Laminated solar cell, photovoltaic module, power generation device and power utilization device

Abstract

The utility model provides a laminated solar cell, a photovoltaic module and an electric device. The laminated solar cell comprises a first electrode and a second electrode; at least two battery cells disposed between the first electrode and the second electrode, and a composite layer; the at least two battery units comprise a first battery unit and a second battery unit which are sequentially arranged along a first direction, the composite layer is arranged between the first battery unit and the second battery unit, and the first direction is an incident direction of light; wherein the second cell unit comprises a second hole transport layer, a second light absorption layer and a second electron transport layer which are sequentially arranged along the first direction; the second cell further includes an electron blocking layer disposed between the second hole transport layer and the second light absorbing layer. The laminated solar cell has high open-circuit voltage and high photoelectric conversion efficiency.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a stacked solar cell, a photovoltaic module, a power generation device and a power consumption device. Background Art

[0002] Solar cells, also known as photovoltaic cells, are devices that convert light energy directly into electrical energy through the photoelectric effect or photochemical effect. As an ideal renewable energy source, solar cells are receiving more and more attention.

[0003] With the development of solar cell technology, people have higher and higher requirements on the performance of solar cells. Tandem solar cells have good application prospects because of their high photoelectric conversion efficiency.

[0004] For tandem solar cells, especially all-perovskite tandem solar cells, the bottom cell unit usually has a wide bandgap and the top cell unit has a narrow bandgap. Limited by the bandgap of the light absorption layer in the top cell unit, the materials used in the hole transport layer arranged in the top cell unit mainly include organic hole transport materials, resulting in a low thickness of the hole transport layer. Due to the thickness limitation, the hole transport layer has a weak blocking effect on electrons, and non-radiative recombination of holes and electrons still exists in the top cell unit, which limits the improvement of the photoelectric conversion efficiency of the tandem solar cell. Utility Model Content

[0005] The present application is made in view of the above-mentioned problems, and its purpose is to provide a tandem solar cell, a photovoltaic module and a photovoltaic device. The tandem solar cell can achieve multi-layer blocking of electrons in the second battery unit by arranging an electron blocking layer and a second hole transport layer in the second battery unit, thereby enhancing the electron blocking effect and reducing the non-radiative recombination of electrons and holes, thereby improving the open circuit voltage and photoelectric conversion efficiency of the tandem solar cell.

[0006] In order to achieve the above-mentioned purpose, the present application provides a stacked solar cell, the stacked solar cell includes a first electrode and a second electrode; at least two battery cells arranged between the first electrode and the second electrode, and a composite layer; the at least two battery cells include a first battery cell and a second battery cell arranged in sequence along a first direction, and the composite layer is arranged between the first battery cell and the second battery cell, wherein the first direction is the incident direction of light; wherein the second battery cell includes a second hole transport layer, a second light absorption layer and a second electron transport layer arranged in sequence along the first direction; the second battery cell further includes an electron blocking layer arranged between the second hole transport layer and the second light absorption layer. In the present application, on the basis of the second hole transport layer, by arranging an electron blocking layer, multi-layer blocking of electrons in the second battery cell can be achieved, the electron blocking effect can be enhanced, and the non-radiative recombination of electrons and holes can be reduced, thereby improving the open circuit voltage and photoelectric conversion efficiency of the stacked solar cell.

[0007] In some embodiments, the thickness of the electron blocking layer is 1 nm to 20 nm. By controlling the thickness of the electron blocking layer within the above range, the electron blocking layer can produce less light absorption while playing an electron blocking role, and is also conducive to reducing the absorption of sunlight by the electron blocking layer.

[0008] In some embodiments, the thickness of the electron blocking layer is 5 nm to 15 nm. By controlling the thickness of the electron blocking layer within the above range, the open circuit voltage and photoelectric conversion efficiency of the stacked solar cell can be further improved.

[0009] In some embodiments, the electron blocking layer is arranged as nanoparticles distributed in an island shape. By arranging the electron blocking layer as nanoparticles distributed in an island shape, the lateral transmission of holes can be reduced, which is conducive to improving the utilization rate of holes.

[0010] In some embodiments, the average particle size of the nanoparticles is 5 nm to 15 nm. By controlling the average particle size of the nanoparticles within the above range, the aggregation of the nanoparticles can be reduced, which is beneficial to further reduce the lateral transmission of holes.

[0011] In some embodiments, the thickness of the second hole transport layer is 5 nm to 10 nm. By arranging the electron blocking layer and the second hole transport layer, multi-layer blocking of electrons in the second battery cell can be achieved, and even if the thickness of the second hole transport layer is within the above range, strong blocking of electrons can still be generated in the second battery cell.

[0012] In some embodiments, the first battery unit is arranged on the first electrode and includes a first hole transport layer, a first light absorption layer, a first hole blocking layer, a first electron transport layer, and a second hole blocking layer arranged in sequence along a first direction. By arranging the first hole blocking layer and the second hole blocking layer, multi-layer blocking of holes in the first battery unit can be achieved, the hole blocking effect is enhanced, and the non-radiative recombination of holes and electrons is further reduced, thereby improving the open circuit voltage and photoelectric conversion efficiency of the stacked solar cell.

[0013] In some embodiments, the second battery cell further includes a third hole blocking layer disposed between the second light absorbing layer and the second electron transport layer. The third hole blocking layer blocks holes to further reduce non-radiative recombination of electrons and holes.

[0014] In some embodiments, the second battery unit further includes a fourth hole blocking layer arranged between the second electron transport layer and the second electrode. By arranging the first hole blocking layer, the second hole blocking layer, the third hole blocking layer and the fourth hole blocking layer, multi-layer blocking of holes can be achieved, the hole blocking effect is enhanced, and the open circuit voltage and photoelectric conversion efficiency of the stacked solar cell are further improved.

[0015] In some embodiments, the resistivity of the electron blocking layer is greater than or equal to 10 12 The electron blocking layer has a strong blocking effect on electrons.

[0016] In some embodiments, the material of the electron blocking layer includes any one of inorganic oxides, inorganic nitrides, inorganic carbides, inorganic silicides, inorganic sulfides, and carbon materials.

[0017] In some embodiments, the first light absorbing layer and the second light absorbing layer respectively include perovskite materials. Compared with other tandem solar cells, the photoelectric conversion efficiency of the tandem solar cell is further improved.

[0018] In some embodiments, the band gap of the second light absorbing layer is narrower than the band gap of the first light absorbing layer.

[0019] A second aspect of the present application provides a photovoltaic module, which includes the stacked solar cell provided in the first aspect.

[0020] A third aspect of the present application provides a power generation device, which includes the stacked solar cell provided in the first aspect.

[0021] A fourth aspect of the present application provides an electrical device, which includes the stacked solar cell provided in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of a stacked solar cell according to an embodiment of the present application.

[0023] Figure 2 It is a schematic structural diagram of a stacked solar cell according to an embodiment of the present application.

[0024] Figure 3 It is a schematic structural diagram of a stacked solar cell according to an embodiment of the present application.

[0025] Figure 4 It is a schematic structural diagram of a stacked solar cell according to an embodiment of the present application.

[0026] Description of reference numerals:

[0027] 10, 100, 200, 300 stacked solar cells; 11 first electrode; 12 second electrode; 13 first battery unit; 131 first hole transport layer; 132 first light absorption layer; 133 first hole blocking layer; 134 first electron transport layer; 135 second hole blocking layer; 14 second battery unit; 141 second hole transport layer; 142 second light absorption layer; 143 second electron transport layer; 144 electron blocking layer; 145 third hole blocking layer; 146 fourth hole blocking layer; 15 composite layer. DETAILED DESCRIPTION

[0028] Hereinafter, an embodiment of a laminated solar cell, a photovoltaic module, a power generation device and an electric device of the present application will be specifically disclosed in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following descriptions are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0029] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0030] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0031] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0032] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0033] If not specifically stated, the terms used in this application have the commonly known meanings generally understood by those skilled in the art.

[0034] If not otherwise specified, the values ​​of the parameters mentioned in this application can be measured using various test methods commonly used in the art, for example, they can be measured according to the test methods given in this application.

[0035] The term "layer" as used in this application refers to any substantially layered structure. A layer may have a thickness that varies over the range in which the layer extends. Typically, a layer has a thickness that is approximately constant. The "thickness" of a layer as used in this application refers to the average thickness of the layer. The thickness of a layer can be easily measured using conventional methods.

[0036] If not specifically stated, reference in the present application to a layer being on / located on another layer includes the case where the first layer is directly on the second layer, i.e., the two layers are in direct contact, as well as the case where there are other layers (such as a third layer) interposed between the first layer and the second layer.

[0037] The term "perovskite" used in this application refers to a material having a three-dimensional crystal structure related to the three-dimensional crystal structure of CaTiO3, or a layer material having a structure related to the structure of CaTiO3. Materials having a three-dimensional crystal structure related to CaTiO3 are well known and can be referred to as perovskites having a "3D perovskite structure", or "3D perovskites". Materials containing layers of perovskite materials are well known and are referred to as "2D layered perovskites" in the art. When receiving sunlight, the electrons in the perovskite are excited, and the electrons jump from the valence band to the conduction band, generating electron-hole pairs. Unless otherwise specified, "perovskite" mentioned in this application refers to 3D perovskite materials. The general chemical formula of the perovskite can be expressed as ABX3, where A is generally a cation with a larger radius. For example, A includes: CH(NH2)2 + (abbreviated as FA + )、CH3NH3 + , K + , Rb + , Cs + At least one of. B is a cation with a smaller radius, and B includes but is not limited to Pb 2+ Sn 2+ Mg 2+ , Ca 2+ , Ba 2+ 、Zn 2+ ,Ge 2+ 、Co 2+ , at least one of. X is an anion, for example, X includes: Cl - Br - ,I - 、SCN - 、CNO - 、OCN - 、OSCN - SH - OH - , CP - , CN - 、SeCN -At least one of. When the perovskite includes more than one A cation, different A cations can be distributed in an orderly or disordered manner on the A site. When the perovskite includes more than one B cation, different B cations can be distributed in an orderly or disordered manner on the B site. When the perovskite includes more than one X anion, different X anions can be distributed in an orderly or disordered manner on the X site.

[0038] Solar cells, also known as photovoltaic cells, are devices that convert light energy directly into electrical energy through the photoelectric effect or photochemical effect. As an ideal renewable energy source, solar cells are gaining more and more attention.

[0039] With the development of solar cell technology, people have higher and higher requirements on the performance of solar cells. A stacked solar cell includes at least two stacked battery cells. Through the band gap combination of each battery cell, the absorption of sunlight in a wide band range is achieved, and the utilization rate of sunlight is improved. Therefore, the stacked solar cell has a high photoelectric conversion efficiency.

[0040] Each battery cell in the stacked solar cell is arranged with a light absorption layer and a carrier transport layer (for example, an electron transport layer, a hole transport layer). Among them, the light absorption layer uses a light-absorbing material (for example, a perovskite material) that can absorb photons to generate electron-hole pairs. Under the action of the electric field, the electron-hole pairs are dissociated into carriers (electrons, holes). The directional movement of dissociated carriers forms an electric current. The presence of the carrier transport layer can enhance the dissociation effect of electrons and holes, thereby effectively improving the photoelectric conversion efficiency of the battery.

[0041] For tandem solar cells, especially all-perovskite tandem solar cells, the bottom cell (also referred to herein as the first cell, which refers to the cell that first receives incident light) generally has a wide bandgap, and the top cell (also referred to herein as the second cell, which refers to the cell that receives incident light that passes through the bottom cell) has a narrow bandgap. When the perovskite cell is used as the second cell, the bandgap of the arranged light absorbing layer (also referred to herein as the second light absorbing layer) is 1.1eV-1.4eV.

[0042] The band gap is equal to the difference between the LUMO energy level and the HOMO energy level. Since the band gap of the second light absorption layer is narrower, the HOMO energy level of the second light absorption layer is more positive. The hole transport material that needs to be band matched is mainly an organic hole transport material, which makes the thickness of the second hole transport layer usually between 5nm and 10nm. Due to the thickness limitation, the blocking effect of the second hole transport layer on electrons is limited. There is still non-radiative recombination of holes and electrons in the second cell of the perovskite cell unit, which limits the room for improvement of the photoelectric conversion efficiency of the stacked solar cell.

[0043] In view of this, the embodiment of the present application provides a tandem solar cell. A photovoltaic module, a power generation device and an electrical device comprising the tandem solar cell. The tandem solar cell can achieve multi-layer blocking of electrons in the second battery cell of the perovskite battery cell by arranging an electron blocking layer and a second hole transport layer, thereby enhancing the electron blocking effect and reducing the non-radiative recombination of electrons and holes, thereby improving the open circuit voltage and photoelectric conversion efficiency of the tandem solar cell.

[0044] Tandem solar cells

[0045] Figure 1 The schematic diagram of an embodiment of the stacked solar cell of the present application. The stacked solar cell 10 includes a first electrode 11 and a second electrode 12; at least two battery cells and a composite layer 15 arranged between the first electrode 11 and the second electrode 12, wherein the at least two battery cells include a first battery cell 13 and a second battery cell 14 arranged in sequence along a first direction; the composite layer 15 is arranged between the first battery cell 13 and the second battery cell 14, wherein the first direction is the incident direction of light; wherein the second battery cell 14 includes a second hole transport layer 141, a second light absorption layer 142 and a second electron transport layer 143 arranged in sequence along the first direction; the second battery cell 14 further includes an electron blocking layer 144 arranged between the second hole transport layer 141 and the second light absorption layer 142.

[0046] In the present application, on the basis of the second hole transport layer 141, by arranging the electron blocking layer 144, it is possible to achieve multi-layer blocking of electrons in the second battery unit 14, enhance the electron blocking effect, and further reduce the non-radiative recombination of electrons and holes, thereby improving the open circuit voltage and photoelectric conversion efficiency of the stacked solar cell.

[0047] The term "tandem solar cell" in the present application refers to a solar cell having a structure in which at least two battery units are arranged in sequence along the incident direction of light. By stacking at least two battery units, the utilization rate of incident sunlight can be increased.

[0048] The present application has no particular limitation on the number of battery cells included in the stacked solar cell 10. For example, the number of battery cells included in the stacked solar cell may be 2, 3, 4, etc.

[0049] Hereinafter, the stacked solar cell 10 including two battery cells (a first battery cell 13 and a second battery cell 14) will be described as an example.

[0050] The first electrode 11 is made of a transparent conductive material. The present application has no particular limitation on the transparent conductive material included in the first electrode 11. Exemplarily, the transparent conductive material includes at least one of indium tin oxide, fluorine-doped tin oxide (TCO), antimony-doped tin oxide, indium-doped tungsten oxide, indium-doped zinc oxide, aluminum-doped zinc oxide, and boron-doped zinc oxide.

[0051] The present application has no particular limitation on the thickness of the first electrode 11 , and the electrode thickness commonly used in the art may be adopted.

[0052] The material used for the second electrode 12 includes a conductive material. The present application has no particular restrictions on the conductive material included in the second electrode 12. For example, the conductive material includes at least one of the above-mentioned transparent conductive materials, metals and their alloys, and carbon single-substance materials. Exemplarily, the metals and their alloys include at least one of gold, silver, copper, aluminum, nickel, chromium, bismuth, platinum, magnesium, molybdenum, and tungsten. Exemplarily, the carbon single-substance material includes at least one of graphite, graphene, and carbon nanotubes.

[0053] The present application has no particular limitation on the thickness of the second electrode 12 , and the electrode thickness commonly used in the art may be adopted.

[0054] The composite layer 15 is arranged between the first battery cell 13 and the second battery cell 14, and is used to provide a place for the recombination of the electrons generated by the first battery cell 13 and the holes generated by the second battery cell 14. The material contained in the composite layer 15 is not particularly limited in the present application. For example, the composite layer 15 includes at least one of gold, platinum, indium tin oxide, indium zinc oxide, iron, cobalt, nickel, zinc, manganese, cadmium, silver, and copper. The thickness of the composite layer 15 is not particularly limited in the present application, and the composite layer thickness commonly used in the art can be used.

[0055] The first battery unit 13 is arranged on the first electrode 11. In a specific example, the first battery unit is a perovskite solar cell. Through the design of the perovskite material, the first battery unit 13 can have a wider band gap (for example, a band gap of 1.6eV-2.3eV), which is conducive to the first battery unit 13 and the second battery unit 14 with a narrow band gap forming a laminated solar cell 10 with high photoelectric conversion efficiency.

[0056] In the present application, the second battery unit 14 is arranged on the composite layer 15 and includes a second hole transport layer 141, a second light absorption layer 142, a second electron transport layer 143 arranged in sequence along the first direction, and an electron blocking layer 144 arranged between the second hole transport layer 141 and the second light absorption layer 142.

[0057] The second hole transport layer 141 is arranged between the composite layer 15 and the second light absorbing layer 142, and is used to transport the holes generated by the excitation of the second light absorbing layer 142 to the composite layer 15. Limited by the band gap of the second light absorbing layer 142, the materials used in the second hole transport layer 141 are mostly organic hole transport materials. Exemplarily, the organic hole transport material includes: at least one of [2-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphoric acid, poly-3,4-ethylenedioxythiophene, polystyrene sulfone, polystyrene sulfonic acid, poly-3-hexylthiophene, triphenylamine with triptycene as the core, 3,4-ethylenedioxythiophene-methoxytriphenylamine, N-(4-phenylamino)carbazole-spirobifluorene, and polythiophene.

[0058] In some embodiments, the thickness of the second hole transport layer 141 is 5 nm to 10 nm. For example, the thickness of the second hole transport layer is 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, or a value between any two values, but not limited thereto. By arranging the electron blocking layer 144 and the second hole transport layer 141, multi-layer blocking of electrons in the second battery cell 14 can be achieved. Even if the thickness of the second hole transport layer 141 is within the above range, strong blocking of electrons can still be generated in the second battery cell 14.

[0059] The second light absorbing layer 142 is made of a second light absorbing material. The second light absorbing material includes a perovskite material. By designing the perovskite material, the second light absorbing layer 142 can have a narrower band gap, which is conducive to the second battery unit 14 and the first battery unit 13 with a wide band gap forming a stacked solar cell with high photoelectric conversion efficiency.

[0060] In some embodiments, the band gap of the second light absorbing layer 142 is 1.1 eV to 1.4 eV. The perovskite material used for the second light absorbing layer 142 is, for example, MA 0.3 FA 0.7 Pb 0.5 Sn 0.5 I3、MAPb 0.85 Sn 0.15 I3, FAPb 0.5 Sn 0.5 I3、FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3.

[0061] The present application has no particular limitation on the thickness of the second light absorbing layer 142 , and the thickness of the light absorbing layer conventionally used in the art may be adopted.

[0062] The second electron transport layer 143 is made of an electron transport material. The present application does not particularly limit the electron transport material included in the second electron transport layer 143. Exemplary electron transport materials include: fullerene and its derivatives (e.g., C 60 ), metal oxides (such as oxides containing at least one of magnesium, cadmium, zinc, indium, lead, tungsten, bismuth, mercury, titanium, silver, manganese, iron, and vanadium), silicon oxide, strontium titanate, calcium titanate, lithium fluoride, and at least one of calcium fluoride.

[0063] The electron blocking layer 144 is disposed between the second light absorbing layer 142 and the second hole transporting layer 141 , and is used to block the electrons generated by the second light absorbing layer 142 .

[0064] In some embodiments, the electron blocking layer 144 is arranged as a film structure. In other embodiments, the electron blocking layer 144 is arranged as island-shaped distributed nanoparticles. By arranging the electron blocking layer 144 as island-shaped distributed nanoparticles, the lateral transmission of holes can be reduced, which is conducive to improving the utilization rate of holes.

[0065] The term "nanoparticle" in the present application refers to a particle with a size (particle diameter) of nanometer level, and the nanoparticle can be at least one of spherical, approximately spherical, and polyhedral. Exemplarily, the nanoparticle is at least one of spherical, oblate, and prolate ellipsoidal.

[0066] In some embodiments, the average particle size of the nanoparticles is 1nm to 20nm, and optionally, the particle size of the nanoparticles is 5nm to 15nm. For example, the average particle size of the nanoparticles is 1nm, 2nm, 4nm, 6nm, 8nm, 10nm, 12nm, 14nm, 16nm, 18nm, 20nm or a value between the ranges formed by any two values, but not limited thereto. By controlling the average particle size of the nanoparticles within the above range, the aggregation of the nanoparticles can be reduced, which is conducive to further reducing the lateral transmission of holes.

[0067] In some embodiments, the resistivity of the electron blocking layer 144 is greater than or equal to 10 12 Ω·m. For example, the resistivity of the electron blocking layer 144 is 10 12 Ω·m、2*10 12 Ω·m、3*10 12 Ω·m、4*10 12 Ω·m、5*10 12 Ω·m、6*10 12 Ω·m、7*10 12 Ω·m、8*10 12 Ω·m、9*10 12 Ω·m、10*10 12Ω·m or a value between any two values, but not limited thereto. The electron blocking layer 144 has a strong blocking effect on electrons.

[0068] In some embodiments, the material used for the electron blocking layer 144 includes at least one of an inorganic electron blocking material and an organic electron blocking material. The inorganic electron blocking material includes at least one of an inorganic oxide, an inorganic nitride, an inorganic carbide, an inorganic silicide, an inorganic sulfide, and a carbon material. Exemplarily, the materials used for the electron blocking layer 144 include: antimony oxide, aluminum oxide, cobalt oxide, boron oxide, bismuth oxide, chromium oxide, copper oxide, magnesium oxide, molybdenum oxide, silicon dioxide, vanadium oxide, zirconium oxide, aluminum carbonitride, aluminum nitride, boron nitride, calcium nitride, chromium nitride, europium nitride, magnesium nitride, silicon nitride, titanium nitride, vanadium nitride, zirconium nitride, gallium nitride, aluminum carbide, boron carbide, chromium carbide, molybdenum carbide, silicon carbide, titanium carbide, vanadium carbide, tungsten carbide, zirconium carbide, cobalt silicide, magnesium silicide, molybdenum silicide, niobium silicide, titanium silicide, tungsten silicide, zirconium silicide, aluminum sulfide, antimony sulfide, bismuth sulfide, barium sulfide, boron sulfide, calcium sulfide, chromium sulfide, cobalt sulfide, europium sulfide, gallium sulfide, magnesium sulfide, molybdenum sulfide, silicon disulfide, tungsten sulfide, vanadium sulfide, and zirconium sulfide. Exemplarily, the organic electron blocking material includes at least one of diphenylaminocarbazole and methyltriphenylaminecarboxylic acid.

[0069] In some embodiments, the thickness of the electron blocking layer 144 is 1 nm to 20 nm, and optionally, 5 nm to 15 nm. For example, the thickness of the electron blocking layer 144 is 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, or a value between any two values, but not limited thereto. By controlling the thickness of the electron blocking layer 144 within the above range, the electron blocking layer 144 can generate less light absorption while playing an electron blocking role, and is also conducive to reducing the absorption of sunlight by the electron blocking layer 144.

[0070] According to this application, Figure 2The structural diagram of a tandem solar cell 100 according to another embodiment is exemplarily shown. In this embodiment, the first cell unit 13 is disposed on the first electrode 11 and includes a first hole transport layer 131, a first light absorption layer 132, a first hole blocking layer 133, a first electron transport layer 134, and a second hole blocking layer 135 that are sequentially arranged in a first direction. According to specific examples, the first light absorption layer contains a perovskite material. A composite layer 15 is disposed on the second hole blocking layer 135. A second cell unit is disposed on the composite layer 15. By disposing the first hole blocking layer 133 and the second hole blocking layer 135, multi-layer blocking of holes in the first cell unit 13 can be achieved, enhancing the hole blocking effect, further reducing the non-radiative recombination of holes and electrons, and thereby improving the open-circuit voltage and photoelectric conversion efficiency of the tandem solar cell.

[0071] The first hole transport layer 131 is disposed on the first electrode 11 and includes a hole transport material. The present application places no particular limitation on the hole transport material included in the first hole transport layer 131. For example, the first hole transport layer 131 includes at least one of an inorganic hole transport material and an organic hole transport material. Exemplarily, the inorganic hole transport material includes at least one of metal oxides and cuprous thiocyanate. Exemplarily, the metal oxides include tin oxide (SnOx, where 1 < x < 2), nickel oxide (NiOx, 1 ≤ x ≤ 2), and cuprous oxide (Cu2O). Specific examples of the organic hole transport material are the same as those of the organic hole transport material in the above embodiment and will not be elaborated here.

[0072] The first light absorption layer 132 is disposed on the first hole transport layer 131, and the material used includes a perovskite material. To improve the photoelectric conversion efficiency, the first light absorption layer 132 including the perovskite material (which may be referred to as the first perovskite material hereinafter) is designed to have a relatively wide bandgap. The first perovskite material is well-known to those skilled in the art. Exemplarily, the first perovskite material includes FA 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3, FA 0.15 Cs 0.85 Pb(I 0.73 Br 0.27 )3, Cs 0.12 MA 0.05 FA 0.83 Pb(I 0.6 Br 0.4 )3.

[0073] In some embodiments, the tandem solar cell is a full perovskite tandem solar cell, wherein the first light absorbing layer 132 and the second light absorbing layer 142 both include perovskite materials. Perovskite materials have high photoelectric conversion efficiency, and compared with other tandem solar cells, the photoelectric conversion efficiency of the full perovskite tandem solar cell is further improved.

[0074] In some embodiments, the band gap of the perovskite material in the first light absorbing layer 132 is wider than the band gap of the perovskite material in the second light absorbing layer 142. For example, the band gap of the first perovskite material is 1.6 eV-2.3 eV, and the band gap of the second perovskite material is 1.1 eV-1.4 eV.

[0075] The first hole blocking layer 133 is arranged on the first light absorbing layer 132 and includes a first hole blocking layer material. The first hole blocking material can use a conventional hole blocking material, but the difference between the HOMO energy level of the first hole blocking material and the HOMO energy level of the first perovskite material must be less than 0. Exemplarily, the first hole blocking material includes: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), SnO2, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBI), 1,3-bis(3,5-bipyridin-3-ylphenyl)benzene (B3PyPB), diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide (TSPO1), 2,7-bis(2,2'-bipyridin-5-yl)triphenylene (BPy-TP2), bis(8 -hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum, (6-(1,10-phenanthroline-3-yl)naphthalene-2-yl)diphenylphosphine oxide (Phen-NaDPO), 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, 2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole, 3,5-diphenyl-4-(1-naphthyl)-1H-1,2,4-triazole, and at least one of benzophenanthroline.

[0076] The first electron transport layer 134 is arranged on the first hole blocking layer 133 and includes an electron transport material. The present application has no particular restriction on the electron transport material included in the first electron transport layer 134. The specific example of the electron transport material included in the first electron transport layer 134 is the same as that in the above embodiment, and will not be repeated here.

[0077] The second hole blocking layer 135 is arranged on the first electron transport layer 134 and includes a second hole blocking layer material. The second hole blocking material can use a conventional hole blocking material. Exemplarily, the second hole blocking material may include at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), fullerene and its derivatives (e.g., PCBM), SnOz (1.5≤z≤2), and SnO2.

[0078] In some embodiments, the second battery cell further includes a third hole blocking layer disposed between the second light absorbing layer and the second electron transport layer. The third hole blocking layer blocks holes to further reduce non-radiative recombination of electrons and holes.

[0079] The third hole blocking layer includes a third hole blocking material. The third hole blocking material can be a conventional hole blocking material, but the difference between the HOMO energy level of the third hole blocking material and the HOMO energy level of the second light absorbing material must be less than 0. In some embodiments, the third hole blocking material can be the same as the first hole blocking material. In some embodiments, the third hole blocking material can further include: CuPc, 8-hydroxyquinoline-lithium, BN-ICz-1(C 50 H 40 BN3) at least one.

[0080] According to one embodiment, see Figure 3 The structural diagram of the stacked solar cell 200 of this embodiment is shown as an example. In this embodiment, the first battery unit 13 is arranged on the first electrode 11, and includes a first hole transport layer 131, a first light absorption layer 132, a first hole blocking layer 133, a first electron transport layer 134, and a second hole blocking layer 135 arranged in sequence along the first direction. The second battery unit 14 is arranged on the composite layer 15, and includes a second hole transport layer 141, an electron blocking layer 144, a second light absorption layer 142, a third hole blocking layer 145, and a second electron transport layer 143 arranged in sequence along the first direction. The second electrode 12 is arranged on the second electron transport layer 143. By arranging the first hole blocking layer 133, the second hole blocking layer 135 and the third hole blocking layer 145, multi-layer blocking of holes can be achieved, the hole blocking effect can be enhanced, and the open circuit voltage and photoelectric conversion efficiency of the stacked solar cell can be further improved.

[0081] In this embodiment, the other layers are the same as those in the previous embodiment and will not be described again.

[0082] In some embodiments, the second battery cell further includes a fourth hole blocking layer disposed between the second electron transport layer and the second electrode. The fourth hole blocking layer blocks holes to further reduce non-radiative recombination of electrons and holes.

[0083] According to one embodiment, see Figure 4 The structural diagram of the stacked solar cell 300 of this embodiment is exemplarily shown. In this embodiment, the first battery unit 13 is arranged on the first electrode 11, and includes a first hole transport layer 131, a first light absorption layer 132, a first hole blocking layer 133, a first electron transport layer 134, and a second hole blocking layer 135 arranged in sequence along the first direction. The composite layer 15 is arranged on the second hole blocking layer 135, and the second battery unit 14 is arranged on the composite layer 15. The second battery unit 14 includes a second hole transport layer 141, an electron blocking layer 144, a second light absorption layer 142, a third hole blocking layer 145, a second electron transport layer 143, and a fourth hole blocking layer 146 stacked in sequence, and the second electrode 12 is arranged on the fourth hole blocking layer 146. In this embodiment, by arranging the first hole blocking layer 133, the second hole blocking layer 135, the third hole blocking layer 145 and the fourth hole blocking layer 146, it is possible to achieve multi-layer blocking of holes, enhance the hole blocking effect, and further improve the open circuit voltage and photoelectric conversion efficiency of the stacked solar cell.

[0084] The fourth hole blocking layer 146 includes a fourth hole blocking material. The present application has no particular limitation on the fourth hole blocking material. Exemplarily, the fourth hole blocking material may include fullerene and its derivatives (e.g., C 60 The fourth hole blocking material may be the same as or different from the second hole blocking material.

[0085] In this embodiment, the other layers are the same as those in the previous embodiment and will not be described again.

[0086] The present application does not particularly limit the preparation method of each functional layer of the stacked solar cell, which may include preparation methods used in the art, such as evaporation, atomic layer deposition, spin coating, etc. to form the functional layer.

[0087] The embodiment of the present application also provides a photovoltaic module. Generally, the photovoltaic module includes the above-mentioned laminated solar cell, a welding ribbon connecting multiple laminated solar cells, a junction box for current transmission, and a battery packaging component.

[0088] In some embodiments, the battery packaging component includes photovoltaic glass, which covers the laminated solar cell to protect the laminated solar cell. At the same time, photovoltaic glass has very good light transmittance and high hardness, and can adapt to large temperature differences between day and night and severe weather environments.

[0089] In some embodiments, the cell packaging component includes an ethylene-vinyl acetate copolymer (EVA) film, which is arranged between the photovoltaic glass and the laminated solar cell to bond the photovoltaic glass and the solar cell.

[0090] In some embodiments, the battery packaging component includes a photovoltaic backsheet, which also plays a role in protecting the laminated solar cells.

[0091] Optionally, the material of the photovoltaic back sheet can be a polyvinyl fluoride composite film or a thermoplastic elastic material. The material of the photovoltaic back sheet has the characteristics of insulation, waterproofness, and aging resistance.

[0092] In some embodiments, the battery packaging component includes a solar aluminum frame, which includes an aluminum alloy material and has the characteristics of high strength and good corrosion resistance, etc. It can support and protect the solar cell.

[0093] An embodiment of the present application also provides a power generation device, including the stacked solar cell provided in the above embodiment.

[0094] An embodiment of the present application also provides an electrical device, comprising the stacked solar cell provided in the above embodiment.

[0095] In some embodiments, the electrical device may also be a lighting device, an energy storage device, etc., and the embodiments of the present application include but are not limited to the above. For example, the electrical device may be a solar water heater, a solar street light, a solar photovoltaic generator, etc.

[0096] Example 1

[0097] Preparation of tandem solar cells

[0098] (1) Providing a first electrode: Take a FTO conductive glass with a specification of 2.0*2.0 cm, remove 0.35 cm of FTO at both ends by laser etching, and expose the glass substrate; ultrasonically clean the etched FTO conductive glass with a cleaning solution, deionized water, and ethanol in sequence; blow dry the solvent of the FTO conductive glass under a nitrogen gun, and put it into a UV ozone machine for further cleaning.

[0099] (2) Providing a first hole transport layer: On the FTO conductive glass treated with UV ozone, a 15 mg / mL NiOx (1≤x≤2) nanoparticle aqueous solution was spin-coated at a rate of 2000 rpm / s in a glove box to form a first hole transport layer with a thickness of 30 nm, and then thermally annealed at 150°C for 10 min.

[0100] (3) Providing a first light absorption layer: Weigh 1659 mg of lead iodide, 880 mg of lead bromide, 240 mg of bromoformamidine, 495 mg of iodoformamidine, 187 mg of cesium iodide, and 102 mg of cesium bromide and dissolve them in 1 mL of a mixed solution of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (the volume ratio of DMF to DMSO is 4:1). Stir for 1 hour, filter with a 0.22 μm organic filter membrane to obtain a perovskite precursor solution, take 100 μL of the perovskite precursor solution, spin-coat the perovskite precursor solution on the first hole transport layer at 5000 rpm, then place it in a vacuum flash evaporation device for 30 seconds, transfer it to a 100°C hot stage for annealing for 10 minutes, and form a first light absorption layer (FA) with a thickness of 500 nm. 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3).

[0101] (4) Providing a first electron transport layer: ALD is performed to deposit SnO2 with a thickness of 20 nm on the above-mentioned first light absorption layer as the first electron transport layer.

[0102] (5) Providing a composite layer: Au with a thickness of 1 nm is evaporated on the second hole blocking layer as a composite layer.

[0103] (6) Providing a second hole transport layer: Spin coating a mixed solution of poly (3,4-ethylenedioxythiophene) and polystyrene sulfone on the above composite layer at a spin coating speed of 3000 rpm for 20 s, and then transferring to a hot stage for annealing at 150° C. for 15 min to form a second hole transport layer with a thickness of 10 nm.

[0104] (7) Providing an electron blocking layer: Al2O3 with a thickness of 10 nm is deposited on the above-mentioned second hole transport layer as an electron blocking layer.

[0105] (8) Providing a second light absorbing layer: adding 2 mg of iodoformamidine, 85 mg of iodomethylamine, 4 mg of lead iodide, and 335 mg of stannous iodide to 1 mL of a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO is 2:1), stirring at 600 rpm on a magnetic stirrer for 2 h, filtering to obtain a perovskite precursor solution; spin coating 100 μL of the perovskite precursor solution on the second hole transport layer, first at a spin coating speed of 1 000 rpm, acceleration 200 rpm / s spin coating for 10 s, then spin coating at a spin coating speed of 3000 rpm, acceleration 1000 rpm / s spin coating for 20 s, then drop 500 μL of ethyl acetate onto the spin-coated perovskite precursor solution, then spin-coat the above perovskite precursor solution again, the spin coating speed is 4000 rpm, the spin coating time is 20 s, and then transfer to a hot stage for annealing at 100 ° C for 10 min to form a second light absorption layer (FA) with a thickness of 1 μm 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3).

[0106] (9) Providing a second electron transport layer: spin-coat a 15 mg / mL fullerene derivative (PCBM) chlorobenzene solution on the second light absorbing layer to form a second electron transport layer with a thickness of 10 nm.

[0107] (10) Providing a second electrode: On the second electron transport layer, metal copper (Cu) is evaporated to a thickness of 100 nm as the second electrode.

[0108] Performance testing of tandem solar cells

[0109] Open circuit voltage (Voc) and photoelectric conversion efficiency (PCE) test of stacked solar cells

[0110] In the atmospheric environment, AM1.5G standard light source is used as the sunlight simulation light source, and a four-channel digital source meter (Keithley2440) is used to measure the volt-ampere characteristic curve of the battery under the irradiation of the light source. According to the volt-ampere characteristic curve, the open circuit voltage, short circuit current density (Jsc), and passivation factor FF (Fill Factor) of the stacked solar cell are obtained.

[0111] PCE=Pout / Popt

[0112] =Voc×Jsc×(Vmpp×Jmpp) / (Voc×Jsc)

[0113] =Voc×Jsc×FF.

[0114] Pout, Popt, Vmpp, and Jmpp are the battery operating output power, incident light power, battery maximum power point voltage, and maximum power point current, respectively.

[0115] Comparative Example 1

[0116] A stacked solar cell was prepared according to the method of Example 1, except that no electron blocking layer was formed.

[0117] The performance test was carried out in the same manner as in Example 1. The test results are shown in Table 1.

[0118] Table 1

[0119] Serial number Electron blocking layer materials Voc(V) PCE(%) Example 1 <![CDATA[Al2O3]]> 2.032 26.45 Comparative Example 1 - 1.998 25.96

[0120] It can be seen from Table 1 that the calcium tandem solar cell prepared in Example 1 has an electron blocking layer arranged between the second hole transport layer and the second light absorption layer. Compared with the calcium tandem solar cell prepared in Comparative Example 1, the open circuit voltage and photoelectric conversion efficiency of the calcium tandem solar cell prepared in Example 1 are improved.

[0121] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A stacked solar cell, comprising a first electrode and a second electrode; at least two battery cells arranged between the first electrode and the second electrode, and a composite layer; The at least two battery cells include a first battery cell and a second battery cell sequentially arranged along a first direction, and the composite layer is arranged between the first battery cell and the second battery cell, wherein: The first direction is the incident direction of light; Wherein, the second battery unit comprises a second hole transport layer, a second light absorption layer and a second electron transport layer arranged in sequence; Characterized in that the second battery unit further includes an electron blocking layer arranged between the second hole transport layer and the second light absorption layer.

2. The tandem solar cell according to claim 1, characterized in that: The thickness of the electron blocking layer is 1 nm to 20 nm.

3. The tandem solar cell according to claim 2, characterized in that: The thickness of the electron blocking layer is 5 nm to 15 nm.

4. The tandem solar cell according to claim 1, characterized in that: The electron blocking layer is arranged as nanoparticles distributed in an island shape.

5. The stacked solar cell according to claim 4, characterized in that: The average particle size of the nanoparticles is 5 nm to 15 nm.

6. The tandem solar cell according to any one of claims 1 to 5, characterized in that: The thickness of the second hole transport layer is 5 nm to 10 nm.

7. The tandem solar cell according to claim 1, characterized in that: The first battery unit is arranged on the first electrode, and includes a first hole transport layer, a first light absorption layer, a first hole blocking layer, a first electron transport layer, and a second hole blocking layer sequentially arranged along a first direction.

8. The tandem solar cell according to any one of claims 1 to 5, characterized in that: The second battery cell further includes a third hole blocking layer disposed between the second light absorbing layer and the second electron transporting layer.

9. The tandem solar cell according to any one of claims 1 to 5, characterized in that: The second battery cell further includes a fourth hole blocking layer disposed between the second electron transport layer and the second electrode.

10. The tandem solar cell according to claim 1, characterized in that: The resistivity of the electron blocking layer is greater than or equal to 10 12 Ω·m.

11. The tandem solar cell according to claim 10, characterized in that: The material of the electron blocking layer includes any one of inorganic oxides, inorganic nitrides, inorganic carbides, inorganic silicides, inorganic sulfides, and carbon materials.

12. The tandem solar cell according to claim 7, characterized in that: The first light absorbing layer and the second light absorbing layer include perovskite materials respectively.

13. The tandem solar cell according to claim 1, characterized in that: The band gap of the second light absorbing layer of the second cell arrangement is 1.1 eV to 1.4 eV.

14. A photovoltaic module, characterized in that: The photovoltaic module comprises the stacked solar cell according to any one of claims 1 to 13.

15. A power generation device, characterized in that: The power generation device comprises the stacked solar cell according to any one of claims 1 to 13.

16. An electrical device, characterized in that: The electric device comprises the tandem solar cell according to any one of claims 1 to 13.

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