Novel passivated selective contact structure, solar cell, solar cell assembly, and solar cell system

Abstract

Disclosed in the present application are a novel passivated selective contact structure, a solar cell, a solar cell assembly, and a solar cell system. The novel passivated selective contact structure comprises a silicon substrate, wherein the surface of the silicon substrate comprises a front side of the silicon substrate and / or a back side of the silicon substrate, and the surface of the silicon substrate comprises a passivated selective contact region and a non-passivated selective contact region; the non-passivated selective contact region comprises a passivation anti-reflection layer disposed on the surface of the silicon substrate; and the passivated selective contact region comprises a passivation layer, a selective transport layer and a metal electrode, which are sequentially stacked from inside to outside, the passivation layer covers a partial region of the surface of the silicon substrate, and the projection of the selective transport layer on the surface of the silicon substrate covers a partial region of the surface of the silicon substrate. By means of a synergistic effect among the passivation anti-reflection layer, the selective transport layer and the passivation layer in the present application, an excellent passivated contact effect is achieved.

Description

Novel passivation selective contact structure and solar cell, component and system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202410393895.3 filed on April 2, 2024, entitled “Back-contact solar cells, components and systems” and application number 202410394005.0 filed on April 2, 2024, entitled “Novel passivated selective contact structure and solar cells, components and systems”, the entire contents of these Chinese patent applications are incorporated herein by reference. Technical Field

[0003] The present invention generally relates to the technical field of solar cells, and in particular to a novel passivation selective contact structure and solar cells, components and systems. Background Art

[0004] The current efficiency improvement of crystalline silicon solar cells faces the problem of optimizing the p-region. For example, in PERC and some p-type back contact (BC) cell designs, the p-region provides field effect passivation in the form of aluminum back field, but the passivation effect is poor (J0~600fA / cm 2 ), the main reason is that the local corrosion of the aluminum paste on the silicon substrate significantly increases defects, while forming metal-induced interface defects that increase the capture of carriers, and the weak field passivation effect caused by the low doping concentration of aluminum back field and the severe Auger recombination loss, which largely restrict the V OC For cells based on p-type poly-Si (such as TOPCon and TOPCon-BC), there are difficulties in boron or gallium doping, severe recombination losses caused by internal expansion, and optical parasitic absorption losses caused by high doping of narrow band gap. For cells based on p-region boron hydride-doped amorphous silicon (a-Si:H) (such as silicon heterojunction SHJ), there are severe optical parasitic absorption losses, which restrict the short-circuit current (J SC Therefore, how to improve the passivation effect, reduce the recombination loss and suppress the optical parasitic absorption loss has a very important impact on improving the performance of solar cells. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, the present invention provides a novel passivation selective contact structure and solar cells, modules and systems. The introduction of wide bandgap high or low work function materials or band-matched materials can significantly optimize carrier transport and passivation mechanisms. Compared with doped polysilicon or amorphous silicon, it can effectively avoid the serious optical parasitic absorption problem caused by narrow bandgap high doping concentration. Compared with aluminum back field, it avoids the damage caused by direct contact between metal and silicon substrate and the defect-induced recombination loss and Auger recombination loss caused by diffusion into the silicon substrate, thereby improving the passivation effect and increasing the photoelectric conversion efficiency of solar cells and modules.

[0006] In a first aspect, the present invention provides a novel passivation selective contact structure, comprising: a silicon substrate, wherein the surface of the silicon substrate comprises a front surface of the silicon substrate and / or a back surface of the silicon substrate, and the surface of the silicon substrate comprises a passivation selective contact region and a non-passivation selective contact region;

[0007] The non-passivation selective contact region includes a passivation anti-reflection layer disposed on the surface of the silicon substrate;

[0008] The passivation selective contact region includes a passivation layer, a selective transmission layer and a metal electrode which are sequentially stacked from the inside to the outside.

[0009] As an optional solution, when the back side of the silicon substrate includes a passivation selective contact area and a non-passivation selective contact area, the back side includes a plurality of first areas and a plurality of second areas arranged at intervals, the first area includes a passivation selective contact area and a non-passivation selective contact area, wherein in the first area, the passivation layer is the passivation layer of the first area, and the metal electrode is the first metal electrode.

[0010] As an optional solution, the second region includes a tunneling dielectric layer, a doped polysilicon layer, and a second metal electrode stacked from the inside out on the surface of the silicon substrate.

[0011] As an optional solution, the second region also includes a passivation layer of the second region; and / or the second region also includes a selective transmission layer, the passivation layer of the second region is the same as or different from the passivation layer of the first region, and the selective transmission layer of the second region is different from the selective transmission layer of the first region.

[0012] As an optional solution, the silicon substrate in the second region includes an N-type doped layer, and the selective transport layer in the first region includes a hole selection layer and an electron transport layer.

[0013] As an optional solution, the first metal electrode and the second metal electrode are formed by at least one process of printing, PVD, electroplating or chemical plating;

[0014] and / or, the first metal electrode and the second metal electrode are formed in the same process;

[0015] And / or, the first metal electrode and the second metal electrode each include at least one of silver, copper, aluminum, nickel, chromium, molybdenum, indium, and tin.

[0016] As an optional solution, based on the projection on the surface of the silicon substrate, the projection of the passivation layer covers a part or all of the surface of the silicon substrate, and the projection of the selective transmission layer covers a part or all of the surface of the silicon substrate;

[0017] Alternatively, the projected area of ​​the passivation layer is greater than or equal to the projected area of ​​the selective transmission layer.

[0018] Alternatively, the projected area of ​​the selective transmission layer is greater than or equal to the projected area of ​​the metal electrode.

[0019] As an optional solution, based on the projection on the surface of the silicon substrate, the projection of the passivation layer in the first region covers the entire area or a portion of the surface of the silicon substrate located in the first region, and the projection of the selective transmission layer in the first region covers the entire area or a portion of the surface of the silicon substrate located in the first region; or

[0020] The projection of the passivation layer in the second region covers the entire or partial area of ​​the silicon substrate surface in the second region, and the projection of the selective transmission layer in the second region covers the entire or partial area of ​​the silicon substrate surface in the second region.

[0021] As an optional solution, the passivation anti-reflection layer includes aluminum oxide and silicon nitride layers stacked from the inside out.

[0022] As an optional solution, the thickness of the passivation layer is 0.1-300 nm.

[0023] As an optional scheme, the selective transport layer includes a hole-selective transport layer and / or an electron-selective transport layer; the hole-selective transport layer includes a hole-selective layer, or a hole-selective layer and a hole-transport layer stacked from the inside to the outside, or a hole-selective layer and an electron-transport layer stacked from the inside to the outside; the electron-selective transport layer includes an electron-selective layer, or an electron-selective layer and a hole-transport layer stacked from the inside to the outside, or an electron-selective layer and an electron-transport layer stacked from the inside to the outside.

[0024] As an optional solution, the hole selection layer is selected from materials with a work function greater than 4.8 eV, or a valence band gap ΔE V A material with a V of less than 0.5 eV, or a monolayer material; the hole transport layer is selected from at least one of doped or intrinsic oxides, nitrides, carbides, oxynitrides, oxycarbons, oxycarbonitrides, chalcogenides, halides, thiocyanates, and organic conductive polymers;

[0025] The electron selective layer is selected from materials with a work function less than 4.2 eV, or a conduction band gap ΔE C<0.5eV material, or organic conductive polymer; the electron transport layer is selected from at least one of doped or intrinsic oxides, nitrides, carbides, oxynitrides, carbon oxides, carbonitride oxides, chalcogenides, halides, or organic conductive polymers.

[0026] As an optional solution, the hole selection layer is selected from at least one of doped or intrinsic molybdenum oxide, vanadium oxide, tungsten oxide, chromium oxide, titanium oxide, copper oxide, nickel oxide, cobalt oxide, rhenium oxide, copper iodide, PEDOT:PSS, silicon carbide, silicon oxycarbide and a phosphate group monolayer;

[0027] The hole transport layer is selected from at least one of doped or intrinsic nickel oxide, copper oxide, copper iodide, copper thiocyanate, thienyl, PEDOT:PSS, PTAA, Spiro-OMeTAD and fluorinated indoprofen derivatives;

[0028] The electron selective layer is at least one selected from doped or intrinsic lithium fluoride, magnesium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, cerium fluoride, europium fluoride, tantalum oxide, zinc oxide, indium oxide, titanium oxide, magnesium oxide, zinc oxide, tin oxide, cesium oxide, niobium oxide, barium oxide, tantalum nitride, titanium nitride, titanium oxynitride, silicon carbide, cesium chloride, cesium bromide, cesium iodide, cesium carbonate, potassium carbonate, rubidium carbonate, calcium carbonate, strontium carbonate, barium carbonate, zinc sulfide, cadmium sulfide, indium sulfide, fullerene derivatives and bathocuproine;

[0029] The electron transport layer is selected from at least one of doped or intrinsic zinc oxide, indium oxide, tin oxide, titanium oxide, cadmium sulfide, cadmium selenide, fullerene derivatives and bathocuproine.

[0030] As an optional solution, the passivation layer is selected from at least one of silicon oxide, silicon oxynitride, aluminum oxide, phosphorus oxide, boron oxide, hafnium oxide, silicon carbide, titanium oxide, tin oxide, amorphous silicon, microcrystalline silicon and nanocrystalline silicon.

[0031] As an optional solution, the thickness of the hole selective transport layer is 0.1-700 nm, and the thickness of the passivation anti-reflection layer is 0-525 nm;

[0032] Alternatively, the thickness of the electron selective transport layer is 0.1-700 nm.

[0033] In a second aspect, the present invention provides a solar cell comprising the novel passivation selective contact structure in the first region of the first aspect.

[0034] In a third aspect, the present invention provides a solar cell assembly comprising a solar cell according to the second aspect, a cover plate, an adhesive film, and a back plate.

[0035] In a fourth aspect, the present invention provides a solar cell system comprising a solar cell assembly according to the third aspect, an energy conversion device, and an energy storage device.

[0036] The first region passivation selective contact structure of the present invention is a new type of passivation selective contact structure, which forms a strong built-in electric field by introducing a material with a higher work function or a material with a lower work function, or forms a strong built-in electric field by introducing a material that matches the energy band of one of the conduction band or valence band of the silicon substrate, thereby enhancing asymmetric carrier transport and separation, effectively enhancing carrier extraction and passivation capabilities, and improving the selectivity coefficient. The introduction of the passivation layer provides chemical and field effect passivation for the new passivation selective contact region, especially chemical passivation can effectively suppress interface defect states, providing a prerequisite for the excellent field passivation provided by the selective layer. The combination of the transport layer can compensate for the carrier transport difficulties caused by the large resistance of the selective layer, reduce the block resistance, improve the fill factor, and is particularly suitable for local metallization structures. The additional chemical passivation gain of the passivation selective contact region can be further enhanced by introducing hydrogen, such as adopting a nitrogen-hydrogen mixed gas annealing (FGA) process. The superimposed passivation anti-reflection layer can provide more hydrogen passivation gain; thus, under the synergistic effect of the passivation layer, the selection layer, the transmission layer and the passivation anti-reflection layer, an excellent passivation contact effect is achieved; and there is no need to use narrow-bandgap highly doped silicon materials, which reduces optical parasitic absorption losses and jointly improves the photoelectric conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0038] FIG1 is a schematic structural diagram of a novel passivation selective contact structure (P region structure) according to an embodiment of the present invention;

[0039] FIG2 is a partial enlarged view of A in FIG1 ;

[0040] FIG3 is another partial enlarged view of A in FIG1 ;

[0041] FIG4 is another partial enlarged view of A in FIG1 ;

[0042] FIG5 is a schematic structural diagram of another novel passivation selective contact structure ((N region structure)) according to an embodiment of the present invention;

[0043] FIG6 is a schematic structural diagram of a battery according to Example 1;

[0044] FIG7 is a schematic structural diagram of a battery according to Example 2;

[0045] FIG8 is a schematic structural diagram of a battery according to Example 3;

[0046] FIG9 is a schematic structural diagram of a battery according to Example 4;

[0047] FIG10 is a schematic structural diagram of a battery according to Example 5;

[0048] FIG11 is a schematic structural diagram of a back-contact solar cell of the cell of Example 6;

[0049] FIG12 is a schematic structural diagram of a back-contact solar cell of Example 7;

[0050] FIG13 is a schematic structural diagram of a back-contact solar cell according to an embodiment of the present invention;

[0051] FIG14 is a schematic structural diagram of a back-contact solar cell according to Example 8;

[0052] FIG15 is a schematic structural diagram of a back-contact solar cell of Example 9.

[0053] In the figure, 10, silicon substrate, 11, passivation anti-reflection layer, 111, aluminum oxide layer, 112, silicon nitride layer; 20, first passivation layer, 30, hole selective transport layer, 31, hole selection layer, 32, transport layer, 40, first metal electrode, 50, second passivation layer, 61, electron selection layer, 70, selective emitter, 80, second metal electrode, 90, tunneling dielectric layer, 91, doped polysilicon layer, 92, light extension region. DETAILED DESCRIPTION

[0054] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only portions relevant to the invention are shown in the accompanying drawings.

[0055] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0056] To improve passivation, related technologies employ field-effect passivation (FEP) by providing a hole-selective layer, thereby enhancing carrier separation and reducing recombination losses. However, FEP alone cannot significantly eliminate interface defects with silicon. Therefore, a chemical passivation layer must be used in conjunction with the passivation layer to eliminate defect-induced recombination caused by interface defects, thereby improving passivation performance.

[0057] Based on the above problems, an embodiment of the present application provides a novel passivation selective contact structure, comprising: a silicon substrate 10, wherein the surface of the silicon substrate 10 comprises a passivation selective contact region and a non-passivation selective contact region;

[0058] The non-passivation selective contact region includes a passivation anti-reflection layer disposed on the surface of the silicon substrate 10;

[0059] The passivation selective contact region comprises a passivation layer, a selective transmission layer and a metal electrode which are sequentially stacked on the surface of the silicon substrate from the inside to the outside.

[0060] The surface of the silicon substrate includes the front side of the silicon substrate and / or the back side of the silicon substrate. The back side of the silicon substrate refers to the backlight side, and the front side of the silicon substrate refers to the light-receiving side.

[0061] It can be understood that the passivation anti-reflection layer is directly disposed on the surface of the silicon substrate 10 .

[0062] In one possible implementation, when the surface of the silicon substrate includes the back side of the silicon substrate, the solar cell including the above-mentioned novel passivation selective contact structure can be a back contact cell, a back contact solar cell having a polycrystalline silicon tunneling oxygen passivation contact structure, an amorphous silicon microcrystalline silicon passivation contact structure, or both of the above structures or including a wide band gap non-doped silicon (dopant-free) material; or when the surface of the silicon substrate includes the back side of the silicon substrate, the solar cell including the above-mentioned novel passivation selective contact structure can be a double-sided contact cell (for example, including but not limited to a double-sided electrode solar cell having a polycrystalline silicon tunneling oxygen passivation contact structure, an amorphous silicon microcrystalline silicon passivation contact structure, or both of the above structures or including a wide band gap non-doped silicon (dopant-free) material), wherein the back side of the double-sided contact cell adopts the above-mentioned novel passivation selective contact structure and the front side adopts the traditional structure.

[0063] In another possible implementation, when the surface of the silicon substrate includes the front side of the silicon substrate, the solar cell including the above-mentioned novel passivation selective contact structure can be a double-sided contact cell (for example, including but not limited to a polycrystalline silicon tunneling oxygen passivation contact structure, an amorphous silicon microcrystalline silicon passivation contact structure, a double-sided electrode solar cell having both of the above structures or containing a wide bandgap non-doped silicon (dopant-free) material), wherein the front side of the double-sided contact cell adopts the above-mentioned novel passivation selective contact structure and the back side adopts the traditional structure.

[0064] In another possible implementation, when the surface of the silicon substrate includes the front and back surfaces of the silicon substrate, the solar cell including the novel passivation selective contact structure may be a double-sided contact cell, including but not limited to a double-sided electrode solar cell having a polycrystalline silicon tunneling oxygen passivation contact structure, an amorphous silicon microcrystalline silicon passivation contact structure, a combination of the aforementioned structures, or a wide-bandgap non-doped silicon (dopant-free) material. That is, both the front and back surfaces of the silicon substrate employ the novel passivation selective contact structure.

[0065] The following embodiments are first described by taking the application of the novel passivation selective contact structure to a double-sided contact battery (ie, the front or back of the double-sided contact battery adopts the novel passivation selective contact structure) as an example.

[0066] It should be noted that, unless otherwise specified, the description of the novel passivation selective contact structure in the following embodiments may be limited to the structure on the front side of the battery, the structure on the back side of the battery, or both the front side and the back side.

[0067] The novel passivation selective contact structure of the embodiment of the present application forms a strong built-in electric field by introducing a material with a higher work function or a material with a lower work function, or forms a strong built-in electric field by introducing a material that matches the energy band of one of the conduction band or valence band of the silicon substrate, thereby enhancing asymmetric carrier transport and separation, effectively enhancing carrier extraction and passivation capabilities, and improving the selectivity coefficient. The introduction of the passivation layer provides chemical and field effect passivation for the passivation selective contact area, especially chemical passivation can effectively suppress interface defect states, providing a prerequisite for the excellent field passivation provided by the selective layer. The combination of the transport layer can compensate for the carrier transport difficulties caused by the large resistance of the selective layer, reduce the block resistance, improve the fill factor, and is particularly suitable for local metallization structures. The additional chemical passivation gain of the passivation selective contact area in the first region can be further enhanced by introducing hydrogen, such as adopting a nitrogen-hydrogen mixed gas annealing (FGA) process. The superimposed passivation anti-reflection layer can provide more hydrogen passivation gain; thus, under the synergistic effect of the passivation layer, the selection layer, the transmission layer and the passivation anti-reflection layer, an excellent passivation contact effect is achieved; and there is no need to use narrow-bandgap highly doped silicon materials, which reduces optical parasitic absorption losses and jointly improves the photoelectric conversion efficiency.

[0068] As a feasible method, the passivation layer covers part of the surface of the silicon substrate 10, and the projection of the selective transmission layer on the surface of the silicon substrate 10 covers part of the surface of the silicon substrate 10, forming a local selective passivation contact structure, as shown in FIG1 .

[0069] The local selective passivation contact structure in this embodiment achieves an excellent passivation contact effect under the synergistic effect of the passivation anti-reflection layer, the passivation layer and the selective transmission layer.

[0070] As shown in FIG1 , the back side of the silicon substrate 10 is sequentially stacked with a passivation layer 20 , a hole selection layer 31 , a transmission layer 32 , a passivation anti-reflection layer 11 and a first metal electrode 40 from the inside out. The first metal electrode 40 is in direct contact with the transmission layer 32 .

[0071] As shown in Figure 5, the surface of the silicon substrate 10 is stacked with a tunneling dielectric layer (for example, a tunneling oxygen layer) 90, a doped polysilicon layer 91, an electron selection layer 61 and a second metal electrode 80 from the inside to the outside. The second metal electrode 80 is in contact with the electron selection layer 61, and the projection of the electron selection layer 61 on the surface of the silicon substrate 10 covers a partial area of ​​the silicon substrate 10.

[0072] In a preferred embodiment, the passivation anti-reflection layer 11 includes an aluminum oxide layer 111 and a silicon nitride layer 112 stacked from the inside out.

[0073] Among them, aluminum oxide and silicon nitride can both play a passivation role, and the anti-reflection effect mainly depends on silicon nitride; in the preferred scheme, a multi-layer anti-reflection structure is set up, and silicon nitride can be set as a multi-layer silicon nitride layer with different refractive indices; or a material with a lower refractive index can be set on the surface of silicon nitride as an anti-reflection layer, such as magnesium fluoride.

[0074] In addition, silicon nitride may also be silicon nitride doped with oxygen, carbon, or both carbon and oxygen, that is, silicon oxynitride, silicon carbide nitride, silicon oxycarbon nitride, and the like.

[0075] In some embodiments, aluminum oxide may be replaced by intrinsic or doped amorphous silicon, nanocrystalline silicon, microcrystalline silicon, microcrystalline silicon oxide, nanocrystalline silicon oxide, amorphous silicon oxide, phosphorus oxide, boron oxide, hafnium oxide, silicon carbide, titanium oxide, gallium oxide, zinc oxide, or tantalum oxide.

[0076] As an achievable method, the projected area of ​​the passivation layer is greater than or equal to the projected area of ​​the selective transmission layer, based on the projection on the surface of the silicon substrate 10. This embodiment is conducive to ensuring a good passivation effect.

[0077] In a preferred embodiment, the passivation layer covers the entire surface of the silicon substrate 10, and the projection of the selective transmission layer on the surface of the silicon substrate 10 covers a partial surface of the silicon substrate 10. It can also be understood that the projection of the passivation layer on the surface of the silicon substrate 10 covers the entire surface of the silicon substrate 10, and the projection of the selective transmission layer on the surface of the silicon substrate 10 covers the entire surface of the silicon substrate 10, forming a full-area passivation selective contact structure.

[0078] In a preferred embodiment, the projected area of ​​the selective transmission layer is greater than or equal to the projected area of ​​the metal electrode, based on the projection on the surface of the silicon substrate 10. That is, the metal electrode may fully or partially cover the selective transmission layer.

[0079] Since the selection layer and the transmission layer have high optical transmittance, and the transmission layer has high lateral conductivity, the projection area of ​​the metal electrode is as small as possible without affecting the carrier transmission, which is conducive to ensuring higher photon utilization.

[0080] As an achievable manner, the thickness of the passivation layer is 0.1-300 nm.

[0081] In some embodiments, the passivation layer includes a first passivation layer 20 and a second passivation layer 50; the selective transport layer includes a hole selective transport layer 30 and / or an electron selective transport layer, which is selected according to the actual battery structure; the first passivation layer 20 is set corresponding to the hole selective transport layer 30, and the second passivation layer 50 is set corresponding to the electron selective transport layer.

[0082] It should be noted that the first passivation layer 20 in this embodiment can be a passivation layer provided on the front side of the silicon substrate 10, or a passivation layer provided on the back side of the silicon substrate 10. Matching or corresponding to the first passivation layer 20, the second passivation layer 50 can be a passivation layer provided on the back side of the silicon substrate 10, or a passivation layer provided on the front side of the silicon substrate 10.

[0083] Specifically, in some embodiments, the thickness of the first passivation layer 20 and the second passivation layer 50 are each 0.1-300 nm.

[0084] In some other embodiments, the thickness of the first passivation layer 20 and the second passivation layer 50 is 0.1 nm-10 nm respectively. In a preferred embodiment, the thickness of the first passivation layer 20 and the second passivation layer 50 is 1.6 nm respectively.

[0085] As an achievable manner, the passivation layer is at least one selected from silicon oxide, silicon oxynitride, aluminum oxide, phosphorus oxide, boron oxide, hafnium oxide, silicon carbide, titanium oxide, tin oxide, amorphous silicon, microcrystalline silicon, and nanocrystalline silicon.

[0086] As a feasible manner, the hole selective transport layer 30 includes a hole selective layer 31, or a hole selective layer 31 and a hole transport layer stacked from the inside to the outside, or a hole selective layer 31 and an electron transport layer stacked from the inside to the outside; the electron selective transport layer includes an electron selective layer 61, or an electron selective layer 61 and a hole transport layer stacked from the inside to the outside, or an electron selective layer 61 and an electron transport layer stacked from the inside to the outside.

[0087] The electron transport layer and the hole transport layer may be collectively referred to as a transport layer 32 .

[0088] It is understandable that when the area ratio of the hole selection layer 31 to the metal electrode 40 is not large, the transport layer can be omitted.

[0089] In some embodiments, the hole selection layer 31 is selected from materials with a work function greater than 4.8 eV, or a valence band gap ΔE VA material with a V of less than 0.5 eV, or a monolayer material; the hole transport layer is selected from at least one of doped or intrinsic oxides, nitrides, carbides, oxynitrides, oxycarbons, oxycarbonitrides, chalcogenides, halides, thiocyanates, and organic conductive polymers;

[0090] The electron selective layer 61 is selected from materials with a work function less than 4.2 eV, or a conduction band gap ΔE C A material with a lattice strength of less than 0.5 eV, or an organic conductive polymer; the electron transport layer is selected from at least one of doped or intrinsic oxides, nitrides, carbides, oxynitrides, carbon oxides, carbonitride oxides, chalcogenides, halides, or organic conductive polymers.

[0091] Specifically, the hole selection layer 31 is selected from at least one of doped or intrinsic molybdenum oxide, vanadium oxide, tungsten oxide, chromium oxide, titanium oxide, copper oxide, nickel oxide, cobalt oxide, rhenium oxide, copper iodide, PEDOT:PSS, silicon carbide, silicon oxycarbide, and a phosphate group monolayer;

[0092] The hole transport layers are each independently selected from at least one of doped or intrinsic nickel oxide, copper oxide, copper iodide, copper thiocyanate, thienyl, PEDOT:PSS, PTAA, Spiro-OMeTAD, and fluorinated indoprofen derivatives;

[0093] The electron selective layer 61 is at least one selected from the group consisting of doped or intrinsic lithium fluoride, magnesium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, cerium fluoride, europium fluoride, tantalum oxide, zinc oxide, indium oxide, titanium oxide, magnesium oxide, zinc oxide, tin oxide, cesium oxide, niobium oxide, barium oxide, tantalum nitride, titanium nitride, titanium oxynitride, silicon carbide, cesium chloride, cesium bromide, cesium iodide, cesium carbonate, potassium carbonate, rubidium carbonate, calcium carbonate, strontium carbonate, barium carbonate, zinc sulfide, cadmium sulfide, indium sulfide, fullerene derivatives, and bathocuproine.

[0094] The electron transport layer is selected from at least one of doped or intrinsic zinc oxide, indium oxide, tin oxide, titanium oxide, cadmium sulfide, cadmium selenide, fullerene derivatives and bathocuproine.

[0095] Furthermore, the thickness of the hole selective transport layer 30 is 0.1 nm-700 nm, and the thickness of the passivation anti-reflection layer is 0 nm-525 nm.

[0096] In some embodiments, the electron selective transport layer has a thickness of 0.1 nm to 700 nm.

[0097] In a preferred embodiment, the thickness of the hole selective transport layer 30 is 0.5 nm-340 nm.

[0098] In a preferred embodiment, the thickness of the electron selective transport layer is 0.5 nm-340 nm.

[0099] In a preferred embodiment, the thickness of the passivation anti-reflection layer 11 is 30 nm-300 nm.

[0100] In some embodiments, the thickness of the electron selective layer is 0.1 nm-100 nm, preferably 0.5 nm-40 nm; the thickness of the electron transport layer is 0 nm-600 nm, preferably 0 nm-300 nm; the thickness of the hole transport layer is 0-600 nm, preferably 0-300 nm.

[0101] For example, as shown in Figure 1, the back side of the silicon substrate is stacked with a first passivation layer 20, a hole-selective layer 31, a transport layer 32, a passivation anti-reflection layer 11, and a first metal electrode 40, from the inside out. The first metal electrode 40 is in direct contact with the hole-selective layer 31. To illustrate the overlapping relationship between the different layers in the P-region slot area, as shown in Figures 2-4, the ideal situation is that the first passivation layer 20 and the hole-selective transport layer 30 just cover the bottom surface and sidewalls of the slot area, as shown in Figure 2. This ensures a good passivation effect while not covering the passivation anti-reflection layer, thereby ensuring a high bifaciality. Of course, considering the processing technology, the first passivation layer 20 and the hole-selective transport layer 30 can also cover part of the passivation anti-reflection layer, but the coverage area should be as small as possible, as shown in Figure 3. The slot area can extend from the passivation anti-reflection layer 11 to the surface of the silicon substrate 10 (as shown in Figure 4), or it can extend into the interior of the silicon substrate 10 (as shown in Figure 3). This is not specifically limited in the embodiments of the present application.

[0102] In summary, the novel passivation selective contact structure of the present application forms a strong built-in electric field by introducing a material with a higher work function or a material with a lower work function, or forms a strong built-in electric field by introducing a material that matches the energy band of one of the conduction band or valence band of the silicon substrate, thereby enhancing asymmetric carrier transport and separation, effectively enhancing carrier extraction and passivation capabilities, and improving the selectivity coefficient. The introduction of the passivation layer provides chemical and field effect passivation for the novel passivation selective contact area, especially chemical passivation can effectively suppress interface defect states, providing a prerequisite for the excellent field passivation provided by the selective layer. The combination of the transport layer can compensate for the carrier transport difficulties caused by the large resistance of the selective layer, reduce the block resistance, improve the fill factor, and is particularly suitable for local metallization structures. The additional chemical passivation gain of the passivation selective contact area can be further enhanced by introducing hydrogen, such as adopting a nitrogen-hydrogen mixed gas annealing (FGA) process. The superimposed passivation anti-reflection layer can provide more hydrogen passivation gain; thus, under the synergistic effect of the passivation layer, the selection layer, the transmission layer and the passivation anti-reflection layer, an excellent passivation contact effect is achieved; and there is no need to use narrow-bandgap highly doped silicon materials, which reduces optical parasitic absorption losses and jointly improves the photoelectric conversion efficiency.

[0103] The present invention provides a solar cell comprising the aforementioned novel passivation selective contact structure. Thus, the solar cell possesses all the features and advantages of the aforementioned novel passivation selective contact structure, which will not be elaborated upon here. Overall, the solar cell exhibits excellent cell performance.

[0104] It should be noted that, unless otherwise specified, the same terms in the following embodiments have the same meanings as those in the above embodiments, and are not described in detail to avoid repetition. In the absence of conflict, the various embodiments and features in the embodiments of this application can be combined with each other.

[0105] Another embodiment of the present application discloses a novel passivation selective contact structure comprising a silicon substrate 10. The back surface of the silicon substrate 10 comprises a plurality of first regions and a plurality of second regions spaced apart from each other. The first regions comprise a passivation selective contact region and a non-passivation selective contact region. The passivation selective contact region comprises a passivation layer, a selective transmission layer or a highly doped silicon layer, and a metal electrode stacked sequentially from the inside out, while the non-passivation selective contact region comprises a passivation anti-reflection layer disposed directly on the surface of the silicon substrate.

[0106] 10 , in the first region, the passivation layer is the passivation layer of the first region, and the metal electrode is the first metal electrode. For ease of description, the passivation layer of the first region in this embodiment may be referred to as the “first passivation layer 20 ”.

[0107] It can be understood that, as shown in FIG10 , the novel passivation selective contact structure of the embodiment of the present application can be applied to back contact batteries.

[0108] It can be understood that the first region and the second region correspond to the positive and negative electrodes of the battery, and the non-passivation selective contact area can be used to ensure the passivation anti-reflection effect of the battery, while also providing field and chemical passivation effects; it can also be used to isolate the passivation selective contact area to avoid leakage short circuits, where the isolation method includes but is not limited to the use of high-resistance insulating materials, such as stacked aluminum oxide layers and silicon nitride layers, or spatial isolation, such as forming a groove space by recessing toward the inside of the substrate, or both.

[0109] In the embodiments of the present application, a passivation anti-reflection layer is provided in the non-passivation selective contact area, which is beneficial for improving the passivation effect and increasing the bifaciality. The passivation anti-reflection layer can be at least one of aluminum oxide, silicon nitride, and silicon oxynitride, or a stacked arrangement of the aforementioned. Of course, other anti-reflection materials, such as magnesium fluoride, can also be provided.

[0110] It should be noted that the passivation anti-reflection layer in this embodiment may be the same as the passivation anti-reflection layer in the aforementioned embodiment, and to avoid repetition, it is not described here.

[0111] The first passivation layer 20 can be made of any material, and is generally selected from materials with a wide band gap, stable properties, and / or positive and negative fixed charges, and / or containing chemical passivation elements such as oxygen and hydrogen. Depending on different batteries, the first passivation layer 20 can be a tunneling transmission type material (for example, but not limited to silicon oxide or aluminum oxide) or a thermal emission transmission type material (for example, but not limited to titanium oxide), etc., and is selected specifically according to the actual processing technology and battery type; the selection layer is in direct contact with the first passivation layer 20 and the silicon substrate 10. Due to the large work function difference, a large energy band bending is formed on the surface of the silicon substrate, generating a strong built-in electric field, or an asymmetric energy band exists, with a very small band step on one side, which promotes carrier separation and achieves a good field passivation effect.

[0112] It can be understood that, based on the fact that the first region of the back-contact solar cell in the embodiment of the present application includes the above-mentioned structure, the corresponding second region can be a tunneling dielectric layer / doped polysilicon passivation contact structure; or the second region can also be an amorphous silicon microcrystalline silicon heterojunction passivation contact structure. The embodiment of the present application does not make specific limitations on this, and it can be set according to actual needs.

[0113] It can be understood that in the embodiment of the present application, the “tunneling dielectric layer” can specifically be a “tunneling oxygen layer”.

[0114] It can also be understood that the novel passivation selective contact structure in the embodiment of the present application further includes a first metal electrode 40 and a second metal electrode 80 , both of which are composed of a single layer or multiple layers of metal.

[0115] The back-contact solar cell provided in this application solves the problems of unsatisfactory passivation and low bifaciality of existing back-contact solar cells. Specifically, by introducing the aforementioned novel passivation selective contact structure solar cell into the back-contact cell, the same technical effect can be achieved, which will not be repeated here.

[0116] As an achievable method, the second region includes a tunneling dielectric layer 90, a doped polysilicon layer 91, and a second metal electrode 80 stacked from the inside out on the surface of the silicon substrate. In this embodiment, the second region adopts a tunneling dielectric layer / doped polysilicon layer structure, which is easy to process and facilitates the use of traditional TBC process flows.

[0117] For example, as shown in FIG11 , the first region is provided with a first passivation layer 20 and a hole selective transport layer 30 , and the second region is provided with a tunnel dielectric layer 90 , a doped polysilicon layer 91 and a second metal electrode 80 .

[0118] In one embodiment, the second region further includes a second passivation layer 50 (i.e., the passivation layer of the second region); as shown in Figure 12, and / or the second region further includes a selective transmission layer, the second passivation layer 50 is the same as or different from the first passivation layer 20, and the selective transmission layer of the second region is different from the selective transmission layer of the first region.

[0119] In another embodiment, the second region includes a passivation selective contact region and a non-passivation selective contact region of the second region, that is, both the second region and the first region adopt the novel passivation selective contact structure in the embodiment of the present application.

[0120] It should be noted that the first passivation layer 20 and the second passivation layer 50 are the same or different, which means that the material of the first passivation layer 20 is the same or different from the material of the second passivation layer 50; the selective transmission layer of the second region is different from the selective transmission layer of the first region, which means that the polarity type of the selective layer of the second region is different from the polarity type of the selective transmission layer of the first region, for example: the selective layer of the first region is a hole selective layer, and the selective layer of the second region is an electron selective layer; for another example: the selective layer of the first region is an electron selective layer, and the selective layer of the second region is a hole selective layer.

[0121] It should also be noted that the selection layer and the transmission layer in this embodiment are the same as the selection layer and the transmission layer in the previous embodiment, and to avoid repetition, they are not described here.

[0122] For example, as shown in Figure 13, the passivation selective contact area of ​​the first region is set with a first passivation layer 20, a hole selection layer 31 and a transmission layer 32, and the passivation selective contact area of ​​the second region is a tunneling dielectric layer 90, a doped polysilicon layer 91, a second passivation layer 50 and a second metal electrode 80.

[0123] For example, as shown in Figure 12, the passivation selective contact area of ​​the first region is set with a first passivation layer 20, a hole selection layer 31 and a transmission layer 32, and the passivation selective contact area of ​​the second region is a tunneling dielectric layer 90, a doped polysilicon layer 91, a second passivation layer 50, an electron selection layer 61 and a second metal electrode 80.

[0124] In this embodiment, a selective transmission layer and / or a second passivation layer is provided in the second region to form a passivation selective contact region in the second region, which is beneficial to further improve the passivation effect and enhance the optical utilization rate.

[0125] In some embodiments, the silicon substrate 10 in the second region includes a P-type doped layer, and the selective transport layer in the first region includes an electron selective transport layer.

[0126] It can be understood that the P-type doped layer can be a doped layer (P+ layer) formed when the second metal electrode is aluminum and an aluminum electrode is formed on the surface of the silicon substrate; that is, the second region adopts aluminum back field technology; specifically, the second region includes a passivation anti-reflection layer and an aluminum electrode, and the aluminum electrode contacts the silicon substrate through the passivation anti-reflection layer.

[0127] For example, the passivation selective contact region of the first region is provided with a first passivation layer 20 and an electron selective transport layer 30 , and the passivation selective contact region of the second region includes a second metal electrode 80 , which is an aluminum electrode.

[0128] In some other embodiments, the silicon substrate 10 in the second region includes an N-type doped layer, and the selective transport layer in the first region includes a hole selection layer and an electron transport layer.

[0129] As an achievable manner, the first metal electrode 40 and the second metal electrode 80 are prepared by at least one of printing, PVD, electroplating or chemical plating processes;

[0130] and / or, the first metal electrode 40 and the second metal electrode 80 are prepared in the same process;

[0131] And / or, the first metal electrode 40 and the second metal electrode 80 each include at least one of silver, copper, aluminum, nickel, chromium, molybdenum, indium, and tin.

[0132] In a specific embodiment, the first metal electrode 40 and the second metal electrode 80 may also be formed using other processes, but these processes must match the material characteristics of the selective transmission layer. For example, some selective transmission layer materials are not resistant to high temperatures, so low-temperature metallization is required. Other fabrication processes may include CVD, laser transfer, and the like.

[0133] As an achievable manner, based on the projection on the surface of the silicon substrate, the projected area of ​​the first passivation layer 20 is greater than or equal to the projected area of ​​the selective transmission layer in the first region;

[0134] The projected area of ​​the second passivation layer 50 is greater than or equal to the projected area of ​​the selective transmission layer in the second region.

[0135] This embodiment is conducive to ensuring a good passivation effect and avoiding the formation of composite losses.

[0136] As an achievable manner, based on the projection on the surface of the silicon substrate, the projection of the first passivation layer 20 covers a portion of the surface of the silicon substrate 10 located in the first region, and the projection of the selective transmission layer in the first region covers a portion of the surface of the silicon substrate 10 located in the first region;

[0137] Alternatively, the projection of the first passivation layer 20 covers the entire surface of the silicon substrate 10 located in the first region, and the projection of the selective transmission layer in the first region covers the entire surface of the silicon substrate 10 located in the first region.

[0138] In this embodiment, the passivation selective contact structure in the first region may be a local structure or a global structure.

[0139] As an achievable manner, based on the projection on the surface of the silicon substrate 10, the projection of the second passivation layer 50 covers a portion of the surface of the silicon substrate 10 located in the second region, and the projection of the selective transmission layer in the second region on the surface of the silicon substrate 10 covers a portion of the surface of the silicon substrate 10 located in the second region;

[0140] Alternatively, the projection of the second passivation layer 50 covers the entire surface of the silicon substrate 10 in the second region, and the projection of the selective transmission layer in the second region covers the entire surface of the silicon substrate 10 in the second region.

[0141] In this embodiment, the passivation selective contact structure in the second region may be a local structure or a global structure.

[0142] As an achievable manner, based on the projection on the surface of the silicon substrate 10 , the projected area of ​​the selective transmission layer in the first region is greater than or equal to the projected area of ​​the first metal electrode 40 ;

[0143] The projected area of ​​the selective transmission layer in the second region is greater than or equal to the projected area of ​​the second metal electrode 80 .

[0144] Since the selective transmission layer has very high transmittance and lateral conductivity, the projection areas of the first metal electrode 40 and the second metal electrode 80 are as small as possible without affecting the selective transmission layer, which is conducive to ensuring a higher double-sidedness.

[0145] This embodiment is beneficial for ensuring the passivation effect while improving the double-sidedness rate.

[0146] The hole selection layer 31 is made of a material with a high work function. Due to the large work function difference between the hole selection layer 31 and the silicon substrate, the hole selection layer 31 is mainly used to form an induced electric field on the silicon substrate to repel electrons and extract holes. When the projected area of ​​the hole selection layer 31 is not much larger than the projected area of ​​the first metal electrode 40, the transport layer 32 can be omitted; the same applies to the electron selection layer and the transport layer.

[0147] As an achievable approach, one or more anti-reflection layers, such as magnesium fluoride, may be further provided on the outer surfaces of the hole-selective transport layer 30, the electron-selective transport layer, and the passivation anti-reflection layer 11. Specifically, if the hole-selective transport layer 30 is located outermost, an anti-reflection layer is provided on the outer surface of the hole-selective transport layer; if the electron-selective transport layer is located outermost, an anti-reflection layer is provided on the outer surface of the electron-selective transport layer; and if the passivation anti-reflection layer 11 is located outermost, an anti-reflection layer is provided on the outer surface of the passivation anti-reflection layer 11.

[0148] In summary, the novel non-silicon passivated selective contact structure of the present application introduces high-quality non-silicon materials to form a strong back field or junction, enhancing asymmetric carrier transport and separation, effectively enhancing carrier extraction and passivation capabilities, and improving the selectivity coefficient. The introduction of the passivation layer provides chemical and field-effect passivation for the passivated selective contact region. In particular, chemical passivation significantly reduces interface defect states, providing a prerequisite for the high-quality field passivation provided by the selective layer. The selective transport layer can compensate for the carrier transport difficulties caused by the high resistance of the selective layer, reducing the sheet resistance and improving the FF, and is particularly suitable for local metallization. Additional hydrogen passivation gain can be introduced through other processes, such as the FGA process, to further enhance the passivation effect. The superposition of a passivation anti-reflection layer can provide additional chemical passivation gain. In this way, the synergistic effect of the passivation layer, the selective transport layer, and the passivation anti-reflection layer achieves an excellent passivation contact effect. Moreover, the use of narrow-bandgap highly doped silicon materials in the first region is eliminated, reducing optical parasitic absorption losses and improving photoelectric conversion efficiency.

[0149] An embodiment of the present application provides a method for preparing a back-contact solar cell, comprising the following steps:

[0150] S1, after forming a passivation anti-reflection layer on the back side of the silicon substrate, forming a silicon substrate exposed area on the passivation anti-reflection layer located in a first area on the silicon substrate;

[0151] S2, depositing a first passivation layer on the exposed area of ​​the silicon substrate;

[0152] S3, preparing a selective transmission layer on the first passivation layer;

[0153] S4. Metallization is performed in the first region to form a first metal electrode.

[0154] Alternatively, to simplify the process, the passivation anti-reflection layers in the first and second regions can be simultaneously opened to form the silicon substrate and exposed doped polysilicon regions, respectively. Steps S1 through S4 are then repeated to form the structure shown in Figure 15. Because 91-doped polysilicon is a degenerate or nearly degenerate semiconductor, the passivation and selectivity layers have limited impact on contact performance and do not significantly adversely affect performance, while significantly simplifying the process.

[0155] It should be noted that the overall process of the back-contact solar cell of the embodiment of the present application retains the traditional back-contact cell process to the greatest extent. Only the major changes in the process are described here. Taking the P-type back-contact cell as an example, the main differences are as follows:

[0156] In step S1, after the back aluminum oxide silicon nitride is prepared, the previous p-type BC cell laser grooving and screen printing aluminum paste process is deleted, and a grooved area is formed instead. The grooved area can adopt low-loss or non-destructive grooving technology, or can also introduce dry (such as non-destructive laser technology) and / or wet (such as corrosion-resistant mask and chemical cleaning) grooving technology;

[0157] The preparation method of depositing the first passivation layer in step S2 is varied and depends on the material selection. For example, for tunneling silicon oxide or other passivation materials, including tunneling aluminum oxide, intrinsic amorphous silicon, intrinsic silicon carbide, intrinsic nanocrystalline silicon, intrinsic microcrystalline silicon, nanocrystalline silicon oxide, microcrystalline silicon oxide, amorphous silicon oxide, silicon oxynitride, silicon oxycarbide, hafnium oxide, phosphorus oxide, boron oxide, titanium oxide, tin oxide, the preparation process may include thermal oxidation growth, nitric acid oxidation, ozone oxidation, plasma-assisted nitrous oxide oxidation, CVD, ALD, VPE, PVD, solution method; of course, it can also be a two-step or multi-step oxidation method including the above methods;

[0158] The preparation method of the selective transport layer in step S3 also selects different processes according to the characteristics of different materials; of course, different methods can also be used for some materials for preparation, which will not be elaborated in detail here. For example, the preparation method of the selective transport layer may include, but is not limited to, CVD (APCVD, LPCVD, UHVCVD, LCVD, photo-CVD, PECVD, HDPCVD, MPCVD, HTCVD, MTCVD, ICPCVD, MOCVD, HWCVD), ALD (Thermal ALD, PEALD), VPE, PVD (including thermal evaporation, electron beam evaporation, magnetron sputtering, reactive sputtering, DC sputtering, RF sputtering, ion beam sputtering, ion plating, ion beam deposition, ion assisted deposition (IAD), MBE, LPE, HWE, close space sublimation (CSS)) and solution method (including spin coating, spray coating, drip coating, meniscus coating, dipping, CBD, SILAR, electroplating, chemical plating, anodic reaction deposition);

[0159] The preparation process of the first metal electrode in step S4 includes but is not limited to PVD, CVD, electroplating, chemical plating, printing or laser transfer, etc.

[0160] The preparation process of the back contact of the embodiment of the present application is simple to operate and retains the previous process as a whole, saving costs, and the prepared battery has a good passivation contact effect.

[0161] As a feasible method, for the second region of the back-contact solar cell, the second region is a tunneling dielectric layer / doped polysilicon layer, and an electron selection layer is set on the doped polysilicon layer, and the electron selection layer is deposited on the doped polysilicon layer using a mask plate only in the groove area of ​​the second region.

[0162] The following uses specific examples to illustrate the application of the novel passivation selective contact structure of the embodiments of the present application in various types of solar cells.

[0163] Example 1

[0164] As shown in Figure 6, taking a p-type silicon substrate as an example, the silicon substrate 10 has a front side and a back side. The back side passivation selective contact region of the silicon substrate 10 includes a first passivation layer 20, a hole selective layer 31, a transport layer 32, and a first metal electrode 40 stacked from the inside out on the back side of the silicon substrate 10. The first metal electrode contacts the transport layer 32. The first passivation layer 20 covers a portion of the surface of the silicon substrate 10. The hole selective layer 31 and the transport layer cover the first passivation layer 20, and their projections on the silicon substrate surface cover a portion of the silicon substrate surface. The non-passivation selective contact region includes an aluminum oxide layer 111 and a silicon nitride layer 112. The front side passivation selective contact region of the silicon substrate 10 includes a selective emitter 70 stacked from the inside out on the surface of the silicon substrate 10, and a second metal electrode 80. The second metal electrode 80 contacts the selective emitter 70. The non-passivation selective contact region includes a light diffusion layer 92, an aluminum oxide layer 111, and a silicon nitride layer 112.

[0165] That is, the back side of the silicon substrate in the embodiment shown in FIG. 6 adopts the novel passivation selective contact structure in the embodiment of the present application.

[0166] Example 2

[0167] Different from Example 1, as shown in Figure 7, the front-side passivation selective contact area of ​​the silicon substrate 10 includes a selective emitter 70, an electron selection layer 61, and a second metal electrode 80 stacked from the inside to the outside on the surface of the silicon substrate 10. The second metal electrode 80 is in contact with the electron selection layer 61, and the projection of the electron selection layer 61 on the surface of the silicon substrate 10 covers a partial area of ​​the surface of the silicon substrate 10.

[0168] It is understood that in Examples 1 and 2, the front side of the silicon substrate 10 is a textured surface; the emitter on the front side can be a selective emitter or a non-selective emitter; at least one anti-reflection layer (ARC) can be provided outside the silicon nitride layer, the transmission layer, or the selective layer on the front and back sides of the silicon substrate;

[0169] In addition, the above-mentioned battery can also be a back-junction battery, that is, the front side is a p-region and the back side is an n-region; or the silicon substrate can also be an n-type silicon substrate; the battery structure is not specifically described and limited here.

[0170] That is, in the example shown in FIG7 , the back side of the battery adopts the novel passivation selective contact structure described in the embodiment of the present application.

[0171] In Examples 1 and 2, the aluminum back surface field in the PERL cell is replaced by the novel passivation selective contact structure of the embodiments of the present application, thereby avoiding direct contact between the metal and the silicon substrate, and avoiding damage to the silicon by the metal, reducing the recombination loss, and forming a strong built-in electric field due to the work function difference of the non-doped silicon material itself, without introducing the recombination loss caused by high doping; and the use of transmission materials with high transmittance and good transmission performance can effectively reduce the area ratio of the metal electrode, and the novel passivation selective contact structures all use high-transmittance materials with wide bandgap and low parasitic absorption, which can significantly improve the back optical utilization rate.

[0172] Example 3

[0173] As shown in FIG8 , a passivation selective contact region and a non-passivation selective contact region are provided on the front surface of the silicon substrate 10 . Among them, the passivation selective contact area on the front side of the silicon substrate 10 includes a first passivation layer 20, a hole selection layer 31, a transmission layer 32 and a first metal electrode 40 stacked from the inside to the outside on the surface of the silicon substrate 10. The projection of the first passivation layer 20 on the surface of the silicon substrate 10 covers a partial area of ​​the surface of the silicon substrate 10. The projection area of ​​the first metal electrode 40 can be equal to or smaller than the projection area of ​​the selective transmission layer. To ensure the optical utilization rate of the front side, the smaller the projection area of ​​the first metal electrode 40 is, the better without affecting the transmission performance; the non-passivation selective contact area includes an aluminum oxide layer 111 and a silicon nitride layer 112 stacked from the inside to the outside; the passivation selective contact area on the back side of the silicon substrate 10 includes a tunneling oxide layer 90, a doped polysilicon layer 91, and a second metal electrode 80 stacked from the inside to the outside on the surface of the silicon substrate 10, and the second metal electrode 80 is in contact with the doped polysilicon layer 91; the non-passivation selective contact area includes an aluminum oxide layer 111 and a silicon nitride layer 112.

[0174] It can be understood that in the embodiment shown in FIG. 8 , the front surface of the silicon substrate adopts the novel passivation selective contact structure in the embodiment of the present application.

[0175] Example 4

[0176] Different from Example 3, as shown in Figure 9, the passivation selective contact area on the back side of the silicon substrate 10 includes an electron selection layer 61 arranged on the doped polysilicon layer 91, the electron selection layer 61 covers a portion of the doped polysilicon layer 91, the projection of the electron selection layer 61 on the surface of the silicon substrate 10 covers a portion of the surface of the silicon substrate 10, and the second metal electrode 80 is in contact with the electron selection layer 61.

[0177] It can be understood that the aluminum oxide layer and the silicon nitride layer in Examples 3 and 4 can also be replaced or superimposed with at least one other anti-reflection layer with a lower refractive index, such as magnesium fluoride.

[0178] It can be understood that in the embodiment shown in FIG. 9 , the front side of the silicon substrate adopts the novel passivation selective contact structure in the embodiment of the present application.

[0179] In addition, Examples 3 and 4 can also be applied to tunneling oxygen polysilicon back field cells on N-type silicon substrates; for example, when the silicon substrate is an n-type silicon substrate and a p-type emitter is used on the front side, the hole selective transport layer 30 is arranged on the p-type emitter, and the passivation selective contact area on the back side of the silicon substrate can be a stacked tunneling oxygen layer, a doped polysilicon layer and a first metal electrode 40; for another example, when the silicon substrate is an n-type silicon substrate and a p-type emitter is used on the front side, the hole selective transport layer 30 is arranged on the p-type emitter, and the passivation selective contact area on the back side of the silicon substrate includes an electron selective layer 61, which is arranged on the doped polysilicon layer and covers a partial area of ​​the doped polysilicon layer. The projection of the electron selective layer 61 on the surface of the silicon substrate covers a partial area of ​​the surface of the silicon substrate. The embodiments of the present application no longer describe the structure in detail.

[0180] In Examples 3 and 4 above, the hole selection layer 31 can be made of either n-type or p-type material. The transport layer 32 can also be made of either p-type or n-type material, depending on the actual structure.

[0181] In Examples 3 and 4, the new passivation selective contact structure replaces the boron-doped polysilicon layer or the boron diffusion structure formed inside the silicon substrate, avoiding the recombination loss caused by the high-doping area and the insufficient transmission capacity caused by the low doping; and the new passivation selective contact structure has low optical parasitic absorption loss and can be used in conjunction with a non-burn-through metallization process, thereby eliminating the risk of burn-through of the n-region doped polysilicon layer, allowing the thickness of the doped polysilicon layer in the n-region to be thinned, thereby reducing the optical parasitic absorption loss caused by the doped polysilicon in the n-region.

[0182] Example 5

[0183] As shown in FIG10 , the front side of the silicon substrate 10 includes an aluminum oxide layer 111 and a silicon nitride layer 112 stacked from the inside out on the surface of the silicon substrate. The back side of the silicon substrate 10 includes a plurality of first regions and a plurality of second regions distributed at intervals. Each first region and each second region respectively includes a non-passivation selective contact region and a passivation selective contact region. The non-passivation selective contact region includes an aluminum oxide layer 111 and a silicon nitride layer 112 stacked from the inside out on the surface of the silicon substrate. The passivation selective contact region of the first region includes a first passivation layer 20, a hole selection layer 30 stacked from the inside out on the surface of the silicon substrate. 1. Transmission layer 32 and first metal electrode 40; the passivation selective contact region of the second region includes a tunneling dielectric layer 90, a doped polysilicon layer 91, and a second metal electrode 80 stacked from the inside out on the surface of the silicon substrate 10. The second metal electrode 80 is in contact with the doped polysilicon layer 91. The aluminum oxide layer 111 and the silicon nitride layer 112 cover the doped polysilicon layer 91 outside the projection area of ​​the second metal electrode 80. The first passivation layer 20 covers the entire surface of the silicon substrate 10 in the first region, and the projection of the hole selective layer 31 on the silicon substrate 10 covers the entire surface of the silicon substrate 10 in the first region. In other words, in the example shown in Figure 10, the first region adopts the novel passivation selective contact structure of the embodiment of the present application.

[0184] Example 6

[0185] Different from Example 5, as shown in FIG11 , the first passivation layer 20 covers a portion of the surface of the silicon substrate 10 located in the first region, and the projection of the hole selection layer 31 on the silicon substrate 10 covers a portion of the surface of the silicon substrate 10 located in the first region.

[0186] Example 7

[0187] Unlike Example 6, as shown in FIG12 , the passivation selective contact region of the second region further includes a second passivation layer 50 and an electron selective layer 61 stacked on the doped polysilicon layer 91. The second metal electrode 80 contacts the electron selective layer 61, and the projection of the electron selective layer 61 on the doped polysilicon layer 91 partially covers the doped polysilicon layer 91. In other words, in the embodiment shown in FIG12 , the first region adopts the novel passivation selective contact structure of the embodiment of the present application.

[0188] Example 8

[0189] Different from Example 6, as shown in FIG14 , the first passivation layer 20 not only covers the interface between the hole selection layer 31 and the silicon substrate 10 , but also covers the entire surface of the silicon nitride 112 and the interface between the doped polysilicon layer 91 and the second metal electrode 80 .

[0190] Example 9

[0191] Different from Example 6, as shown in FIG15 , the first passivation layer 20 covers the entire surface of the silicon nitride 112 , a hole selection layer 31 and a transport layer 32 are further provided on the first passivation layer 20 in the second region, and the first metal electrode 40 is in contact with the transport layer 32 .

[0192] It can be understood that the second passivation layer 50 in Example 7 can also cover the entire area of ​​the doped polysilicon layer 91 in the second region.

[0193] The materials of the hole selection layer 31 and the transport layer 32 can be either n-type materials or p-type materials; in some embodiments, the transport layer 32 may not be provided.

[0194] The electron selective layer 61 and the doped polysilicon layer 91 may not be provided with the second passivation layer 50 .

[0195] The embodiments of the present application further provide a solar cell assembly comprising the aforementioned solar cell, a cover plate, an adhesive film, and a back plate. It is understood that the solar cell assembly possesses all the features and advantages of the aforementioned solar cells, which will not be elaborated upon here. In general, the solar cell assembly has a high cell efficiency.

[0196] The present application also provides a solar cell system comprising the aforementioned solar cell assembly, an energy conversion device, and an energy storage device. It is understood that the solar cell system possesses all the features and advantages of the aforementioned solar cells, which will not be further elaborated here. In general, the solar cell system has a high cell efficiency.

[0197] It should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used above to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0198] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features having similar functions disclosed in this application.

Claims

1. A novel passivation selective contact structure, characterized in that: include: A silicon substrate, wherein the surface of the silicon substrate includes the front side of the silicon substrate and / or the back side of the silicon substrate, and the surface of the silicon substrate includes a passivation selective contact region and a non-passivation selective contact region; The non-passivation selective contact region includes a passivation anti-reflection layer disposed on the surface of the silicon substrate; The passivation selective contact region includes a passivation layer, a selective transmission layer and a metal electrode which are sequentially stacked from the inside to the outside.

2. The novel passivation selective contact structure according to claim 1, characterized in that: In the case where the back side of the silicon substrate includes the passivation selective contact area and the non-passivation selective contact area, the back side includes a plurality of first areas and a plurality of second areas arranged at intervals, the first area includes the passivation selective contact area and the non-passivation selective contact area, wherein in the first area, the passivation layer is the passivation layer of the first area, and the metal electrode is a first metal electrode.

3. The novel passivation selective contact structure according to claim 2, characterized in that: The second region includes a tunnel dielectric layer, a doped polysilicon layer and a second metal electrode stacked from the inside out on the surface of the silicon substrate.

4. The novel passivation selective contact structure according to claim 2 or 3, characterized in that: The second region further includes a passivation layer of the second region; and / or the second region further includes the selective transmission layer, the passivation layer of the second region is the same as or different from the passivation layer of the first region, and the selective transmission layer of the second region is different from the selective transmission layer of the first region.

5. The novel passivation selective contact structure according to claim 2, characterized in that: The silicon substrate in the second region includes an N-type doped layer, and the selective transport layer in the first region includes a hole selection layer and an electron transport layer.

6. The back contact solar cell according to claim 3, characterized in that The first metal electrode and the second metal electrode are formed by at least one process selected from the group consisting of printing, PVD, electroplating, and chemical plating; And / or, the first metal electrode and the second metal electrode are formed in the same process; And / or, each of the first metal electrode and the second metal electrode includes at least one of silver, copper, aluminum, nickel, chromium, molybdenum, indium and tin.

7. The novel passivation selective contact structure according to any one of claims 1 to 6, characterized in that: Based on the projection on the surface of the silicon substrate, the projection of the passivation layer covers a part or all of the surface of the silicon substrate, and the projection of the selective transmission layer covers a part or all of the surface of the silicon substrate; Alternatively, the projected area of ​​the passivation layer is greater than or equal to the projected area of ​​the selective transmission layer; Alternatively, the projected area of ​​the selective transmission layer is greater than or equal to the projected area of ​​the metal electrode.

8. The novel passivation selective contact structure according to claim 4, characterized in that: Based on the projection on the surface of the silicon substrate, the projection of the passivation layer in the first region covers the entire area or a portion of the surface of the silicon substrate located in the first region, and the projection of the selective transmission layer in the first region covers the entire area or a portion of the surface of the silicon substrate located in the first region; or The projection of the passivation layer in the second region covers the entire or partial area of ​​the silicon substrate surface in the second region, and the projection of the selective transmission layer in the second region covers the entire or partial area of ​​the silicon substrate surface in the second region.

9. The novel passivation selective contact structure according to any one of claims 1 to 8, characterized in that: The passivation anti-reflection layer includes aluminum oxide and silicon nitride layers stacked from the inside out.

10. The novel passivation selective contact structure according to any one of claims 1 to 9, characterized in that: The thickness of the passivation layer is 0.1-300 nm.

11. The novel passivation selective contact structure according to any one of claims 1 to 10, characterized in that: The selective transport layer includes a hole selective transport layer or an electron selective transport layer; the hole selective transport layer includes a hole selective layer, or a hole selective layer and a hole transport layer stacked from the inside to the outside, or a hole selective layer and an electron transport layer stacked from the inside to the outside; the electron selective transport layer includes an electron selective layer, or an electron selective layer and a hole transport layer stacked from the inside to the outside, or an electron selective layer and an electron transport layer stacked from the inside to the outside.

12. The novel passivation selective contact structure according to claim 11, characterized in that: The hole selection layer is selected from materials with a work function greater than 4.8 eV, or a valence band gap ΔE V A material with a V of less than 0.5 eV, or a monomolecular layer material; the hole transport layer is selected from at least one of doped or intrinsic oxides, nitrides, carbides, oxynitrides, carbon oxides, carbonitride oxides, chalcogenides, halides, thiocyanates and organic conductive polymers; The electron selective layer is selected from materials with a work function less than 4.2 eV, or a conduction band gap ΔE C A material with a lattice strength of less than 0.5 eV, or an organic conductive polymer; the electron transport layer is selected from at least one of doped or intrinsic oxides, nitrides, carbides, oxynitrides, carbon oxides, carbonitride oxides, chalcogenides, halides, or organic conductive polymers.

13. The novel passivation selective contact structure according to claim 11, characterized in that: The hole selection layer is selected from at least one of doped or intrinsic molybdenum oxide, vanadium oxide, tungsten oxide, chromium oxide, titanium oxide, copper oxide, nickel oxide, cobalt oxide, rhenium oxide, copper iodide, PEDOT:PSS, silicon carbide, silicon oxycarbide and a phosphate group monolayer; The hole transport layer is selected from at least one of doped or intrinsic nickel oxide, copper oxide, copper iodide, copper thiocyanate, thienyl, PEDOT:PSS, PTAA, Spiro-OMeTAD and fluorinated indoprofen derivatives; The electron selective layer is selected from at least one of doped or intrinsic lithium fluoride, magnesium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, cerium fluoride, europium fluoride, tantalum oxide, zinc oxide, indium oxide, titanium oxide, magnesium oxide, zinc oxide, tin oxide, cesium oxide, niobium oxide, barium oxide, tantalum nitride, titanium nitride, titanium oxynitride, silicon carbide, cesium chloride, cesium bromide, cesium iodide, cesium carbonate, potassium carbonate, rubidium carbonate, calcium carbonate, strontium carbonate, barium carbonate, zinc sulfide, cadmium sulfide, indium sulfide, fullerene derivatives and bathocuproine; The electron transport layer is selected from at least one of doped or intrinsic zinc oxide, indium oxide, tin oxide, titanium oxide, cadmium sulfide, cadmium selenide, fullerene derivatives and bathocuproine.

14. The novel passivation selective contact structure according to any one of claims 1 to 13, characterized in that: The passivation layer is selected from at least one of silicon oxide, silicon oxynitride, aluminum oxide, phosphorus oxide, boron oxide, hafnium oxide, silicon carbide, titanium oxide, tin oxide, amorphous silicon, microcrystalline silicon and nanocrystalline silicon.

15. The novel passivation selective contact structure according to claim 11, characterized in that: The thickness of the hole selective transport layer is 0.1-700 nm, and the thickness of the passivation anti-reflection layer is 0-525 nm; Alternatively, the thickness of the electron selective transport layer is 0.1-700 nm.

16. A solar cell, characterized in that: The invention comprises the novel passivation selective contact structure as described in any one of claims 1 to 15.

17. A solar cell module, characterized in that: The solar cell, cover plate, adhesive film and back plate described in claim 16 are included.

18. A solar cell system, characterized in that: It comprises a solar cell assembly, an energy conversion device and an energy storage device as described in claim 17.

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