WO2024066940A1

WO2024066940A1 - Solar cell with spontaneous polarization structure

Info

Publication number: WO2024066940A1
Application number: PCT/CN2023/116803
Authority: WO
Inventors: 解俊杰; 吴兆; 刁一凡; 孙朱行
Original assignee: 隆基绿能科技股份有限公司
Priority date: 2022-09-30
Filing date: 2023-09-04
Publication date: 2024-04-04

Abstract

A solar cell with a spontaneous polarization structure, the solar cell comprising an absorption layer (2) and a carrier transport layer (1, 3), which are arranged in a stacked manner, wherein a spontaneous polarization layer (8) is arranged between the carrier transport layer (1, 3) and an electrode (4), or the spontaneous polarization layer (8) is arranged between the carrier transport layer (1, 3) and a passivation layer (5, 51, 52).

Description

A solar cell with spontaneous polarization structure

This application claims priority to the Chinese patent application filed with the Chinese Patent Office on September 30, 2022, with application number 202211206892.1 and application name “Solar Cell with Spontaneous Polarization Structure”, and the Chinese patent application filed with the Chinese Patent Office on September 30, 2022, with application number 202211206951.5 and application name “Solar Cell with Spontaneous Polarization Structure”, the entire contents of which are incorporated by reference in this application.

Technical Field

The present application belongs to the technical field of solar cells, and in particular, relates to a solar cell with a spontaneous polarization structure.

Background technique

In existing solar cells, the carrier transport layer is in contact with the electrode. The carrier transport layer is usually made of semiconductor material, and the electrode is usually made of metal material. When the semiconductor material and the metal material are in contact, there is usually a large potential barrier or more defects, which causes non-radiative recombination of photogenerated carriers and leads to loss of battery conversion efficiency.

Application Contents

In order to solve the problems existing in the prior art, the present application provides a solar cell with a spontaneous polarization structure.

In a first aspect, the present application provides a solar cell with a spontaneous polarization structure, wherein the solar cell includes an absorption layer and a carrier transport layer stacked together, and a spontaneous polarization layer is arranged between the carrier transport layer and the electrode.

Optionally, the solar cell comprises a first carrier transport layer, an absorption layer, and a second carrier transport layer which are stacked in sequence, and the first carrier transport layer and the second carrier transport layer have opposite conductivity types.

Electrodes are provided on the first carrier transport layer and the second carrier transport layer at the side of the surface away from the absorption layer.

A spontaneous polarization layer is provided between the first carrier transport layer and the electrode, and/or between the second carrier transport layer and the electrode.

Optionally, the carrier transport layer includes a first carrier transport layer and a second carrier transport layer that are alternately arranged, and the first carrier transport layer and the second carrier transport layer have opposite conductivity types.

An electrode is arranged on a surface side of the carrier transport layer away from the absorption layer.

Optionally, the material forming the spontaneous polarization layer is selected from one or more of an inorganic ferroelectric material, an organic ferroelectric material, and a composite material consisting of a dielectric material and a ferroelectric material.

Optionally, the inorganic ferroelectric material is selected from one or more of barium titanate, strontium titanate, titanium oxide, lead zirconate titanate, lead magnesium niobate, sodium bismuth titanate, bismuth ferrite, and bismuth manganate.

Optionally, the organic ferroelectric material is selected from one or two of polyvinylidene fluoride, its copolymer and copolyamide.

Optionally, the thickness of the spontaneous polarization layer is less than or equal to 10 nm.

Optionally, the spontaneous polarization layer is a single crystal layer or a polycrystalline layer.

Optionally, the remanent polarization intensity of the spontaneous polarization layer is greater than 0.96 μC/cm ⁻² .

Optionally, the coercive electric field strength of the spontaneous polarization layer is greater than 50 kV·cm ^-1 .

Optionally, the polarization direction of the spontaneous polarization layer is the same as the positive charge transport direction in the solar cell.

Optionally, the spontaneous polarization layer completely covers the first carrier transport layer and/or the second carrier transport layer.

Optionally, a passivation layer is provided between the first carrier transport layer and the absorption layer, and/or between the second carrier transport layer and the absorption layer.

Optionally, the material forming the absorption layer is one of crystalline silicon, halide perovskite, IIIA-VA group compound, copper indium gallium selenide, and copper zinc selenium sulfur.

Optionally, an intrinsic amorphous silicon isolation layer is provided between the first carrier transport layer and the second carrier transport layer.

In a second aspect, the present application also provides a solar cell with a spontaneous polarization structure, which includes an absorption layer, a passivation layer and a carrier transport layer stacked together, wherein a spontaneous polarization layer is arranged between the carrier transport layer and the passivation layer.

A passivation layer is provided between the first carrier transport layer and the absorption layer, and/or between the second carrier transport layer and the absorption layer.

A spontaneous polarization layer is provided between the first carrier transport layer and the passivation layer, and/or between the second carrier transport layer and the passivation layer,

Electrodes are arranged on surfaces of the first carrier transport layer and the second carrier transport layer away from the absorption layer.

A spontaneous polarization layer is provided between the carrier transport layer and the passivation layer,

An electrode is arranged on a surface of the carrier transport layer away from the absorption layer.

Optionally, the material forming the passivation layer is an inorganic passivation material, an organic passivation material or an ionic liquid, wherein the inorganic passivation material is selected from one of silicon oxide, aluminum oxide, and amorphous silicon, and the organic passivation material is selected from one of organic amine, ether, Lewis acid, and Lewis base.

The solar cell with a spontaneous polarization structure of the present application has an ordered electric dipole moment inside the spontaneous polarization layer, which can spontaneously form an ordered built-in electric field, and can assist the more efficient transmission of carriers inside the battery. At the same time, the built-in electric field strength of the spontaneous polarization layer is determined by its own material properties, the film layer processing and the polarization process. Therefore, when the carriers move under the built-in electric field of the spontaneous polarization layer, they do not consume the photoelectric voltage of the photovoltaic process; by reasonably designing and configuring the direction of the built-in electric field and the photoelectric voltage of the spontaneous polarization layer, it can also reduce the battery voltage loss and even increase the open circuit voltage.

The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

FIG. 1 is a schematic diagram of the basic structure of a solar cell in the prior art.

FIG. 2 is a schematic diagram of the basic structure of a solar cell with a passivation layer in the prior art.

FIG3 is a schematic diagram of the solar cell structure of the present application.

FIG4 is a schematic diagram of the working principle of the spontaneous polarization layer of the present application.

FIG5 is a schematic structural diagram of a solar cell according to a specific embodiment of the present application.

FIG6 is a schematic structural diagram of a solar cell according to a specific embodiment of the present application.

FIG. 7 is a schematic diagram of the structure of a solar cell according to a specific embodiment of the present application.

FIG8 is a schematic diagram of the structure of a solar cell according to a specific embodiment of the present application.

FIG. 9 is a schematic structural diagram of a solar cell with a spontaneous polarization structure of the present application.

FIG10 is a schematic diagram of the working principle of the spontaneous polarization layer of the present application.

FIG. 11 is a schematic structural diagram of a solar cell according to a specific embodiment of the present application.

FIG. 12 is a schematic diagram of the structure of a solar cell according to a specific embodiment of the present application.

FIG. 13 is a schematic diagram of the structure of a solar cell according to a specific embodiment of the present application.

FIG. 14 is a schematic diagram of the structure of a solar cell according to a specific embodiment of the present application.

FIG. 15 is a schematic diagram of the structure of a solar cell according to a specific embodiment of the present application.

Reference numerals:
1 first carrier transport layer, 2 absorption layer, 3 second carrier transport layer, 4 electrode, 5
Passivation layer, 51 first passivation layer, 52 second passivation layer, 6 anti-reflection layer, 7 intrinsic polysilicon layer isolation layer, 8 spontaneous polarization layer.

Specific embodiments

In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" means two or more, unless otherwise clearly and specifically defined. "Several" means one or more, unless otherwise clearly and specifically defined.

In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

The basic structure of an existing solar cell is shown in FIG1 , which includes a first current carrier arranged in a stacked manner. The first carrier transport layer 1, the absorption layer 2 and the second carrier transport layer 3, and an electrode 4 is arranged on the surface side of the first carrier transport layer 1 and the second carrier transport layer 3 away from the absorption layer. The first carrier transport layer 1 and the second carrier transport layer 3 are usually made of semiconductor materials, and the electrode 4 is usually made of metal materials. When the semiconductor material and the metal material are in contact, there will usually be a large potential barrier or more defects, causing non-radiative recombination of photogenerated carriers, resulting in a loss of battery conversion efficiency. In addition, in order to inhibit the recombination at the interface of the absorption layer 2-first carrier transport layer 1 and the absorption layer 2-second carrier transport layer 3, a passivation layer is usually provided at the two interfaces, that is, the first passivation layer 51 and the second passivation layer 52 in the structure described in Figure 2. The passivation layer can passivate the defects at the interface, eliminate the interface transmission barrier, and reduce the probability of non-radiative recombination of carriers.

However, after adding the passivation layer, when the passivation layer is in direct contact with the carrier transport layer, due to the "high resistivity" or "insulation" characteristics of the passivation layer, the carriers penetrate the passivation layer mainly through the "quantum tunneling" effect, and the direct tunneling efficiency is relatively low.

In view of the problems existing in the prior art, the present application provides a solar cell with a spontaneous polarization structure, which includes an absorption layer and a carrier transport layer stacked together, and a spontaneous polarization layer is arranged between the carrier transport layer and the electrode.

On the one hand, the present application provides a solar cell with a spontaneous polarization structure. As shown in a, b of FIG. 3, FIG. 5 and FIG. 7, the solar cell includes a first carrier transport layer 1, an absorption layer 2 and a second carrier transport layer 3 stacked in sequence, and the first carrier transport layer 1 and the second carrier transport layer 3 have opposite conductivity types.

An electrode 4 is disposed on a surface of the first carrier transport layer 1 and the second carrier transport layer 3 away from the absorption layer 2 .

A spontaneous polarization layer 8 is provided between the first carrier transport layer 1 and the electrode 4, and/or between the second carrier transport layer 3 and the electrode 4. That is, the spontaneous polarization layer 8 can be provided only between the first carrier transport layer 1 and the electrode 4, or only between the second carrier transport layer 3 and the electrode 4, or can be provided simultaneously between the first carrier transport layer 1 and the electrode 4, and between the second carrier transport layer 3 and the electrode 4. The thickness and material of the spontaneous polarization layer 8 between the first carrier transport layer 1 and the electrode 4 can be the same as or different from those of the spontaneous polarization layer 8 between the second carrier transport layer 3 and the electrode 4.

As shown in FIG. 3 a, the spontaneous polarization layer 8 can completely cover the first carrier transport layer 1 and/or the second carrier transport layer 3. The spontaneous polarization layer 8 may also partially cover the first carrier transport layer 1 and/or the second carrier transport layer 3, or may only cover the area where the first carrier transport layer 1 and/or the second carrier transport layer 3 are in contact with the electrode 4, as shown in b of FIG. 3 .

The spontaneous polarization layer 8 is composed of a spontaneous polarization material. The material of the spontaneous polarization layer 8, i.e., the spontaneous polarization material, has the characteristics shown in a of FIG4 , i.e., in its lattice, the centers of positive and negative charges do not overlap, thereby generating a certain electric dipole moment P inside the lattice; and this electric dipole moment P can be deflected under the induction of an external electric field. (The dipole moment is a localized electric field, and there is only an electric field, and there is no free-moving charge, so it will not become a defect recombination center)

In the spontaneously polarized layer composed of spontaneously polarized materials, the directions of the electric dipole moments P in different regions are different and are usually randomly distributed. The film or bulk material as a whole is electrically neutral to the outside, as shown in FIG4 b.

When an external electric field E is applied to the spontaneous polarization layer, the randomly distributed electric dipole moment P inside the spontaneous polarization layer will be oriented, as shown in Figure 4c; this process is called the "polarization" of the material. After the spontaneous polarization layer is polarized, the oriented dipole moment will be maintained, forming a built-in electric field inside it, and this built-in electric field can exist stably for a long time.

Therefore, a spontaneous polarization layer 8 with a built-in electric field is introduced into the battery structure. By reasonably setting the polarization direction, its built-in electric field will assist the carrier transport inside the battery and inhibit reverse recombination, thereby improving the conversion efficiency of the battery. The built-in electric field P is an intrinsic property of the spontaneous polarization layer, does not affect the photovoltage, and can assist the carriers to cross the barrier between the electrode 4 and the carrier transport layer, reduce efficiency loss, and improve conversion efficiency. Further, the material of the spontaneous polarization layer 8 is selected from one or more of inorganic ferroelectric materials, organic ferroelectric materials, and composite materials composed of dielectric materials and ferroelectric materials. Among them, the inorganic ferroelectric material is selected from one or more of barium titanate, strontium titanate, titanium oxide, lead zirconate titanate, lead magnesium niobate, sodium bismuth titanate, bismuth ferrite, and bismuth manganate. The organic ferroelectric material is selected from one or more of polyvinylidene fluoride and its copolymers, and copolyamides. The copolymer of polyvinylidene fluoride can be, for example, P(VDF-TrFE) and P(VDF-TrFE-CFE).

Since the spontaneous polarization material usually has a wide band gap and is an insulating material, the transmission of carriers in the spontaneous polarization layer mainly relies on the tunneling mechanism. Therefore, in order to meet the requirements of electron tunneling, the thickness of the spontaneous polarization layer 8 usually cannot be too thick.

In a specific embodiment, the thickness of the spontaneous polarization layer 8 is less than or equal to 10 nm, for example, it can be 10nm, 9nm, 8nm, 7nm, 6nm, 5nm, 4nm, 3nm, 2nm, 1nm, 0.5nm, etc.

The spontaneous polarization characteristic of the spontaneously polarized material is caused by the misalignment of the centers of positive and negative charges inside the lattice, which is a natural property of the material's crystal structure. Therefore, the spontaneously polarized layer 8 is required to be a single crystal layer or a polycrystalline layer, rather than an amorphous layer.

During the operation of the solar cell, the residual polarization intensity _Pr of the spontaneous polarization layer 8 needs to be greater than the surface charge density of the passivation layer, so that the polarization direction of the spontaneous polarization layer can be maintained and not be covered, weakened or even flipped by the local electric field of the passivation layer.

Taking the surface charge density _Qf of the Al2O3 passivation layer in a PERC cell as an example, to achieve effective field passivation, it is required that:
_Qf ＞6× ^1012cm ^-2 ＝6×1012× ^1.6 × ^10-19C /cm ^-2 ＝0.96μC/cm ^-2 ，

In a specific embodiment, the remanent polarization intensity of the spontaneous polarization layer 8 is greater than 0.96 μC/cm ^-2 , for example, it can be 1 μC/cm ^-2 , 2 μC/cm ^-2 , 3 μC/cm ^-2 , 4 μC/cm ^-2 , 5 μC/cm ^-2 , 6 μC/cm ^-2 , 7 μC/cm ^-2 , 8 μC/cm ^-2 , 9 μC/cm ^-2 , 10 μC/cm ^-2 , 11 μC/cm ^-2 , 12 μC/cm ^-2 , 13 μC/cm ^-2 , 14 μC/cm ^-2 , 15 μC/cm ^-2 , 16 μC/cm ^{-2, 17 μC/cm -2} ^, 18 μC/cm ^-2 , 19 μC/cm ^-2 , 20 μC/cm ^-2 , 25 μC/cm ^-2 , 30 μC/cm ^-2 , 35 μC/cm ^-2 , 40μC/cm ^-2 , 50μC/cm ^-2 .

Electrons are mainly transported in the spontaneous polarization layer 8 by tunneling mechanism, and their transport behavior can be compared with the electron transport behavior in the ferroelectric tunnel junction. The junction resistivity of the common ferroelectric tunnel junction is generally not more than 10 ⁶ Ω·cm; the maximum operating current of the single junction solar cell is not more than 50mA·cm ^-2 , then in the working state, the maximum electric field intensity generated by the photovoltaic current on the spontaneous polarization layer is:
E＝(50mA·cm ^-2 )×(10 ⁶ Ω·cm)
=0.05×10 ⁶ A·Ω·cm ^-1
=5×10 ⁴ V·cm ^-1 =50 kV·cm ^-1

Therefore, the coercive field strength E _c of the spontaneous polarization layer 8 should be greater than the above E value, ie, E _c >50 kV·cm ^-1 , to ensure that the ordered polarization of the spontaneous polarization layer 8 is not flipped under working conditions, which would adversely affect the device performance.

In a specific embodiment, the coercive electric field strength of the spontaneous polarization layer 8 is greater than 50 kV·cm ^-1 , for example, 51 kV·cm ^-1 , 52 kV·cm ^-1 , 53 kV·cm ^-1 , 54 kV·cm ^-1 , 55 kV·cm ^-1 , 60 kV·cm ^-1 , 65 kV·cm ^-1 , 70 kV·cm -1 , 75 kV·cm ^-1 , 80 kV·cm ^-1 , 85 kV·cm ^-1 , kV·cm ^-1 , 90kV·cm ^-1 , 95kV·cm ^-1 , 100kV·cm ^-1 , 110kV·cm ^-1 , 120kV·cm ^-1 .

In order to realize the function of the spontaneous polarization layer 8 of "assisting carrier transport and improving transport efficiency", the polarization direction of the spontaneous polarization layer 8 is required to be the same as the positive charge transport direction in the battery. In this case, the polarization electric field inside it can promote carrier transport.

The spontaneous polarization layer 8 can be prepared by methods known in the art, such as physical vapor deposition, atomic layer deposition, molecular beam epitaxy, etc., so as to achieve the purpose of accurately controlling the thickness and promoting good crystallization of the material.

The absorption layer 2 may be made of various materials known in the art, such as crystalline silicon, halide perovskite, IIIA-VA group compounds, copper indium gallium selenide, copper zinc selenium sulfur, and the like.

The first carrier transport layer 1 and the second carrier transport layer 3 are carrier transport layers known in the art, and may be electron transport layers or hole transport layers. When the first carrier transport layer 1 is an electron transport layer, the second carrier transport layer 3 is a hole transport layer. When the first carrier transport layer 1 is a hole transport layer, the second carrier transport layer 3 is an electron transport layer.

Further, a passivation layer may be provided between the first carrier transport layer 1 and the absorption layer 2, and/or between the second carrier transport layer 3 and the absorption layer 2. That is, the passivation layer 5 may be provided only between the first carrier transport layer 1 and the absorption layer 2, or only between the second carrier transport layer 3 and the absorption layer 2, or the passivation layer 5 may be provided between the first carrier transport layer 1 and the absorption layer 2 and between the second carrier transport layer 3 and the absorption layer 2 at the same time, that is, the first passivation layer 51 and the second passivation layer 52. The thickness and material of the first passivation layer 51 and the second passivation layer 52 may be the same or different.

The passivation layer, including the first passivation layer 51 and the second passivation layer 52 , is a passivation layer known in the art.

The electrode 4 is an electrode known in the art, such as a silver electrode, a copper electrode or other metal electrodes, or may be an electrode composed of a transparent conductive layer and a metal electrode.

Other functional layers, such as anti-reflection layers, may be provided on the surfaces of the first carrier transport layer 1 and the second carrier transport layer 3 away from the absorption layer 2 as required.

On the other hand, the present application also provides another solar cell with a spontaneous polarization structure, that is, a back-contact solar cell with a spontaneous polarization structure. As shown in c, d of Figure 3, Figure 6 and Figure 8, the solar cell includes an absorption layer 2 and a carrier transport layer arranged in a stacked manner. The carrier transport layer includes a first carrier transport layer 1 and a second carrier transport layer 3 arranged alternately, and the first carrier transport layer 1 and the second carrier transport layer 3 have opposite conductivity types.

An electrode 4 is provided on the surface side of the carrier transport layer away from the absorption layer 2. A spontaneous polarization layer 8 is provided between the carrier transport layer and the electrode 4, that is, between the first carrier transport layer 1 and the electrode 4, and/or between the second carrier transport layer 3 and the electrode 4. The spontaneous polarization layer 8 can be provided only between the first carrier transport layer 1 and the electrode 4, or only between the second carrier transport layer 3 and the electrode 4, or can be provided between the first carrier transport layer 1 and the electrode 4, and between the second carrier transport layer 3 and the electrode 4 at the same time. The thickness and material of the spontaneous polarization layer 8 between the first carrier transport layer 1 and the electrode 4 can be the same as or different from that of the spontaneous polarization layer 8 between the second carrier transport layer 3 and the electrode 4.

As shown in c of FIG. 3 , the spontaneous polarization layer 8 may completely cover the first carrier transport layer 1 and the second carrier transport layer 3. The spontaneous polarization layer 8 may also partially cover the first carrier transport layer 1 and/or the second carrier transport layer 3, or may only cover the area where the first carrier transport layer 1 and/or the second carrier transport layer 3 are in contact with the electrode 4, as shown in d of FIG. 3 .

Furthermore, a passivation layer may be provided between the first carrier transport layer 1 and the absorption layer 2 , and between the second carrier transport layer 3 and the absorption layer 2 .

An intrinsic amorphous silicon isolation layer 7 may be disposed between the first carrier transport layer 1 and the second carrier transport layer 3. The intrinsic amorphous silicon isolation layer 7 may isolate the two carrier transport layers and reduce recombination.

Other functional layers, such as an anti-reflection layer, may also be disposed on the surface of the absorption layer 2 away from the passivation layer 5 .

The specific materials and properties of the first carrier transport layer 1 , the absorption layer 2 , the second carrier transport layer 3 , the electrode 4 , the passivation layer 5 , and the spontaneous polarization layer 8 are as described above.

Example

Example 1

In this embodiment, the solar cell is an HJT cell, and a spontaneous polarization layer structure is arranged inside the silver grid line of the HJT cell, as shown in FIG5. The solar cell includes a first carrier transport layer 1, a first passivation layer 51, an absorption layer 2, a second passivation layer 52, and a second carrier transport layer 3 stacked in sequence. An electrode 4 is disposed on a surface side of the transport layer 3 away from the absorption layer 2. A spontaneous polarization layer 8 is disposed between the second carrier transport layer 3 and the electrode 4.

The electrode 4 is a silver grid electrode, and the absorption layer 2 is an n-type single crystal silicon absorption layer. The first carrier transport layer 1 is an n-type amorphous silicon transport layer. The second carrier transport layer 3 is a p-type amorphous silicon transport layer. The first passivation layer 51 and the second passivation layer 52 are intrinsic amorphous silicon passivation layers. The spontaneous polarization layer 8 is a Pb(Zr _0.3 Ti _0.7 )O ₃ spontaneous polarization layer with a thickness of 6 nm, Pr=22μC/cm ^-2 , Ec=70kV·cm ^-1 , and the polarization direction is from the second carrier transport layer 3 to the first carrier transport layer 3.

Example 2

Embodiment 2 is substantially the same as Embodiment 1, except that a spontaneous polarization layer 8 is also provided between the first carrier transport layer 1 and the electrode 4, that is, a spontaneous polarization layer 8 is provided on the inner sides of the electrodes on both sides.

Example 3

In this embodiment, the solar cell is a back contact HJT cell, and the structure is shown in FIG6. The solar cell includes an anti-reflection layer 6, an absorption layer 2, a passivation layer 5, and a carrier transport layer stacked in sequence. The carrier transport layer includes a first carrier transport layer 1 and a second carrier transport layer 3 alternately arranged. An electrode 4 is arranged on the side of the surface of the carrier transport layer away from the absorption layer 2. A spontaneous polarization layer 8 is arranged between the carrier transport layer and the electrode 4. An intrinsic amorphous silicon isolation layer 7 is arranged between the first carrier transport layer 1 and the second carrier transport layer 3.

The electrode 4 is a silver grid electrode, and the absorption layer 2 is an n-type single crystal silicon absorption layer. The first carrier transport layer 1 is an n+ amorphous silicon transport layer. The second carrier transport layer 3 is a p+ amorphous silicon transport layer. The passivation layer 5 is an intrinsic amorphous silicon passivation layer. The spontaneous polarization layer 8 is a BiFeO ₃ spontaneous polarization layer with a thickness of 8 nm, Pr = 45 μC/cm ^-2 , Ec = 100 kV·cm ^-1 .

Example 4

Embodiment 4 is substantially the same as Embodiment 3, except that a spontaneous polarization layer 8 is provided only between the first carrier transport layer 1 and the electrode 4 .

Example 5

In this embodiment, the solar cell is a topcon cell, and a spontaneous polarization layer structure is arranged inside the silver grid line of the topcon cell, as shown in FIG7 . The solar cell comprises The anti-reflection layer 6, the first carrier transport layer 1, the absorption layer 2, the passivation layer 5 and the second carrier transport layer 3 are stacked. An electrode 4 is arranged on the surface side of the first carrier transport layer 1 and the second carrier transport layer 3 away from the absorption layer 2. A spontaneous polarization layer 8 is arranged between the second carrier transport layer 3 and the electrode 4.

The electrode 4 is a silver grid electrode, and the absorption layer 2 is an n-type single crystal silicon absorption layer. The first carrier transport layer 1 is a p-type emitter. The second carrier transport layer 3 is an n+ polysilicon transport layer. The passivation layer 5 is a SiO ₂ tunnel passivation layer. The spontaneous polarization layer 8 is a Pb(Zr _0.3 Ti _0.7 )O ₃ spontaneous polarization layer with a thickness of 6 nm, Pr=22μC/cm ^-2 , Ec=70kV·cm ^-1 , and the polarization direction is from the second carrier transport layer 3 to the first carrier transport layer 3.

Example 6

Embodiment 6 is substantially the same as Embodiment 5, except that a spontaneous polarization layer 8 is also provided between the first carrier transport layer 1 and the electrode 4, that is, a spontaneous polarization layer 8 is provided on the inner side of the electrodes on both sides.

Example 7

In this embodiment, the solar cell is a back-contact TOPCon cell, and the structure is shown in FIG8 . The solar cell includes an anti-reflection layer 6, an absorption layer 2, a passivation layer 5, and a carrier transport layer stacked in sequence. The carrier transport layer includes a first carrier transport layer 1 and a second carrier transport layer 3 alternately arranged. An electrode 4 is arranged on the side of the surface of the carrier transport layer away from the absorption layer 2. A spontaneous polarization layer 8 is arranged between the carrier transport layer and the electrode 4. An intrinsic amorphous silicon isolation layer 7 is arranged between the first carrier transport layer 1 and the second carrier transport layer 3.

The electrode 4 is a silver grid electrode, and the absorption layer 2 is an n-type single crystal silicon absorption layer. The first carrier transport layer 1 is an n+ polysilicon transport layer. The second carrier transport layer 3 is a p+ polysilicon transport layer. The passivation layer 5 is a SiO ₂ tunnel passivation layer. The spontaneous polarization layer 8 is a Pb(Zr _0.3 Ti _0.7 )O ₃ spontaneous polarization layer with a thickness of 6 nm, Pr=22μC/cm ^-2 , Ec=70kV·cm ^-1 , and the polarization direction is from the second carrier transport layer 3 to the first carrier transport layer 3.

Example 8

Embodiment 8 is substantially the same as Embodiment 7, except that a spontaneous polarization layer 8 is provided only between the first carrier transport layer 1 and the electrode 4 .

The main parameters of each embodiment are shown in Table 1.

Table 1

On the other hand, the present application provides a solar cell with a spontaneous polarization structure. As shown in FIG9 a, FIG11 and FIG15, the solar cell includes a first carrier transport layer 1, an absorption layer 2 and a second carrier transport layer 3 stacked in sequence, and the first carrier transport layer 1 and the second carrier transport layer 3 have opposite conductivity types.

A passivation layer 5 is provided between the first carrier transport layer 1 and the absorption layer 2, and/or between the second carrier transport layer 3 and the absorption layer 2, that is, the passivation layer 5 may be provided only between the first carrier transport layer 1 and the absorption layer 2, or only between the second carrier transport layer 3 and the absorption layer 2, or the passivation layer 5 may be provided between the first carrier transport layer 1 and the absorption layer 2 and between the second carrier transport layer 3 and the absorption layer 2 at the same time, that is, the first passivation layer 51 and the second passivation layer 52. The thickness and material of the first passivation layer 51 and the second passivation layer 52 may be the same or different.

A spontaneous polarization layer 8 is provided between the first carrier transport layer 1 and the passivation layer 5, and/or between the second carrier transport layer 3 and the passivation layer 5. That is, the spontaneous polarization layer 8 can be provided only between the first carrier transport layer 1 and the passivation layer 5, or only between the second carrier transport layer 3 and the passivation layer 5, or can be provided simultaneously between the first carrier transport layer 1 and the first passivation layer 51, and between the second carrier transport layer 3 and the second passivation layer 52. The thickness and material of the spontaneous polarization layer 8 between the first carrier transport layer 1 and the passivation layer 5 can be the same as or different from that of the spontaneous polarization layer 8 between the second carrier transport layer 3 and the passivation layer.

Electrodes 4 are arranged on surfaces of the first carrier transport layer 1 and the second carrier transport layer 3 away from the absorption layer 2 .

In a specific embodiment, the solar cell structure is shown in FIG11. The solar cell includes an anti-reflection layer 6, a first carrier transport layer 1, an absorption layer 2, a passivation layer 5, and a second carrier transport layer 3 which are stacked in sequence. Electrodes 4 are provided on the surfaces of the first carrier transport layer 1 and the second carrier transport layer 3 away from the absorption layer 2. A spontaneous polarization layer 8 is provided between the first carrier transport layer 1 and the passivation layer 5.

In a specific embodiment, the solar cell structure is different from the structure shown in Figure 11 in that there is a passivation layer 51 between the first carrier transport layer 1 and the absorption layer 2, and a spontaneous polarization layer 8 is also arranged between the first carrier transport layer 1 and the first passivation layer 51.

In a specific embodiment, the solar cell structure is shown in FIG15. The solar cell includes a first carrier transport layer 1, a first passivation layer 51, an absorption layer 2, a second passivation layer 52, and a second carrier transport layer 3 which are stacked in sequence. An electrode 4 is provided on the surface of the first carrier transport layer 1 and the second carrier transport layer 3 away from the absorption layer 2. A spontaneous polarization layer 8 is provided between the second carrier transport layer 3 and the second passivation layer 52.

In a specific embodiment, the solar cell structure is different from the structure shown in FIG. 15 in that a spontaneous polarization layer 8 is also provided between the first carrier transport layer 1 and the first passivation layer 51 .

The spontaneous polarization layer 8 is composed of a spontaneous polarization material. The material of the spontaneous polarization layer 8, i.e., the spontaneous polarization material, has the characteristics shown in a of FIG11 , i.e., in its lattice, the centers of positive and negative charges do not overlap, thereby generating a certain electric dipole moment P inside the lattice; and this electric dipole moment P can be deflected under the induction of an external electric field. (The dipole moment is a localized electric field, and there is only an electric field, and there is no freely moving charge, so it will not become a defect recombination center)

In the spontaneously polarized layer composed of spontaneously polarized materials, the directions of the electric dipole moments P in different regions are different and are usually randomly distributed. The film or bulk material as a whole is electrically neutral to the outside, as shown in FIG10 b.

When an external electric field E is applied to the spontaneous polarization layer, the randomly distributed electric dipole moment P inside the spontaneous polarization layer will be oriented, as shown in c of Figure 10; this process is called the "polarization" of the material. After the spontaneous polarization layer is polarized, the oriented dipole moment will be maintained, forming a built-in electric field inside it, and the built-in electric field can exist stably for a long time.

Therefore, a spontaneous polarization layer 8 with a built-in electric field is introduced into the battery structure. By reasonably setting the polarization direction, its built-in electric field will assist the carrier transmission inside the battery and inhibit reverse recombination, thereby improving the conversion efficiency of the battery. The built-in electric field P is an intrinsic property of the spontaneous polarization layer and does not affect the photo-generated voltage. It can assist the carriers to cross the potential barrier caused by the passivation layer and reduce the efficiency loss caused by the passivation layer.

Further, the material of the spontaneous polarization layer 8 is selected from one or more of inorganic ferroelectric materials, organic ferroelectric materials, and composite materials composed of dielectric materials and ferroelectric materials. Among them, the inorganic ferroelectric material is selected from one or more of barium titanate, strontium titanate, titanium oxide, lead zirconate titanate, lead magnesium niobate, sodium bismuth titanate, bismuth ferrite, and bismuth manganate. The organic ferroelectric material is selected from one or more of polyvinylidene fluoride and its copolymers, and copolyamides. The copolymer of polyvinylidene fluoride can be, for example, P(VDF-TrFE) and P(VDF-TrFE-CFE).

In a specific embodiment, the thickness of the spontaneous polarization layer 8 is less than or equal to 10 nm, for example, it can be 10 nm, 9 nm, 8 nm, 7 nm, 6 nm, 5 nm, 4 nm, 3 nm, 2 nm, 1 nm, 0.5 nm, etc.

The spontaneous polarization characteristic of the spontaneously polarized material is caused by the non-coincidence of the center positions of positive and negative charges inside the lattice, which is a natural property of the material's crystal structure. Therefore, the spontaneous polarization layer 8 is required to be a single crystal layer or a polycrystalline layer, that is, a layer formed by single crystal material or polycrystalline material, rather than an amorphous layer.

Taking the surface charge density _Qf of _{the Al2O3} _passivation layer in a PERC cell as an example, if effective field passivation is to be achieved, it is required that:
_Qf ＞6× ^1012cm ^-2 ＝6×1012× ^1.6 × ^10-19C /cm ^-2 ＝0.96μC/cm ^-2 ，

In a specific embodiment, the coercive electric field strength of the spontaneous polarization layer 8 is greater than 50 kV·cm ^-1 , for example, 51 kV·cm ^-1 , 52 kV·cm- ¹ , 53 kV·cm ^{-1, 54 kV·cm-1} ^, 55 kV·cm- ¹ , 60 kV·cm ^-1 ^, 65 kV·cm- ¹ , 70 kV·cm- ¹ , 75 kV·cm ^-1 , 80 kV·cm-1, 85 kV·cm ^-1 , 90 kV·cm- ¹ , 95 kV·cm-1, 100 kV·cm- ¹ , 110 kV·cm ^- ¹ , 120 kV·cm ^-1 .

The absorption layer 2 can be made of various materials known in the art, such as crystalline silicon, halide perovskite, IIIA-VA group compounds, copper indium gallium selenide, and copper zinc selenium sulfur, etc.

The materials forming the passivation layer, including the first passivation layer 51 and the second passivation layer 52, are passivation layers known in the art, such as inorganic passivation materials such as silicon oxide, aluminum oxide, amorphous silicon, or organic passivation materials such as organic amines, ethers, Lewis acids, Lewis bases, or ionic liquids.

The electrode 4 is an electrode known in the art, such as a silver electrode, a copper electrode or other metal electrodes.

On the other hand, the present application also provides another solar cell with a spontaneous polarization structure, that is, a back-contact solar cell with a spontaneous polarization structure. As shown in FIG9 b, FIG12-FIG14, the solar cell includes an absorption layer 2, a passivation layer 5, and a carrier transport layer stacked in sequence. The carrier transport layer includes a first carrier transport layer 1 and a second carrier transport layer 3 alternately arranged, and the first carrier transport layer 1 and the second carrier transport layer 3 have opposite conductivity types.

A spontaneous polarization layer 8 is provided between the carrier transport layer and the passivation layer 5, that is, a spontaneous polarization layer 8 is provided between the first carrier transport layer 1 and the passivation layer 5, and/or between the second carrier transport layer 3 and the passivation layer 5. The spontaneous polarization layer 8 can be provided only between the first carrier transport layer 1 and the passivation layer 5, or only between the second carrier transport layer 3 and the passivation layer 5, or can be provided simultaneously between the first carrier transport layer 1 and the passivation layer 5, and between the second carrier transport layer 3 and the passivation layer 5. An electrode 4 is provided on the surface of the carrier transport layer away from the absorption layer 2.

Furthermore, an intrinsic amorphous silicon isolation layer 7 may be disposed between the first carrier transport layer 1 and the second carrier transport layer 3. The intrinsic amorphous silicon isolation layer 7 may isolate the two carrier transport layers and reduce recombination.

In a specific embodiment, the solar cell is a back contact cell, the structure of which is shown in FIG. 12. The solar cell comprises an anti-reflection layer 6, an absorption layer 2, a passivation layer 5 and a spontaneous polarization layer 8 which are stacked in sequence. A first carrier transport layer 1 and a second carrier transport layer 3 are alternately arranged on the surface of the spontaneous polarization layer 8 away from the absorption layer 2. An intrinsic amorphous silicon isolation layer 7 is arranged between the first carrier transport layer 1 and the second carrier transport layer 3. An electrode 4 is arranged on the surface of the carrier transport layer away from the absorption layer 2.

In a specific embodiment, the solar cell is a back contact cell, and the structure is shown in FIG14 . The only difference from the structure shown in FIG12 is that a spontaneous polarization layer 8 is provided only between the first carrier transport layer 1 and the passivation layer 5 .

In a specific embodiment, the solar cell is a back contact cell, and the structure is shown in FIG14. The solar cell includes an anti-reflection layer 6, an absorption layer 2, a passivation layer 5, and a spontaneous polarization layer 8 stacked in sequence. A first carrier transport layer 1 and a second carrier transport layer 3 are alternately arranged on the surface of the spontaneous polarization layer 8 away from the absorption layer 2. An intrinsic amorphous silicon isolation layer 7 is arranged between the first carrier transport layer 1 and the second carrier transport layer 3. An electrode 4 is arranged on the surface of the carrier transport layer away from the absorption layer 2.

In a specific embodiment, the solar cell is a back contact cell, and the solar cell structure is different from the structure shown in FIG. 14 only in that a spontaneous polarization layer 8 is provided only between the first carrier transport layer 1 and the passivation layer 5 .

The material forming the passivation layer 5 is a passivation layer known in the art, for example, it can be an inorganic passivation material such as silicon oxide, aluminum oxide, amorphous silicon, or an organic passivation material such as organic amine, ether, Lewis acid, Lewis base, or an ionic liquid.

The specific materials and properties of the first carrier transport layer 1 , the absorption layer 2 , the second carrier transport layer 3 , the electrode 4 , and the spontaneous polarization layer 8 are as described above.

Example

Example 9

In this embodiment, the solar cell is a TOPCon cell, and a spontaneous polarization layer structure is arranged outside the tunnel passivation layer, and the structure is shown in FIG11. The solar cell includes an anti-reflection layer 6, a first carrier transport layer 1, an absorption layer 2, a passivation layer 5, and a second carrier transport layer 3 stacked in sequence. Electrodes 4 are arranged on the surfaces of the first carrier transport layer 1 and the second carrier transport layer 3 away from the absorption layer 2. A spontaneous polarization layer 8 is arranged between the first carrier transport layer 1 and the passivation layer 5.

The electrode 4 is a silver grid electrode, and the absorption layer 2 is an n-type single crystal silicon absorption layer. The first carrier transport layer 1 is a p-type emitter. The passivation layer 5 is a SiO ₂ tunnel passivation layer. The second carrier transport layer 3 is an n-type polysilicon transport layer. The spontaneous polarization layer 8 is a BiFeO ₃ spontaneous polarization layer with a thickness of 8 nm, Pr = 45 μC/cm ^-2 , Ec = 100 kV·cm ^-1 , and the polarization direction is from the first carrier transport layer 1 to the second carrier transport layer 3.

Example 10

In this embodiment, the solar cell is a TOPCon cell, and a spontaneous polarization layer structure is arranged outside the tunnel passivation layer. The solar cell includes an anti-reflection layer 6, a first carrier transport layer 1, a first passivation layer 51, an absorption layer 2, a second passivation layer 52, and a second carrier transport layer 3 stacked in sequence. An electrode 4 is arranged on the surface of the first carrier transport layer 1 and the second carrier transport layer 3 away from the absorption layer 2. A spontaneous polarization layer 8 is arranged between the first carrier transport layer 1 and the first passivation layer 51, and between the second carrier transport layer 3 and the second passivation layer 52.

The electrode 4 is a silver grid electrode, and the absorption layer 2 is an n-type single crystal silicon absorption layer. The first carrier transport layer 1 is a p-type emitter. The first passivation layer 51 and the second passivation layer 52 are SiO ₂ tunnel passivation layers. The second carrier transport layer 3 is an n-type polysilicon transport layer. The spontaneous polarization layer 8 is a BiFeO ₃ spontaneous polarization layer with a thickness of 8nm, Pr=45μC/cm ^-2 , Ec=100kV·cm ^-1 , and the polarization direction is from the first carrier transport layer 1 to the second carrier transport layer 3.

Embodiment 11:

In this embodiment, the solar cell is a back-contact TOPCon cell, and the structure is shown in FIG12. The solar cell includes an anti-reflection layer 6, an absorption layer 2, a passivation layer 5, and a spontaneous polarization layer 8 stacked in sequence. A first carrier transport layer 1 and a second carrier transport layer 3 are alternately arranged on the surface of the spontaneous polarization layer 8 away from the absorption layer 2. An intrinsic amorphous silicon isolation layer 7 is arranged between the first carrier transport layer 1 and the second carrier transport layer 3. An electrode 4 is arranged on the surface of the carrier transport layer away from the absorption layer 2.

The electrode 4 is a silver grid electrode, and the absorption layer 2 is an n-type single crystal silicon absorption layer. The first carrier transport layer 1 is an n+ polysilicon transport layer. The passivation layer 5 is a SiO ₂ tunnel passivation layer. The second carrier transport layer 3 is a p+ polysilicon transport layer. The spontaneous polarization layer 8 is a BaTiO ₃ spontaneous polarization layer with a thickness of 2nm, Pr=10μC/cm ^-2 , Ec=200kV·cm ^-1 .

Embodiment 12:

In this embodiment, the solar cell structure is shown in FIG13. This embodiment is substantially the same as Embodiment 3, except that a spontaneous polarization layer 8 is provided only between the first carrier transport layer 1 and the passivation layer 5. The spontaneous polarization layer 8 is made of Pb(Zr _0.3 Ti _0.7 )O ₃ , with a thickness of 6 nm, Pr=22 μC/cm ^-2 , and Ec=70 kV·cm ^-1 .

Embodiment 13:

In this embodiment, the solar cell is a back contact HJT cell, and the structure is shown in FIG14. The solar cell includes an anti-reflection layer 6, an absorption layer 2, a passivation layer 5, and a spontaneous polarization layer 8 stacked in sequence. A first carrier transport layer 1 and a second carrier transport layer 3 are alternately arranged on the surface of the spontaneous polarization layer 8 away from the absorption layer 2. An intrinsic amorphous silicon isolation layer 7 is arranged between the first carrier transport layer 1 and the second carrier transport layer 3. An electrode 4 is arranged on the surface of the carrier transport layer away from the absorption layer 2.

The electrode 4 is a silver grid electrode, and the absorption layer 2 is an n-type single crystal silicon absorption layer. The first carrier transport layer 1 is an n+ amorphous silicon transport layer. The passivation layer 5 is an intrinsic amorphous silicon passivation layer. The second carrier transport layer 3 is a p+ amorphous silicon transport layer. The spontaneous polarization layer 8 is a BaTiO ₃ spontaneous polarization layer with a thickness of 2nm, Pr=10μC/cm ^-2 , Ec=200kV·cm ^-1 .

Example 14

This embodiment is substantially the same as Embodiment 5, except that a spontaneous polarization layer 8 is provided only between the first carrier transport layer 1 and the passivation layer 5 .

Embodiment 15

In this embodiment, the solar cell is a HJT cell, and a spontaneous polarization layer structure is arranged outside the tunnel passivation layer, and the structure is shown in FIG15. The solar cell includes a first carrier transport layer 1, a first passivation layer 51, an absorption layer 2, a second passivation layer 52, and a second carrier transport layer 3 stacked in sequence. An electrode 4 is arranged on the surface of the first carrier transport layer 1 and the second carrier transport layer 3 away from the absorption layer 2. A spontaneous polarization layer 8 is arranged between the second carrier transport layer 3 and the second passivation layer 52.

Among them, the electrode 4 is a silver grid electrode, and the absorption layer 2 is an n-type single crystal silicon absorption layer. The first carrier transport layer 1 is a p+ amorphous silicon transport layer. The second carrier transport layer 3 is an n+ amorphous silicon transport layer. The first passivation layer 51 and the second passivation layer 52 are intrinsic amorphous silicon passivation layers. The spontaneous polarization layer 8 is a BaTiO ₃ spontaneous polarization layer with a thickness of 2nm, Pr=10μC/cm ^-2 , Ec=200kV·cm ^-1 .

Embodiment 16: This embodiment is basically the same as Embodiment 7, except that A spontaneous polarization layer 8 is provided between the carrier transport layer 1 and the first passivation layer 51 , and between the second carrier transport layer 3 and the second passivation layer 52 .

The main parameters of each embodiment are shown in Table 2.

Table 2 Main parameters of each embodiment

In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

A solar cell with a spontaneous polarization structure is characterized in that the solar cell comprises an absorption layer and a carrier transport layer which are stacked, and a spontaneous polarization layer is arranged between the carrier transport layer and the electrode.
The solar cell according to claim 1, characterized in that the solar cell comprises a first carrier transport layer, an absorption layer, and a second carrier transport layer stacked in sequence, the first carrier transport layer and the second carrier transport layer having opposite conductivity types,

Electrodes are provided on the first carrier transport layer and the second carrier transport layer at the side of the surface away from the absorption layer.

A spontaneous polarization layer is provided between the first carrier transport layer and the electrode, and/or between the second carrier transport layer and the electrode.
The solar cell according to claim 1, characterized in that the carrier transport layer comprises a first carrier transport layer and a second carrier transport layer which are alternately arranged, and the first carrier transport layer and the second carrier transport layer have opposite conductivity types,

An electrode is arranged on a surface side of the carrier transport layer away from the absorption layer.
The solar cell according to claim 1 is characterized in that the material forming the spontaneous polarization layer is selected from one or more of an inorganic ferroelectric material, an organic ferroelectric material, and a composite material composed of a dielectric material and a ferroelectric material.
The solar cell according to claim 4 is characterized in that the inorganic ferroelectric material is selected from one or more of barium titanate, strontium titanate, titanium oxide, lead zirconate titanate, lead magnesium niobate, sodium bismuth titanate, bismuth ferrite, and bismuth manganate.
The solar cell according to claim 4, characterized in that the organic ferroelectric material is selected from one or two of polyvinylidene fluoride, its copolymer and copolyamide.
The solar cell according to claim 1, characterized in that the thickness of the spontaneous polarization layer is less than or equal to 10 nm.
The solar cell according to claim 1, characterized in that the spontaneous polarization layer is a single crystal layer or a polycrystalline layer.
The solar cell according to claim 1, characterized in that the remanent polarization intensity of the spontaneous polarization layer is greater than 0.96 μC/cm -2 .
The solar cell according to claim 1, characterized in that the spontaneous polarization layer The coercive electric field strength is greater than 50 kV·cm -1 .
The solar cell according to claim 1, characterized in that the polarization direction of the spontaneous polarization layer is the same as the positive charge transmission direction in the solar cell.
The solar cell according to claim 1, characterized in that the spontaneous polarization layer completely covers the first carrier transport layer and/or the second carrier transport layer.
The solar cell according to claim 1, characterized in that a passivation layer is provided between the first carrier transport layer and the absorption layer, and/or between the second carrier transport layer and the absorption layer.
The solar cell according to claim 1 is characterized in that the material forming the absorption layer is one of crystalline silicon, halide perovskite, IIIA-VA group compound, copper indium gallium selenide, and copper zinc selenium sulfur.
The solar cell according to claim 3, characterized in that an intrinsic amorphous silicon isolation layer is provided between the first carrier transport layer and the second carrier transport layer.
A solar cell with a spontaneous polarization structure is characterized in that the solar cell comprises an absorption layer, a passivation layer and a carrier transport layer which are stacked, and a spontaneous polarization layer is arranged between the carrier transport layer and the passivation layer.
The solar cell according to claim 16, characterized in that the solar cell comprises a first carrier transport layer, an absorption layer, and a second carrier transport layer stacked in sequence, the first carrier transport layer and the second carrier transport layer having opposite conductivity types,

A passivation layer is provided between the first carrier transport layer and the absorption layer, and/or between the second carrier transport layer and the absorption layer.

A spontaneous polarization layer is provided between the first carrier transport layer and the passivation layer, and/or between the second carrier transport layer and the passivation layer,

Electrodes are arranged on surfaces of the first carrier transport layer and the second carrier transport layer away from the absorption layer.
The solar cell according to claim 16, characterized in that the carrier transport layer comprises a first carrier transport layer and a second carrier transport layer which are alternately arranged, and the first carrier transport layer and the second carrier transport layer have opposite conductivity types,

A spontaneous polarization layer is provided between the carrier transport layer and the passivation layer,

An electrode is arranged on a surface of the carrier transport layer away from the absorption layer.
The solar cell according to claim 16 is characterized in that the material forming the spontaneous polarization layer is selected from one or more of an inorganic ferroelectric material, an organic ferroelectric material, and a composite material composed of a dielectric material and a ferroelectric material.
The solar cell according to claim 19 is characterized in that the inorganic ferroelectric material is selected from one or more of barium titanate, strontium titanate, titanium oxide, lead zirconate titanate, lead magnesium niobate, sodium bismuth titanate, bismuth ferrite, and bismuth manganate.
The solar cell according to claim 19, characterized in that the organic ferroelectric material is selected from one or two of polyvinylidene fluoride, its copolymer, and copolyamide.
The solar cell according to claim 16, characterized in that the thickness of the spontaneous polarization layer is less than or equal to 10 nm.
The solar cell according to claim 16, characterized in that the spontaneous polarization layer is a single crystal layer or a polycrystalline layer.
The solar cell according to claim 16, wherein the remanent polarization intensity of the spontaneous polarization layer is greater than 0.96 μC/cm -2 .
The solar cell according to claim 16, wherein the coercive electric field strength of the spontaneous polarization layer is greater than 50 kV·cm -1 .
The solar cell according to claim 16, characterized in that the polarization direction of the spontaneous polarization layer is the same as the positive charge transmission direction in the solar cell.
The solar cell according to claim 16 is characterized in that the material forming the absorption layer is one of crystalline silicon, halide perovskite, IIIA-VA group compound, copper indium gallium selenide, and copper zinc selenium sulfur.
The solar cell according to claim 16 is characterized in that the material forming the passivation layer is an inorganic passivation material, an organic passivation material or an ionic liquid, wherein the inorganic passivation material is selected from one of silicon oxide, aluminum oxide, and amorphous silicon, and the organic passivation material is selected from one of organic amine, ether, Lewis acid, and Lewis base.
The solar cell according to claim 18, characterized in that an intrinsic amorphous silicon isolation layer is provided between the first carrier transport layer and the second carrier transport layer.