Photovoltaic device, preparation method, power utilization device and power generation device

Abstract

The invention relates to a photovoltaic device, a preparation method, a power utilization device and a power generation device. The photovoltaic device comprises a hole transport layer and a perovskite layer which are arranged in a stacked mode. The perovskite layer comprises a first perovskite material, and the hole transport layer comprises nickel oxide; recording the thickness direction of the perovskite layer as a Z direction; the hole transport layer comprises bivalent nickel ions and trivalent nickel ions; marking the molar ratio of divalent nickel ions to trivalent nickel ions as RNi < 2 + > / 3 +; rNi < 2 + > / 3 + in the hole transport layer is greater than 0 and less than 1; on a projection plane perpendicular to the Z direction, the Moran index of RNi < 2 + > / 3 + in the hole transport layer is low, for example, the Moran index is smaller than or equal to 0.4. The photovoltaic device has improved photoelectric conversion efficiency.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and further to photovoltaic devices, preparation methods, electrical devices, and power generation devices. Background Technology

[0002] Photovoltaic devices (PV devices) are optoelectronic devices that convert light energy into electrical energy using a photoelectric conversion mechanism. A typical application of PV devices is the solar cell. With the development of photovoltaic technology, solar cells are increasingly widely used in distributed photovoltaic power generation systems, off-grid power systems, and in portable electronic devices providing power for outdoor applications. The photoelectric conversion efficiency of a PV device reflects its ability to absorb incident light and is one of the core indicators for evaluating its performance. Improving the photoelectric conversion efficiency of PV devices remains a crucial research topic in the field of photovoltaic technology. Summary of the Invention

[0003] According to various embodiments and examples of this application, a photovoltaic device, a fabrication method, an electrical device, and a power generation device are provided. The photovoltaic device has improved photoelectric conversion efficiency.

[0004] In some embodiments of the first aspect of this application, a photovoltaic device is provided, comprising a hole transport layer and a perovskite layer stacked thereon; the perovskite layer comprises a first perovskite material, and the hole transport layer comprises nickel oxide; the thickness direction of the perovskite layer is denoted as the Z direction;

[0005] The hole transport layer comprises divalent nickel ions and trivalent nickel ions; the molar ratio of divalent nickel ions to trivalent nickel ions is denoted as R. Ni2+ / 3+ ;

[0006] R in the hole transport layer Ni2+ / 3+ Greater than 0 and less than 1;

[0007] On the projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ The Moran index is less than or equal to 0.4.

[0008] In the aforementioned photovoltaic device, the hole transport material in the hole transport layer includes nickel oxide, and the R in the hole transport layer is controlled. Ni2+ / 3+ The value is greater than 0 and less than 1. At this time, the trivalent nickel ions (Ni) in the hole transport layer 3+ The content is higher than that of divalent nickel ions (Ni). 2 + The content of ) through the self-doping effect of trivalent nickel ions can provide a higher concentration of vacancies in the lattice, which is beneficial to improving the hole transport capability of the hole transport layer; furthermore, R Ni2+ / 3+The lower Moran index on the projection plane perpendicular to the Z direction indicates better in-plane uniformity of trivalent nickel ion doping concentration in the hole transport layer. This suggests higher uniformity of trivalent nickel ion doping, greater continuity of the hole transport path, and a more uniform distribution of the built-in electric field, all of which contribute to hole transport. Furthermore, the uniform doping of trivalent nickel ions stabilizes the work function and HOMO level of nickel oxide, forming a more stable alignment with the valence band top of perovskite, thus promoting efficient hole extraction. Through these multiple effects, the photoelectric conversion efficiency of photovoltaic devices can be significantly improved. It is understood that we do not wish to be limited to the aforementioned theories.

[0009] In some embodiments of this application, R in the hole transport layer Ni2+ / 3+ The value is 0.5~0.9, and can be selected as 0.6~0.8.

[0010] By controlling R in the hole transport layer Ni2+ / 3+ Within the aforementioned range, the hole transport capability of the hole transport layer can be improved through the self-doping effect of trivalent nickel ions throughout the entire hole transport layer. It can also better control the probability of redox reactions that trivalent nickel ions may have with perovskite, thereby achieving good intrinsic stability of perovskite. This can improve the photoelectric conversion efficiency of the device while also achieving good device stability.

[0011] In some embodiments of this application, on a projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ The Moran index is less than or equal to 0.35. At this point, the doping concentration of trivalent nickel ions in the hole transport layer has better in-plane uniformity, which is beneficial for achieving continuity of the hole transport path and improving hole transport capability. In addition, uniform distribution can reduce excessively high local trivalent nickel ion concentration, reduce the probability of trivalent nickel ions reacting with the first perovskite material, and thus better improve the photoelectric conversion efficiency of photovoltaic devices.

[0012] In some embodiments of this application, the difference between the maximum and minimum thickness of the hole transport layer is denoted as Δh, wherein Δh is less than or equal to 5 nm and the percentage of Δh to the average thickness of the hole transport layer is less than or equal to 25%;

[0013] Optionally, Δh is a percentage of the average thickness of the hole transport layer that is less than or equal to 20%.

[0014] At this point, the hole transport layer has a relatively uniform thickness, which is beneficial for providing uniform in-plane hole transport capability, better suppressing local accumulation of interface charge, and improving the photoelectric conversion efficiency of the device.

[0015] In some embodiments of this application, the average thickness of the hole transport layer is greater than or equal to 10 nm. This allows for better coverage of the perovskite layer, providing uniform and effective hole transport capability, which is beneficial for achieving higher photoelectric conversion efficiency.

[0016] In some embodiments of this application, the average thickness of the hole transport layer is 10 nm to 50 nm. This achieves good coverage of the perovskite layer, provides good hole collection efficiency and uniform, effective hole transport capability, better controls the resistance of the hole transport layer, and facilitates better in-plane uniformity of trivalent nickel ion self-doping, thus improving photoelectric conversion efficiency.

[0017] In some embodiments of this application, the nickel oxide in the hole transport layer and the first perovskite material in the perovskite layer have a coherent structure at the interface. In this case, the nickel oxide crystal and the perovskite crystal have better lattice matching. Better lattice matching leads to better electron cloud sharing characteristics and reduces interface defects, thereby improving the hole transport capability of the hole transport interface and ultimately enhancing photoelectric conversion efficiency.

[0018] In some embodiments of this application, the hole transport layer has a surface B1 facing the perovskite layer, and the Moran index of the potential distribution at the surface B1 of the hole transport layer is less than or equal to 0.4, optionally less than or equal to 0.35; wherein the potential at the surface B1 is obtained by measuring the potential of the hole transport surface B1 using a Kelvin atomic force microscope.

[0019] By controlling the potential distribution at surface B1 of the hole transport layer within the aforementioned range, a more uniform potential distribution can be achieved at the interface near the perovskite layer in the hole transport layer. This facilitates more uniform and efficient extraction of holes at the transport interface, thereby improving photoelectric conversion efficiency. Furthermore, it also enhances the stability of the hole transport interface, thus improving device stability.

[0020] In some embodiments of this application, the perovskite layer has a first surface facing the hole transport layer and a second surface opposite to the first surface in the Z direction; a first region with a thickness of 5 nm to 10 nm exists in the perovskite layer from the first surface to a range extending 30 nm toward the interior of the perovskite layer; the first region is located between the first surface and the second surface;

[0021] The absolute value of the energy difference between the Fermi level and the valence band top of the first perovskite material in the first region is denoted as E1, and the absolute value of the energy difference between the Fermi level and the conduction band bottom of the first perovskite material in the first region is denoted as E2, where E1 <E2。

[0022] At this point, the Fermi level at the interface near the hole transport layer in the perovskite layer is closer to the top of the valence band. This is beneficial for improving the energy level matching with the hole transport layer at the perovskite layer interface, thereby improving the efficiency of hole collection and transport, and further enhancing the photoelectric conversion efficiency.

[0023] In some embodiments of this application, the difference between E2 and E1 of the first perovskite material in the first region is 1.0 eV to 1.5 eV, and can be optionally 1.0 eV to 1.2 eV. In this case, the degree of shift of the Fermi level phase towards the top of the valence band at the interface near the hole transport layer in the perovskite layer can be better controlled, which is beneficial to achieving better energy level matching at the interface and improving photoelectric conversion efficiency.

[0024] In some embodiments of this application, the perovskite layer has a first surface facing the hole transport layer; the Moran index of the potential distribution at the first surface of the perovskite layer is less than or equal to 0.4, optionally less than or equal to 0.35; wherein the potential at the first surface is obtained by measuring the potential of the first surface of the perovskite layer using a Kelvin atomic force microscope.

[0025] By controlling the potential distribution at the first surface of the perovskite layer within the aforementioned range, it is beneficial to achieve a more uniform potential distribution at the interface near the hole transport layer in the perovskite layer. This, in turn, facilitates more uniform and efficient extraction of holes at the perovskite interface, thereby improving photoelectric conversion efficiency. Furthermore, it also helps to improve the stability of the perovskite interface, which in turn enhances device stability.

[0026] In some embodiments of this application, the thickness of the perovskite layer is 200nm~1500nm, and can be selected as 400nm~1000nm.

[0027] When the thickness of the perovskite layer is within the aforementioned range, it can not only enable the perovskite layer to have high light absorption capacity, achieve better short-circuit current density and open-circuit voltage, but also help to better match the thickness of the perovskite layer with the effective diffusion length of photogenerated carriers, thereby enabling the carriers to be collected more effectively, which is conducive to achieving higher photoelectric conversion efficiency overall.

[0028] In some embodiments of this application, the area of ​​the perovskite layer on a projection plane perpendicular to the Z direction is greater than or equal to 0.09 cm². 2 Optionally, greater than or equal to 1m 2 .

[0029] The aforementioned methods for improving device performance can be implemented over a relatively large device area. Furthermore, they can uniformly improve the hole transport capability at the hole transport interface over a relatively large device area, which is beneficial for improving the photoelectric conversion efficiency of large-area devices. In addition, they can also achieve better stability for large-area devices.

[0030] In some embodiments of this application, the photovoltaic device satisfies one or more of the following features:

[0031] (c1) The photovoltaic device has an inverted structure or a formal structure;

[0032] (c2) The photovoltaic device further includes an electron transport layer, which is disposed on the side of the perovskite layer away from the hole transport layer;

[0033] (c3) The photovoltaic device includes a first electrode and a second electrode, the hole transport layer and the perovskite layer are both disposed between the first electrode and the second electrode, and the hole transport layer is located between the perovskite layer and the first electrode.

[0034] The aforementioned embodiments can be universally applied to photovoltaic devices with either conventional or inverted structures, thereby improving photoelectric conversion efficiency. Furthermore, they can achieve better device stability. In particular, inverted photovoltaic devices can achieve higher photoelectric conversion efficiency.

[0035] In some embodiments of this application, the hole transport layer is located on the light-incident side of the perovskite layer. In this case, light mainly enters the perovskite layer from the hole transport layer, and the location where the perovskite layer is excited by photons to generate charge carriers mainly occurs at the interface near the hole transport layer. Through the aforementioned scheme, the hole transport layer can efficiently and uniformly collect and transport holes, achieving a high photoelectric conversion efficiency.

[0036] In some embodiments of this application, the photovoltaic device includes a first electrode, a hole transport layer, a perovskite layer, an electron transport layer, and a second electrode stacked together. The hole transport layer, the perovskite layer, and the electron transport layer are all located between the first electrode and the second electrode. The hole transport layer and the electron transport layer are respectively located on both sides of the perovskite layer. The hole transport layer is located between the perovskite layer and the first electrode, and the electron transport layer is located between the perovskite layer and the second electrode. The first electrode is the light-incident electrode.

[0037] At this point, light can enter from the first electrode, and the interface of the perovskite layer near the hole transport layer is excited by photons to generate carrier pairs. At this point, holes can be efficiently and uniformly extracted and transported by the hole transport layer, achieving high photoelectric conversion efficiency.

[0038] In some embodiments of this application, the photovoltaic device includes a solar cell, which includes the hole transport layer and the perovskite layer stacked together.

[0039] The aforementioned hole transport layer and perovskite layer can be incorporated into solar cells to improve their photoelectric conversion efficiency. Furthermore, this can also lead to higher device stability.

[0040] In some embodiments of this application, the photovoltaic device includes a solar cell, which is a multi-junction solar cell. The multi-junction solar cell includes a first cell unit, which includes the hole transport layer and the perovskite layer stacked together.

[0041] The aforementioned hole transport layer and perovskite layer can be incorporated into multi-junction solar cells to improve their photoelectric conversion efficiency. Furthermore, this can also achieve higher device stability.

[0042] When solar cells are multi-junction solar cells, they are advantageous in improving the utilization rate of incident light, while also retaining the aforementioned advantages of high photoelectric conversion efficiency. Multi-junction solar cells can be monolithic integrated tandem solar cells or mechanically tandem solar cells, offering flexibility in form and a wide range of applications.

[0043] In some embodiments of this application, the multi-junction solar cell further includes a second cell stacked with the first cell; the second cell and the first cell are connected by an interconnect layer, or the second cell and the first cell are isolated by an insulating layer; the second cell includes a second light-absorbing layer, and the band gap of the second light-absorbing layer is different from that of the perovskite layer.

[0044] In this way, by setting up multiple light-absorbing layers with different band gaps, multi-junction solar cells can effectively absorb light of different wavelengths, broaden the spectral range of light absorbed by multi-junction solar cells, and improve the photoelectric conversion efficiency of multi-junction solar cells.

[0045] In some embodiments of this application, the second light-absorbing layer in the second battery cell includes a second semiconductor active material, which includes one or more of the following: a second perovskite material, a silicon-containing semiconductor material, copper zinc tin sulfide, copper zinc tin selenide, copper zinc tin selenide sulfide, copper indium gallium selenide, copper indium gallium diselenide, copper indium selenide, cadmium telluride, gallium arsenide, and organic active materials.

[0046] The aforementioned embodiments can be universally applied to the aforementioned different types of multi-junction solar cells.

[0047] In some embodiments of this application, the multi-junction solar cell includes a first electrode, a perovskite layer, an interconnect layer, a second light-absorbing layer, and a second electrode stacked together. The interconnect layer is located between the perovskite layer and the second light-absorbing layer. The first electrode is located on the side of the perovskite layer facing away from the interconnect layer, and the second electrode is located on the side of the second light-absorbing layer facing away from the interconnect layer. Thus, two cell units in the multi-junction solar cell are connected through the interconnect layer to achieve current matching between the two cell units. This results in a relatively smaller size, the ability to absorb light of different wavelengths, a wider absorption spectrum range for the multi-junction solar cell, and an improved photoelectric conversion efficiency. In some embodiments of this application, the hole transport layer is located between the first electrode and the perovskite layer.

[0048] In some embodiments of this application, the multi-junction solar cell includes a first electrode, a perovskite layer, a third electrode, an insulating layer, a fourth electrode, a second light-absorbing layer, and a second electrode stacked together. The third electrode, the insulating layer, and the fourth electrode are stacked between the perovskite layer and the second light-absorbing layer. The third electrode is disposed on the side of the insulating layer facing the perovskite layer, the fourth electrode is disposed on the side of the insulating layer facing the second light-absorbing layer, the first electrode is located on the side of the perovskite layer away from the third electrode, and the second electrode is located on the side of the second light-absorbing layer away from the fourth electrode. Thus, the multi-junction solar cell forms a mechanically stacked cell. The insulating layer isolates the two cell units, preventing direct conduction of charge carriers and eliminating the need for current matching. Furthermore, each cell has its own separate positive and negative electrodes for current extraction, allowing for flexible circuit adjustments. In some embodiments of this application, the hole transport layer is located between the first electrode and the perovskite layer.

[0049] In some embodiments of the second aspect of this application, a method for fabricating a photovoltaic device is provided, comprising the following steps:

[0050] The substrate is preheated, and physical vapor deposition is performed on the substrate using a nickel oxide target under the condition of introducing an oxidizing gas. A first annealing is performed at a first temperature to form a hole transport layer; wherein the first temperature is higher than or equal to 140°C, and the hole transport layer comprises nickel oxide.

[0051] A perovskite precursor solution is coated on the surface of the hole transport layer and then vacuum dried to remove some of the solvent, forming a perovskite mesophase film layer. The perovskite precursor solution comprises a perovskite precursor material and a solvent. The perovskite mesophase film layer includes a second region close to the hole transport layer and a third region far from the hole transport layer. The second region is located between the hole transport layer and the third region, and the solvent residue in the second region is higher than that in the third region.

[0052] The perovskite intermediate phase film layer is subjected to a second annealing at a second temperature, and then to a third annealing at a third temperature to form a perovskite layer; wherein the second temperature is lower than the third temperature; and the duration of the second annealing at the second temperature is shorter than the duration of the third annealing at the third temperature.

[0053] The photovoltaic device described in the first aspect of this application can be prepared;

[0054] In some embodiments, the formed perovskite layer comprises a first perovskite material; the thickness direction of the perovskite layer is denoted as the Z direction; the hole transport layer comprises divalent nickel ions and trivalent nickel ions; R in the hole transport layer Ni2+ / 3+ Greater than 0 and less than 1; on the projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ The Moran index is less than or equal to 0.4.

[0055] The aforementioned method prepares a hole transport layer containing nickel oxide via physical vapor deposition under the condition of introducing an oxidizing gas. The oxidizing gas increases interstitial oxygen, thereby inducing some divalent nickel ions to transform into trivalent nickel ions with higher oxidation states, achieving self-doping of trivalent nickel ions. This provides a higher concentration of vacancies in the lattice, which is beneficial for improving hole transport capability at the interface. Furthermore, the hole transport layer formed by physical vapor deposition has a relatively uniform distribution, effectively suppressing nickel oxide agglomeration and improving the in-plane uniformity of nickel oxide distribution. Moreover, the oxidizing gas can uniformly contact the physical vapor deposition layer, achieving better in-plane uniformity of the trivalent nickel ion doping ratio, resulting in high continuity of the hole transport path and a more uniform distribution of the built-in electric field, which is conducive to hole transport. Simultaneously, the uniform doping of trivalent nickel ions also promotes greater stability of the work function and HOMO energy level of nickel oxide, forming a more stable alignment relationship with the valence band top of perovskite, promoting efficient hole extraction. Therefore, the photoelectric conversion efficiency of the prepared photovoltaic device can be significantly improved.

[0056] In the above preparation method, vacuum drying is used to remove part of the solvent, forming a perovskite mesophase film layer containing residual solvent. The amount of residual solvent at the lower interface (near the hole transport layer, such as the second region) is higher than that at the upper interface (far from the hole transport layer, such as the third region). Gradient annealing is then performed at a second and a third temperature to form the perovskite layer. The selective anchoring effect of the hole transport layer on ions with different charge states in the perovskite precursor solution is utilized (for example, when the perovskite precursor solution simultaneously contains monovalent formamidinium cations (FA...)). + ) and divalent lead ions (Pb 2+ When the hole transport layer is in use, it can preferentially anchor the FA. + The residual solvent with its gradient distribution also aids in the migration of ions in the perovskite precursor solution, which is conducive to the formation of an energy level structure at the lower interface of the perovskite layer where the Fermi level is closer to the top of the valence band (VBM).

[0057] Furthermore, the uniform doping of trivalent nickel ions, the gradient distribution of residual solvent, and the gradient annealing at the second and third temperatures work together to better coordinate the selective anchoring effect of the hole transport layer and the auxiliary migration effect of the residual solvent, thereby helping to moderately enhance the approach of the Fermi level at the lower interface of the perovskite layer to the top of the valence band.

[0058] It's understandable that they don't want to be limited to the aforementioned theories.

[0059] The above method, which involves physical vapor deposition and post-treatment annealing under oxidizing gas conditions, can effectively control the crystallization of the hole transport layer, achieve effective and uniform trivalent nickel ion self-doping effect, and enable the hole transport layer to achieve more efficient conductivity and better energy level matching with perovskite.

[0060] Furthermore, the hole transport layer and perovskite layer formed by the aforementioned method exhibit good lattice matching at the interface. For example, nickel oxide crystal and perovskite crystal can form a coherent structure.

[0061] By doping with trivalent nickel ions, the energy level structure at the interface near the hole transport layer in the perovskite layer can be optimized, bringing the Fermi level of the first perovskite material closer to the valence band top. This improves the energy level matching between the perovskite layer and the hole transport layer at the perovskite layer interface, enhancing hole collection and transport efficiency, and ultimately improving photoelectric conversion efficiency. Furthermore, by controlling the amount of trivalent nickel ion doping, the degree to which the Fermi level of the first perovskite material at the hole transport layer side interface approaches the valence band top can be adjusted.

[0062] By utilizing the energy level modulation effect of nickel oxide on the perovskite material at the perovskite layer interface and the good lattice matching characteristics between nickel oxide and perovskite, the perovskite components can be induced to form perovskite crystals with excellent crystallinity, which is beneficial to improving photoelectric conversion efficiency.

[0063] For example, at the interface of the perovskite layer near the hole transport layer, an energy level structure with the Fermi level closer to the top of the valence band can be formed. This is beneficial for improving the energy level matching with the hole transport layer at the perovskite layer interface, improving the collection and transport efficiency of holes, and further improving the photoelectric conversion efficiency.

[0064] As another example, an improved uniform potential distribution can be formed at the interface near the hole transport layer in the perovskite layer, which facilitates more uniform and efficient extraction of holes at the perovskite interface, thus improving photoelectric conversion efficiency. Furthermore, the improved uniformity of the potential distribution at the perovskite layer interface also enhances the stability of the perovskite interface, thereby improving device stability.

[0065] The above-described preparation method is applicable to the fabrication of large-area devices, and can obtain a hole transport layer with excellent hole transport capability over a large area. Furthermore, based on the hole transport layer, a large-area perovskite layer with excellent crystallinity and uniformity can be obtained. The perovskite layer formed by the above method exhibits excellent large-area uniformity.

[0066] In some embodiments of this application, the method for fabricating the photovoltaic device satisfies one or more of the following features:

[0067] (d1) The substrate includes a first electrode;

[0068] (d2) In the step of preheating the substrate, the preheating temperature is 90℃~110℃, and the preheating time is 5min~15min; at this time, it is beneficial to make the nickel source generated by the nickel oxide target more effective and uniform in physical vapor deposition, and to make the molar ratio of divalent nickel ions to trivalent nickel ions (R) more uniform. Ni2+ / 3+ Within a suitable range and with good uniformity of distribution, R Ni2+ / 3+ It exhibits good in-plane uniformity;

[0069] (d3) The oxidizing gas includes oxygen and hydrogen peroxide gas; at this time, it is beneficial to improve the dispersion of the oxidizing gas and improve the problem that the molecules are prone to aggregation when using a single type of oxidizing gas, resulting in uneven oxidation of the film; at the same time, it is also possible to control the oxidizing property of the oxidizing gas more precisely, which is beneficial to obtaining a hole transport layer film with more uniform oxidation valence state of nickel.

[0070] Optionally, the volume ratio of oxygen to hydrogen peroxide in the oxidizing gas is 70:30 to 99:1; in this case, the oxidizing power of the oxidizing gas can be controlled to a more suitable degree, which is more conducive to obtaining a hole transport layer film with more uniformity and more controllable oxidation valence state of nickel.

[0071] (d4) The gas flow rate of the oxidizing gas is 1 sccm to 5 sccm; at this time, the oxidation state of nickel in nickel oxide can be better controlled, and the ratio of divalent nickel ions to trivalent nickel ions can be better controlled.

[0072] (d5) The physical vapor deposition method includes magnetron sputtering;

[0073] (d6) The first temperature is 140℃~160℃, and the duration of the first annealing is 5min~25min; at this time, it is beneficial to better control the degree of reaction between nickel and oxidizing gas, thereby better controlling the doping ratio of trivalent nickel ions.

[0074] (d7) The temperature for vacuum drying is 5℃~15℃, the pressure for vacuum drying is 1Pa~20Pa, and the duration for vacuum drying is 5s~40s.

[0075] (d8) The second temperature is 85℃~95℃, and the third temperature is 110℃~120℃;

[0076] (d9) The duration of the second annealing is 2 min to 5 min, and the duration of the third annealing is 5 min to 10 min.

[0077] By controlling one or more parameters such as substrate preheating parameters, the composition and flow rate of the oxidizing gas, and the annealing temperature and duration of the first annealing, the doping ratio and uniformity of trivalent nickel ions can be effectively controlled. For example, by increasing the oxidizing power of the oxidizing gas, increasing the flow rate of the oxidizing gas, increasing the annealing temperature (T1) of the first annealing, and extending the annealing duration (t1) of the first annealing, the degree of reaction between nickel and the oxidizing gas can be increased, thereby increasing the doping ratio of trivalent nickel ions.

[0078] By controlling parameters such as temperature, pressure, and duration during the vacuum drying process, the solvent removal rate can be controlled, thereby better controlling the amount of solvent residue at the upper and lower interfaces of the perovskite layer and the gradient between the solvent residue at the upper and lower interfaces (where the interface of the perovskite layer on the hole transport layer side is denoted as the lower interface, and the interface on the other side of the perovskite layer in the thickness direction is denoted as the upper interface), thus finely controlling the energy level structure of the perovskite material in the interface region (such as the first region) near the hole transport layer.

[0079] In the step of forming the perovskite layer, by controlling one or more parameters such as the temperature, pressure and duration of vacuum drying, the temperature and duration of the second annealing, and the temperature and duration of the third annealing, the energy level structure of the perovskite material in the interface region (such as the first region) near the hole transport layer in the perovskite layer can be well controlled.

[0080] In the step of forming the perovskite layer, by controlling one or more parameters such as the temperature, pressure and duration of vacuum drying, the temperature and duration of the second annealing, and the temperature and duration of the third annealing, the crystallization quality of the perovskite can be well controlled. For example, the uniformity of the potential distribution in the interface region (such as the first region) near the hole transport layer in the perovskite layer can be well controlled.

[0081] In some embodiments of this application, a photovoltaic device as described in the first aspect of this application is obtained.

[0082] In some embodiments of the third aspect of this application, an electrical device is provided, which includes at least one of the photovoltaic device described in the first aspect of this application and the photovoltaic device prepared by the method of preparing the photovoltaic device described in the second aspect of this application.

[0083] In some embodiments of the fourth aspect of this application, a power generation device is provided, which includes at least one of the photovoltaic device described in the first aspect of this application and the photovoltaic device prepared by the method of preparing the photovoltaic device described in the second aspect of this application.

[0084] Both power-consuming and power-generating devices, including those using the aforementioned photovoltaic devices, can leverage the advantages of photovoltaic devices.

[0085] Details of one or more embodiments or examples of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0086] To better describe and illustrate the embodiments, examples, or models provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments, examples, or models, or the best mode of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. It should also be noted that the drawings are drawn in a simplified form and are only intended to facilitate and clarify the illustration of this application. The various dimensions of each part shown in the drawings are arbitrarily shown and may be precise or not drawn to scale. For example, the dimensions of parts are appropriately exaggerated in some places in the drawings to make the illustration clearer. Unless otherwise specified, the parts in the drawings are not drawn to scale. This application does not limit every dimension of every part. In the drawings:

[0087] Figure 1 This is a schematic diagram of a portion of the structure of a photovoltaic device according to an embodiment of this application. The photovoltaic device includes a hole transport layer and a perovskite layer stacked together. The hole transport layer has a surface B1 facing the perovskite layer and a surface B2 that is opposite to surface B1 in the Z direction. The perovskite layer has a first surface facing the hole transport layer and a second surface that is opposite to the first surface in the Z direction.

[0088] Figure 2 This is a schematic diagram of a portion of the structure of a photovoltaic device according to an embodiment of this application. The photovoltaic device includes a hole transport layer and a perovskite layer stacked together. The perovskite layer has a first surface facing the hole transport layer and includes a first region near the first surface.

[0089] Figure 3 This is a schematic diagram of a portion of the structure of a photovoltaic device according to an embodiment of this application. The photovoltaic device includes a hole transport layer, a perovskite layer, and an electron transport layer stacked together, with the perovskite layer located between the hole transport layer and the electron transport layer.

[0090] Figure 4 yes Figure 1 In one embodiment of the structure shown, the hole transport layer is located on the light-incident side of the perovskite layer.

[0091] Figure 5 This is a schematic diagram of the structure of a photovoltaic device according to an embodiment of the present application. The photovoltaic device includes a first electrode, a hole transport layer, a perovskite layer, an electron transport layer and a second electrode stacked together. In the thickness direction of the perovskite layer, the hole transport layer and the electron transport layer are respectively disposed on both sides of the perovskite layer. The first electrode is disposed on the side of the hole transport layer away from the perovskite layer, and the second electrode is disposed on the side of the electron transport layer away from the perovskite layer.

[0092] Figure 6This is a schematic diagram of the structure of a photovoltaic device with an inverted structure according to an embodiment of this application. The photovoltaic device includes an incident electrode, a hole transport layer, a perovskite layer, an electron transport layer, and a back electrode stacked together. In the thickness direction of the perovskite layer, the hole transport layer and the electron transport layer are respectively disposed on both sides of the perovskite layer. The incident electrode is disposed on the side of the hole transport layer away from the perovskite layer, and the back electrode is disposed on the side of the electron transport layer away from the perovskite layer.

[0093] Figure 7 This is a schematic diagram of the structure of a photovoltaic device according to an embodiment of this application. The photovoltaic device includes a light-incident electrode, an electron transport layer, a perovskite layer, a hole transport layer, and a back electrode stacked together. In the thickness direction of the perovskite layer, the hole transport layer and the electron transport layer are respectively disposed on both sides of the perovskite layer. The light-incident electrode is disposed on the side of the electron transport layer away from the perovskite layer, and the back electrode is disposed on the side of the hole transport layer away from the perovskite layer.

[0094] Figure 8 This is a schematic diagram of the structure of a photovoltaic device according to an embodiment of this application. The photovoltaic device includes a substrate layer, a first electrode, a first charge transport layer, a perovskite layer, a second charge transport layer, and a second electrode stacked together. In the thickness direction of the perovskite layer, the first charge transport layer and the second charge transport layer are respectively disposed on both sides of the perovskite layer. It can be understood that one of the first charge transport layer and the second charge transport layer is a hole transport layer and the other is an electron transport layer. The first electrode is disposed on the side of the first charge transport layer away from the perovskite layer, the second electrode is disposed on the side of the second charge transport layer away from the perovskite layer, and the substrate layer is disposed on the side of the first electrode away from the perovskite layer.

[0095] Figure 9 This is a schematic diagram of the structure of a photovoltaic device according to an embodiment of this application. The photovoltaic device is provided with a first channel region, a second channel region and a third channel region.

[0096] Figure 10 This is a schematic diagram of an electrical device according to one embodiment of this application, in which a photovoltaic device is used as a power generation device.

[0097] Explanation of reference numerals in the attached figures:

[0098] 20, Photovoltaic device; 100, Perovskite layer; Z, Thickness direction of perovskite layer; B1, Surface B1; B2, Surface B2; 110, First region; 101, First surface; 102, Second surface; 610, Hole transport layer; 620, Electron transport layer; 310, First charge transport layer; 320, Second charge transport layer; 410, First electrode; 420, Second electrode; 500, Substrate layer; 700, Light-incident side electrode; 800, Back electrode; P1, First channel; P2, Second channel; P3, Third channel; 6, Electrical device.

[0099] It should be noted that, Figure 2 The dashed lines marked within the perovskite layer only indicate the positions of the corresponding areas on both sides in the thickness direction of the perovskite layer, but do not mean that the marked areas form an interface of different phases with the adjacent parts within the perovskite layer; in some embodiments, the phases on both sides shown by the dashed lines are continuously distributed. Detailed Implementation

[0100] The following describes in detail, with appropriate reference to the accompanying drawings, some embodiments and examples of the photovoltaic device, manufacturing method, power supply device, and power generation device of this application. However, some unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0101] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be included or excluded independently and can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0" and "5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when describing a parameter as an integer ≥ 2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 for that parameter. For instance, when describing a parameter as an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0102] In this application, the term "numerical value" includes the number itself and its reasonable approximations. The definition of "numerical value" can apply to discrete numerical points or to the endpoints of a numerical range. Unless otherwise specified, the term "approximation" covers a numerical interval based on a reasonable range of fluctuations of the number itself. This reasonable range of fluctuations can vary depending on the type and magnitude of the number. This reasonable range of fluctuations can be reasonably determined based on the accuracy of the testing or measurement method. Therefore, when referring to a numerical value or a numerical range, unless otherwise specified, it should be understood that the numerical value includes its reasonable approximation, and the numerical range includes reasonable approximations at both endpoints. Those skilled in the art will understand that acceptable fluctuation ranges of the relevant approximations can be included within the definition of the numerical value or the numerical range. In this application, unless otherwise specified, "N1" can be reasonably understood as "about N1," and "N1~N2" can be reasonably understood as "about N1 to about N2," where N1 and N2 are two unequal numerical values.

[0103] In this application, unless otherwise specified, "about" means within a reasonable range above and below the number, and the range of fluctuation may vary depending on the type and value of the number. For example, a range of ±10%, ±5%, ±2%, ±1% may be allowed.

[0104] In this application, the terms "multiple," "various," or "multiple items" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one item or two or more (greater than or equal to) items. It can be understood that when "any number of" items are involved, it refers to any suitable combination of multiple items, that is, a combination of "any number of" items in a manner that does not conflict and enables the implementation of this application.

[0105] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0106] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0107] Those skilled in the art will understand that, unless otherwise specified, the order in which the steps are written in the various embodiments or methods of this application does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of this application may be performed sequentially or randomly, but are preferably performed sequentially. For example, if method M includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, method M may also include step (c), meaning that step (c) can be added to method M in any order. For example, method M may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0108] In this application, open-ended technical features or solutions described using terms such as "containing," "comprising," or "including" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, if 'a' includes a1, a2, and a3, it may also include other members or exclude additional members unless otherwise specified. This can be considered as providing both features or solutions where "a consists of a1, a2, and a3" or "a is selected from a1, a2, and a3," and features or solutions where "a includes not only a1, a2, and a3, but also other members."

[0109] In this application, unless otherwise specified, M (e.g., m1) means that m1 is a non-limiting example of M, and it is understood that M is not limited to m1.

[0110] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "with" or "without." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. Unless otherwise specified, the descriptions such as "optionally include" and "optionally contain" in this application, taking "optionally include" as an example, mean "may include or not include."

[0111] In this application, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. Any and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "M and / or N" represents the group consisting of M, N, and "a combination of M and N". "Containing M and / or N" can mean "containing M, containing N, and containing both M and N", or "containing M, containing N, or containing both M and N", and can be appropriately understood according to the context.

[0112] In this document, the word "suitable" in "suitable combination" or "suitable method" refers to the technical solution that can implement this application.

[0113] In this document, terms such as "preferred," "better," and "good" are merely descriptions of implementation methods or embodiments that achieve better results and should be understood not to limit the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "preferred" term shall be independent.

[0114] In this application, terms such as "further," "even more," "especially," "for example," "as," "example," and "exemplary" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0115] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0116] In this application, the term "room temperature" generally refers to 4℃~35℃, and may refer to 20℃±5℃. In some embodiments or examples of this application, room temperature refers to 20℃~30℃.

[0117] In this application, when a unit is specified for a data range, if the unit is only followed by the right endpoint, it indicates that the units for the left and right endpoints are the same. For example, 3~5μm or 3-5μm both mean that the unit for the left endpoint "3" and the right endpoint "5" is μm (micrometer), and both have the same meaning as 3μm~5μm. Furthermore, similar descriptions of other parameters such as temperature and concentration are interpreted in the same way.

[0118] In this application, unless otherwise specified, wt% means weight percentage, which is numerically equal to the corresponding mass percentage.

[0119] In the description of the embodiments or examples of this application, the terms "center", "longitudinal", "lateral", "length", "height", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc., indicating the orientation or positional relationship are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of this application.

[0120] In this application, unless otherwise expressly specified and limited, in the device structure, the first feature "above" or "below" the second feature can be in direct contact with the first feature, or indirect contact between the first and second features through an intermediate medium. In this application, unless otherwise expressly specified and limited, the first feature "above" or "below" the second feature can indicate a horizontal relative position, or it can simply indicate the existence of an attachment relationship without specifying a horizontal relative position.

[0121] In this application, the exemplary descriptions such as "in some implementations (or embodiments)" and "in one implementation (or embodiment)" may cover, but are not limited to, the following meanings: these solutions can be combined with other solutions in a suitable manner to form new technical solutions.

[0122] In this application, the terms "first surface," "second surface," "first region," "second region," "third region," "first charge transport layer," "second charge transport layer," "first electrode," "second electrode," "third electrode," "fourth electrode," "first channel region," "second channel region," "third channel region," "first battery cell," "second battery cell," "first charge carrier," "second charge carrier," "third charge carrier," "fourth charge carrier," "first temperature," "first light absorption layer," "second light absorption layer," "first perovskite material," "second perovskite material," "third perovskite material," "second temperature," "first solvent," and "second solvent," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features.

[0123] In this application, unless otherwise specified, "layered arrangement" refers to the description of the stacking direction between layered structures and does not constitute a limitation on the structural composition of the stacked body. For example, "including stacked structural layer A and structural layer B" means that the stacking direction of structural layer A and structural layer B is along their respective thickness directions; that is, the thickness direction of structural layer A is consistent with or substantially consistent with the thickness direction of structural layer B. It is understood that structural layer A and structural layer B can be arranged adjacent to each other, and it is also permissible to arrange other intermediate structural layers between structural layer A and structural layer B.

[0124] Unless otherwise stated, the improvements described in this application are not intended to be limited to any theoretical constraints.

[0125] In this application, unless otherwise specified, a "photovoltaic device" is a photoelectric device capable of converting light energy into electrical energy using a photoelectric conversion mechanism. The core structural layer for photoelectric conversion in a photovoltaic device is the active layer, which includes a semiconductor active material. In a photovoltaic device, the semiconductor active material absorbs photons to generate carrier pairs (which are electron-hole pairs), and this active layer can be called a "light-absorbing layer" or "light-absorbing layer." Photovoltaic devices can achieve the conversion of light energy into electrical energy through any suitable mechanism. The active layer in a photovoltaic device can generate carrier pairs (which are electron-hole pairs) under the excitation of incident photons, and the flow of electrons and holes generates current, thereby achieving the conversion from light energy to electrical energy. The source of light energy includes solar energy, but is not limited to it. Examples of applications of photovoltaic devices may include, but are not limited to, solar cells.

[0126] In this application, unless otherwise specified, "active layer" refers to a structural layer comprising a semiconductor active material. The semiconductor active material can be any suitable type of semiconductor active material capable of photoelectric conversion. Non-limiting examples of semiconductor active materials may include one or more of perovskite materials, silicon-containing semiconductor materials, copper zinc tin sulfide, copper zinc tin selenide, copper zinc tin selenide sulfide, copper indium gallium selenide, copper indium gallium diselenide, copper indium selenide, cadmium telluride, and organic active materials. Exemplarily, the semiconductor active material may include one or more of perovskite materials, gallium arsenide (GaAs), cadmium telluride (CdTe), copper indium selenide (CIGS), and organic active materials.

[0127] In this application, unless otherwise specified, "solar cell" refers to a battery capable of converting solar energy into electrical energy using a photoelectric conversion mechanism. It is understood that a solar cell includes a light-absorbing layer. When the light-absorbing layer comprises perovskite material, the solar cell is a "perovskite solar cell".

[0128] In some embodiments of this application, when the photovoltaic device is operating, after the light-absorbing layer is illuminated, the internal electrons gain energy and break free from the binding force of the light-absorbing layer to form negatively charged electron carriers, and simultaneously form positively charged hole carriers, thus generating electron-hole pairs. The free electrons and free holes propagate in opposite directions, causing electrons and holes to flow and forming an external current, thereby realizing the conversion of light energy into electrical energy. Furthermore, after the light-absorbing layer absorbs photons, it is stimulated to generate electron-hole pairs. These pairs further dissociate to form free carriers with opposite charges. The free electrons propagate towards the negative electrode, and the free holes propagate towards the positive electrode. Both types of free carriers are collected by their respective electrodes, further forming a photocurrent in the circuit of the photovoltaic device.

[0129] In some embodiments of this application, in a photovoltaic device, free electrons are transported to the negative electrode through an electron transport layer, and free holes are transported to the positive electrode through a hole transport layer. The two types of free carriers are collected by their respective electrodes, and further form a photocurrent in the circuit of the photovoltaic device.

[0130] In photovoltaic devices, the electron transport layer can extract and transport electron carriers and block free holes from passing through.

[0131] In photovoltaic devices, the hole transport layer can extract and transport hole carriers and block free electrons from passing through.

[0132] In this application, unless otherwise specified, from the perspective of the type of semiconductor active material, photovoltaic devices in which the active layer includes perovskite material can be referred to as "perovskite devices". The active layer in a perovskite device can be referred to as a "perovskite layer".

[0133] In this application, unless otherwise specified, "perovskite layer" refers to the active layer comprising perovskite material. The perovskite layer has a certain thickness, for example, but not limited to 100nm~2000nm, and optionally 200nm~1500nm.

[0134] In this application, unless otherwise specified, the perovskite layer has two opposing surfaces, referred to as the first surface and the second surface, in a direction substantially perpendicular to the thickness direction (Z direction) of the perovskite layer. The distance between the first surface and the second surface approximately corresponds to the thickness of the perovskite layer. In some embodiments of this application, the first surface and the second surface of the perovskite layer respectively contact different structural layers disposed adjacent to the perovskite layer. In some embodiments, the first surface and the second surface of the perovskite layer respectively contact different charge transport layers.

[0135] In some embodiments of this application, the perovskite layer has a first surface and a second surface that are opposite to each other in the thickness direction of the perovskite layer; typically, the first surface and the second surface are substantially perpendicular to the thickness direction of the perovskite layer.

[0136] In this application, the "thickness direction of the perovskite layer" can be denoted as the Z-direction. Typically, the first and second surfaces of the perovskite layer are substantially perpendicular to the Z-direction. It can be understood that when a photovoltaic device includes a hole transport layer stacked with the perovskite layer, the thickness direction of the hole transport layer is substantially aligned with the Z-direction.

[0137] The photoelectric conversion efficiency (PCE) of a photovoltaic (PV) device reflects its ability to absorb incident light and is one of the core indicators for evaluating PV device performance. Taking perovskite solar cells as an example, the interfacial charge transport capability is crucial for achieving high efficiency. Specifically, the structure and quality of the hole transport layer significantly impact device efficiency. Nickel oxide hole transport layers have gained widespread industrial application due to their excellent intrinsic stability and outstanding hole transport capability. However, with the increasing crystallinity of nickel oxide, nickel oxide nanofilms are prone to nanoparticle aggregation, which prevents the formation of a continuous crystal field structure, leading to a weakening of hole transport capability.

[0138] Doping the interface of the hole transport layer with high-valence cations may increase the intrinsic hole concentration and thus improve the hole transport capability; however, high-valence cations such as trivalent iron have strong oxidizing properties, which can easily cause interface energy level pinning, affecting the efficiency of interface charge transport, and also easily affecting device stability.

[0139] Therefore, it is necessary to further optimize the hole transport capability of the hole transport layer containing nickel oxide.

[0140] According to various embodiments and examples of this application, a photovoltaic device, a fabrication method, an electrical device, and a power generation device are provided. The photovoltaic device has improved photoelectric conversion efficiency.

[0141] In some embodiments of this application, a photovoltaic device is provided, comprising a hole transport layer and a perovskite layer stacked together; the perovskite layer comprises a first perovskite material, and the hole transport layer comprises nickel oxide; the molar ratio (R0) of divalent nickel ions to trivalent nickel ions in the hole transport layer is specified. Ni2+ / 3+ R is greater than 0 and less than 1; on the projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ The Moran index is low; for example, R in the hole transport layer. Ni2+ / 3+ The Moran index on the projection plane perpendicular to the Z direction is less than or equal to 0.4.

[0142] It is understood that the perovskite layer includes a perovskite material (denoted as the first perovskite material). In some embodiments of this application, the first perovskite material accounts for more than or equal to 95% of the mass of the perovskite layer, and may be selected as 95% to 100%.

[0143] In this application, "divalent nickel ion" can be represented as Ni 2+ "Trivalent nickel ion" can be represented as Ni 3+ .

[0144] In this application, the molar ratio (Ri) of divalent nickel ions to trivalent nickel ions is involved. Ni2+ / 3+ Unless otherwise specified, “N” refers to the molar amount (N) of divalent nickel ions within a certain region. 2+ ) and the molar amount of trivalent nickel ions (N 3+ The ratio of R to ) Ni2+ / 3+ =N 2+ / N 3+ For example, R in the hole transport layer Ni2+ / 3+ It refers to the ratio of the molar amount of divalent nickel ions in the hole transport layer to the molar amount of trivalent nickel ions in the hole transport layer.

[0145] It is understandable that the molar ratio (R0) of divalent nickel ions to trivalent nickel ions... Ni2+ / 3+ Numerically, it can be equal to the average molar volume concentration of divalent nickel ions in the same region (C). 2+ The average molar volume concentration C of trivalent nickel ions 3+ The ratio of (i.e., R) Ni2+ / 3+ =C 2+ / C 3+ ).

[0146] It is understandable that when R Ni2+ / 3+ When the value is greater than 0 and less than 1, the hole transport layer includes divalent nickel ions and trivalent nickel ions, and the content of trivalent nickel ions is higher than that of divalent nickel ions.

[0147] Figure 1 This is a schematic diagram of a portion of the structure of a photovoltaic device according to an embodiment of this application. The photovoltaic device includes a hole transport layer 610 and a perovskite layer 100 stacked together. The hole transport layer 610 has a surface B1 facing the perovskite layer 100 and a surface B2 that is opposite to the surface B1 in the Z direction. The perovskite layer 100 has a first surface 101 facing the hole transport layer 610 and a second surface 102 that is opposite to the first surface 101 in the Z direction.

[0148] Figure 2 This is a schematic diagram of a portion of the structure of a photovoltaic device according to an embodiment of this application. The photovoltaic device includes a hole transport layer 610 and a perovskite layer 100 stacked together. The perovskite layer 100 has a first surface 101 facing the hole transport layer 610, and the perovskite layer 100 includes a first region 110 adjacent to the first surface 101. It can be understood that the first region 110 is located between the first surface 101 and the second surface 102.

[0149] In this application, unless otherwise specified, "first region" is the interface region in the perovskite layer near the first surface, and the characteristics of the first region can reflect the characteristics of the interface region in the perovskite layer near the hole transport layer.

[0150] The first region has a relatively thin thickness (e.g., 5nm~10nm), which can match the detection depth during X-ray photoelectron spectroscopy (XPS) detection and the detection depth during energy level testing, such as the detection depth when using ultraviolet photoelectron spectroscopy (UPS) to test energy levels.

[0151] In some embodiments of this application, a region with a thickness of 5 nm to 10 nm that exists in the perovskite layer from the first surface to a range extending 30 nm toward the interior of the perovskite layer is referred to as the first region.

[0152] In some embodiments of the first aspect of this application, a photovoltaic device is provided, which includes a hole transport layer and a perovskite layer stacked together; the perovskite layer includes a first perovskite material, and the hole transport layer includes nickel oxide; the thickness direction of the perovskite layer is denoted as the Z direction;

[0153] The hole transport layer consists of divalent nickel ions and trivalent nickel ions; the molar ratio of divalent nickel ions to trivalent nickel ions is denoted as R. Ni2+ / 3+ ;

[0154] R in the hole transport layer Ni2+ / 3+ Greater than 0 and less than 1;

[0155] On the projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ The Moran index is less than or equal to 0.4.

[0156] In the aforementioned photovoltaic device, the hole transport material in the hole transport layer includes nickel oxide, and the R in the hole transport layer is controlled. Ni2+ / 3+ The value is greater than 0 and less than 1. At this time, the trivalent nickel ions (Ni) in the hole transport layer 3+ The content is higher than that of divalent nickel ions (Ni). 2 + The content of ) through the self-doping effect of trivalent nickel ions can provide a higher concentration of vacancies in the lattice, which is beneficial to improving the hole transport capability of the hole transport layer; furthermore, R Ni2+ / 3+The lower Moran index on the projection plane perpendicular to the Z direction indicates better in-plane uniformity of trivalent nickel ion doping concentration in the hole transport layer. This suggests higher uniformity of trivalent nickel ion doping, greater continuity of the hole transport path, and a more uniform distribution of the built-in electric field, all of which contribute to hole transport. Furthermore, the uniform doping of trivalent nickel ions stabilizes the work function and HOMO level of nickel oxide, forming a more stable alignment with the valence band top of perovskite, thus promoting efficient hole extraction. Through these multiple effects, the photoelectric conversion efficiency of photovoltaic devices can be significantly improved. It is understood that we do not wish to be limited to the aforementioned theories.

[0157] Unless otherwise stated in this application, "the molar ratio of divalent nickel ions to trivalent nickel ions (R...)" Ni2+ / 3+ "(")" can be obtained through X-ray photoelectron spectroscopy (XPS). Instruments such as Thermo Fisher Scientific ESCALAB Qxi can be used to perform in-plane full elemental scanning or selected elemental scanning on the exposed surface of the area to be tested, which can obtain the elemental distribution information of the region corresponding to the detection depth, including element type, element valence state, and molar ratio of elements with different valence states.

[0158] Elemental distribution information and three-dimensional distribution maps at different depths can be obtained by sputtering the sample surface layer by layer and combining it with full elemental scanning. The depth sampling depth of XPS testing is 0.5 nm to 10 nm, and it can be achieved through ion sputtering (such as Ar). + C +0 The sample is peeled off layer by layer using either a cluster ion beam or an ion beam. After each layer is peeled off, an XPS full spectrum or a specific elemental spectrum (including at least the constituent elements of nickel oxide) is acquired. The thickness of each layer can be adjusted according to the thickness of the sample to be tested.

[0159] R in the hole transport layer Ni2+ / 3+ It can be calculated based on XPS scan results at different thickness locations in the hole transport layer of the test sample, using the sum of the counts of divalent nickel ions at different thickness locations (Q). 2+ The sum of the counts of ions and trivalent nickel ions (Q) 3+ R is calculated from the ratio of ) Ni2+ / 3+ =Q 2+ / Q 3+ Argon ion beams (Ar) can be used. + Layer-by-layer sputtering etching is used to expose the surface under test or the cross-section under test at different thicknesses.

[0160] Based on the three-dimensional distribution map of the XPS scan results, the divalent nickel ion count and trivalent nickel ion count structure of the signal acquisition area corresponding to different thickness locations can also be calculated. Furthermore, the total divalent nickel ion count (Q) of the entire hole transport layer of the test sample can be obtained. 2+ The sum of the counts of ions and trivalent nickel ions (Q)3+ ), and then calculate R Ni2+ / 3+ This is easily implemented by those skilled in the art.

[0161] In this application, unless otherwise stated, "Moran's I" has a well-known statistical meaning and is a classic statistic used to measure spatial autocorrelation. In this application, it is used to measure the uniformity of spatial data point distribution. When the Moran's I is approximately 0, there is no significant spatial correlation, corresponding to random uniformity of data points. When the Moran's I is greater than 0, the larger the value, the stronger the positive correlation of data points, the more obvious the "clustering" or "patching" characteristics of the data point distribution, and the worse the uniformity of data point distribution. When the Moran's I is less than 0, the data points show a significant negative correlation, with high and low values ​​regularly repelling and interleaving each other. In the extreme case, when it approaches -1, high and low values ​​maximize mutual repulsion and interleaving.

[0162] Unless otherwise stated, this application relates to R Ni2+ / 3+ The Moran's index of the potential distribution, where the corresponding Moran's index is greater than or equal to 0. In some embodiments, the Moran's index is greater than 0. Exemplarily, in some embodiments, MLI E2 Greater than or equal to 0, optionally, MLI E2 Greater than 0.

[0163] In this application, the analysis object of the Moran index can include various types of in-plane information, including but not limited to "the molar ratio of divalent nickel ions to trivalent nickel ions (Rm)". Ni2+ / 3+ ")", select the potential distribution at the surface or cross section, etc.

[0164] Unless otherwise stated, all references to R in this application shall be construed as R. Ni2+ / 3+ When using parameters such as electrical potential data for Moran's index analysis, the following parameters are processed in the following manner:

[0165] 1. Parameters to be analyzed at different locations: Obtain the values ​​of the parameters to be analyzed at different locations within the region to be analyzed.

[0166] 2. Calculate the Moran index (I) using the selected statistical formula:

[0167]

[0168] Where n is the number of data points; W is the sum of all weights; ij x is an element in the spatial weight matrix; i and x j These are the parameter values ​​for the i-th and j-th positions; This is the average value of all position parameter values.

[0169] 3. Setting the spatial weight matrix:

[0170] The spatial weight matrix uses inverse distance weights, i.e. ,in The distance between the i-th and j-th positions is... p is the distance attenuation parameter; unless otherwise specified, p is 2.

[0171] 4. Statistical area and sampling interval of data points: The statistical area is 10 μm × 10 μm, and the sampling interval of data points is 50 nm.

[0172] In some embodiments of this application, R in the hole transport layer Ni2+ / 3+ The range is 0.5 to 0.9, and can be selected from 0.6 to 0.8. It can also be any of the following values ​​or a range composed of any two of the following values: 0.5, 0.52, 0.54, 0.55, 0.56, 0.58, 0.6, 0.62, 0.64, 0.65, 0.66, 0.68, 0.7, 0.72, 0.74, 0.75, 0.76, 0.78, 0.8, 0.82, 0.84, 0.85, 0.86, 0.88, 0.9, etc.

[0173] By controlling R in the hole transport layer Ni2+ / 3+ Within the aforementioned range, the hole transport capability of the hole transport layer can be improved through the self-doping effect of trivalent nickel ions throughout the entire hole transport layer. It can also better control the probability of redox reactions that trivalent nickel ions may have with perovskite, thereby achieving good intrinsic stability of perovskite. This can improve the photoelectric conversion efficiency of the device while also achieving good device stability.

[0174] In some embodiments of this application, on a projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ Moran's Index (MLI) Ni ) less than or equal to 0.4, optionally, MLI Ni Less than or equal to 0.35; in addition, MLI Ni It can also be less than or equal to any of the following values, or greater than or equal to 0 and less than or equal to any of the following values, or greater than 0 and less than or equal to any of the following values, or be any of the following values ​​or a range selected from any two of the following values: 0, 0.02, 0.04, 0.05, 0.06, 0.08, 0.10, 0.12, 0.14, 0.15, 0.16, 0.18, 0.20, 0.22, 0.24, 0.25, 0.26, 0.28, 0.30, 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, etc. Further optionally, on the projection plane perpendicular to the Z direction, R in the hole transport layer... Ni2+ / 3+The Moran index is greater than 0. At this point, the doping concentration of trivalent nickel ions in the hole transport layer has better in-plane uniformity, which is beneficial for achieving continuity of the hole transport path and improving hole transport capability. In addition, uniform distribution can reduce excessively high local trivalent nickel ion concentration, reduce the probability of trivalent nickel ions reacting with the first perovskite material, and thus better improve the photoelectric conversion efficiency of photovoltaic devices.

[0175] In some embodiments of this application, on a projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ Moran's Index (MLI) Ni () is greater than 0.

[0176] In this application, the difference between the maximum and minimum thickness of the hole transport layer is denoted as Δh, and the average thickness of the hole transport layer can be denoted as h. m Δh and h m The ratio can be denoted as P. Δh P Δh =Δh / h m ×100%.

[0177] In some embodiments of this application, Δh is less than or equal to 5 nm, and may also be less than or equal to any of the following values ​​or a range selected from any two of the following values: 0 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, etc.

[0178] In some embodiments of this application, P Δh Less than or equal to 25%, optionally, P Δh Less than or equal to 20%, P Δh It can also be less than or equal to any of the following percentages or a range consisting of any two of the following percentages: 0.1%, 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 24%, 25%, etc.

[0179] In some embodiments of this application, the difference between the maximum and minimum thickness of the hole transport layer is denoted as Δh, where Δh is less than or equal to 5 nm and Δh is a percentage of the average thickness of the hole transport layer (P). Δh ) less than or equal to 25%, optionally, Δh is a percentage of the average thickness of the hole transport layer (P Δh ) less than or equal to 20%; in addition, P ΔhIt can also be less than or equal to any of the following percentages or a range consisting of any two of the following percentages: 0.1%, 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 24%, 25%, etc.

[0180] Based on the scanning electron microscope (SEM) test images of the longitudinal section of the photovoltaic device, the thickness of each functional layer (including the hole transport layer, perovskite layer, etc.) can be measured. Non-limiting examples of SEM instruments include the Sigma 300 scanning electron microscope from ZEISS GmbH, Germany; the EVO 15 backscatter scanning electron microscope from ZEISS GmbH, Germany; the Zeiss SUPRA 55; and the Apreo 2 SEM field emission scanning electron microscope.

[0181] In this application, unless otherwise specified, "the longitudinal section of the photovoltaic device" refers to the section obtained by cutting along the thickness direction of the perovskite layer, which is substantially parallel to the thickness direction (Z direction) of the perovskite layer.

[0182] At this point, the hole transport layer has a relatively uniform thickness, which is beneficial for providing uniform in-plane hole transport capability, better suppressing local accumulation of interface charge, and improving the photoelectric conversion efficiency of the device.

[0183] In some embodiments of this application, the average thickness of the hole transport layer is greater than or equal to 10 nm. This allows for better coverage of the perovskite layer, providing uniform and effective hole transport capability, which is beneficial for achieving higher photoelectric conversion efficiency.

[0184] In some embodiments of this application, the average thickness of the hole transport layer is 10 nm to 50 nm, optionally 15 nm to 50 nm, further optionally 20 nm to 50 nm, and may also be any of the following thicknesses or a range selected from any two of the following thicknesses: 10 nm, 12 nm, 14 nm, 15 nm, 16 nm, 18 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc. This achieves better coverage of the perovskite layer, provides better hole collection efficiency and uniform and effective hole transport capability, better controls the resistance of the hole transport layer, and facilitates better in-plane uniformity of trivalent nickel ion self-doping, thus improving photoelectric conversion efficiency.

[0185] In some embodiments of this application, nickel oxide in the hole transport layer and the first perovskite material in the perovskite layer have a coherent structure at the interface. In this case, the nickel oxide crystal and the perovskite crystal have better lattice matching, which can improve the hole transport capability of the hole transport interface and thus better improve the photoelectric conversion efficiency.

[0186] In this application, unless otherwise stated, the term "coherent" in crystal has a well-known meaning in the field of crystallography, which means that the atomic arrangement of the crystals on both sides of the interface is highly matched, and the atoms at the interface are simultaneously located at the nodes of the two adjacent phase lattices and are shared by the two adjacent crystal structures.

[0187] Whether the crystal structure at the two-phase interface is coherent depends primarily on the degree of atomic matching between the crystals on both sides of the interface. The core criterion is whether the atoms at the interface simultaneously occupy nodes in both phase lattices, i.e., lattice continuity and mismatch. The following method can be used to determine whether the crystal structure at the two-phase interface is coherent: A coherent interface requires complete atomic matching at the interface, meaning that the atoms on the interface simultaneously belong to lattice nodes in both phases, and the two phase lattices are seamlessly connected at the interface without local distortion. For semi-coherent interfaces, mismatch is adjusted by periodically introducing dislocations.

[0188] Focused ion beam and transmission electron microscopy (HRTEM) methods, in high-resolution mode, can be used to observe the coherence and misalignment of atoms at the interface between nickel oxide in the hole transport layer and the perovskite phase in the perovskite layer. For example, an HRTEM instrument can be used.

[0189] In some embodiments of this application, the hole transport layer has a surface B1 facing the perovskite layer, and the potential distribution at the surface B1 of the hole transport layer has a Moran index (MLI). HP ) less than or equal to 0.4, optionally, MLI HP Less than or equal to 0.35; in addition, MLI HP The potential can also be less than or equal to any of the following values, greater than or equal to 0 and less than or equal to any of the following values, greater than 0 and less than or equal to any of the following values, or a range consisting of any of the following values ​​or any two of the following values: 0, 0.02, 0.04, 0.05, 0.06, 0.08, 0.10, 0.12, 0.14, 0.15, 0.16, 0.18, 0.20, 0.22, 0.24, 0.25, 0.26, 0.28, 0.30, 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, etc.; wherein, the potential at surface B1 is obtained by measuring the potential of surface B1 of the hole transport layer using a Kelvin atomic force microscope. Further optionally, the Moran exponent of the potential distribution at surface B1 of the hole transport layer is greater than 0.

[0190] In some embodiments of this application, the hole transport layer has a surface B1 facing the perovskite layer, and the Moran exponent of the potential distribution at the surface B1 of the hole transport layer is greater than 0.

[0191] By controlling the potential distribution at surface B1 of the hole transport layer within the aforementioned range, a more uniform potential distribution can be achieved at the interface near the perovskite layer in the hole transport layer. This facilitates more uniform and efficient extraction of holes at the transport interface, thereby improving photoelectric conversion efficiency. Furthermore, it also enhances the stability of the hole transport interface, thus improving device stability.

[0192] In this application, unless otherwise stated, the "Moran index of the potential distribution of the first surface" is obtained by Kelvin atomic force microscopy (KPFM) combined with Moran index analysis.

[0193] The instrument used for KPFM testing can be Bruker FastScan Bio.

[0194] KPFM testing can be performed as follows: By observing the change in electrostatic force between the probe and the sample, when the probe approaches the surface to be tested, due to the difference in their work functions, electrons will flow from the high Fermi level to the low Fermi level until the Fermi level is flattened. The contact potential difference can be deduced from the work function difference during this process, thereby obtaining potential data. By further combining in-plane scanning, the potential distribution data of the surface to be tested can be obtained.

[0195] When performing statistical analysis on the Moran index of the potential distribution of a selected surface, the potential data is used as the parameter to be analyzed, and the parameter processing method is as described above.

[0196] In some embodiments of this application, the perovskite layer has a first surface facing the hole transport layer and a second surface opposite to the first surface in the Z direction; in the perovskite layer, there is a first region with a thickness of 5nm to 10nm extending from the first surface to the interior of the perovskite layer within a range of 30nm; the first region is located between the first surface and the second surface.

[0197] The absolute value of the difference between the Fermi level and the valence band top of the first perovskite material in the first region is denoted as E1, and the absolute value of the difference between the Fermi level and the conduction band bottom of the first perovskite material in the first region is denoted as E2, where E1 <E2。

[0198] At this point, the Fermi level at the interface near the hole transport layer in the perovskite layer is closer to the top of the valence band. This is beneficial for improving the energy level matching with the hole transport layer at the perovskite layer interface, thereby improving the efficiency of hole collection and transport, and further enhancing the photoelectric conversion efficiency.

[0199] In this application, unless otherwise specified, the terms "conduction band bottom (CBM)," "Fermi level (EF)," "valence band top (VBM)," and "band gap (Eg)" for semiconductor materials have their well-known meanings in the art. Unless otherwise specified, the energy levels of CBM, EF, and VBM are all based on the vacuum level, and all three energy levels are negative. EF is located between CBM and VBM, while CBM is closer to the vacuum level; that is, the energy level structure from top to bottom is vacuum level, CBM, EF, and VBM. The band gap is the distance between the conduction band bottom and the valence band top, i.e., Eg = CBM - VBM.

[0200] In this application, unless otherwise specified, "vacuum level" has a well-known meaning in the art, referring to the absolute zero point of electron potential energy, corresponding to the energy benchmark of an electron freely at rest outside a material, and numerically equal to the minimum energy required for an electron to completely escape the constraints of the material itself. The vacuum level provides a common benchmark for comparing the energy levels of different semiconductor materials. The "Fermi level" refers to the highest energy level occupied by an electron at T=0K; the "work function" refers to the minimum energy required to move an electron from the interior of a solid to its surface. Numerically, the work function is equal to the difference between the vacuum level and the Fermi level.

[0201] Those skilled in the art can use methods known or existing in the art to obtain the “conduction band bottom (CBM),” “Fermi level (EF),” “valence band top (VBM),” and “band gap (Eg)” of the perovskite material in the perovskite layer.

[0202] By sputtering the sample surface layer by layer and combining it with UPS surface scanning tests, the in-plane energy level structure distribution information at different depths is obtained. For example, the energy level data of the perovskite material in the first region (first perovskite material) can be obtained by testing as follows: obtain the sample to be tested with the perovskite layer exposed in the first region, first perform an absorption spectral scan, and then perform a UPS full-spectrum scan and E... cutoff The energy levels of the first region's CBM, EF, and VBM are obtained through scanning and Ev scanning, and the band gap can be calculated. Etching is then performed to expose other target regions (such as the thickness center region), followed by an absorption spectroscopy scan, and then UPS full-spectrum and Ev scanning. cutoff Ev scanning yields the energy level structures CBM, EF, and VBM for perovskite regions of different thicknesses (such as the thickness center region), and the band gap (Eg) can be calculated.

[0203] The thickness of each layer during the peeling process can be adjusted according to the thickness of the perovskite layer. For example, when the perovskite layer thickness is 400 nm, information can be collected at different thicknesses with intervals of 20 nm to 100 nm. For instance, an absorption spectrum scan of the sample surface can be performed first, followed by UPS full-spectrum and E... cutoff Ev scan, followed by absorption spectral scans at 20nm~30nm intervals (e.g., 20nm, 25nm, or 30nm) around 100nm from the first interface, and then UPS full spectrum and Ev scans. cutoff E v The scanning process involves performing a UPS (Up-Side Array) scan of the remaining region every 50 nm until the second interface region is reached. This allows for the acquisition of energy level structure information for perovskite regions of varying thicknesses and the area near the second interface. One of the first and second interfaces corresponds to the interface at the first surface, and the other corresponds to the interface at the second surface.

[0204] Absorption spectroscopy scanning refers to ultraviolet-visible-near-infrared absorption spectroscopy, which can obtain a spectrum showing the change in the absorptivity of incident light with the wavelength of photons, and can obtain information including but not limited to band gap.

[0205] UPS full-spectrum scanning uses ultraviolet light as the excitation source to excite electrons in the sample and measure the kinetic energy distribution of these photoelectrons.

[0206] E cutoff The Secondary Electron Cutoff (SEC) scan is used to measure the high-energy region of the "secondary electron cutoff" and obtain work function data.

[0207] Ev (Valence band spectrum) scans measure a fine spectrum from the vicinity of the Fermi level to the top of the valence band.

[0208] Absorption spectroscopy scanning refers to ultraviolet-visible-near-infrared absorption spectroscopy, which can obtain a spectrum showing the change in the absorptivity of incident light with the wavelength of photons, and can obtain information including but not limited to band gap.

[0209] UPS full-spectrum scanning uses ultraviolet light as the excitation source to excite electrons in the sample and measure the kinetic energy distribution of these photoelectrons.

[0210] E cutoff The Secondary Electron Cutoff (SEC) scan is used to measure the high-energy region of the "secondary electron cutoff" and obtain work function data.

[0211] Ev (Valence band spectrum) scans measure a fine spectrum from the vicinity of the Fermi level to the top of the valence band.

[0212] Taking a perovskite layer sample from one embodiment as an example, the perovskite layer thickness is 450 nm. The perovskite layer thickness region of 30 nm near the hole transport layer is defined as the lower interface region (a first region exists within the perovskite lower interface region). The perovskite layer portion within the 30 nm range of the thickness center region is used to represent the bulk phase (thickness center region) of the perovskite layer, and the perovskite layer thickness portion within the 30 nm range on the other side is defined as the perovskite upper interface region.

[0213] Examples of instruments used to acquire perovskite material in perovskite layers include models such as the Thermo Fisher Scientific ESCALAB QXi, which can perform both UPS and XPS scans.

[0214] The X-ray photoelectron spectroscopy (XPS) test procedure can be as follows:

[0215] Elemental distribution information at different depths can be obtained by sputtering the sample surface layer by layer and combining it with full elemental scanning. The depth sampling depth of XPS testing is 0.5 nm to 10 nm, and it can be achieved through ion sputtering (such as Ar). + C +0 The sample is peeled off layer by layer using either a cluster ion beam or an ion beam, and XPS full spectrum or specific elemental spectrum is acquired after each layer is peeled off. The thickness of each layer can be adjusted according to the thickness of the perovskite layer. For example, when the thickness of the perovskite layer is 400 nm, information can be acquired at different thicknesses by peeling off layers at intervals of 20 nm to 100 nm.

[0216] XPS testing can be used to determine the location of different thicknesses of the perovskite layer, thereby allowing the selection of an appropriate etching ion beam rate. Then, UPS is used to perform band structure testing on the target area.

[0217] The UPS testing process can be as follows:

[0218] (i) First use Ar + An ion beam is used to etch a 450 nm perovskite film, and the signal of a selected element (such as Pb) in the perovskite crystal phase of the perovskite layer is detected. 4f (Related signals) to determine the etching location, pending Pb 4f When the signal intensity drops to 1 / e of the plateau intensity, it is defined as the perovskite etching is complete, and the etching rate of the perovskite layer by the ion beam is calculated. Among them, the signal of the selected element in the perovskite crystal phase has a high concentration in the perovskite layer, and it is easy to form a region with the elements of the possible adjacent structural layers, thereby determining the boundary between the perovskite layer and the possible adjacent structural layers.

[0219] (ii) Identify the sample to be tested, first perform an absorption spectrum scan, then perform UPS full spectrum and E... cutoff Ev scanning was performed to obtain the corresponding CBM, EF, and VBM positions; then etching was performed to expose the center region of the thickness, followed by an absorption spectroscopy scan, and then UPS full spectrum and Ev scanning were performed. cutoff Energy level structures of the perovskite bulk phase were obtained by Ev scanning.

[0220] In some embodiments of this application, the difference E2 between the first perovskite material in the first region is E 2-1 (E) 2-1 =E2-E1) is 1.0eV~1.8eV, E 2-1 It can also be any of the following values ​​or a range consisting of any two of the following values: 1.0 eV, 1.02 eV, 1.04 eV, 1.05 eV, 1.06 eV, 1.08 eV, 1.1 eV, 1.12 eV, 1.14 eV, 1.15 eV, 1.16 eV, 1.18 eV, 1.2 eV, 1.25 eV, 1.3 eV, 1.35 eV, 1.4 eV, 1.45 eV, 1.5 eV, 1.6 eV, 1.7 eV, 1.8 eV, etc. For example, E... 2-1 It can also be selected from any of the following suitable ranges: 1.0eV~1.3eV, 1.0eV~1.5eV, 1.0eV~1.2eV, etc.

[0221] By controlling E 2-1 The magnitude of E controls the degree to which the Fermi level phase near the hole transport layer in the perovskite layer shifts towards the top of the valence band. 2-1 The larger the value, the greater the shift of the Fermi level towards the top of the valence band. In this case, the Fermi level is closer to the top of the valence band.

[0222] In some embodiments of this application, the difference E2 between the first perovskite material in the first region is E 2-1 (E) 2-1 =E2-E1) is 1.0eV~1.5eV, and can be selected as 1.0eV~1.2eV, E 2-1Alternatively, the value can be any of the following values ​​or a range selected from any two of the following values: 1.0 eV, 1.02 eV, 1.04 eV, 1.05 eV, 1.06 eV, 1.08 eV, 1.1 eV, 1.12 eV, 1.14 eV, 1.15 eV, 1.16 eV, 1.18 eV, 1.2 eV, 1.25 eV, 1.3 eV, 1.35 eV, 1.4 eV, 1.45 eV, 1.5 eV, etc. In this case, the degree of shift of the Fermi level phase towards the valence band top at the interface near the hole transport layer in the perovskite layer can be better controlled, which is beneficial for achieving better energy level matching at the interface and improving photoelectric conversion efficiency.

[0223] In some embodiments of this application, the perovskite layer has a first surface facing the hole transport layer; the potential distribution at the first surface of the perovskite layer has a Moran index (MLI). PP ) less than or equal to 0.4, optionally, MLI PP Less than or equal to 0.35; in addition, MLI PP The potential can also be less than or equal to any of the following values, greater than or equal to 0 and less than or equal to any of the following values, greater than 0 and less than or equal to any of the following values, or a range consisting of any of the following values ​​or any two of the following values: 0, 0.02, 0.04, 0.05, 0.06, 0.08, 0.10, 0.12, 0.14, 0.15, 0.16, 0.18, 0.20, 0.22, 0.24, 0.25, 0.26, 0.28, 0.30, 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, etc.; wherein, the potential at the first surface is obtained by measuring the potential of the first surface of the perovskite layer using a Kelvin atomic force microscope. The test method can be found in the description above.

[0224] By controlling the potential distribution at the first surface of the perovskite layer within the aforementioned range, it is beneficial to achieve a more uniform potential distribution at the interface near the hole transport layer in the perovskite layer. This, in turn, facilitates more uniform and efficient extraction of holes at the perovskite interface, thereby improving photoelectric conversion efficiency. Furthermore, it also helps to improve the stability of the perovskite interface, which in turn enhances device stability.

[0225] In some embodiments of this application, the thickness of the perovskite layer is 200 nm to 1500 nm, optionally 400 nm to 1000 nm, and may also be any of the following values ​​or a range selected from any two of the following values: 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, etc. Exemplarily, the thickness of the perovskite layer may also be any of the following ranges: 400 nm to 800 nm, 400 nm to 600 nm, 200 nm to 600 nm, 200 nm to 800 nm, etc.

[0226] When the thickness of the perovskite layer is within the aforementioned range, it can not only enable the perovskite layer to have high light absorption capacity, achieve better short-circuit current density and open-circuit voltage, but also help to better match the thickness of the perovskite layer with the effective diffusion length of photogenerated carriers, thereby enabling the carriers to be collected more effectively, which is conducive to achieving higher photoelectric conversion efficiency overall.

[0227] In some embodiments of this application, the area of ​​the perovskite layer on a projection plane perpendicular to the Z direction is greater than or equal to 0.09 cm². 2 Optionally, greater than or equal to 1m 2 .

[0228] The aforementioned methods for improving device performance can be implemented over a relatively large device area. Furthermore, they can uniformly improve the hole transport capability at the hole transport interface over a relatively large device area, which is beneficial for improving the photoelectric conversion efficiency of large-area devices. In addition, they can also achieve better stability for large-area devices.

[0229] When the size of the photovoltaic device is large, and the detection method involved in this application cannot cover the entire device area, an appropriate number of test samples can be selected based on the relative relationship between the area that the detection method can cover and the device area. For example, a reasonably distributed and appropriately sized sampling area can be selected on a projection plane perpendicular to the Z direction. The qualitative analysis results of each area can be used to determine whether it meets the corresponding characteristics, and the average value can be calculated as the test value based on the quantitative analysis results of each area. For example, for an area of ​​1 square meter (m²)... 2 For devices with this capability, ≥3 (e.g., 3~6) regions can be selected for detection.

[0230] In some embodiments of this application, the area of ​​the perovskite layer on the projection plane perpendicular to the Z direction can be any of the following values, or greater than or equal to any of the following values, or selected from a range consisting of any two of the following values: 0.09 cm2 、0.1 cm 2 、0.12 cm 2 、0.125 cm 2 、0.15 cm 2 、0.16 cm 2 、0.175 cm 2 、0.18 cm 2 、0.2cm 2 、0.22 cm 2 、0.225 cm 2 、0.25 cm 2 、1 cm 2 、4 cm 2 、9 cm 2 、10 cm 2 、16 cm 2 、20 cm 2 、25 cm 2 、36cm 2 、49 cm 2 、50 cm 2 、60 cm 2 、64 cm 2 、65 cm 2 、70 cm 2 、80 cm 2 、81 cm 2 、90 cm 2 、100 cm 2 、120cm 2 、121 cm 2 、125 cm 2 、130 cm 2 、140 cm 2 、144 cm 2 、150 cm 2 、160 cm 2 、169 cm 2 、170 cm 2 、180cm 2 、190 cm 2 、196 cm 2 、200 cm 2 、225 cm 2 、250 cm 2 、256 cm 2 、260 cm 2 、280 cm 2 、289 cm 2 、290cm 2、300 cm 2 、320 cm 2 、324 cm 2 、325 cm 2 、330 cm 2 、350 cm 2 、360 cm 2 、361 cm 2 、370 cm 2 、380cm 2 、400 cm 2 、440 cm 2 、441 cm 2 、450 cm 2 、480 cm 2 、484 cm 2 、500 cm 2 、600 cm 2 、625 cm 2 、660cm 2 、676 cm 2 、680 cm 2 、700 cm 2 、720 cm 2 、729 cm 2 、730 cm 2 、780 cm 2 、784 cm 2 、800 cm 2 、820cm 2 、840 cm 2 、841 cm 2 、850 cm 2 、860 cm 2 、900 cm 2 、950 cm 2 、961 cm 2 、980 cm 2 、0.1 m 2 、0.12m 2 、0.14 m 2 、0.15 m 2 、0.16 m 2 、0.18 m 2 、0.2 m 2 、0.3 m 2 、0.4 m 2 、0.5 m 2 、0.6 m 2 、0.7 m 2 、0.8m2 0.9 m 2 10000 cm 2 (1 m 2 ), 1.1 m 2 1.2 m 2 1.3 m 2 1.4 m 2 1.5 m 2 1.6 m 2 1.7 m 2 1.8m 2 1.9 m 2 2 m 2 2.1 m 2 2.2 m 2 2.3 m 2 2.4 m 2 2.5 m 2 2.6 m 2 2.7 m 2 2.8 m 2 2.9 m 2 3m 2 3.2 m 2 3.4 m 2 3.5 m 2 3.6 m 2 3.7 m 2 3.8 m 2 4 m 2 4.2 m 2 4.4 m 2 4.5 m 2 wait.

[0231] In some embodiments of this application, the photovoltaic device satisfies one or more of the following features:

[0232] (c1) Photovoltaic devices have either an inverted structure or a conventional structure;

[0233] (c2) The photovoltaic device also includes an electron transport layer 620, which is disposed on the side of the perovskite layer 100 away from the hole transport layer 620, as described in [reference]. Figure 3 ;

[0234] (c3) The photovoltaic device includes a first electrode and a second electrode, and both the hole transport layer and the perovskite layer are disposed between the first electrode and the second electrode. The hole transport layer is located between the perovskite layer and the first electrode.

[0235] The aforementioned embodiments can be universally applied to photovoltaic devices with either conventional or inverted structures, thereby improving photoelectric conversion efficiency. Furthermore, they can achieve better device stability. In particular, inverted photovoltaic devices can achieve higher photoelectric conversion efficiency.

[0236] In some embodiments of this application, the hole transport layer 610 is located on the light-incident side of the perovskite layer 100, as can be seen in the following reference. Figure 4 At this point, light mainly enters the perovskite layer from the hole transport layer. The location where the perovskite layer is excited by photons to generate charge carriers mainly occurs at the interface near the hole transport layer. Through the aforementioned scheme, the hole transport layer can efficiently and uniformly collect and transport holes, achieving a high photoelectric conversion efficiency.

[0237] In the thickness direction of the perovskite layer, for a photovoltaic device, when light can be incident on only one side, that side is called the "light-incident side"; when light can be incident on both sides of the photovoltaic device, the side with higher device efficiency (PCE) when light is incident is defined as the "light-incident side".

[0238] In some embodiments of this application, the photovoltaic device includes a first electrode and a second electrode, with a perovskite layer located between the first electrode and the second electrode.

[0239] In some embodiments of the photovoltaic device described in this application, one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode.

[0240] In some embodiments of the photovoltaic device described in this application, at least one of the first electrode and the second electrode is a transparent electrode. Either transparent electrode can be used for light incident.

[0241] In some embodiments of the photovoltaic device described in this application, both the first electrode and the second electrode can be transparent electrodes.

[0242] In some embodiments of the photovoltaic device described in this application, when the first electrode and the second electrode each include only one transparent electrode, the transparent electrode is defined as the "light-incident side electrode". When the photovoltaic device includes two transparent electrodes, the transparent electrode that provides higher device efficiency when light is incident on the corresponding transparent electrode is defined as the "light-incident side electrode".

[0243] In some embodiments of the photovoltaic device described in this application, the electrode on the light-emitting side can be defined as the "back electrode".

[0244] It is understood that the incident light-side electrode is a transparent electrode. The back electrode may or may not be a transparent electrode; for example, the back electrode may be a metal electrode. The meanings of transparent electrode and metal electrode are well known to those skilled in the art, and their implications are understandable.

[0245] In some embodiments of this application, one of the "first electrode" and the "second electrode" is a transparent electrode for light incident. In some embodiments, the first electrode is a transparent electrode.

[0246] In some embodiments of this application, the second electrode is a metal electrode.

[0247] In some embodiments of this application, the first electrode is a transparent electrode and the second electrode is a metal electrode.

[0248] In some embodiments of this application, the back electrode is a metal electrode.

[0249] In some embodiments of this application, the incident light side electrode is a transparent electrode and the back electrode is a metal electrode.

[0250] In some embodiments of this application, both the incident electrode and the back electrode are transparent electrodes.

[0251] In this application, unless otherwise stated, a "transparent electrode" may also be referred to as a "light-transmitting electrode," which is an electrode that allows light to pass through and enter adjacent functional layers.

[0252] In some embodiments of this application, the photovoltaic device includes a first electrode 410, a hole transport layer 610, a perovskite layer 100, an electron transport layer 620, and a second electrode 420 stacked together. The hole transport layer 610, the perovskite layer 100, and the electron transport layer 620 are all located between the first electrode 410 and the second electrode 420. The hole transport layer 610 and the electron transport layer 620 are respectively located on opposite sides of the perovskite layer 100. The hole transport layer 610 is located between the perovskite layer 100 and the first electrode 410, and the electron transport layer 620 is located between the perovskite layer 100 and the second electrode 420. (See reference...) Figure 5 In some embodiments, the first electrode is the incident light side electrode.

[0253] At this point, light can enter from the first electrode, and the interface of the perovskite layer near the hole transport layer is excited by photons to generate carrier pairs. At this point, holes can be efficiently and uniformly extracted and transported by the hole transport layer, achieving high photoelectric conversion efficiency.

[0254] In some embodiments of this application, the first electrode 410 is the incident light side electrode 700, and the second electrode 420 is the back electrode 800, as can be found in the references. Figure 6 .

[0255] Figure 6This is a schematic diagram of the structure of a photovoltaic device with an inverted structure according to an embodiment of this application. The photovoltaic device includes a light-incident electrode 700, a hole transport layer 610, a perovskite layer 100, an electron transport layer 620, and a back electrode 800 stacked together. In the thickness direction (Z direction) of the perovskite layer, the hole transport layer 610 and the electron transport layer 620 are respectively disposed on both sides of the perovskite layer 100. The light-incident electrode 700 is disposed on the side of the hole transport layer 610 away from the perovskite layer 100, and the back electrode 800 is disposed on the side of the electron transport layer 620 away from the perovskite layer 100. At this time, the hole transport layer 610 is located between the perovskite layer 100 and the light-incident electrode 700, and the electron transport layer 620 is located between the perovskite layer 100 and the back electrode 800.

[0256] In some embodiments of this application, the second electrode 420 is the incident light side electrode 700, and the first electrode 410 is the back electrode 800, as can be seen in the following references. Figure 7 .

[0257] Figure 7 This is a schematic diagram of the formal structure of a photovoltaic device according to an embodiment of this application. The photovoltaic device includes a light-incident electrode 700, an electron transport layer 620, a perovskite layer 100, a hole transport layer 610, and a back electrode 800 stacked together. In the thickness direction (Z direction) of the perovskite layer, the hole transport layer 610 and the electron transport layer 620 are respectively disposed on both sides of the perovskite layer 100. The light-incident electrode 700 is disposed on the side of the electron transport layer 620 away from the perovskite layer 100, and the back electrode 800 is disposed on the side of the hole transport layer 610 away from the perovskite layer 100. At this time, the electron transport layer 620 is located between the perovskite layer 100 and the light-incident electrode 700, and the hole transport layer 610 is located between the perovskite layer 100 and the back electrode 800.

[0258] In some embodiments of this application, the photovoltaic device includes a first charge transport layer and a second charge transport layer, wherein the first charge transport layer and the second charge transport layer are located on opposite sides of the perovskite layer in the thickness direction of the perovskite layer. Further, one of the first charge transport layer and the second charge transport layer is an electron transport layer, and the other is a hole transport layer. In some embodiments, the first charge transport layer is a hole transport layer. In other embodiments, the first charge transport layer is an electron transport layer.

[0259] Figure 8This is a schematic diagram of a photovoltaic device according to an embodiment of this application. The photovoltaic device includes a substrate layer 500, a first electrode 410, a first charge transport layer 310, a perovskite layer 100, a second charge transport layer 320, and a second electrode 420 stacked together. In the thickness direction (Z direction) of the perovskite layer, the first charge transport layer 310 and the second charge transport layer 320 are respectively disposed on opposite sides of the perovskite layer 100. The first electrode 410 is disposed on the side of the first charge transport layer 310 away from the perovskite layer 100, and the second electrode 420 is disposed on the side of the second charge transport layer 320 away from the perovskite layer 100. The substrate layer 500 is disposed on the side of the first electrode 410 away from the perovskite layer 100. It can be understood that one of the first charge transport layer 310 and the second charge transport layer 320 can be a hole transport layer 610, and the other can be an electron transport layer 620.

[0260] In some embodiments of this application, the photovoltaic device can be a formal structure or an inverted structure.

[0261] In some embodiments of this application, the photovoltaic device is an inverted pin structure or a formal nip structure.

[0262] In some embodiments of this application, the photovoltaic device includes a solar cell, which includes a hole transport layer and a perovskite layer stacked together.

[0263] The aforementioned hole transport layer and perovskite layer can be incorporated into solar cells to improve their photoelectric conversion efficiency. Furthermore, this can also lead to higher device stability.

[0264] In some embodiments of this application, the photovoltaic device includes a single-junction solar cell, which includes a hole transport layer and a perovskite layer stacked together.

[0265] In some embodiments of this application, a single-junction solar cell includes a first electrode, a perovskite layer, and a second electrode, with the perovskite layer located between the first and second electrodes. Further, one of the first and second electrodes is a positive electrode, and the other is a negative electrode.

[0266] The aforementioned hole transport layer and perovskite layer can be incorporated into a single-junction solar cell to improve its photoelectric conversion efficiency. Furthermore, it can also achieve higher device stability.

[0267] In some embodiments of this application, the photovoltaic device includes a multijunction solar cell.

[0268] In this application, unless otherwise specified, a "multi-junction solar cell" refers to a solar cell in which two or more cell cells made of semiconductor active materials with different band gaps are stacked together in series optically and / or electrically. Multi-junction solar cells can broaden the absorption spectrum of solar cells, maximizing the conversion of light energy into electrical energy, and also help reduce thermal relaxation losses. Multi-junction solar cell design is an important way to overcome the Shockley-Queisser limit efficiency of single-junction solar cells. A multi-junction solar cell includes at least two cell cells, each cell cell including at least one light-absorbing layer, and each light-absorbing layer has a different band gap.

[0269] It is understandable that a "cell" in a multi-junction solar cell includes at least a light-absorbing layer. The light-absorbing layers in different cells can provide different band gaps.

[0270] In this application, unless otherwise specified, "battery cell" and "battery section" have the same meaning and can be used interchangeably.

[0271] In this application, unless otherwise specified, "light-absorbing layer" and "light-absorbing layer" have the same meaning and can be used interchangeably.

[0272] In this application, unless otherwise specified, "band gap" has a commonly known meaning in the art and can be analyzed, compared, and confirmed using conventional methods within the art. Without limitation, the band gap of a material can be determined by its absorption or emission spectra; commonly used optical methods include ultraviolet-visible absorption spectroscopy, photoluminescence spectroscopy, and Raman spectroscopy.

[0273] When solar cells are multi-junction solar cells, they are beneficial for improving the utilization rate of incident light, while also retaining the aforementioned advantage of high photoelectric conversion efficiency. Multi-junction solar cells can be monolithic integrated tandem solar cells or mechanically tandem solar cells, offering flexibility in form and a wide range of applications.

[0274] In some embodiments of this application, the photovoltaic device includes a solar cell, which is a multi-junction solar cell. The multi-junction solar cell includes a first cell unit, which includes a light-absorbing layer (which may be referred to as a first light-absorbing layer or first light-absorbing layer). The first light-absorbing layer may include the aforementioned perovskite layer.

[0275] The first light-absorbing layer includes a first semiconductor active material.

[0276] In some embodiments of this application, the first light-absorbing layer is the aforementioned perovskite layer. In this case, the first semiconductor active material includes the first perovskite material.

[0277] In some embodiments of this application, the photovoltaic device includes a solar cell, which is a multi-junction solar cell. The multi-junction solar cell includes a first cell unit, which includes a hole transport layer and a perovskite layer stacked together.

[0278] The aforementioned hole transport layer and perovskite layer can be incorporated into multi-junction solar cells to improve their photoelectric conversion efficiency. Furthermore, this can also achieve higher device stability.

[0279] In some embodiments of this application, the multijunction solar cell further includes a second cell stacked with the first cell cell; the second cell cell and the first cell cell are connected by an interconnect layer, or the second cell cell and the first cell cell are isolated by an insulating layer; the second cell cell includes a light absorption layer (which may be referred to as the second light absorption layer or the second light-absorbing layer), and the second light absorption layer and the first light absorption layer have different band gaps.

[0280] In some embodiments of this application, the interconnect layer includes a carrier recombination layer or a tunneling layer. In some embodiments, the interconnect layer can be a carrier recombination layer or a tunneling layer.

[0281] In some embodiments of this application, the interconnect layer includes a carrier recombination layer.

[0282] In some embodiments of this application, the interconnect layer includes a tunneling layer.

[0283] In some embodiments of this application, the second light-absorbing layer and the perovskite layer have different band gaps. Thus, by providing multiple light-absorbing layers with different band gaps, the multi-junction solar cell can effectively absorb light of different wavelengths, broadening the spectral range of absorbed light and improving the photoelectric conversion efficiency of the multi-junction solar cell.

[0284] In some embodiments, the multijunction solar cell is a tandem solar cell.

[0285] In some embodiments of this application, the multijunction solar cell further includes a second cell stacked with the first cell cell; the second cell cell and the first cell cell are connected by an interconnect layer, or the second cell cell and the first cell cell are isolated by an insulating layer; the second cell cell includes a light-absorbing layer (i.e., a second light-absorbing layer), and the second light-absorbing layer and the perovskite layer have different band gaps.

[0286] In this way, by setting up multiple light-absorbing layers with different band gaps, multi-junction solar cells can effectively absorb light of different wavelengths, broaden the spectral range of light absorbed by multi-junction solar cells, and improve the photoelectric conversion efficiency of multi-junction solar cells.

[0287] In some embodiments of this application, the light-absorbing layer (i.e., the second light-absorbing layer) in the second battery cell includes a semiconductor active material (which may be referred to as the second semiconductor active material). The second semiconductor active material includes one or more of the following: second perovskite material, silicon-containing semiconductor material, copper zinc tin sulfide, copper zinc tin selenide, copper zinc tin selenide sulfide, copper indium gallium selenide, copper indium gallium diselenide, copper indium selenide, cadmium telluride, gallium arsenide, organic active material, etc.

[0288] The aforementioned embodiments can be universally applied to the aforementioned different types of multi-junction solar cells.

[0289] In some embodiments of this application, a carrier recombination layer or a tunneling layer is provided between the monolithically integrated battery cells.

[0290] In this application, unless otherwise specified, the "carrier recombination layer" is a structural layer in which electrons and holes transported from two different battery cells recombine, enabling the two battery cells to achieve ohmic connection and share the positive and negative electrodes.

[0291] In some embodiments of this application, a carrier recombination layer is provided between the first battery cell and the second battery cell.

[0292] In some embodiments of this application, interconnection structures are provided between the battery cells connected in series, which can provide tunneling junctions (also known as tunneling layers) to realize tunneling conduction and electrical series connection between different battery cells, while maintaining optical transparency so that photons can pass smoothly through the previous battery cell to the next battery cell.

[0293] In some embodiments of this application, an interconnection structure is provided between the first battery cell and the second battery cell.

[0294] In some embodiments of this application, a tunnel junction may be formed between the first battery cell and the second battery cell.

[0295] In some embodiments of this application, the charge carrier recombination layer is a structural layer in which electrons transported from the first battery cell and holes transported from the second battery cell recombine, or in which holes transported from the first battery cell and electrons transported from the second battery cell recombine, thereby connecting the first battery cell and the second battery cell in series.

[0296] In some embodiments of this application, a multi-junction solar cell includes a first electrode, a perovskite layer, an interconnect layer, a second light-absorbing layer, and a second electrode stacked together. The interconnect layer is located between the perovskite layer and the second light-absorbing layer. The first electrode is located on the side of the perovskite layer facing away from the interconnect layer, and the second electrode is located on the side of the second light-absorbing layer facing away from the interconnect layer. Thus, two cell units in the multi-junction solar cell are connected through the interconnect layer to achieve current matching between the two cell units. This results in a relatively smaller size, the ability to absorb light of different wavelengths, a wider absorption spectrum range for the multi-junction solar cell, and an improved photoelectric conversion efficiency. In some embodiments of this application, a hole transport layer is located between the first electrode and the perovskite layer.

[0297] In some embodiments of this application, a multi-junction solar cell includes a first electrode, a perovskite layer, a third electrode, an insulating layer, a fourth electrode, a second light-absorbing layer, and a second electrode stacked together. The third electrode, insulating layer, and fourth electrode are stacked between the perovskite layer and the second light-absorbing layer. The third electrode is located on the side of the insulating layer facing the perovskite layer, the fourth electrode is located on the side of the insulating layer facing the second light-absorbing layer, the first electrode is located on the side of the perovskite layer away from the third electrode, and the second electrode is located on the side of the second light-absorbing layer away from the fourth electrode. Thus, the multi-junction solar cell forms a mechanically stacked cell. The insulating layer isolates the two cell units, preventing direct conduction of charge carriers and eliminating the need for current matching. Furthermore, each cell has its own separate positive and negative electrodes for current extraction, allowing for flexible circuit adjustments. In some embodiments of this application, a hole transport layer is located between the first electrode and the perovskite layer.

[0298] In this application, unless otherwise specified, a multi-junction solar cell with two battery cells may also be referred to as a "tandem solar cell". A tandem solar cell may be a two-terminal structure or a four-terminal structure.

[0299] In some embodiments of this application, the tandem solar cell has a two-end structure. In this case, two cell units are directly connected in series through a tunneling layer or a carrier recombination layer. The tandem solar cell only has two output electrodes, one positive and the other negative, and the current between the two cell units remains consistent. This type of tandem solar cell can also be called a monolithic integrated tandem cell, which refers to cell units stacked along the thickness direction that are electrically connected in series between a pair of electrode layers. Different cell units are connected through a carrier recombination layer or a tunneling layer to achieve current matching between adjacent cell units, so that adjacent cell units form an integrated structure of electrical and optical series connection.

[0300] In some embodiments of this application, the tandem solar cell includes a first electrode, a first light-absorbing layer, a carrier recombination layer, a second light-absorbing layer, and a second electrode. The first light-absorbing layer and the second light-absorbing layer are respectively disposed on both sides of the carrier recombination layer. The first electrode is located on the side of the first light-absorbing layer away from the carrier recombination layer, and the second electrode is located on the side of the second light-absorbing layer away from the carrier recombination layer.

[0301] In some embodiments of this application, the tandem solar cell includes a first electrode, a first light-absorbing layer, a tunneling layer, a second light-absorbing layer, and a second electrode. The first light-absorbing layer and the second light-absorbing layer are respectively disposed on both sides of the tunneling layer. The first electrode is located on the side of the first light-absorbing layer away from the tunneling layer, and the second electrode is located on the side of the second light-absorbing layer away from the tunneling layer.

[0302] In some embodiments of this application, the tandem solar cell has a four-terminal structure. In this case, the cell cells are electrically independent and operate independently, with coupling between the cell cells only through optical means; no carrier recombination layer or tunneling layer is provided between the cell cells. Each cell cell has its own pair of electrodes (positive and negative), and the entire tandem solar cell has four electrical output terminals, corresponding to the four electrodes. Two cell cells are isolated in the stacking direction by an insulating layer to prevent short circuits between the two cell cells.

[0303] In some implementations, the bandgap of the perovskite layer (i.e., the first light-absorbing layer) is Eg2, where 1.65 eV ≤ Eg2 ≤ 2.2 eV; the bandgap of the second light-absorbing layer is Eg1, where 1.1 eV ≤ Eg1 ≤ 1.6 eV. This bandgap configuration of the perovskite layer and the second light-absorbing layer effectively absorbs both short-wavelength and long-wavelength light, improving the photoelectric conversion efficiency of the multi-junction solar cell. In this implementation, the cell unit corresponding to the second light-absorbing layer is a narrow-bandgap solar cell, and the cell unit corresponding to the perovskite layer is a wide-bandgap solar cell.

[0304] In some embodiments, the second light-absorbing layer comprises one or more of the following compounds: a second perovskite material, a silicon-containing semiconductor material, copper zinc tin sulfide, copper zinc tin selenide, copper zinc tin selenide sulfide, copper indium gallium selenide, copper indium gallium diselenide, copper indium selenide, cadmium telluride, gallium arsenide, organic active materials, etc. These materials can absorb light of different wavelengths with the perovskite layer, thereby broadening the spectral range of light absorption in the multi-junction solar cell and improving its photoelectric conversion efficiency. In some embodiments of this application, the definition of the second perovskite material is the same as that of the first perovskite material, but the composition differs to obtain a second light-absorbing layer with a different bandgap, used to absorb light of different wavelengths with the perovskite layer, broadening the absorption spectral range of the multi-junction solar cell and improving its photoelectric conversion efficiency. Exemplarily, the second light-absorbing layer comprises a second perovskite material, thereby obtaining a perovskite-perovskite multi-junction solar cell. In another example, the second light-absorbing layer comprises a crystalline silicon material, thereby obtaining a perovskite-crystalline silicon multi-junction solar cell.

[0305] Organic active materials are typically composed of blends of electron donor and electron acceptor materials. Common electron donor materials include poly(3-hexylthiophene) (P3HT), wide-bandgap polymer donor PM6, and high-efficiency polymer donor D18, while common electron acceptor materials include fullerene acceptors (such as PC). 61 BM, PC 71 BM, etc.), and non-fullerene acceptors (such as Y6 series materials, indendrothiophene derivatives, BTP series, etc.). Exemplary organic active materials include PM6:Y6 and P3HT:PC. 61 One of BM, D18:BTP-eC9, etc. can be used to obtain multiple types.

[0306] Silicon-containing semiconductor materials include, but are not limited to, crystalline silicon materials or amorphous silicon materials. Crystalline silicon materials can include monocrystalline silicon or polycrystalline silicon.

[0307] In some embodiments, a multi-junction solar cell includes a first electrode and a second electrode, with a first light-absorbing layer and a second light-absorbing layer both located between the first electrode and the second electrode, the first light-absorbing layer being closer to the first electrode and the second light-absorbing layer being closer to the second electrode.

[0308] In some implementations, the first electrode in a multi-junction solar cell is a transparent electrode. This allows light to enter the multi-junction solar cell from the first electrode. Furthermore, the band gap of the second light-absorbing layer is Eg1, 1.1 eV ≤ Eg1 ≤ 1.6 eV; the band gap of the perovskite layer is Eg2, 1.65 eV ≤ Eg2 ≤ 2.2 eV. Thus, light entering from the first electrode first passes through the perovskite layer, where it absorbs short-wavelength light (such as ultraviolet to visible light), and then enters the second light-absorbing layer, where it absorbs longer-wavelength light (such as near-infrared light). This allows for greater utilization of different wavelengths of light, improving the photoelectric conversion efficiency of the multi-junction solar cell. Furthermore, the perovskite layer, acting as the top light-absorbing layer, absorbs ultraviolet-visible light, protecting the second light-absorbing layer, which acts as the bottom light-absorbing layer.

[0309] In other embodiments, the bandgap of the second light-absorbing layer is Eg3, where 1.65 eV ≤ Eg3 ≤ 2.2 eV; and the bandgap of the perovskite layer is Eg4, where 1.1 eV ≤ Eg4 ≤ 1.6 eV. Thus, the bandgap settings of the second light-absorbing layer and the perovskite layer can absorb short-wavelength and long-wavelength light respectively, improving the photoelectric conversion efficiency of the multi-junction solar cell. In this embodiment, the cell unit corresponding to the second light-absorbing layer is a wide-bandgap solar cell, and the cell unit corresponding to the perovskite layer is a narrow-bandgap solar cell.

[0310] In other embodiments, the second light-absorbing layer comprises a third perovskite material. Thus, the resulting multi-junction solar cell is a perovskite-perovskite multi-junction solar cell. In some embodiments of this application, the third perovskite material is defined as the same type as the first perovskite material described above, but with a different composition to obtain a second light-absorbing layer with a different bandgap. This layer is used to absorb light of different wavelengths with the perovskite layer, broadening the absorption spectrum range of the multi-junction solar cell and improving its photoelectric conversion efficiency. Exemplarily, the third perovskite material includes APbI. z Br 3-z The material shown is defined as above, where 0 < z < 3.

[0311] In other embodiments, the second electrode in a multi-junction solar cell is a transparent electrode. This allows light to enter the multi-junction solar cell through the second electrode. Furthermore, the band gap of the second light-absorbing layer is Eg3, 1.65 eV ≤ Eg3 ≤ 2.2 eV; the band gap of the perovskite layer is Eg4, 1.1 eV ≤ Eg4 ≤ 1.6 eV. Thus, light entering from the second electrode first passes through the second light-absorbing layer, which absorbs short-wavelength light (such as ultraviolet to visible light), and then enters the perovskite layer, where it absorbs longer-wavelength light (such as near-infrared light). This allows for greater utilization of different wavelengths of light, improving the photoelectric conversion efficiency of the multi-junction solar cell. Furthermore, the second light-absorbing layer, acting as the top cell's light-absorbing layer, absorbs ultraviolet-visible light, protecting the perovskite layer as the bottom cell's light-absorbing layer.

[0312] In some embodiments, a multi-junction solar cell includes a first electrode, a perovskite layer, an interconnect layer, a second light-absorbing layer, and a second electrode stacked together, with the interconnect layer located between the perovskite layer and the second light-absorbing layer. The interconnect layer may include a carrier recombination layer or a tunneling layer. Thus, the multi-junction solar cell forms a monolithic integrated tandem cell, with two cell units connected by an interconnect layer (e.g., through a carrier recombination layer or a tunneling layer) to achieve current matching between the two cell units. It has a relatively smaller size, can absorb light of different wavelengths, broadens the absorption spectrum range of the multi-junction solar cell, and improves the photoelectric conversion efficiency of the multi-junction solar cell.

[0313] In some embodiments, a multijunction solar cell includes a first electrode, a perovskite layer, a tunneling layer, a second light-absorbing layer, and a second electrode stacked together, with the tunneling layer located between the perovskite layer and the second light-absorbing layer.

[0314] In some implementations, a multijunction solar cell includes a first charge transport layer, a second charge transport layer, a third charge transport layer, and a fourth charge transport layer.

[0315] In this application, the first charge transport layer, the second charge transport layer, the third charge transport layer, and the fourth charge transport layer are used to transport the first charge carrier, the second charge carrier, the third charge carrier, and the fourth charge carrier, respectively. One of the first charge carrier and the second charge carrier is an electron and the other is a hole. One of the third charge carrier and the fourth charge carrier is an electron and the other is a hole.

[0316] In some embodiments, a multi-junction solar cell includes a first electrode, an optional first charge transport layer, a perovskite layer, an optional second charge transport layer, a carrier recombination layer or tunneling layer, an optional third charge transport layer, a second light-absorbing layer, an optional fourth charge transport layer, and a second electrode, all stacked together. The multi-junction solar cell includes at least one of the first and second charge transport layers, and also includes a hole transport layer. Further, when all four charge transport layers are present, the first and third charge transport layers are identical and selected from either an electron transport layer or a hole transport layer, and the second and fourth charge transport layers are identical and selected from either an electron transport layer or a hole transport layer. Thus, a first electrode, an optional first charge transport layer, a perovskite layer, and an optional second charge transport layer form a first battery cell. An optional third charge transport layer, a second light absorption layer, an optional fourth charge transport layer, and a second electrode form a second battery cell. The carrier recombination layer is used to recombine and annihilate electrons generated from the perovskite layer and holes generated from the second light absorption layer (or holes generated from the perovskite layer and electrons generated from the second light absorption layer) that are transported towards the carrier recombination layer, thereby achieving low-ohmic tunnel recombination between the first battery cell containing the perovskite layer and the second battery cell containing the second light absorption layer, ensuring the connectivity between the two battery cells. The tunneling layer is located between the two battery cells, and its main function is to achieve efficient transport of electrons and holes. Through the tunneling effect, the tunneling layer allows electrons and holes to be transported from the bottom battery to the top battery, thereby reducing energy loss caused by electron thermal relaxation and improving the photoelectric conversion efficiency of the battery. Exemplarily, the second light absorption layer includes a second perovskite material, thus obtaining a perovskite-perovskite multi-junction solar cell. In another example, the second light-absorbing layer comprises crystalline silicon, thereby resulting in a perovskite-crystalline silicon multijunction solar cell.

[0317] In some embodiments of this application, multi-junction solar cells may include all four charge transport layers simultaneously, or may include only one or more of them; this is not limited here. The presence of charge transport layers helps to extract and transport electrons or holes generated by the perovskite layer or the second light-absorbing layer, enhancing the extraction and transport effect of electrons and holes and improving the performance of the multi-junction solar cell. The materials for the corresponding electron transport layer and hole transport layer are selected as defined above; the materials for the electron transport layer or hole transport layer corresponding to the first and second cell units may be the same or different.

[0318] In some embodiments, a multi-junction solar cell includes a first electrode, a hole transport layer, a perovskite layer, an electron transport layer, a carrier recombination layer or a tunneling layer, an optional hole transport layer, a second light-absorbing layer, an optional electron transport layer, and a second electrode, all stacked together.

[0319] In this application, the carrier recombination layer comprises one or more of the following: metallic materials, transparent conductive oxides, and carbon materials. Further, the transparent conductive oxide layer comprises, but is not limited to, one or more of the following: fluorine-doped tin oxide (FTO), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), indium zinc oxide (IZO), tungsten-doped indium oxide (IWO), indium gallium zinc oxide (IGZO), and antimony-doped tin oxide (ATO). Further, the metallic materials include, but are not limited to, one or more of the following: gold, copper, silver, platinum, aluminum, and iron. Further, the carbon materials include, but are not limited to, one or more of the following: graphite, graphene, and carbon nanotubes.

[0320] In some implementations, the thickness of the carrier recombination layer is 0.1 nm to 200 nm. For example, it can be 0.1 nm, 0.8 nm, 1 nm, 2 nm, 10 nm, 30 nm, 50 nm, 90 nm, 100 nm, 130 nm, 150 nm, 160 nm, 200 nm, or any two of the above values ​​as endpoints.

[0321] In some implementations, the components of the tunneling layer include, but are not limited to, PEDOT (poly-3,4-ethylenedioxythiophene), transparent metal oxides, etc.

[0322] In other embodiments, a multi-junction solar cell includes a first electrode, a perovskite layer, a third electrode, an insulating layer, a fourth electrode, a second light-absorbing layer, and a second electrode stacked together. The third electrode, insulating layer, and fourth electrode are stacked between the perovskite layer and the second light-absorbing layer. The third electrode is positioned on the side of the insulating layer facing the perovskite layer, and the fourth electrode is positioned on the side of the insulating layer facing the second light-absorbing layer. In this way, the multi-junction solar cell forms a mechanically stacked cell. The insulating layer isolates the two cell units, preventing direct parallel connection of charge carriers and eliminating the need for current matching. Furthermore, each cell unit has its own independent positive and negative electrodes for current extraction, allowing for flexible circuit adjustments.

[0323] In this application, the fifth charge transport layer, the sixth charge transport layer, the seventh charge transport layer, and the eighth charge transport layer are used to transport the fifth charge carrier, the sixth charge carrier, the seventh charge carrier, and the eighth charge carrier, respectively. One of the fifth and sixth charge carriers is an electron and the other is a hole. One of the seventh and eighth charge carriers is an electron and the other is a hole.

[0324] In some embodiments, a multi-junction solar cell includes a first electrode, an optional fifth charge transport layer, a perovskite layer, an optional sixth charge transport layer, a third electrode, an insulating layer, a fourth electrode, an optional seventh charge transport layer, a second light-absorbing layer, an optional eighth charge transport layer, and a second electrode, all stacked together. The multi-junction solar cell includes at least one of the fifth and sixth charge transport layers, and also includes a hole transport layer. Further, when all five to eight charge transport layers are present, the fifth charge transport layer is selected from either a hole transport layer or an electron transport layer; the sixth charge transport layer is selected from either a hole transport layer or an electron transport layer different from the fifth charge transport layer; the seventh charge transport layer is selected from either a hole transport layer or an electron transport layer; and the eighth charge transport layer is selected from either a hole transport layer or an electron transport layer different from the seventh charge transport layer. The definitions and material selections of the corresponding hole transport layer or electron transport layer are as described above and will not be repeated here. Thus, a first electrode, optionally a fifth charge transport layer, a perovskite layer, optionally a sixth charge transport layer, and a third electrode form a first battery cell; a fourth electrode, optionally a seventh charge transport layer, a second light-absorbing layer, optionally an eighth charge transport layer, and a second electrode form a second battery cell. The first and second battery cells are electrically isolated by an insulating layer. Each battery cell has two electrodes, for a total of four electrodes. The circuits of the two battery cells are independent of each other, forming a four-terminal multi-junction solar cell. This allows for adjustment of the current in the multi-junction solar cell. Exemplarily, the second light-absorbing layer comprises a second perovskite material, resulting in a perovskite-perovskite multi-junction solar cell. In another example, the second light-absorbing layer comprises crystalline silicon, resulting in a perovskite-crystalline silicon multi-junction solar cell.

[0325] Furthermore, since the third and fourth electrodes are located in the middle of the multi-junction solar cell, in order to further increase the light energy utilization of the multi-junction solar cell and enable the remaining light after absorption by one cell to enter the next cell, the third and fourth electrodes can be set as light-transmitting electrodes, and the materials can be selected from one or more of the above-mentioned transparent conductive oxides.

[0326] In some embodiments, the material of the insulating layer includes, but is not limited to, glass or an insulating adhesive. Further, the glass is transparent glass; further, the insulating adhesive is a transparent adhesive.

[0327] In some embodiments, the multi-junction solar cell may also include multi-junction solar cells composed of 3, 4, or 5 cells, such as 3-junction solar cells, 4-junction solar cells, 5-junction solar cells, etc., and may be mechanically stacked cells, monolithically integrated stacked cells, or hybrid stacked cells composed of both, without limitation here.

[0328] It is understood that the hole transport layer includes a hole transport material. The hole transport material in the aforementioned first battery cell includes at least nickel oxide.

[0329] The hole transport material in the second battery cell can be any suitable hole transport material.

[0330] It is understood that the hole transport layer includes a hole transport material. When the hole transport layer is located on the light-incident side of the light-absorbing layer (such as a perovskite layer), those skilled in the art can select a suitable hole transport material to achieve the desired transmittance.

[0331] Without limitation, the hole transport material in the hole transport layer may include, but is not limited to, one or more of the following materials and their derivatives: hole transport organic materials and hole transport inorganic materials.

[0332] In some embodiments of this application, the hole transport material includes hole transport organics. Without limitation, the hole transport organics may include, but are not limited to, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene, poly-3-hexylthiophene, methoxytriphenylamine-fluoroformamidinium, triphenylamine with a triphenylene core, 3,4-ethylenedioxythiophene-methoxytriphenylamine, N-(4-aniline)carbazole-spirobifluorene, polythiophene, carbazole-based monomers or polymers (such as [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid... The hole transport material comprises one or more of the following: [4-(9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), [4-(3,6-dibromo-9H-carbazole-9-yl)butyl]phosphonic acid (Br-4PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dibromo-9H-carbazole-9-yl)ethyl]phosphonic acid (Br-2PACz), triphenylamine monomers or polymers, aromatic monomers or polymers, etc. In some embodiments of this application, the hole transport material includes hole transport inorganic substances. Non-limitingly, the hole transport inorganic material may include, but is not limited to, one or more of metal oxides (which may be referred to as the first metal oxide), cuprous iodide and cuprous thiocyanate, molybdenum sulfide, etc.; wherein, the metal oxide in the hole transport material may include, but is not limited to, one or more of nickel oxide, molybdenum oxide, cuprous oxide, vanadium oxide, and tungsten oxide. As a non-limiting example, in the hole transport material, the metal element in the first metal oxide may include one or more of nickel (Ni), molybdenum (Mo), copper (Cu), vanadium (V), and tungsten (W).

[0333] It is understood that the electron transport layer includes electron transport materials. When the electron transport layer is located on the light-incident side of the light-absorbing layer (such as a perovskite layer), those skilled in the art can select a suitable electron transport material to achieve the desired transmittance.

[0334] It is understood that the electron transport layer includes electron transport materials. Without limitation, the electron transport materials in the electron transport layer may include, but are not limited to, one or more of the following materials and their derivatives, impurities, and passivated materials: fullerenes and their derivatives, imide compounds, metal oxides, metal sulfides, metal fluorides, cyano-containing polyphenylacetylene, boron-containing polymers, copper bath, red phenanthroline, hydroxyquinoline aluminum, oxadiazole compounds, quinone compounds, etc.; exemplarily, fullerenes and their derivatives include, but are not limited to, [6,6]-phenyl-C 61 methyl butyrate (PC) 61 BM), [6,6]-phenyl-C 71 methyl butyrate (PC) 71 BM), Fullerene C 60 Fullerene C 61 Fullerene C 70 The imide compounds include, but are not limited to, one or more of perylene imide materials, naphthalene imide materials, phthalimide, succinimide, N-bromosuccinimide, glutarimide, or maleimide; metal oxides (which may be referred to as second metal oxides), perylene imide materials, naphthalene imide materials, etc. Among these, the metal oxides in the electron transport materials may include one or more of tin oxide, zinc oxide, etc. As a non-limiting example, in the electron transport materials, the metal element in the second metal oxide may include one or more of tin (Sn), magnesium (Mg), indium (In), molybdenum (Mo), titanium (Ti), and zinc (Zn). Metal sulfides include indium sulfide or zinc sulfide; metal fluorides include one or more of lithium fluoride (LiF), sodium fluoride, magnesium fluoride (MgF2), and calcium fluoride (CaF2).

[0335] Without limitation, the metal oxide in the first charge transport layer may refer to a first metal oxide (in which case the first charge transport layer is a hole transport layer) or a second metal oxide (in which case the first charge transport layer is an electron transport layer).

[0336] In some embodiments of this application, the first charge transport layer is a hole transport layer. In this case, in addition to the first metal oxide, the first charge transport layer may also include one or more other types of hole transport materials, as described above.

[0337] In some embodiments of this application, the first charge transport layer is an electron transport layer. In this case, in addition to the second metal oxide, the first charge transport layer may also include one or more other types of electron transport materials, as described above.

[0338] In this application, the terms "first metal oxide" and "second metal oxide" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features.

[0339] The definition of the first perovskite material can be found in the context of this application, or a suitable material may be selected from the perovskite materials described below. The definitions of the second and third perovskite materials can also be found in the context of this application, or a suitable material may be selected from the perovskite materials described below.

[0340] In this application, unless otherwise specified, "perovskite material" refers to a class of semiconductor materials having a crystal structure similar to that of the natural mineral calcium titanate (CaTiO3). Typically, perovskite materials comprise a first cation, a second cation, and an anion. The anion and the second cation together form an octahedral structure, with the anion located at the body center of the octahedron and the second cation located at the six vertices. The first cation fills the voids between the octahedra to achieve charge balance and maintain crystal structure stability. Adjacent octahedral structures are connected by sharing vertices, thus forming a continuous crystal lattice structure. Unless otherwise specified, the first cation may be denoted as A and referred to as an A-site ion or A-site cation; the second cation may be denoted as B and referred to as a B-site ion or B-site cation; and the anion may be denoted as X and referred to as an X-site ion or X-site anion.

[0341] In some embodiments of this application, the first cation is relatively large and the second cation is relatively small.

[0342] In some embodiments of this application, the perovskite tolerance factor is in the range of 0.85 to 1.0. This is advantageous for obtaining a more stable perovskite crystal structure.

[0343] In this application, "perovskite tolerance factor (t)" has a meaning known in the art, and its calculation formula is as follows: , where R A R is the ionic radius of the A-site ion. B R is the ionic radius of the B-site ion. X Let X be the ionic radius of the ion at the X site.

[0344] The first cation in a perovskite material can be an organic cation, an inorganic cation, or a mixture of organic and inorganic cations; it is understood that the first cation in a perovskite material can be one or more types. In some embodiments of this application, the first cation includes a monovalent cation, and more specifically, it can be a monovalent cation.

[0345] The second cation in a perovskite material can be an organic cation, an inorganic cation, or a mixture of organic and inorganic cations; it is understood that the type of the second cation in the perovskite material can be one or more. In some embodiments of this application, the second cation includes a divalent cation, and more specifically, a divalent cation. In some embodiments of this application, the second cation includes a combination of a monovalent cation (denoted as C) and a trivalent cation (denoted as D).

[0346] In some embodiments of this application, the anions in the perovskite material include one or more of halogens and pseudohalogens. "Pseudohalogens," also known as halogen-like substances, refer to atomic groups composed of two or more elements that, as a whole, possess chemical properties similar to halogens. Anionic pseudohalogens may be referred to as pseudohalogen anions. Non-limiting examples of pseudohalogens may include one or more of thiocyano (SCN), oxocyano (OCN), etc. Non-limiting examples of pseudohalogen anions may include SCN. - OCN - CNO - OSCN - SH - CN - SeCN - One or more of the following. It is understood that pseudohalogens present in perovskite materials can act as X-site ions. In some embodiments of this application, the X-site anion is a monovalent anion.

[0347] In some embodiments of this application, the perovskite material includes perovskite-type metal halides.

[0348] Unless otherwise stated in this application, the anions in perovskite materials or perovskite-type metal halides may include one or more of halogen anions and pseudohalogen anions.

[0349] In some embodiments of this application, the anion in the perovskite material or perovskite-type metal halide is selected from one or more of halogen anions and pseudohalogen anions.

[0350] In some embodiments of this application, the perovskite material or perovskite-type metal halide may include at least one of ABX3 and A2CDX6; wherein A is a monovalent cation, B is a divalent cation, X is a monovalent anion, C is a monovalent cation, and D is a trivalent cation.

[0351] Without limitation, in perovskite-type metal halides, A can be a monovalent inorganic cation, a monovalent organic cation, or a mixed cation of monovalent organic and monovalent inorganic cations.

[0352] In some embodiments of this application, in the perovskite material or perovskite-type metal halide, A is a monovalent inorganic cation; optionally, A includes Li. + Na + K + 、Rb + and Cs + One or more of them.

[0353] In some embodiments of this application, in the perovskite material or perovskite-type metal halide, A is a monovalent organic cation. Optionally, A includes at least one of methylamino, ethylamino, propylamino, butylamino, pentamino, hexamino, formamidinyl, and imidazolyl.

[0354] Without limitation, the A in perovskite materials or perovskite-type metal halides may include Cs. + K + 、Rb + Li + One or more of monovalent organic cations, etc.

[0355] Non-limiting examples of monovalent organic cations include (NR) 31 R 32 R 33 R 34 ) + 、(R 31 R 32 N=CR 33 R 34 ) + 、(R 31 R 32 NC(R 35 )=NR 33 R 34 ) + or (R) 31 R 32 NC(NR 35 R 36 )=R 33 R 34 ) + , where R 31 R 32 R 33 R 34 R 35 and R 36 Each is independently selected from H and C. 1-20 Alkyl, aryl, substituted C 1-20 Alkyl or substituted aryl; wherein, C 1-20 Alkyl and substituted C 1-20 The "C" in alkyl 1-20 Each alkyl group can be independently selected as C. 1-15Alkyl, further optionally C 1-10 Alkyl, and further optionally C 1-8 Alkyl, and further optionally C 1-6 Alkyl, and further optionally C 1-4 Alkyl, and further optionally C 1-3 Alkyl, and further optionally methyl. The "aryl" in aryl and substituted aryl groups can each independently be C10. 6-20 Aryl, further optionally C 6-12 Aryl, and further alternatively C 6-10 Aryl, further optionally phenyl or naphthyl, and further optionally phenyl. Substituted C 1-20 In alkyl and substituted aryl groups, each substituent is independently C1. 1-10 Hydrocarbon group, further optionally C 1-6 Alkyl or C 6-10 Aryl, and may further be methyl or phenyl.

[0356] Non-limiting examples of monovalent organic cations include CH3NH3 + (Methylamine, MA) + ), NH2CH=NH2 + (Formamidin, can be written as FA) + ), dimethylamine cation, ethylamine cation, propylamine cation, butylamine cation, pentamine cation, hexamine cation, imidazole cation.

[0357] In some embodiments of this application, in the perovskite-type metal halide, A includes a monovalent organic cation and Cs. + One or more of them.

[0358] In some embodiments of this application, in the perovskite material or perovskite-type metal halide, B includes divalent cations of one or more of the following elements: lead, tin, zinc, titanium, antimony, bismuth, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, and europium.

[0359] In some embodiments of this application, in the perovskite material or perovskite-type metal halide, C represents a monovalent inorganic cation; optionally, C includes Cs. + Ag + K + and Ru + One or more of them.

[0360] In some embodiments of this application, D represents a trivalent metal cation; optionally, D includes Bi. 3+ Ni 3+ Fe 3+ Sb 3+ In 3+and Cu 3+ One or more of them, and further optionally, D includes In 3+ Bi 3+ Sb 3+ One or more of them.

[0361] In some embodiments of this application, X represents a halide anion; optionally, X includes F. - Cl - ,Br - and I - One or more of them, and optionally, X includes Cl - ,Br - and I - One or more of them.

[0362] In some embodiments of this application, the perovskite material includes perovskite-type metal halides, and the monovalent cation of the perovskite material includes FA. + and Cs + .

[0363] In some embodiments of this application, the perovskite material includes perovskite-type metal halides, and the monovalent cation of the perovskite material includes FA. + MA + and Cs + .

[0364] In some embodiments of this application, FA + The molar percentage of monovalent cations in perovskite materials is 0.8~1.0.

[0365] In some embodiments of this application, MA + The molar percentage of monovalent cations in perovskite materials is 0 to 1.0.

[0366] In some embodiments of this application, Cs + The molar percentage of monovalent cations in perovskite materials is 0~1.0.

[0367] In some embodiments of this application, the perovskite material includes perovskite-type metal halides, and the divalent cation of the perovskite material includes Pb. 2+ Furthermore, it can be used for Pb 2+ .

[0368] In some embodiments of this application, the perovskite material includes perovskite-type metal halides, and the monovalent anions of the perovskite material include iodide anions and bromide anions.

[0369] In some embodiments of this application, the molar percentage of iodine anions in the monovalent anions of the perovskite material is 0 to 1.0.

[0370] In some embodiments of this application, the molar percentage of bromide anions in the monovalent anions of perovskite materials is 0 to 1.0.

[0371] In this document, unless otherwise specified, "alkyl" refers to a monovalent residue formed by the loss of a hydrogen atom from a saturated hydrocarbon containing a primary (normal) carbon atom, or a secondary carbon atom, or a tertiary carbon atom, or a quaternary carbon atom, or a combination thereof. Phrases containing this term, such as "C", are also included. 1-6 "Alkyl" refers to an alkyl group containing 1 to 6 carbon atoms, and each time it appears, it can be independently C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, or C6 alkyl. Suitable examples include, but are not limited to: methyl (Me, -CH3), ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 2-propyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, -CH(CH3)CH2CH3), 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH3)3), 1-pentyl (n -pentyl, -CH2CH2CH2CH2CH3), 2-pentyl (-CH(CH3)CH2CH2CH3), 3-pentyl (-CH(CH2CH3)2), 2-methyl-2-butyl (-C(CH3)2CH2CH3), 3-methyl-2-butyl (-CH(CH3)CH(CH3)2), 3-methyl-1-butyl (-CH2CH2CH(CH3)2), 2-methyl-1-butyl (-CH2CH(CH3)CH2CH3), 1-hexyl (-CH2CH2CH2CH2CH2CH3), 2-hexyl (-CH(CH3)CH2CH2CH2CH3), 3-hexyl (-CH(CH2CH3)(CH2CH2CH3)), 2-methyl-2-pentyl (-C(CH3)2CH2CH2CH3).

[0372] In this application, unless otherwise specified, the term "aryl" refers to an aromatic hydrocarbon group derived from an aromatic cyclic hydrocarbon compound by losing one hydrogen atom, that is, forming a monovalent linking site directly on the ring. It can be a monocyclic aryl, a fused-ring aryl, or a polycyclic aryl; for polycyclic rings, at least one is an aromatic ring system. For example, "C6- 10 "Aryl" refers to an aryl group containing 6 to 10 carbon atoms. Each time it appears, it can be independently C6 aryl, C8 aryl, C9 aryl, or C6 aryl. 10 Aryl. For example, "C6- 20"Aryl" refers to an aryl group containing 6 to 20 carbon atoms. Each time it appears, it can be independently, but is not limited to, C6 aryl (such as phenyl), C8 aryl (such as benzocyclobutenyl), C9 aryl (such as indenyl), C6 aryl, C8 aryl, C9 ... 10 Aryl (such as naphthyl), C 12 Aryl (such as acenaphthene, biphenyl), C 13 Aryl (such as fluorene), C 14 Aryl (such as anthracene, phenanthrene), C 18 Aryl (such as phenylene) or C 20 Aryl groups (such as dinaphthalene-based phenyl groups). Examples of suitable aromatic cyclic hydrocarbons that can be derived to form aryl groups include, but are not limited to: benzene, benzocyclobutene, biphenyl, indene, naphthalene, acenaphthene, fluorene, anthracene, phenanthrene, triphenylene, dinaphthalene-based phenyl groups and their derivatives.

[0373] Without limitation, in perovskite-type metal halides, B can be an inorganic cation.

[0374] In some embodiments of this application, in the perovskite-type metal halide, B includes a divalent cation. Optionally, B includes a divalent cation of one or more of the following elements: lead, tin, zinc, titanium, antimony, bismuth, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, europium, etc.

[0375] Without limitation, B in perovskite-type metal halides may include Pb. 2+ Sn 2+ Fe 2+ Mn 2+ Ni 2+ 、Ge 2+ Co 2+ and Sb 2+ One or more of them.

[0376] In perovskite-type metal halides, X can be an inorganic anion, an organic anion, or a mixture of organic and inorganic anions.

[0377] In some embodiments of this application, in the perovskite-type metal halide, X is a halide anion; optionally, X includes F. - Cl - ,Br - and I - One or more of them, and optionally, X includes Cl - ,Br - and I - One or more of the following. In some embodiments, X in the perovskite metal halide can be I. - ,Br - and Cl - One or more of them.

[0378] Without limitation, X in perovskite-type metal halides may include I. - ,Br - One or two of them. X can be I. - ,Br - Or a combination thereof. In some embodiments, X is I. - .

[0379] Non-limitingly, in perovskite-type metal halides, C can be an inorganic cation, an organic cation, or a mixed organic-inorganic cation. In some embodiments of this application, C is a monovalent inorganic cation; optionally, C includes Cs. + Ag + K + and Ru + One or more of the following. In some embodiments of this application, C can be silver ions (Ag). + ).

[0380] In a non-limiting sense, in perovskite metal halides, D can be an inorganic cation, an organic cation, or a mixed organic-inorganic cation.

[0381] In some embodiments of this application, D is a trivalent metal cation; optionally, D includes Bi. 3+ Ni 3+ Fe 3+ Sb 3+ In 3+ , and Cu 3+ One or more of them, and further optionally, D includes In 3+ Bi 3+ Sb 3+ One or more of these. In some embodiments, D is a bismuth cation (Bi). 3+ ), antimony cation (Sb) 3+ ) and indium cation (In 3+ At least one of the following.

[0382] It is understood that electrodes include conductive materials. For electrodes that can be used as incident light electrodes, those skilled in the art can select appropriate types of conductive materials to achieve the desired transmittance.

[0383] Non-limiting, the first electrode and the second electrode may each independently comprise a conductive material. The conductive material in the first electrode and the conductive material in the second electrode may each independently comprise an organic conductive material, an inorganic conductive material, or an organic-inorganic mixed conductive material.

[0384] As an example, organic-inorganic hybrid conductive materials include both organic and inorganic conductive components.

[0385] As a non-limiting example, organic conductive materials may include conductive polymers, wherein non-limiting examples of conductive polymers may include one or more of PEDOT (poly-3,4-ethylenedioxythiophene), polythiophene, polyacetylene, etc.

[0386] As a non-limiting example, inorganic conductive materials may include one or more of transparent conductive oxides, metallic conductive materials, and carbon conductive materials. Non-limiting examples of transparent conductive oxides may include one or more of fluorine-doped tin oxide (FTO), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), indium zinc oxide (IZO), tungsten-doped indium oxide (IWO), indium gallium zinc oxide (IGZO), and antimony-doped tin oxide (ATO). Metallic conductive materials may include one or more of gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), bismuth (Bi), platinum (Pt), magnesium (Mg), molybdenum (Mo), and tungsten (W).

[0387] In some embodiments of this application, non-limiting examples of inorganic conductive materials include metallic conductive materials. Further, metallic conductive materials may include any one of gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), bismuth (Bi), platinum (Pt), magnesium (Mg), or any suitable mixture of the aforementioned elements.

[0388] It is understood that transparent electrodes comprise transparent conductive materials. In some embodiments of this application, the transparent conductive material contained in the transparent electrode may include conductive oxides. Non-limitingly, the conductive oxide in the transparent electrode may include one or more of indium tin oxide, fluorine-doped tin oxide, indium-doped tungsten oxide, indium-doped zinc oxide, and aluminum-doped zinc oxide. In some embodiments of this application, the transparent conductive material in the transparent electrode may be exemplified, but is not limited to, one or more of the following materials: fluorine-doped tin oxide (FTO), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), indium zinc oxide (IZO), tungsten-doped indium oxide (IWO), indium gallium zinc oxide (IGZO), and antimony-doped tin oxide (ATO), etc.

[0389] In some embodiments of this application, one of the first electrode and the second electrode is a metal electrode. The metal electrode may include one or more metallic elements selected from gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), bismuth (Bi), platinum (Pt), magnesium (Mg), molybdenum (Mo), tungsten (W), etc.

[0390] In some embodiments of this application, the electrode material of the first electrode includes at least one of indium tin oxide (ITO), lanthanide-doped indium oxide, fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), boron-doped zinc oxide (BZO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), gallium zinc oxide (GZO), tungsten-doped indium oxide (IWO), Au, Ag, Cu, Al, Ni, Cr, Bi, Pt, Mg, Mo, W and their alloys, graphite, graphene, and carbon nanotubes; optionally, it includes at least one of Ag, Cu, C, Au, Al, ITO, AZO, BZO or IZO, and further optionally, it includes at least one of Cu, Ag, and Au.

[0391] In some embodiments of this application, the second electrode is a back electrode. The back electrode may include one or more of indium tin oxide (ITO), lanthanide-doped indium oxide, fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), boron-doped zinc oxide (BZO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), gallium zinc oxide (GZO), and tungsten-doped indium oxide (IWO), and the metal may include one or more metallic elements selected from Au, Ag, Cu, Al, Ni, Cr, Bi, Pt, and Mg.

[0392] The substrate layer involved in the embodiments or examples of this application can be, but is not limited to, a rigid substrate layer or a flexible substrate layer. A non-limiting example of a rigid substrate layer is a glass substrate layer. In some embodiments, the rigid substrate layer is transparent glass. In some embodiments, the substrate layer is provided by a transparent conductive oxide film glass (TCO glass), wherein the glass serves as the substrate layer, and the TCO is a transparent conductive oxide film material; non-limiting examples of TCO materials include ITO, FTO, etc.

[0393] In some embodiments of this application, the material of the flexible substrate layer may be, for example, but not limited to, organic polymer materials. Furthermore, it may be composed of one or more of the following materials mixed in different proportions: including but not limited to polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS), etc.

[0394] It is understood that the structure of the photovoltaic device involved in this application is not limited to the structural layers listed above. Other functional layers or interface layers, such as buffer layers and insertion layers, can also be introduced as needed. In some embodiments, a buffer layer with appropriate energy levels can be provided in the photovoltaic device, which can play one or more of the following roles: reducing energy level barriers, promoting energy level matching, improving carrier extraction efficiency, passivating interface defect states, protecting the light-absorbing layer, inhibiting the oxidation and decomposition of water molecules and oxygen on the battery, improving energy conversion efficiency, and improving device stability. Depending on the location of the buffer layer, the type of buffer layer can include four types: a buffer layer between the hole transport layer and the anode, a buffer layer between the electron transport layer and the cathode, a buffer layer between the hole transport layer and the light-absorbing layer, and a buffer layer between the electron transport layer and the light-absorbing layer. Materials that can be used for buffer layers in photovoltaic devices can include, but are not limited to, Cu2O, NiO, AZO, TiO2, etc. In some embodiments, an insertion layer can be provided between the electron transport layer and the second electrode. This insertion layer is used to block the transport of holes and can also be called a hole blocking layer. Examples of materials for the insertion layer include bath copper phosphate (BCP) and tin oxide.

[0395] In some embodiments of this application, the photovoltaic device includes the following stacked structure: a transparent conductive glass substrate layer, a hole transport layer, a perovskite layer, an electron transport layer, a hole blocking layer (optional), and a back electrode (the back electrode can be a metal electrode or a transparent conductive electrode).

[0396] In this application, unless otherwise specified, "sequentially stacked" refers to the direction of stacking between layered structures and does not constitute a limitation on the structural composition of the stacked body. For example, "including stacked structural layer A and structural layer B" means that the stacking direction of structural layer A and structural layer B is along their respective thickness directions; that is, the thickness direction of structural layer A is consistent with or substantially consistent with the thickness direction of structural layer B. It is understood that other intermediate structural layers are allowed to be set between structural layer A and structural layer B.

[0397] The following are some other descriptions of the structure of photovoltaic devices.

[0398] In some embodiments of this application, the photovoltaic device 20 includes Figure 9 The structure shown ( Figure 9The structure shown is a schematic cross-sectional view of the device along its thickness direction. The photovoltaic device 10 includes a substrate layer 500, a first electrode 410, a first charge transport layer 310, a perovskite layer 100, a second charge transport layer 320, and a second electrode 420, all stacked together. Further, the photovoltaic device 10 has three cross-layered channel regions: a first channel region P1, a second channel region P2, and a third channel region P3. Using the channel group formed by the first channel region P1, the second channel region P2, and the third channel region P3, the device or the solar cell within the device is divided into several series-connected sub-cells. Each sub-cell includes a first channel region P1, a second channel region P2, and a third channel region P3 arranged sequentially, with the second channel region P2 located between the first channel region P1 and the third channel region P3. The first channel region P1, the second channel region P2, and the third channel region P3 can be connected to the spaced-apart structural layers, thereby connecting the circuit between the first electrode of one sub-cell and the second electrode of an adjacent sub-cell, forming a series structure. The first channel region P1, the second channel region P2, and the third channel region P3 can each be an independent linear channel region, formed by laser etching or a photomask. The number of each of the first channel region P1, the second channel region P2, and the third channel region P3 can be one or more. The number of the first channel region P1, the second channel region P2, and the third channel region P3 corresponds to the number of sub-cells. Non-limitingly, the first channel region P1, the second channel region P2, and the third channel region P3 can be configured as follows: the first channel region P1 is used to divide the first electrode 410 to prevent short circuits between adjacent sub-cells; the second channel region P2 is used to penetrate and divide the second charge transport layer 320, the perovskite layer 100, and the first charge transport layer 310, and the second channel region is filled with a conductive material such that both ends of the conductive material are connected to the second electrode 420 and the first electrode 410, respectively. The material of this conductive material can be the same as the material of the second electrode 420 to achieve integral fabrication during the fabrication process of the second electrode 420, or it can be different from the material of the second electrode 420; no limitation is made here; the third channel region P3 is used to penetrate and at least divide the second electrode 420, in Figure 9 In the example, the third channel region P3 is used to penetrate and divide the second electrode 420, the second charge transport layer 320, the perovskite layer 100, and the first charge transport layer 310. One end of the third channel region P3 is connected to the surface of the first electrode 410, and the other end extends out of the outer surface of the second electrode 420. The purpose is to isolate the second electrode between two adjacent sub-cells to prevent short circuits. In this way, a series connection between adjacent sub-cells is achieved.

[0399] In some embodiments of this application, Figure 9 The substrate 500 in the structure shown is a light-incident glass substrate.

[0400] In some embodiments of this application, the filling material in the first channel region P1 of the photovoltaic device can be the same as the first charge transport layer, or it can be filled with insulating material, as long as it can prevent short circuits between adjacent series-connected sub-cells.

[0401] In some embodiments of this application, the filling material in the second channel region P2 of the photovoltaic device may be consistent with the second electrode.

[0402] In some embodiments of this application, the width of the first channel region P1 is 10~50μm, such as 15μm, 25μm, 30μm, etc.

[0403] In some embodiments of this application, the width of the second channel region P2 is 10~200μm, for example 50μm, 60μm, 150μm. Further, the interval between the second channel region P2 and the first channel region P1 can be 20~100μm, for example 20μm, 30μm, 50μm, 100μm, etc.

[0404] In some embodiments of this application, the width of the third channel region P3 is 10~50μm, such as 15μm, 25μm, 50μm, etc. Further, the interval between the third channel region P3 and the second channel region P2 can be 20~100μm, such as 30μm, 50μm, 80μm.

[0405] In some embodiments of this application, the photovoltaic device includes an encapsulating adhesive layer.

[0406] The encapsulating adhesive layer can be used to protect the stability of photovoltaic devices, for example, by isolating them from water, oxygen, and other corrosive substances.

[0407] In some embodiments of this application, the encapsulating adhesive layer includes one or more of the following: epoxy encapsulating adhesive, silicone encapsulating adhesive, polyurethane encapsulating adhesive, UV-curable encapsulating adhesive, ethylene-vinyl acetate copolymer, polyvinyl butyral, ethylene octene copolymer, polyisobutylene, and polyolefin encapsulating adhesive.

[0408] The encapsulating adhesive layer can be stacked using existing techniques in the field. After the photovoltaic device is fabricated, the encapsulating adhesive layer can be stacked at the final structural layer of the solar cell device. In some embodiments of this application, the final structural layer can be a second electrode. For example, lamination technology can be used to laminate the arranged photovoltaic devices or components including photovoltaic devices with the encapsulating adhesive film, thereby creating an encapsulating adhesive layer on the side of the second electrode opposite to the light-absorbing layer.

[0409] Unless otherwise stated, the encapsulating film and encapsulating layer in this application are transparent materials.

[0410] In some embodiments of the second aspect of this application, a method for fabricating a photovoltaic device is provided, which can be used to fabricate the photovoltaic device of the first aspect of this application.

[0411] In some embodiments of this application, a method for fabricating a photovoltaic device is provided, which includes the following steps:

[0412] S100: The substrate is preheated, and a nickel oxide target is used to perform physical vapor deposition on the substrate under the condition of introducing an oxidizing gas, followed by a first annealing to form a hole transport layer; wherein, the hole transport layer includes nickel oxide;

[0413] Optionally, the first annealing is performed at a first temperature, which is higher than or equal to 140°C;

[0414] S200: A perovskite precursor solution is coated on the surface of the hole transport layer and vacuum dried to remove some of the solvent, forming a perovskite intermediate phase film layer; wherein, the perovskite precursor solution includes a perovskite precursor material and a solvent; the perovskite intermediate phase film layer includes a second region close to the hole transport layer and a third region far from the hole transport layer; the second region is located between the hole transport layer and the third region, and the solvent residue in the second region is higher than that in the third region;

[0415] S300: The perovskite intermediate phase film layer is subjected to a second annealing at a second temperature to form a perovskite layer; wherein the second temperature is lower than the third temperature; and the duration of the second annealing at the second temperature is less than the duration of the third annealing at the third temperature.

[0416] The photovoltaic device described in the first aspect of this application can be prepared;

[0417] In some embodiments, the formed perovskite layer includes a first perovskite material; the thickness direction of the perovskite layer is denoted as the Z direction; the hole transport layer includes divalent nickel ions and trivalent nickel ions; R in the hole transport layer Ni2+ / 3+ Greater than 0 and less than 1; on the projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ The Moran index is less than or equal to 0.4.

[0418] In this application, preheating the substrate can enable the nickel source generated by the nickel oxide target to be effectively deposited by physical vapor deposition.

[0419] In step S100, during the first annealing process, the nickel source generated by the nickel oxide target reacts fully with the oxidizing gas, which can control the oxidation valence state of nickel in the hole transport layer formed, thereby controlling the molar ratio of divalent nickel ions to trivalent nickel ions.

[0420] In this application, unless otherwise specified, "perovskite precursor solution" is in solution form and is also referred to as perovskite precursor solution.

[0421] In this application, unless otherwise specified, "perovskite precursor material" refers to a material used to form a perovskite crystal structure, capable of providing the basic elements in the perovskite crystal structure. Typically, the elemental composition of the perovskite precursor material matches the chemical elemental composition of the target perovskite material. Exemplarily, the target perovskite material can adopt the general structural formula of ABX3, in which case a divalent metal cation (such as Pb) is present. 2+ The sum of the atomic ratios of the components is 1; for example, the target perovskite material can be FA. 0.95 MA 0.05 Pb(I 0.95 Br 0.05 3. At this time, the divalent metal cation is Pb. 2+ .

[0422] Unless otherwise specified, in step S200, the first perovskite material is the target perovskite material, and the perovskite precursor material refers to the precursor material that can form the first perovskite material.

[0423] In some embodiments of this application, in step S200, the temperature at which vacuum drying is performed is lower than the perovskite crystallization temperature.

[0424] It is understandable that the third temperature in step S300 is higher than the perovskite crystallization temperature.

[0425] In this application, unless otherwise stated, "perovskite crystallization temperature" refers to the initial crystallization temperature of perovskite, which is the lowest temperature at which the perovskite precursor begins to undergo a phase transition and transform into perovskite crystals.

[0426] The aforementioned method prepares a hole transport layer containing nickel oxide via physical vapor deposition under the condition of introducing an oxidizing gas. The oxidizing gas increases interstitial oxygen, thereby inducing some divalent nickel ions to transform into trivalent nickel ions with higher oxidation states, achieving self-doping of trivalent nickel ions. This provides a higher concentration of vacancies in the lattice, which is beneficial for improving hole transport capability at the interface. Furthermore, the hole transport layer formed by physical vapor deposition has a relatively uniform distribution, effectively suppressing nickel oxide agglomeration and improving the in-plane uniformity of nickel oxide distribution. Moreover, the oxidizing gas can uniformly contact the physical vapor deposition layer, achieving better in-plane uniformity of the trivalent nickel ion doping ratio, resulting in high continuity of the hole transport path and a more uniform distribution of the built-in electric field, which is conducive to hole transport. Simultaneously, the uniform doping of trivalent nickel ions also promotes greater stability of the work function and HOMO energy level of nickel oxide, forming a more stable alignment relationship with the valence band top of perovskite, promoting efficient hole extraction. Therefore, the photoelectric conversion efficiency of the prepared photovoltaic device can be significantly improved.

[0427] In the above preparation method, vacuum drying is used to remove part of the solvent, forming a perovskite mesophase film layer containing residual solvent. The amount of residual solvent at the lower interface (near the hole transport layer, such as the second region) is higher than that at the upper interface (far from the hole transport layer, such as the third region). Gradient annealing is then performed at a second and a third temperature to form the perovskite layer. The selective anchoring effect of the hole transport layer on ions with different charge states in the perovskite precursor solution is utilized (for example, when the perovskite precursor solution simultaneously contains monovalent formamidinium cations (FA...)). + ) and divalent lead ions (Pb 2+ When the hole transport layer is in use, it can preferentially anchor the FA. + The residual solvent with its gradient distribution also aids in the migration of ions in the perovskite precursor solution, which is conducive to the formation of an energy level structure at the lower interface of the perovskite layer where the Fermi level is closer to the top of the valence band (VBM).

[0428] Furthermore, the uniform doping of trivalent nickel ions, the gradient distribution of residual solvent, and the gradient annealing at the second and third temperatures work together to better coordinate the selective anchoring effect of the hole transport layer and the auxiliary migration effect of the residual solvent, thereby helping to moderately enhance the approach of the Fermi level at the lower interface of the perovskite layer to the top of the valence band.

[0429] It's understandable that they don't want to be limited to the aforementioned theories.

[0430] The above method, which involves physical vapor deposition and post-treatment annealing under oxidizing gas conditions, can effectively control the crystallization of the hole transport layer, achieve effective and uniform trivalent nickel ion self-doping effect, and enable the hole transport layer to achieve more efficient conductivity and better energy level matching with perovskite.

[0431] Furthermore, the hole transport layer and perovskite layer formed by the aforementioned method exhibit good lattice matching at the interface. For example, nickel oxide crystal and perovskite crystal can form a coherent structure.

[0432] By doping with trivalent nickel ions, the energy level structure at the interface near the hole transport layer in the perovskite layer can be optimized, bringing the Fermi level of the first perovskite material closer to the valence band top. This improves the energy level matching between the perovskite layer and the hole transport layer at the perovskite layer interface, enhancing hole collection and transport efficiency, and ultimately improving photoelectric conversion efficiency. Furthermore, by controlling the amount of trivalent nickel ion doping, the degree to which the Fermi level of the first perovskite material at the hole transport layer side interface approaches the valence band top can be adjusted.

[0433] By utilizing the energy level modulation effect of nickel oxide on the perovskite material at the perovskite layer interface and the good lattice matching characteristics between nickel oxide and perovskite, the perovskite components can be induced to form perovskite crystals with excellent crystallinity, which is beneficial to improving photoelectric conversion efficiency.

[0434] For example, at the interface of the perovskite layer near the hole transport layer, an energy level structure with the Fermi level closer to the top of the valence band can be formed. This is beneficial for improving the energy level matching with the hole transport layer at the perovskite layer interface, improving the collection and transport efficiency of holes, and further improving the photoelectric conversion efficiency.

[0435] As another example, an improved uniform potential distribution can be formed at the interface near the hole transport layer in the perovskite layer, which facilitates more uniform and efficient extraction of holes at the perovskite interface, thus improving photoelectric conversion efficiency. Furthermore, the improved uniformity of the potential distribution at the perovskite layer interface also enhances the stability of the perovskite interface, thereby improving device stability.

[0436] The above-described preparation method is applicable to the fabrication of large-area devices, and can obtain a hole transport layer with excellent hole transport capability over a large area. Furthermore, based on the hole transport layer, a large-area perovskite layer with excellent crystallinity and uniformity can be obtained. The perovskite layer formed by the above method exhibits excellent large-area uniformity.

[0437] In some embodiments of this application, the target perovskite material includes divalent metal cations. Further, the concentration of the divalent metal cations in the perovskite precursor solution can be 0.5 mol / L to 3 mol / L, optionally 1 mol / L to 2 mol / L, or any of the following concentrations or a range selected from any two of the following concentrations: 0.5 mol / L, 0.6 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.2 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L, 2.4 mol / L, 2.5 mol / L, 3 mol / L, etc.

[0438] In some embodiments of this application, the solvent in the perovskite precursor solution may include one or more of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP).

[0439] In some embodiments of this application, the solvent in the perovskite precursor solution may be a mixture of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0440] In some embodiments of this application, the volume ratio of DMF to DMSO in the perovskite precursor solution is 2 to 6. Exemplarily, the volume ratio of DMF to DMSO can be 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, etc., but is not limited thereto.

[0441] In some embodiments of this application, the method for fabricating the photovoltaic device satisfies one or more of the following features (any numerical parameter of the following features may also be selected from any suitable value or range in the context):

[0442] (d1) The substrate includes a first electrode;

[0443] (d2) In the step of preheating the substrate, the preheating temperature is 90℃~110℃, and the preheating time is 5min~15min; at this time, it is beneficial to make the nickel source generated by the nickel oxide target more effective and uniform in physical vapor deposition, and to make the molar ratio of divalent nickel ions to trivalent nickel ions (R) more favorable. Ni2+ / 3+ Within a suitable range and with good uniformity of distribution, R Ni2+ / 3+ It exhibits good in-plane uniformity;

[0444] (d3) Oxidizing gases include oxygen and hydrogen peroxide; this is beneficial to improve the dispersion of oxidizing gases and improve the problem that molecules tend to aggregate when using a single type of oxidizing gas, resulting in uneven oxidation of the film; at the same time, it can also more precisely control the oxidizing properties of the oxidizing gases, which is beneficial to obtaining a more uniform hole transport layer film with more controllable oxidation valence state of nickel.

[0445] Optionally, the volume ratio of oxygen to hydrogen peroxide in the oxidizing gas is 70:30 to 99:1; at this time, the oxidizing power of the oxidizing gas can be controlled to a more suitable degree, which is more conducive to obtaining a hole transport layer film with more uniformity and more controllable oxidation valence state of nickel.

[0446] (d4) The flow rate of the oxidizing gas is 1 sccm to 5 sccm; at this time, the oxidation state of nickel in nickel oxide can be better controlled, and the ratio of divalent nickel ions to trivalent nickel ions can be better controlled.

[0447] (d5) Physical vapor deposition methods include magnetron sputtering;

[0448] (d6) The first temperature (T1) is 140℃~160℃, and the duration (t1) of the first annealing is 5min~25min. At this time, it is beneficial to better control the degree of reaction between nickel and oxidizing gas, thereby better controlling the doping ratio of trivalent nickel ions.

[0449] (d7) The temperature for vacuum drying is 5℃~15℃, the pressure for vacuum drying is 1Pa~20Pa, and the duration for vacuum drying is 5s~40s.

[0450] (d8) The second temperature (T2) is 85℃~95℃, and the third temperature (T3) is 110℃~120℃;

[0451] (d9) The duration of the second annealing (t2) is 2 min to 5 min, and the duration of the third annealing (t3) is 5 min to 10 min.

[0452] By controlling one or more parameters such as substrate preheating parameters, the composition and flow rate of the oxidizing gas, and the annealing temperature and duration of the first annealing, the doping ratio and uniformity of trivalent nickel ions can be effectively controlled. For example, by increasing the oxidizing power of the oxidizing gas, increasing the flow rate of the oxidizing gas, increasing the annealing temperature (T1) of the first annealing, and extending the annealing duration (t1) of the first annealing, the degree of reaction between nickel and the oxidizing gas can be increased, thereby increasing the doping ratio of trivalent nickel ions.

[0453] By controlling parameters such as temperature, pressure, and duration during the vacuum drying process, the solvent pumping rate can be controlled, thereby better controlling the amount of solvent residue at the upper and lower interfaces of the perovskite layer and the gradient between the solvent residue at the upper and lower interfaces (where the interface of the perovskite layer on the hole transport layer side is denoted as the lower interface, and the interface on the other side of the perovskite layer in the thickness direction is denoted as the upper interface), thus finely controlling the energy level structure of the perovskite material in the interface region (such as the first region) near the hole transport layer.

[0454] By controlling one or more parameters such as the temperature, pressure, and duration of vacuum drying, the temperature and duration of the second annealing, and the temperature and duration of the third annealing, the energy level structure of the perovskite material in the interface region (such as the first region) near the hole transport layer in the perovskite layer can be well controlled.

[0455] By controlling one or more parameters such as the temperature, pressure, and duration of vacuum drying, the temperature and duration of the second annealing, and the temperature and duration of the third annealing, the crystallization quality of perovskite can be better controlled. For example, the uniformity of the potential distribution in the interface region (such as the first region) near the hole transport layer in the perovskite layer can be better controlled.

[0456] In some embodiments of this application, the first temperature (T1) is 140°C to 160°C, and may also be any of the following temperatures or a range selected from any two of the following temperatures: 140°C, 145°C, 150°C, 155°C, 160°C, etc.

[0457] In some embodiments of this application, the duration (t1) of the first annealing is 5 min to 25 min, and may also be any of the following values ​​or a range selected from any two of the following values: 5 min, 6 min, 8 min, 10 min, 12 min, 14 min, 15 min, 16 min, 18 min, 20 min, 22 min, 24 min, 25 min, etc.

[0458] The first temperature (T1) and the duration of the first annealing (t1) can be combined in a suitable manner to better control the amount of solvent residue in the perovskite mesophase film and the distribution gradient of the residual solvent in the Z direction.

[0459] In this application, unless otherwise specified, "the amount of solvent residue in the perovskite mesophase film" may be expressed as "the mass percentage of solvent residue in the perovskite mesophase film (F)". S Characterization can be performed using the initial solvent content before vacuum drying as a baseline; where "the mass percentage of solvent residue in the perovskite mesophase film (F)" is the percentage of solvent remaining in the perovskite mesophase film. S "" refers to the percentage of the total mass of residual solvent in the entire perovskite mesophase film relative to the initial total mass of solvent before vacuum drying. This can be confirmed using the following method: Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is used to perform in-depth analysis of the perovskite mesophase film after vacuum drying (VCD), and the solvent molecule signal intensity (I1) at different depths is monitored. This is then compared with the signal intensity (I0) in the coated perovskite mesophase film before VCD treatment to obtain the solvent mass M1 in the VCD-treated sample and the solvent mass M0 in the coated sample before VCD treatment, thus obtaining the percentage of residual solvent F in the perovskite mesophase film. S =M1 / M0×100%.

[0460] TOF-SIMS detection can be performed using instruments such as PHI nanoTOF Ⅲ Time-of-Flight SIMS, and a suitable ion source (such as Cs) can be selected. + Bi3 ++ (etc.), primary ion energy (e.g., 0.5keV~30keV), imaging region size (e.g., 500×500μm) 2 100×100μm 2 Test parameters such as mass range and mass resolution, sputtering parameters (such as sputtering time, sputtering area, sputtering rate, analysis mode (such as depth profile mode, neutralization mode, etc.)) are used to obtain the three-dimensional distribution information of the corresponding elements or components in the sample to be tested.

[0461] In some embodiments of this application, the thickness of the second region and the third region can each be independently 5nm to 30nm, optionally 5nm to 20nm, or any of the following values ​​or a range selected from any two of the following values: 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 15nm, 20nm, 25nm, 30nm, etc.

[0462] In some embodiments of this application, the thicknesses of the second region and the third region are equal or substantially equal.

[0463] In some embodiments of this application, the second temperature (T2) is 85°C to 95°C, and may also be any of the following temperatures or a range selected from any two of the following temperatures: 85°C, 86°C, 88°C, 90°C, 92°C, 94°C, 95°C, etc.

[0464] In some embodiments of this application, the third temperature (T3) is 110°C to 120°C, and may also be any of the following temperatures or a range selected from any two of the following temperatures: 110°C, 112°C, 114°C, 115°C, 116°C, 118°C, 120°C, etc.

[0465] In some embodiments of this application, the duration (t2) of the second annealing is 2 min to 5 min, and may also be any of the following values ​​or a range selected from any two of the following values: 2 min, 3 min, 4 min, 5 min, etc.

[0466] In some embodiments of this application, the duration (t3) of the third annealing is 5 min to 10 min, and may also be any of the following values ​​or a range selected from any two of the following values: 5 min, 6 min, 8 min, 10 min, etc.

[0467] The second temperature (T2) and the third temperature (T3) can be combined in a suitable manner, as can the second temperature (T2) and the duration of the second annealing (t2), the third temperature (T3) and the duration of the third annealing (t4), and T2, t2, T3, and t3. Such suitable combinations can better control the energy level structure of the perovskite material at the hole transport interface. It is understood that we do not wish to be limited to the aforementioned theories.

[0468] In some embodiments of this application, a photovoltaic device as described in the first aspect of this application is obtained.

[0469] In photovoltaic devices, structural layers other than the perovskite layer can be prepared using one or more of the following methods, including but not limited to: chemical bath deposition, electrochemical deposition, chemical vapor deposition, thermal evaporation, atomic layer deposition, magnetron sputtering, spin coating with a precursor solution, slot coating with a precursor solution, blade coating with a precursor solution, and mechanical pressing. Appropriate methods can be selected to stack the structural layers with adjacent structural layers based on the material properties of each layer. In some embodiments of this application, the structural layers in the photovoltaic device can be prepared using one or more of the following methods, including but not limited to: thermal evaporation, precursor solution coating, etc., wherein the precursor solution coating method can be spin coating with a precursor solution, blade coating with a precursor solution, spray coating with a precursor solution, etc.

[0470] In some embodiments of this application, the method for fabricating a photovoltaic device includes the following steps:

[0471] S10: Perform P1 etching on the first electrode: Perform P1 etching on the first electrode stacked on the substrate layer to form a P1 etching line, exposing the substrate layer to obtain the first substrate, which is then cleaned for later use. The first electrode can be a transparent electrode. The location of the formed P1 etching line can be found in [reference needed]. Figure 9 .

[0472] S20: A first charge transport layer is formed on the first electrode.

[0473] In some implementations, the first charge transport layer may be a hole transport layer.

[0474] S30: A perovskite layer is formed on the first charge transport layer. See the context for photovoltaic device fabrication methods.

[0475] S40: Form a second charge transport layer on the perovskite layer. Perform P2 etching to the depth of the first electrode near the hole transport layer surface. (See reference...) Figure 9 .

[0476] When the first charge transport layer is a hole transport layer, the second charge transport layer is an electron transport layer; when the first charge transport layer is an electron transport layer, the second charge transport layer is a hole transport layer.

[0477] S50: Form a second electrode on the second charge transport layer, perform P3 etching, and etch to the surface of the first electrode near the hole transport layer, then clean the edges. The location of the formed P3 etching line can be found in [reference needed]. Figure 9 .

[0478] In some embodiments of another aspect of this application, a photovoltaic module is provided, which includes a hole transport layer and a perovskite layer stacked together, wherein the stacked hole transport layer and the perovskite layer are described in the relevant description of the first aspect of this application.

[0479] In some embodiments of the third aspect of this application, an electrical device is provided, which includes at least one of the photovoltaic device described in the first aspect of this application and the photovoltaic device prepared by the method of preparing the photovoltaic device described in the second aspect of this application.

[0480] In some embodiments of the fourth aspect of this application, a power generation device is provided, which includes at least one of the photovoltaic device described in the first aspect of this application and the photovoltaic device prepared by the method of preparing the photovoltaic device described in the second aspect of this application.

[0481] Both power-consuming and power-generating devices, including those using the aforementioned photovoltaic devices, can leverage the advantages of photovoltaic devices.

[0482] In some embodiments, the aforementioned optoelectronic device can be a power generation device or power generation apparatus that functions as an electrical device. The type of power generation device or power generation apparatus may include, but is not limited to, integrated power generation. The location of the power generation device or power generation apparatus may include, but is not limited to, the roof or back panel of a vehicle.

[0483] Furthermore, the aforementioned electrical devices may include mobile devices, such as mobile phones and laptops, electric vehicles, electric trains, ships and satellites, power generation systems, etc., but are not limited to these.

[0484] Figure 10 This is an example of an electrical device. The electrical device 6 is a car, and can further be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0485] Another example of an electrical device could be a mobile phone, tablet, laptop, calculator, etc.

[0486] Another example of an electrical device could be a wearable device, such as a watch.

[0487] The following describes some embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where the technology or conditions are not specified in the embodiments, they are performed according to the description above, or according to the technology or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially, or can be synthesized from commercially available products using conventional methods.

[0488] In the following examples, unless otherwise specified, room temperature refers to 20°C to 30°C.

[0489] The unit "sccm" for gas flow rate represents standard cubic centimeters per minute.

[0490] In the following examples, the inverted structure is used as a non-limiting example of a photovoltaic device. It is understood that it can also be set as a formal structure.

[0491] For test results where specific test methods are not specified below, please refer to the description above. For example, the SEM method is used to test the thickness of the functional layer.

[0492] FAI is formamidine iodoformin (CAS No.: 879643-71-7), MABr is methylamine bromide (CAS No.: 6876-37-5), MACl is methylamine chloride (CAS No.: 593-51-1); PC 61 BM is [6,6]-phenyl C61 butyrate methyl ester; BCP is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bath copper spirit).

[0493] I. Fabrication of photovoltaic devices (which can be used in solar cells)

[0494] Step S1, take a group with an area of ​​approximately 2 square meters (m²) 2 On a fluorine-doped tin oxide substrate (FTO conductive glass, first electrode / glass substrate), P1, approximately 25 μm wide, was etched using an infrared laser, dividing the entire glass into 161 sub-cells. The series resistance of the different sub-cells was greater than 10 MΩ (i.e., 1 × 10⁻⁶). 7 The etched conductive glass surface was cleaned by ultrasonic cleaning with deionized water, acetone, ethanol, and isopropanol for 15 minutes each, and then placed in a 70°C drying oven for 120 minutes to remove residual organic impurities, resulting in a clean and dry substrate material. This substrate was then treated with UV-ozone for 15 minutes and transferred to a nitrogen-filled glove box. The thickness of the first electrode was approximately 500 nm.

[0495] Step S2, preparation of the hole transport layer: The FTO substrate is preheated at 100℃ for 10 minutes. A nickel oxide target is used, and a nickel oxide hole transport layer is prepared on the FTO substrate by magnetron sputtering. During sputtering, an oxidizing gas of 2 sccm (the oxidizing gas is a mixture of oxygen and hydrogen peroxide (H2O2) with a volume ratio of 8:2, and the partial pressure of the oxidizing gas in the gas atmosphere is 100%) is introduced at a pressure of 0.5 Pa and a sputtering power of 1500 W. After sputtering, the substrate is annealed at 150℃ for 10 minutes (the first annealing is performed at the first temperature) to prepare a hole transport layer with a thickness of about 17 nm.

[0496] Step S3, Preparation of the perovskite layer:

[0497] Step S3-1: Dissolve PbI2, FAI, PbBr2, MABr, CsI, and MACl (MACl with a molar percentage of 20 mol% relative to Pb, used as an additive) in a mixed solvent of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a volume ratio of 5.5:1, according to FAI... 0.95 MA 0.05 Pb(I 0.95 Br 0.05 The molar ratio of the elements in the chemical formula (corresponding to the first perovskite material) was used to prepare a basic solution of perovskite precursor of 1.4 mol / L. The solution was stirred overnight in a glove box filled with nitrogen to obtain the perovskite precursor solution.

[0498] Step S3-2: Filter the perovskite precursor solution obtained in step S3-1 using a polytetrafluoroethylene filter head. Apply the filtered perovskite precursor solution onto the hole transport layer using a slit coating method. Vacuum dry for 15 seconds (vacuum drying temperature is 10℃, pressure is 25Pa) to remove some solvent, obtaining a perovskite mesophase film layer. The perovskite mesophase film layer contains residual solvent, and the amount of residual solvent at the lower interface (the interface near the hole transport layer) is higher than that at the upper surface of the film layer.

[0499] In this application, unless otherwise specified, the surface of the perovskite mesophase film facing the hole transport layer is referred to as the lower surface of the film, and the surface of the perovskite mesophase film away from the hole transport layer is referred to as the upper surface of the film. In this example, the region extending 20 nm from the lower surface of the film towards the interior of the perovskite mesophase film is referred to as the second region, and the region extending 20 nm from the upper surface of the film towards the interior of the perovskite mesophase film is referred to as the third region. According to the TOF-SIMS test results, the solvent residue in the second region is higher than that in the third region.

[0500] Step S3-3, gradient annealing: The perovskite intermediate phase film containing residual solvent is transferred to a heating stage for gradient annealing. First, it is annealed at 90°C for 4 min (second annealing is performed at the second temperature), and then annealed at 110°C for 6 min (third annealing is performed at the third temperature) to obtain a crystallized perovskite layer with a thickness of approximately 440 nm.

[0501] Step S4, Fabrication of the electron transport layer: PC 61 BM was dissolved in chlorobenzene at a concentration of 20 mg / mL. The resulting electron transport layer solution was coated onto the perovskite layer and then annealed on a heating stage at 70°C for 10 minutes to form an electron transport layer with a thickness of approximately 60 nm.

[0502] Step S5, preparation of the interface layer: Dissolve BCP in methanol to form a 0.5 mg / mL solution, coat it on the electron transport layer, and then anneal it on a heating stage at 70°C for 10 minutes to form the interface layer (here, the hole blocking layer, with a thickness of about 5 nm).

[0503] P2 is laser-etched, with a width of 60 μm and a depth reaching the FTO layer. The spacing between P2 and P1 is 100 μm.

[0504] Step S6, Fabrication of the back electrode (second electrode): Using a vacuum thermal evaporation deposition apparatus, a copper electrode with a thickness of approximately 100 nm is deposited on the interface layer prepared in step S5 at a rate of 0.5~2 Å / s (1 Å / s in this example). Laser etching is then performed on P3, which has a width of 50 μm and a depth reaching the FTO layer. The spacing between P3 and P2 is 80 μm (the etching lines are positioned sequentially as P1 / P2 / P3, see reference). Figure 9 Then, infrared edge cleaning is used on the component. The resulting photovoltaic device is then fabricated.

[0505] Examples 2-9. Photovoltaic devices were prepared using a method essentially the same as in Example 1, except that step S2 for preparing the hole transport layer and / or step S3 for preparing the perovskite layer were different. One or more parameters were changed, including the preheating temperature and duration, the composition and flow rate of the oxidizing gas, the temperature and duration of the first annealing during hole transport layer preparation, the average thickness of the hole transport layer, the vacuum drying parameters (including the temperature and duration of vacuum drying) during perovskite layer preparation, and the parameters of the second and third annealing during perovskite layer preparation (including the temperature and duration of the second and third annealing). The remaining operation steps were the same as in Example 1, and Table 1 can also be consulted.

[0506] Comparative Example 1. A photovoltaic device was prepared using a method that was basically the same as that in Example 1. The difference was that (1) step S2 for preparing the hole transport layer was different, and no oxidizing gas was introduced; (2) in step S3-2 for preparing the perovskite layer, the pressure for vacuum drying was 100 Pa, and the vacuum drying treatment was carried out at 25°C for 60 s; in step S3-3, the gradient annealing performed on the hot stage was adjusted to annealing under a single temperature condition, and the annealing parameters were adjusted to: annealing at 105°C for 12 min; the differences can be found in Table 1, and the remaining operation steps were the same as in Example 1. Table 1 can also be found.

[0507] Comparative Example 2. A photovoltaic device was prepared using the same method as in Example 1, except that (1) step S2 for preparing the hole transport layer was different, and the oxidizing gas was replaced with pure oxygen; (2) in step S3-2 for preparing the perovskite layer, the pressure for vacuum drying was 100 Pa, and the vacuum drying treatment was carried out at 25°C for 60 s; in step S3-3, the gradient annealing performed on the hot stage was adjusted to annealing under a single temperature condition, and the annealing parameters were adjusted to: annealing at 105°C for 12 min; the differences can be found in Table 1, and the remaining operation steps are the same as in Example 1.

[0508] Comparative Example 3. A photovoltaic device was prepared using a method that was basically the same as that in Example 1, except that (1) step S2 for preparing the hole transport layer was different, and the oxidizing gas was replaced with pure hydrogen peroxide (H2O2) gas; (2) in step S3-2 for preparing the perovskite layer, the pressure for vacuum drying was 100 Pa, and the vacuum drying treatment was carried out at 25°C for 60 s; in step S3-3, the gradient annealing performed on the hot stage was adjusted to annealing under a single temperature condition, and the annealing parameters were adjusted to: annealing at 105°C for 12 min; the differences can be found in Table 1, and the remaining operation steps were the same as in Example 1.

[0509] II. Testing Methods

[0510] (a) Confirm the distribution of residual solvent in the perovskite mesophase film layer

[0511] Test method: Time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0512] Instrument: PHI nanoTOF Ⅲ Time-of-Flight SIMS.

[0513] The solvent residue within the perovskite layer and at different thickness locations were determined as follows: TOF-SIMS was used to perform in-depth profiling analysis on the perovskite mesophase film layer after vacuum drying (VCD) treatment, and the solvent molecule signal intensity (I1) at different depths was monitored. This signal intensity (I0) was then compared with that in the coated perovskite mesophase film layer before VCD treatment to obtain the solvent mass M1 in the VCD-treated sample and the solvent mass M0 in the coated sample before VCD treatment. This yielded the mass percentage F of solvent residue in the perovskite mesophase film layer. S =M1 / M0×100%. Based on the test results of the in-depth analysis, the solvent residue in the second and third regions can also be compared.

[0514] (ii) The molar ratio of divalent nickel ions to trivalent nickel ions (R) Ni2+ / 3+ )

[0515] Instrument: Thermo Fisher Scientific ESCALAB QXi.

[0516] By sputtering the sample surface layer by layer and combining it with full elemental scanning, elemental distribution information and three-dimensional distribution maps at different depths are obtained. The depth sampling depth of X-ray photoelectron spectroscopy (XPS) is 0.5 nm to 10 nm, and ion sputtering (such as Ar) is used to obtain elemental distribution information and three-dimensional distribution maps at different depths. + C +0 The sample was peeled off layer by layer using either a cluster ion beam or a single ion beam. After each layer was peeled off, XPS full spectrum or specific elemental spectrum (including at least the constituent elements of nickel oxide) was acquired. The etching rate was approximately 2 nm / s. The X-ray incident angle was 45°.

[0517] See also the description above.

[0518] (III) Energy level structure analysis of the perovskite layer (UPS combined with XPS)

[0519] Instrument: Thermo Fisher Scientific ESCALAB QXi.

[0520] The testing method is as follows:

[0521] (i) First use Ar + Ion beam etching is used to etch the perovskite layer film, and the signal of a selected element (such as Pb) in the perovskite crystal phase of the perovskite layer is detected. 4f (Related signals) to determine the etching location, pending Pb 4f When the signal intensity drops to 1 / e of the plateau intensity, it is defined as the perovskite etching is complete, and the etching rate of the perovskite layer by the ion beam is calculated. Among them, the signal of the selected element in the perovskite crystal phase has a high concentration in the perovskite layer, and it is easy to form a region with the elements of the possible adjacent structural layers, thereby determining the boundary between the perovskite layer and the possible adjacent structural layers.

[0522] (ii) Identify the sample to be tested, first perform an absorption spectrum scan, then perform UPS full spectrum and E... cutoff Ev scanning was performed to obtain the corresponding CBM, EF, and VBM positions; then etching was performed to gradually expose regions of different thicknesses, and absorption spectral scanning was performed on each region of different thicknesses to obtain the UPS full spectrum and Ev. cutoff Ev scanning was used to obtain the energy level structure of regions with different thicknesses of the perovskite layer. UPS scanning incident angle was 2°.

[0523] The VBM value can be directly obtained from the Ev scan results, through E... cutoff The Fermi level can be calculated from the photoelectron energy and the VBM level. The CBM level can be calculated from the band gap obtained from the absorption spectrum and the VBM level.

[0524] The first region is defined as the area extending 5nm to 10nm from the lower interface (the interface facing the hole transport layer) toward the interior of the perovskite layer in the test sample.

[0525] (iv) Electric potential distribution

[0526] Kelvin Atomic Force Microscopy (KPFM) Instrument: Bruker FastScan Bio.

[0527] KPFM test analysis: By measuring the change in electrostatic force between the probe and the sample, when the probe approaches the surface to be tested, due to the difference in their work functions, electrons will flow from the high Fermi level to the low Fermi level until the Fermi level is flattened. The contact potential difference can be deduced from the work function difference in this process, thereby obtaining potential data. By further combining in-plane scanning, the potential distribution data of the surface to be tested can be obtained.

[0528] (V) Moran Index Analysis

[0529] With R Ni2+ / 3+ Electric potential data, etc., are used as parameters to be analyzed. The following parameters are processed in the following manner:

[0530] 1. Parameters to be analyzed at different locations: Obtain the values ​​of the parameters to be analyzed at different locations within the region to be analyzed.

[0531] 2. Calculate the Moran index (I) using the selected statistical formula:

[0532]

[0533] Where n is the number of data points; W is the sum of all weights; ij x is an element in the spatial weight matrix; i and x j These are the parameter values ​​for the i-th and j-th positions; This is the average value of all position parameter values.

[0534] 3. Setting the spatial weight matrix:

[0535] The spatial weight matrix uses inverse distance weights, i.e. ,in The distance between the i-th and j-th positions is... Here is the distance attenuation parameter, and p is 2.

[0536] 4. Statistical area and sampling interval of data points: The statistical area is 10 μm × 10 μm, and the sampling interval of data points is 50 nm.

[0537] (vi) Coherent interface (nickel oxide and perovskite interface)

[0538] TEM testing: High-resolution transmission electron microscopy (HRTEM).

[0539] (vii) Device performance testing

[0540] 1. Initial performance of the device (optoelectronic devices used in solar cells)

[0541] Under normal temperature and pressure (25℃, 1 atmosphere), a standard light source with AM1.5G was used to simulate sunlight, conforming to the national standard IEC61215. The light intensity was corrected using crystalline silicon solar cells to achieve the intensity of one solar cell. The current-voltage characteristic curve (i.e., current-voltage curve) of the solar cell under the illumination of the light source was measured using a four-channel digital source meter (Keithley 2440). The open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and photoelectric conversion efficiency (PCE) of the solar cell were obtained.

[0542] The photoelectric conversion efficiency (PCE) is calculated as follows:

[0543] PCE = Pout / Pin

[0544] = Voc×Jsc×[(Vmpp×Jmpp) / (Voc×Jsc)] / Pin

[0545] = Voc×Jsc×FF / Pin

[0546] Wherein, Pout, Pin, Voc, Jsc, Vmpp, Jmpp, and FF represent the battery's operating output power, incident light power, open-circuit voltage, short-circuit current, maximum power point voltage, maximum power point current, and fill factor, respectively. The incident light power is 100 mW / cm². 2 .

[0547] 2. Device stability determination (aging test)

[0548] After the initial performance test of the device is completed, the cell under test is placed in an atmospheric environment (relative humidity of 65%-85%, ambient temperature of about 15℃-40℃) and left in the dark for 1000 hours. The energy conversion efficiency is then tested again (each test continues until there is no hysteresis in the forward and reverse scans, and the photoelectric conversion efficiency is recorded). The ratio of the photoelectric conversion efficiency after 1000 hours of atmospheric placement to the initial efficiency is calculated and used as the normalized efficiency of the solar cell after 1000 hours of placement, which can be denoted as "1000h retention rate".

[0549] 1000h retention rate = retest efficiency / initial efficiency × 100%. The higher the initial normalized efficiency, the better the device stability.

[0550] III. Test Result Analysis

[0551] In the photovoltaic devices prepared in Examples 1-9, the molar ratio (Ri) of divalent nickel ions to trivalent nickel ions in the hole transport layer is... Ni2+ / 3+ All of these conditions must be greater than 0 and less than 1, meaning that the content of trivalent nickel ions in the hole transport layer is higher than that of divalent nickel ions. Simultaneously, the R... Ni2+ / 3+ Moran's index (MLI) on the projection plane perpendicular to the Z direction Ni Lower MLI Ni All values ​​are less than or equal to 0.4; the photovoltaic devices prepared in Examples 1-9 all have high photoelectric conversion efficiency and good device stability. See Tables 1-2 for details.

[0552] Compared to Example 1, Comparative Example 1 omits the oxidizing gas in the hole transport layer preparation step, and also modifies the vacuum drying and annealing parameters during perovskite layer preparation. In the photovoltaic device prepared in Comparative Example 1, R... Ni2+ / 3+ The value is greater than 1, meaning the content of trivalent nickel ions in the hole transport layer is lower than that of divalent nickel ions; simultaneously, the R value in the hole transport layer of the photovoltaic device prepared in Comparative Example 1 is greater than that in the comparative example 1. Ni2+ / 3+ Moran's index (MLI) on the projection plane perpendicular to the Z direction Ni The doping uniformity of trivalent nickel in Comparative Example 1 is relatively low compared to Comparative Example 1. Furthermore, the photovoltaic device prepared in Example 1 exhibits higher photoelectric conversion efficiency and greater device stability. See Tables 1-2 for details.

[0553] Compared to Example 1, in Comparative Example 2, hydrogen peroxide gas was omitted from the oxidizing gas preparation process (only pure oxygen was used), and in Comparative Example 3, oxygen gas was omitted from the oxidizing gas preparation process (only pure hydrogen peroxide was used). Comparative Examples 2-3 also changed the vacuum drying and annealing parameters in the perovskite layer preparation process. In the photovoltaic devices of Comparative Examples 2-3, the R of the hole transport layer... Ni2+ / 3+ All are greater than R in the hole transport layer of Example 1. Ni2+ / 3+ That is, the doping amount of trivalent nickel ions in the hole transport layer of Comparative Examples 2-3 is reduced; at the same time, the R in the hole transport layer of the photovoltaic device prepared in Comparative Examples 2-3 is reduced. Ni2+ / 3+ Moran's index (MLI) on the projection plane perpendicular to the Z direction Ni)(relatively) high, that is, the doping uniformity of trivalent nickel in Comparative Examples 2-3 is relatively low. Compared with Comparative Examples 2-3, the photovoltaic device prepared in Example 1 has a higher photoelectric conversion efficiency. In addition, the photovoltaic device prepared in Example 1 also has higher device stability. Refer to Table 1-2.

[0554] In the photovoltaic devices prepared in Examples 1-9, the hole transport layer has good thickness uniformity. Refer to "Percentage of Δh to the average thickness of the hole transport layer (P Δh )" in Table 3.

[0555] In the photovoltaic devices prepared in Examples 1-9, there is a coherent structure between nickel oxide in the hole transport layer and the first perovskite material in the perovskite layer at the interface. Refer to Table 3.

[0556] In the photovoltaic devices prepared in Examples 1-9, the potential distribution at the surface B1 of the hole transport layer facing the perovskite layer is relatively uniform. Refer to MLI in Table 2 HP .

[0557] In the photovoltaic devices prepared in Examples 1-9, the potential distribution at the first surface of the perovskite layer facing the hole transport layer is relatively uniform. Refer to MLI in Table 2 PP .

[0558] In the photovoltaic devices prepared in Examples 1-9, the first perovskite material in the interface region (taking the first region as an example) of the perovskite layer close to the hole transport layer all satisfies E1 < E2, that is, all satisfy that the Fermi level is closer to the valence band top. Further, in Examples 1-9, in the energy level structure of the first perovskite material in the first region, the degree to which the Fermi level is closer to the valence band top all satisfies that "the difference between E2 and E1 (E2 - E1) is within the range of 1.0 eV to 1.8 eV". Refer to Table 3 for details. Exemplarily, E2 - E1 in Example 1 is within the range of 1.0 eV to 1.2 eV.

[0559] In Comparative Example 1, the content of trivalent nickel ions in the hole transport layer is lower than that of divalent nickel ions (R Ni2+ / 3+ > 1), and at the same time, the thickness uniformity of the hole transport layer is relatively poor (P Δh is relatively high); at the same time, compared with Example 1, Comparative Example 1 also changes the vacuum drying parameters and annealing parameters during the preparation of the perovskite layer; in the photovoltaic device of Comparative Example 1, in the energy level structure of the first perovskite material in the first region, the difference between E2 and E1 (E2 - E1) is smaller than the corresponding difference in Example 1, that is, in Comparative Example 1, the degree to which the Fermi level approaches the valence band top in the energy level structure of the first perovskite material in the first region is weakened compared with Example 1.

[0560] In Comparative Examples 2-3, the R of the hole transport layer Ni2+ / 3+R is higher than or close to that of the hole transport layer in Example 1 Ni2+ / 3+ That is, the doping amount of trivalent nickel ions in the hole transport layer of Comparative Examples 2-3 is lower than or close to the doping amount of trivalent nickel ions in the hole transport layer of Example 1; at the same time, compared with Example 1, P in Comparative Examples 2-3 Δh The values ​​are relatively high. Comparative Examples 2-3 also changed the vacuum drying parameters and annealing parameters during the preparation of the perovskite layer. The E2-E1 in the photovoltaic devices of Comparative Examples 2-3 is smaller than that in Example 1.

[0561] Compared to Comparative Examples 1-3, in Example 1, by controlling parameters such as the composition of the oxidizing gas during the preparation of the hole transport layer, the crystallization rate of the hole transport layer was controlled within a more suitable range, improving the thickness uniformity of the hole transport layer. Simultaneously, the lattice constant of nickel oxide in the formed hole transport layer is close to that of the perovskite in the perovskite layer, which is beneficial for forming a coherent interface between the hole transport layer and the perovskite, reducing the interface defect concentration, improving the contact tightness and stability with the perovskite layer, and enhancing the interface quality. Correspondingly, in Example 1, the percentage of Δh to the average thickness of the hole transport layer (P) is significantly higher. Δh The density of the hole transport layer was lower than that of Example 1. In addition, compared with Example 1, the defect density at the hole transport layer interface of Comparative Examples 1-3 increased, the lattice matching between the perovskite material and nickel oxide decreased, and no coherent structure between nickel oxide and perovskite material was observed in Comparative Examples 1-3.

[0562] Table 1.

[0563]

[0564] Table 2.

[0565]

[0566] In Table 2, “R” Ni2+ / 3+ "Corresponds to the molar ratio of divalent nickel ions to trivalent nickel ions in the hole transport layer; "MLI Ni "" indicates that on the projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ Moran's index; "I NiOx "This represents the average current measured by KPFM on surface B1 of the hole transport layer facing the perovskite layer; "MLI HP "MLI" represents the Moran index of the potential distribution obtained by KPFM testing on surface B1 of the hole transport layer facing the perovskite layer; PP "" represents the Moran index of the potential distribution obtained by KPFM testing on the first surface of the perovskite layer toward the hole transport layer.

[0567] Table 3.

[0568]

[0569] In Table 3, E1 is the absolute value of the difference between the Fermi level and the valence band top of the first perovskite material in the first region, and E2 is the absolute value of the difference between the Fermi level and the conduction band bottom of the first perovskite material in the first region.

[0570] It is understood that the above embodiments and examples are merely illustrative. Those skilled in the art may also use other preparation methods to obtain the photovoltaic device of the first aspect of this application. For example, the photovoltaic device described in the first aspect of this application may be obtained by adjusting other process parameters without using oxidizing gas. This application does not limit the preparation method of the photovoltaic device described in the first aspect.

[0571] The descriptions of the various implementation methods and embodiments above tend to emphasize the differences between them. Similarities or resemblances can be referenced interchangeably, and for the sake of brevity, they will not be repeated here. The technical features of the implementation methods and embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combinations of these technical features do not contradict each other, they should be considered within the scope of this specification.

[0572] It should be noted that this application is not limited to the above-described embodiments and examples. The above-described embodiments and examples are merely examples, and any embodiments and examples that have the same structure and achieve the same effect as the technical concept within the scope of this application are included in the technical scope of this application. The embodiments and examples described above only illustrate several embodiments and examples of this application, and although the descriptions are relatively detailed, they should not be construed as limiting the scope of the patent. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments or examples, and other ways of constructing embodiments or examples by combining some of the constituent elements of the embodiments or examples, are also included in the scope of this application without departing from the spirit of this application.

Claims

1. A photovoltaic device, characterized in that, It includes a hole transport layer and a perovskite layer stacked together; the perovskite layer includes a first perovskite material, and the hole transport layer includes nickel oxide; the thickness direction of the perovskite layer is denoted as the Z direction. The hole transport layer comprises divalent nickel ions and trivalent nickel ions; the molar ratio of divalent nickel ions to trivalent nickel ions is denoted as R. Ni2+ / 3+ ; R in the hole transport layer Ni2+ / 3+ Greater than 0 and less than 1; On the projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ The Moran index is less than or equal to 0.

4.

2. The photovoltaic device according to claim 1, characterized in that, R in the hole transport layer Ni2+ / 3+ The value is 0.5~0.9, and can be selected as 0.6~0.

8.

3. The photovoltaic device according to claim 1 or 2, characterized in that, On the projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ The Moran index is less than or equal to 0.

35.

4. The photovoltaic device according to any one of claims 1 to 3, characterized in that, The difference between the maximum and minimum thickness of the hole transport layer is denoted as Δh, where Δh is less than or equal to 5 nm and the percentage of Δh to the average thickness of the hole transport layer is less than or equal to 25%. Optionally, Δh is a percentage of the average thickness of the hole transport layer that is less than or equal to 20%.

5. The photovoltaic device according to any one of claims 1 to 4, characterized in that, The average thickness of the hole transport layer is greater than or equal to 10 nm, and can be selected from 10 nm to 50 nm.

6. The photovoltaic device according to any one of claims 1 to 5, characterized in that, The nickel oxide in the hole transport layer and the first perovskite material in the perovskite layer have a coherent structure at the interface.

7. The photovoltaic device according to any one of claims 1 to 6, characterized in that, The hole transport layer has a surface B1 facing the perovskite layer, and the Moran index of the potential distribution at the surface B1 of the hole transport layer is less than or equal to 0.4, optionally less than or equal to 0.35; wherein the potential at the surface B1 is obtained by measuring the potential of the surface B1 of the hole transport layer using a Kelvin atomic force microscope.

8. The photovoltaic device according to any one of claims 1 to 7, characterized in that, The perovskite layer has a first surface facing the hole transport layer and a second surface opposite to the first surface in the Z direction; a first region with a thickness of 5nm to 10nm exists in the perovskite layer from the first surface to a range extending 30nm toward the interior of the perovskite layer; the first region is located between the first surface and the second surface; The absolute value of the energy difference between the Fermi level and the valence band top of the first perovskite material in the first region is denoted as E1, and the absolute value of the energy difference between the Fermi level and the conduction band bottom of the first perovskite material in the first region is denoted as E2, where E1 <E2。 9. The photovoltaic device according to claim 8, characterized in that, The difference between E2 and E1 of the first perovskite material in the first region is 1.0 eV to 1.5 eV, and can be selected as 1.0 eV to 1.2 eV.

10. The photovoltaic device according to any one of claims 1 to 9, characterized in that, The perovskite layer has a first surface facing the hole transport layer; the Moran index of the potential distribution at the first surface of the perovskite layer is less than or equal to 0.4, optionally less than or equal to 0.35; wherein the potential at the first surface is obtained by measuring the potential of the first surface of the perovskite layer using a Kelvin atomic force microscope.

11. The photovoltaic device according to any one of claims 1 to 10, characterized in that, The thickness of the perovskite layer is 200nm~1500nm, and can be selected as 400nm~1000nm.

12. The photovoltaic device according to any one of claims 1 to 11, characterized in that, On a projection plane perpendicular to the Z-direction, the area of ​​the perovskite layer is greater than or equal to 0.09 cm². 2 Optionally, greater than or equal to 1m 2 .

13. The photovoltaic device according to any one of claims 1 to 12, characterized in that, The photovoltaic device satisfies one or more of the following characteristics: (c1) The photovoltaic device has an inverted structure or a formal structure; (c2) The photovoltaic device further includes an electron transport layer, which is disposed on the side of the perovskite layer away from the hole transport layer; (c3) The photovoltaic device includes a first electrode and a second electrode, the hole transport layer and the perovskite layer are both disposed between the first electrode and the second electrode, and the hole transport layer is located between the perovskite layer and the first electrode.

14. The photovoltaic device according to any one of claims 1 to 13, characterized in that, The hole transport layer is located on the light-incident side of the perovskite layer.

15. The photovoltaic device according to any one of claims 1 to 14, characterized in that, The photovoltaic device includes a first electrode, a hole transport layer, a perovskite layer, an electron transport layer, and a second electrode stacked together. The hole transport layer, the perovskite layer, and the electron transport layer are all located between the first electrode and the second electrode. The hole transport layer and the electron transport layer are respectively located on both sides of the perovskite layer. The hole transport layer is located between the perovskite layer and the first electrode, and the electron transport layer is located between the perovskite layer and the second electrode. The first electrode is the incident light side electrode.

16. The photovoltaic device according to any one of claims 1 to 15, characterized in that, The photovoltaic device includes a solar cell, which includes the hole transport layer and the perovskite layer stacked together.

17. The photovoltaic device according to any one of claims 1 to 16, characterized in that, The photovoltaic device includes a solar cell, which is a multi-junction solar cell. The multi-junction solar cell includes a first cell unit, which includes the hole transport layer and the perovskite layer stacked together.

18. The photovoltaic device according to claim 17, characterized in that, The multijunction solar cell further includes a second cell stacked with the first cell; the second cell and the first cell are connected by an interconnect layer, or the second cell and the first cell are isolated by an insulating layer; the second cell includes a second light-absorbing layer, and the band gap of the second light-absorbing layer is different from that of the perovskite layer.

19. The photovoltaic device according to claim 18, characterized in that, The second light-absorbing layer in the second battery cell includes a second semiconductor active material, which includes one or more of the following: a second perovskite material, a silicon-containing semiconductor material, copper zinc tin sulfide, copper zinc tin selenide, copper zinc tin selenide sulfide, copper indium gallium selenide, copper indium gallium diselenide, copper indium selenide, cadmium telluride, gallium arsenide, and organic active materials.

20. The photovoltaic device according to claim 18 or 19, characterized in that, The multi-junction solar cell includes a first electrode, a perovskite layer, an interconnect layer, a second light-absorbing layer, and a second electrode stacked together; wherein the interconnect layer is located between the perovskite layer and the second light-absorbing layer; the first electrode is located on the side of the perovskite layer opposite to the interconnect layer, and the second electrode is located on the side of the second light-absorbing layer opposite to the interconnect layer; optionally, the hole transport layer is located between the first electrode and the perovskite layer; or, The multi-junction solar cell includes a first electrode, a perovskite layer, a third electrode, an insulating layer, a fourth electrode, a second light-absorbing layer, and a second electrode stacked together. The third electrode, the insulating layer, and the fourth electrode are stacked between the perovskite layer and the second light-absorbing layer. The third electrode is disposed on the side of the insulating layer facing the perovskite layer, and the fourth electrode is disposed on the side of the insulating layer facing the second light-absorbing layer. The first electrode is located on the side of the perovskite layer away from the third electrode, and the second electrode is located on the side of the second light-absorbing layer away from the fourth electrode. Optionally, the hole transport layer is located between the first electrode and the perovskite layer.

21. A method for fabricating a photovoltaic device, characterized in that, Includes the following steps: The substrate is preheated, and physical vapor deposition is performed on the substrate using a nickel oxide target under the condition of introducing an oxidizing gas. A first annealing is performed at a first temperature to form a hole transport layer; wherein the first temperature is higher than or equal to 140°C, and the hole transport layer comprises nickel oxide. A perovskite precursor solution is coated on the surface of the hole transport layer and then vacuum dried to remove some of the solvent, forming a perovskite mesophase film layer. The perovskite precursor solution comprises a perovskite precursor material and a solvent. The perovskite mesophase film layer includes a second region close to the hole transport layer and a third region far from the hole transport layer. The second region is located between the hole transport layer and the third region, and the solvent residue in the second region is higher than that in the third region. The perovskite intermediate phase film layer is subjected to a second annealing at a second temperature, and then to a third annealing at a third temperature to form a perovskite layer; wherein the second temperature is lower than the third temperature; and the duration of the second annealing at the second temperature is shorter than the duration of the third annealing at the third temperature. The formed perovskite layer comprises a first perovskite material; the thickness direction of the perovskite layer is denoted as the Z direction; the hole transport layer comprises divalent nickel ions and trivalent nickel ions; the molar ratio of divalent nickel ions to trivalent nickel ions is denoted as R. Ni2+ / 3+ R in the hole transport layer Ni2+ / 3+ Greater than 0 and less than 1; on the projection plane perpendicular to the Z direction, R in the hole transport layer Ni2+ / 3+ The Moran index is less than or equal to 0.

4.

22. The method for fabricating a photovoltaic device according to claim 21, characterized in that, The method for fabricating the photovoltaic device satisfies one or more of the following characteristics: (d1) The substrate includes a first electrode; (d2) In the step of preheating the substrate, the preheating temperature is 90℃~110℃ and the preheating time is 5min~25min; (d3) The oxidizing gas includes oxygen and hydrogen peroxide; Optionally, in the oxidizing gas, the volume ratio of oxygen to hydrogen peroxide is from 70:30 to 99:1; (d4) The gas flow rate of the oxidizing gas is 1 sccm to 5 sccm; (d5) The physical vapor deposition method includes magnetron sputtering; (d6) The first temperature is 140℃~160℃, and the duration of the first annealing is 5min~25min; (d7) The temperature for vacuum drying is 5℃~15℃, the pressure for vacuum drying is 1Pa~20Pa, and the duration for vacuum drying is 5s~40s. (d8) The second temperature is 85℃~95℃, and the third temperature is 110℃~120℃; (d9) The duration of the second annealing is 2 min to 5 min, and the duration of the third annealing is 5 min to 10 min.

23. An electrical appliance, characterized in that, It includes at least one of the photovoltaic devices according to any one of claims 1 to 20 and the photovoltaic devices prepared by the method of claim 21 or 22.

24. A power generation device, characterized in that, It includes at least one of the photovoltaic devices according to any one of claims 1 to 20 and the photovoltaic devices prepared by the method of preparing the photovoltaic device according to claim 21 or 22.

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