Perovskite photovoltaic device and improved preparation method

Abstract

The invention relates to the technical field of perovskite photovoltaic, in particular to a perovskite photovoltaic device and an improved preparation method. The method comprises a step of preparing one or more ultrathin metal layers on a substrate, and further comprises a step of preparing a perovskite photoactive layer by adopting a low-temperature annealing method, the thickness of the ultrathin metal layer is 1-10 nm, and the temperature of low-temperature annealing is less than or equal to 100 DEG C. According to the method, the ultrathin metal layer is prepared on the substrate, so that the obtained electrode has higher thermal diffusion coefficient and thermal conductivity, and the subsequent step of preparing the perovskite photoactive layer can be carried out under a low-temperature condition, so that the thermal stress of an interface is lower, and the conversion efficiency of the perovskite photovoltaic device is higher; the method is simple in process, high in repeatability and low in cost, and can be used for preparing a large-area perovskite photovoltaic device.

Description

Technical Field

[0001] The present invention relates to the field of perovskite photovoltaic technology, and in particular to a perovskite photovoltaic device and an improved preparation method thereof. Background Art

[0002] Perovskite solar cells have been applied to optoelectronic devices such as photodetectors, light-emitting diodes and solar cells due to their high absorption coefficient, low exciton binding energy and adjustable band gap.

[0003] Current perovskite photovoltaic devices are highly dependent on transparent conductive electrodes such as ITO or FTO. For the interface of flexible or rigid perovskite solar cells, the main challenge comes from the residual stress generated by thermal stress during annealing. Electrode materials with high thermal conductivity are beneficial to reduce the temperature difference between the functional layers of the device or with the heating stage, reduce the temperature gradient at the device interface, and thus reduce thermal stress.

[0004] However, the current electrode thermal conductivity is low, and the annealing temperature is difficult to reduce, which leads to high residual thermal stress in the device during the preparation process, and uneven heating and heating of the perovskite film. This will lead to uneven crystallization of the perovskite film during the preparation process, low conversion efficiency, and difficulty in ensuring quality.

[0005] At present, polymers are generally used to solve the above problems, but polymer modification can only be applied to NIP structure perovskite solar cells, and the scope of application is very narrow. At the same time, the method of using polymers for modification is difficult to apply to large-scale production, and the preparation process also requires additional steps such as ultraviolet irradiation, resulting in cumbersome steps, low efficiency, and increased costs. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a perovskite photovoltaic device and an improved preparation method to solve the problems of low electrode thermal conductivity and high annealing temperature.

[0007] The technical solution of the present invention to solve the above technical problems is as follows:

[0008] The present invention provides an improved preparation method of a perovskite photovoltaic device, comprising the steps of preparing one or more ultra-thin metal layers on a substrate, and also comprising the step of preparing a perovskite photoactive layer by a low temperature annealing method;

[0009] The thickness of the ultra-thin metal layer is 1 nm to 10 nm, and the temperature of the low-temperature annealing is less than or equal to 100° C.

[0010] Based on the above technical solution, the present invention can also be improved as follows.

[0011] Furthermore, the material of the ultra-thin metal layer is metal, and the metal is one of silver, copper, gold, aluminum, sodium, molybdenum, tungsten, zinc, nickel, iron, platinum, tin, and lead.

[0012] Furthermore, the material of the ultra-thin metal layer is an alloy, and the alloy is one of a titanium alloy, an aluminum alloy, and a copper alloy; the metal alloy is any one to ten of Cu, Au, Cs, V, Cr, Fe, Ce, Pt, Pb, Co, Mo, Mn, Ni, Ca, Li, Sn, Ba, Zr, Y, Ta, Mg, Rb, Sr, and Be, and the doped metal is one or more of Cu, Au, Cs, V, Cr, Fe, Ce, Pt, Pb, Co, Mo, Mn, Ni, Ca, Li, Sn, Ba, Zr, Y, Ta, Mg, Rb, Sr, and Be.

[0013] Furthermore, in the metal alloy, the mass percentage of doping is 5% to 50%.

[0014] Furthermore, the number of the ultra-thin metal layers is 1 to 5, and the materials of the ultra-thin metal layers are the same or different.

[0015] Furthermore, the temperature of the low temperature annealing is 50°C to 140°C.

[0016] Furthermore, the substrate is one of quartz sheet, PET, PEN, PI, CPI, PU, ​​and TPU.

[0017] Further, the method further comprises the following steps:

[0018] S1, sputtering and depositing the ultra-thin metal layer on the substrate by a magnetron sputtering method;

[0019] S2, preparing a hole transport layer on the ultra-thin metal layer;

[0020] S3, coating the perovskite photoactive layer precursor solution on the hole transport layer, and performing the low-temperature annealing to obtain the perovskite photoactive layer;

[0021] S4. Sequentially prepare an electron transport layer and a top electrode on the perovskite photoactive layer.

[0022] Furthermore, in step S1, the power of the sputtering deposition is 0.1 to 8 kW, the gas environment of the sputtering deposition includes a working gas and a reaction gas, and the volume flow ratio of the working gas to the reaction gas is 300:0 to 150; the working gas is argon, and the reaction gas includes at least one of oxygen, nitrogen, and ammonia.

[0023] Furthermore, in step S3, the perovskite photoactive layer precursor solution includes one or more of bromide, iodide, fluoride, thiocyanate, and tin.

[0024] Furthermore, in step S3, the coating method is one of a one-step solution spin coating method, a two-step solution spin coating method, a blade coating method, and a slit coating method.

[0025] The present invention also provides a perovskite photovoltaic device, which is prepared by the above method.

[0026] The beneficial effects of the present invention are:

[0027] (1) The improved preparation method of the perovskite photovoltaic device of the present invention provides an ultra-thin metal layer on the substrate, which not only has good light transmittance and electrical conductivity, but also has a higher thermal diffusion coefficient and thermal conductivity than conventional ITO electrodes and FTO electrodes, thereby achieving improvement of the electrode;

[0028] (2) The improved preparation method of the perovskite photovoltaic device of the present invention prepares each layer on the improved motor, so that the subsequent steps of preparing the perovskite photoactive layer can be carried out under low temperature conditions, so that the thermal stress of the interface is lower;

[0029] (3) The improved preparation method of the perovskite photovoltaic device of the present invention can also solve the problem of uneven crystallization caused by the heating and uneven heating of the perovskite film, and the obtained perovskite film has a smaller degree of defects, thereby making the conversion efficiency of the perovskite photovoltaic device higher;

[0030] (4) The improved preparation method of the perovskite photovoltaic device of the present invention has a simple process and high repeatability, can be used to prepare large-area perovskite photovoltaic devices, and has low cost;

[0031] (5) The improved preparation method of the perovskite photovoltaic device of the present invention has strong compatibility with other thin film materials that require annealing processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of the perovskite photovoltaic device of the present invention.

[0033] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0034] 1. Ultra-thin metal layer;

[0035] 10. Substrate; 20. Hole transport layer; 30. Perovskite photoactive layer; 40. Electron transport layer; 50. Top electrode. DETAILED DESCRIPTION

[0036] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0037] like Figure 1 As shown, the improved preparation method of the perovskite photovoltaic device of the present invention includes the step of preparing one or more ultra-thin metal layers 1 on a substrate 10, and also includes the step of preparing a perovskite photoactive layer 30 by a low-temperature annealing method; the thickness of the ultra-thin metal layer 1 is 1nm to 10nm, and the temperature of the low-temperature annealing is less than or equal to 100°C.

[0038] The preparation method of the present invention adds an ultra-thin metal layer 1 on the substrate 10 to form an electrode. The electrode not only has good light transmittance, but also has a higher thermal diffusion coefficient and thermal conductivity than conventional ITO electrodes and FTO electrodes, thereby achieving an improvement on the electrode, so that the subsequent steps of preparing the perovskite photoactive layer 30 can be carried out under low temperature conditions, and the thermal stress of the interface is lower, the defect degree of the obtained perovskite film is smaller, and the conversion efficiency of the perovskite photovoltaic device is higher.

[0039] Preferably, the metal is one of silver, copper, gold, aluminum, sodium, molybdenum, tungsten, zinc, nickel, iron, platinum, tin and lead.

[0040] Preferably, the metal alloy is one of a titanium alloy, an aluminum alloy, and a copper alloy;

[0041] Preferably, the metal alloy is any one to ten of Cu, Au, Cs, V, Cr, Fe, Ce, Pt, Pb, Co, Mo, Mn, Ni, Ca, Li, Sn, Ba, Zr, Y, Ta, Mg, Rb, Sr, and Be, and the doped metal is one or more of Cu, Au, Cs, V, Cr, Fe, Ce, Pt, Pb, Co, Mo, Mn, Ni, Ca, Li, Sn, Ba, Zr, Y, Ta, Mg, Rb, Sr, and Be.

[0042] Preferably, in the metal alloy, the mass percentage of doping is 1% to 60%.

[0043] Further preferably, the mass ratio of doping is 5%, 6.5%, 10%, 12.6%, 15%, 18%, 20%, 25%, 28%, 30%, 35%, 40%, 45%, 50%, etc.

[0044] Further preferably, the thickness of the ultra-thin metal layer 1 is 1 nm, 1.5 nm, 2 nm, 2.3 nm, 3.5 nm, 5 nm, 8 nm, 10 nm, etc.

[0045] Preferably, the number of the ultra-thin metal layers 1 is 1 to 5, and the materials of the ultra-thin metal layers 1 are the same or different.

[0046] Preferably, when the number of ultra-thin metal layers 1 is multiple, the total thickness of each ultra-thin metal layer 1 is 5-10 nm.

[0047] Preferably, the annealing temperature is 50° C. to 100° C.; the annealing temperature is significantly lower than the conventional annealing temperature (above 100° C.), and after the above low-temperature annealing, the crystal quality of the perovskite film can be improved.

[0048] More preferably, the annealing temperature is 50°C, 55°C, 60°C, 63.5°C, 70°C, 80°C, 90°C, 100°C, 120°C, 140°C, etc.

[0049] Preferably, the substrate 10 is a rigid substrate or a flexible substrate.

[0050] Further preferably, the substrate 10 is one of quartz sheet, PET, PEN, PI, CPI, PU, ​​and TPU.

[0051] The method for preparing a perovskite photovoltaic device for increasing thermal conductivity of the present invention further comprises the following steps:

[0052] S1. Using a magnetron sputtering method, the ultra-thin metal layer 1 is sputter-deposited on the substrate 10.

[0053] Among them, the power of sputtering deposition is 1~8kw, the gas environment of sputtering deposition includes working gas and reaction gas, the volume flow ratio of working gas to reaction gas is 300:0~150; the working gas is argon, and the reaction gas includes at least one of oxygen, nitrogen, and ammonia.

[0054] Preferably, the gas environment of the sputtering deposition includes argon and oxygen, and the volume flow ratio of argon to oxygen is 300 sccm: 0-40 sccm.

[0055] Further preferably, the volume flow ratio of argon and oxygen is 300sccm:0, 300sccm:5sccm, 300sccm:10sccm, 300sccm:15sccm, 300sccm:20sccm, 300sccm:25sccm, 300sccm:30sccm, 300sccm:35sccm, 300sccm:40sccm, etc.

[0056] Preferably, after magnetron sputtering is completed, a coil is obtained, and resistance test, light transmittance and thermal conductivity test are performed on the coil, and the coil whose test results meet the standards is post-processed to obtain an electrode.

[0057] Preferably, the resistance test standard is 5-25Ω / sq, the transmittance test standard is an average transmittance of 300-850nm>88%, and the thermal conductivity is 1-5W / mk.

[0058] The above-mentioned sputtering deposition method can make the ultra-thin metal layer 1 uniformly deposited on the substrate 10 without agglomerating to form an island-shaped thin film.

[0059] S2, preparing a hole transport layer 20 on the ultra-thin metal layer 1; the hole transport layer 20 is prepared by a conventional method.

[0060] S3, coating the perovskite photoactive layer precursor solution on the hole transport layer 20, and performing low-temperature annealing to obtain the perovskite photoactive layer 30.

[0061] Preferably, the components of the perovskite photoactive layer precursor solution include one or more of cesium bromide, cesium iodide, methylammonium iodide, methylammonium bromide, methylammonium chloride, formamidine hydroiodide, lead bromide, lead iodide, rubidium iodide, potassium iodide, lead thiocyanate, propylene diiodoamine, stannous iodide, tin fluoride, and tin powder.

[0062] Further preferably, the components of the perovskite photoactive layer precursor solution include formamidine hydroiodide, lead iodide and methylammonium chloride, and these components are mixed to obtain a perovskite precursor solution of FAPbI3.

[0063] Preferably, the coating method is one of a one-step solution spin coating method, a two-step solution spin coating method, a blade coating method, and a slit coating method.

[0064] S4, sequentially preparing an electron transport layer 40 and a top electrode 50 on the perovskite photoactive layer 30.

[0065] The above-mentioned preparation method of the present invention can solve the problem of residual thermal stress of the device. By preparing the perovskite photoactive layer on the electrode with high thermal conductivity, the residual thermal stress generated during the annealing process can be reduced. Specifically, by improving the deposition of one or more ultra-thin metal layers 1 by magnetron sputtering, the role of transparent electrode is achieved. Compared with the ordinary electrode material 0.4mm 2 / s and a thermal diffusion coefficient and thermal conductivity of 0.77W / (m·K). The thermal diffusion coefficient of the electrode of the present invention can reach 1 to 2 mm 2 / s, the thermal conductivity can reach 2.5~3.5W / (m·K), which can achieve lower annealing temperature and higher crystallinity of perovskite film.

[0066] The preparation method of the present invention can also solve the problem of uneven crystallization caused by heating and uneven heating of the perovskite film. The perovskite mesophase film is heated quickly and evenly through a lower annealing temperature, thereby forming a uniform and dense perovskite film.

[0067] Compared with other methods for increasing thermal conductivity and reducing thermal stress, the method of the present invention can achieve the goals of high repeatability, large area application and low cost without complicated processes. At the same time, it has strong compatibility with other thin film materials that require annealing processes.

[0068] The present invention is illustrated below by means of specific examples and comparative examples.

[0069] Example

[0070] This embodiment adopts the preparation method of the present invention to prepare a perovskite photovoltaic device. The layer structure of the photovoltaic device is a substrate 10, an ultra-thin metal layer 1, a hole transport layer 20, a perovskite photoactive layer 30, an electron transport layer 40 and a top electrode 50.

[0071] The substrate 10 is PEN, the ultra-thin metal layer 1 is titanium alloy, the doped metal is Pb with a mass percentage of 8.5%, the ultra-thin metal layer 1 has one layer and a thickness of 2.5 nm.

[0072] During the preparation process, the power of sputtering deposition is 8kw, and the gas environment of sputtering deposition includes argon and oxygen, and the volume flow ratio of argon and oxygen is 300sccm:40sccm. The vacuum degree of magnetron sputtering is 10 -4 Pa, the pulling speed of the substrate 10 is 1.5 m / min.

[0073] The electrode prepared in this example has a thermal diffusion coefficient of 1.5 mm 2 / s, thermal conductivity is 3W / (m·K).

[0074] A hole transport layer 20, a perovskite photoactive layer 30, an electron transport layer 40 and a top electrode 50 are sequentially prepared on the above-mentioned electrode.

[0075] The precursor solution of the perovskite photoactive layer 30 is CsFAPb I3, and the coating method is a one-step solution spin coating method. The low-temperature annealing temperature is 80°C.

[0076] Comparative Example 1

[0077] This comparative example is a flexible perovskite photovoltaic device based on a polymer elastomer. The electrode of the device is an ITO transparent electrode, a polymer elastomer is arranged between the electron transport layer and the perovskite active layer, and the other layer structures are the same as those in the embodiment.

[0078] The polymer elastomer has low intermolecular force, flexibility and elongation. The thermal diffusivity of the polymer elastomer is 0.5mm 2 / s, and the thermal conductivity is 1.07W / (m·K), which is much lower than that of the electrode in the embodiment. At the same time, the perovskite active layer of the comparative example is difficult to prepare by low temperature annealing.

[0079] Due to the characteristics of the elastomer, devices based on this elastomer can only be applied to NIP structured perovskite solar cells and cannot be applied to large-area devices. At the same time, the material needs to be spin-coated, heated, and cooled to a specified temperature before being irradiated with ultraviolet light. This preparation process is complicated and has low repeatability. In addition, the spin coating method is not suitable for large-scale production. Usually, the spin coating method is limited to laboratory preparation and cannot be industrialized.

[0080] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0081] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0082] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0083] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 specific features, structures, materials or characteristics described 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.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An improved method for preparing a perovskite photovoltaic device, characterized in that: The method comprises the steps of preparing one or more ultra-thin metal layers (1) on a substrate (10), and also comprises the step of preparing a perovskite photoactive layer (30) by a low-temperature annealing method; The thickness of the ultra-thin metal layer (1) is 1 nm to 10 nm, and the temperature of the low-temperature annealing is less than or equal to 100° C.

2. The improved preparation method of a perovskite photovoltaic device according to claim 1, characterized in that: The material of the ultra-thin metal layer (1) is metal, and the metal is one of Cu, Au, Cs, V, Cr, Fe, Ce, Pt, Pb, Co, Mo, Mn, Ni, Ca, Li, Sn, Ba, Zr, Y, Ta, Mg, Rb, Sr, and Be.

3. The improved preparation method of a perovskite photovoltaic device according to claim 1, characterized in that: The material of the ultra-thin metal layer (1) is an alloy, and the components of the alloy include a high thermal conductivity metal and a doped metal, the high thermal conductivity metal is any one to ten of Cu, Au, Cs, V, Cr, Fe, Ce, Pt, Pb, Co, Mo, Mn, Ni, Ca, Li, Sn, Ba, Zr, Y, Ta, Mg, Rb, Sr, and Be, and the doped metal is one or more of Cu, Au, Cs, V, Cr, Fe, Ce, Pt, Pb, Co, Mo, Mn, Ni, Ca, Li, Sn, Ba, Zr, Y, Ta, Mg, Rb, Sr, and Be.

4. The improved preparation method of a perovskite photovoltaic device according to claim 3, characterized in that: In the metal alloy, the mass percentage of the doped metal is 1% to 60%.

5. The improved preparation method of a perovskite photovoltaic device according to claim 1, characterized in that: The number of layers of the ultra-thin metal layer (1) is 1 to 5, and the materials of each layer of the ultra-thin metal layer (1) are the same or different.

6. The improved preparation method of a perovskite photovoltaic device according to claim 1, characterized in that: The temperature of the low temperature annealing is 50°C to 140°C.

7. The improved preparation method of a perovskite photovoltaic device according to claim 1, characterized in that: The substrate (10) is one of quartz sheet, PET, PEN, PI, CPI, PU and TPU.

8. An improved method for preparing a perovskite photovoltaic device according to any one of claims 1 to 7, characterized in that: The following steps are also included: S1. sputtering and depositing the ultra-thin metal layer (1) on the substrate (10) by a magnetron sputtering method; S2, preparing a hole transport layer (20) on the ultra-thin metal layer (1); S3, coating a perovskite photoactive layer precursor solution on the hole transport layer (20), and performing the low-temperature annealing to obtain the perovskite photoactive layer (30); S4, sequentially preparing an electron transport layer (40) and a top electrode (50) on the perovskite photoactive layer (30).

9. The improved preparation method of a perovskite photovoltaic device according to claim 8, characterized in that: In step S1, the power of the sputtering deposition is 0.1-8kw, the gas environment of the sputtering deposition includes working gas and reaction gas, and the volume flow ratio of the working gas to the reaction gas is 300:0-150; the working gas is argon, and the reaction gas includes at least one of oxygen, nitrogen, and ammonia.

10. The improved preparation method of a perovskite photovoltaic device according to claim 8, characterized in that: In step S3, the perovskite photoactive layer precursor solution includes one or more of bromide, iodide, fluoride, thiocyanate, and tin.

11. The improved preparation method of a perovskite photovoltaic device according to claim 8, characterized in that: In step S3, the coating method is one of a one-step solution spin coating method, a two-step solution spin coating method, a blade coating method, and a slit coating method.

12. A perovskite photovoltaic device, characterized in that: The method is prepared by any one of claims 1 to 11.

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