelectric performance of the perovskite / silicon heterojunction stacked cells prepared in Examples 1-3 and Comparative Examples 1-4 was tested, and the test results are shown in Table 1.

[0070] Table 1. Photovoltaic performance of perovskite / silicon heterojunction stacked cells prepared in Examples 1-3 and Comparative Examples 1-4

[0071]

[0072] From Examples 1-3 and Comparative Example 3 in Table 1, compared with Comparative Example 3 which adopts low power to prepare the transparent electrode of the single-layer ITO layer, after adding the TCO dominant functional layer, Examples 1-3 can significantly improve the short-circuit current and fill factor of the stacked battery, and ultimately improve the photoelectric conversion efficiency of the stacked battery.

[0073] From Examples 1-3 and Comparative Example 4 in Table 1, compared with Comparative Example 4 which adopts high power to prepare the transparent electrode of the single-layer ITO layer, after adding the TCO barrier layer in Examples 1-3, the open circuit voltage, short circuit current and fill factor of the stacked battery can be significantly improved, and finally the photoelectric conversion efficiency of the stacked battery can be improved.

[0074] From Example 1 and Comparative Example 1 in Table 1, compared with the transparent electrode of Comparative Example 1 in which both layers are made of ITO layers, Example 1 improves the open circuit voltage, short circuit current and fill factor of the stacked battery through the mutual cooperation of ITO and IZO, and ultimately improves the photoelectric conversion efficiency of the stacked battery.

[0075] From Example 1 and Comparative Example 2 in Table 1, compared with the transparent electrode of Comparative Example 2 in which both layers are made of IZO layers, Example 1 improves the open circuit voltage, short circuit current and fill factor of the stacked battery through the mutual cooperation of ITO and IZO, and ultimately improves the photoelectric conversion efficiency of the stacked battery.

[0076] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0077] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A transparent electrode for a perovskite / silicon heterojunction stacked cell, characterized in that: It comprises a TCO barrier layer and a TCO dominant functional layer arranged on the TCO barrier layer; the magnetron sputtering power used to prepare the TCO barrier layer is a first power, and the magnetron sputtering power used to prepare the TCO dominant functional layer is a second power, and the second power is higher than the first power; the TCO barrier layer adopts ITO, and the TCO dominant functional layer adopts IZO.

2. The transparent electrode for use in a perovskite / silicon heterojunction stacked cell according to claim 1, characterized in that: The first power is 30-35W.

3. The transparent electrode for use in a perovskite / silicon heterojunction stacked cell according to claim 2, characterized in that: The first power is 35W.

4. The transparent electrode for use in a perovskite / silicon heterojunction stacked cell according to claim 1, characterized in that: The second power is 80-85W.

5. The transparent electrode for use in a perovskite / silicon heterojunction stacked cell according to claim 4, characterized in that: The second power is 80W.

6. The transparent electrode for use in a perovskite / silicon heterojunction stacked cell according to claim 1 or 2, characterized in that: The thickness of the TCO barrier layer is 8-12 nm.

7. The transparent electrode for use in a perovskite / silicon heterojunction stacked cell according to claim 1 or 4, characterized in that: The thickness of the TCO dominant functional layer is 88-92 nm.

8. The method for preparing a transparent electrode for a perovskite / silicon heterojunction stacked cell according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, using ITO as a target material, performing magnetron sputtering on a substrate at the first power to obtain the TCO barrier layer; S2. Using IZO as a target material, magnetron sputtering is performed on the TCO barrier layer at the second power to obtain the TCO dominant functional layer.

9. The method for preparing a transparent electrode for a perovskite / silicon heterojunction stacked cell according to claim 8, characterized in that: The pressure in step S1 and step S2 is 1.8-2.2Pa.

10. A perovskite / silicon heterojunction stacked cell, characterized in that: The transparent electrode comprises the transparent electrode described in any one of claims 1 to 7, or the transparent electrode obtained by the preparation method described in any one of claims 8 to 9.

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