CN210668381U

CN210668381U - Silicon-based laminated solar cell

Info

Publication number: CN210668381U
Application number: CN201922380983.7U
Authority: CN
Inventors: 康海涛; 胡燕; 吴中亚; 郭万武
Original assignee: Jetion Solar Jiangsu Co Ltd
Current assignee: China building materials Junxin (Tongcheng) Technology Co., Ltd
Priority date: 2019-12-26
Filing date: 2019-12-26
Publication date: 2020-06-02
Anticipated expiration: 2029-12-26

Abstract

The utility model relates to a silicon-based laminated solar cell, which comprises a top cell, a bottom cell and a composite layer; the top cell is a perovskite solar cell; the bottom battery is a silicon-based solar battery; the composite layer is between the bottom cell and the top cell; and the composite layer connects the bottom cell and the top cell in series. The composite layer is made of indium tin oxide, fluorine-doped tin oxide, indium zinc oxide or aluminum-doped zinc oxide. The utility model provides a whole stromatolite solar cell passes through the composite bed and establishes ties, reduces the preparation of middle electrode, and process flow is simple to be fit for the volume production.

Description

Silicon-based laminated solar cell

Technical Field

The utility model relates to a solar cell field, concretely relates to silica-based stromatolite solar cell.

Background

At present, a silicon-based solar cell is a mainstream product in the photovoltaic industry, and with the continuous development and innovation of the solar cell technology, the conversion efficiency of a silicon-based single solar cell is close to the theoretical limit of Shockley-Queisser photovoltaic conversion efficiency; in order to meet the development trend of continuously reducing cost and improving efficiency in the photovoltaic industry and realize the goal of low-price internet access in the early days, a solar cell with a novel structure needs to be developed and designed. Wherein the laminated solar cell can not be limited by theoretical limit of Shockley-Queisser conversion efficiency. The laminated solar cell consists of two solar cells which are divided into a top cell and a bottom cell; the top and bottom cells have two materials with different forbidden band widths, which can absorb the sunlight of different wave bands, greatly improving the light utilization rate, and the conversion efficiency can reach 45 percent at most. The types and the structures of the laminated solar cell can be designed to be various, various laminated solar cells can be designed through gallium arsenide, CIGS and amorphous silicon film substrates, but the characteristics of complex process steps, immature and unstable technology, small process window, high manufacturing cost and the like exist, and industrialization is difficult to realize. Therefore, a stacked solar cell which is applicable to industrialization, simple in process and low in manufacturing cost is particularly needed to solve the above problems.

SUMMERY OF THE UTILITY MODEL

Not enough to prior art, the utility model discloses a silica-based stromatolite solar cell.

The utility model discloses the technical scheme who adopts as follows:

a silicon-based laminated solar cell comprises a top cell, a bottom cell and a composite layer; the top cell is a perovskite solar cell; the bottom battery is a silicon-based solar battery; the composite layer is between the bottom cell and the top cell; and the composite layer connects the bottom cell and the top cell in series.

The composite layer is made of indium tin oxide, fluorine-doped tin oxide, indium zinc oxide or aluminum-doped zinc oxide.

The further technical scheme is that the bottom battery comprises a silicon substrate; p on the front surface of the silicon substrate⁺Doping layer; SiO is sequentially arranged on the back surface of the silicon substrate₂A layer and a phosphorus doped polysilicon layer.

The further technical proposal is that SiO₂The thickness of the layer is 2-5 nm.

The further technical scheme is that the thickness of the phosphorus-doped polycrystalline silicon layer is 50-80 nm.

The further technical scheme is that the top battery comprises a perovskite layer; an electron transport layer is arranged on the back of the perovskite layer; a hole transport layer is provided on the front side of the perovskite layer.

The further technical scheme is that the thickness of the perovskite layer is 200-400 nm.

The further technical proposal is that the electron transmission layer comprises first TiO₂A thin film layer and a second TiO₂A thin film layer; the second TiO₂The thin film layer is of a mesoporous structure.

The further technical proposal is that the first TiO is₂The thickness of the thin film layer is 20-30 nm; the second TiO₂The thickness of the thin film layer is 50-70 nm.

The further technical scheme is that the thickness of the hole transport layer is 100 nm.

The further technical scheme is that front transparent conductive glass is prepared on the outer side of the top battery, and back transparent conductive glass is prepared on the outer side of the bottom battery; preparing an upper electrode on the front transparent conductive glass; and a lower electrode is prepared on the back transparent conductive glass.

The utility model has the advantages as follows:

1) the utility model is a tandem type silicon-based laminated double-sided solar structure, which uses a silicon-based solar cell with high industrialization degree as a bottom cell and has the characteristics of wide raw material source, simple process steps, low manufacturing cost and the like; the top battery adopts a perovskite battery, the process is simple and mature, the manufacturing cost is low, the forbidden band width is adjustable, the short-wave light absorption is high, the whole manufacturing process is carried out under the low-temperature condition (less than 300 ℃), the bottom battery cannot be damaged, and the quality of the bottom battery is ensured. The silicon-based laminated solar cell is connected in series, an intermediate electrode does not need to be additionally manufactured, the process steps are simple, the integration level is high, and later-stage component packaging is facilitated.

2) The utility model discloses a N type crystal silicon battery combines to combine tunneling oxide layer passivation contact technique to form end battery, N type crystal silicon battery has the light decay and reduces, resistant metallic impurity pollution performance is good, the process technology is mature, advantages such as photoelectric conversion is efficient and commercialization degree is high, and combine tunneling oxide layer passivation contact technique can provide good back of the body passivation, ultra-thin oxide layer can make many son electron tunneling get into the polycrystalline silicon layer and block minority hole recombination simultaneously, and then the electron is collected by the metal at polycrystalline silicon layer lateral transport, thereby greatly reduced metal contact combined current, the open circuit voltage and the short circuit current of battery have been promoted.

3) The utility model discloses a perovskite battery is as a top battery, and perovskite battery has advantages such as forbidden band width continuously adjustable, light absorption coefficient height, photon circulated and good charge transport nature, and the film material forbidden band width of preparation is adjustable, and it is wide with the end battery matching degree window of N type, but low-cost deposit perovskite film battery and preparation temperature are low, do not harm end battery in the preparation process.

4) The electron transport layer in the top cell adopts TiO with double layers and different structures₂The design can enhance the structural stability of the top cell and the TiO with a mesoporous structure besides playing the role of electron transmission₂Reflection can be increased to enable secondary light absorption by the top cell, thereby increasing the short circuit current of the whole laminated cell.

5) The whole laminated solar cell is connected in series, so that the preparation of intermediate electrodes is reduced, the process flow is simple and the method is suitable for mass production; and the two sides of the solar cell can absorb sunlight, so that the light utilization rate is improved, and the photoelectric conversion efficiency of the whole laminated solar cell is further improved.

Drawings

Fig. 1 is a schematic structural diagram of a silicon-based tandem solar cell.

Fig. 2 is an equivalent circuit diagram of a silicon-based tandem solar cell structure.

In the figure: 1. a lower electrode; 2. back transparent conductive glass; 3. doping a phosphorus polysilicon layer; 4. a layer of SiO 2; 5. a silicon substrate; 6. p⁺Doping layer; 7. compounding layers; 8. first TiO2₂A thin film layer; 9. second TiO₂A thin film layer; 10A perovskite layer; 11. a hole transport layer; 12. front transparent conductive glass; 13. an upper electrode; 14. a bottom cell; 15. and a top battery.

Detailed Description

The utility model discloses a silica-based stromatolite solar cell structure.

Fig. 1 is a schematic structural diagram of a silicon-based tandem solar cell. As shown in fig. 1, the silicon-based tandem solar cell mainly comprises a top cell 15, a bottom cell 14 and a recombination layer 7. The top cell 15 is a perovskite solar cell. The bottom cell 14 is a silicon-based solar cell. The composite layer 7 is prepared between the bottom cell 14 and the top cell 15. And the composite layer 7 connects the bottom cell 14 and the top cell 15 in series without additional fabrication of an intermediate electrode.

The material of the composite layer 7 is preferably Indium Tin Oxide (ITO) or fluorine-doped SnO₂(FTO), Indium Zinc Oxide (IZO), or aluminum-doped zinc oxide (AZO).

A front transparent conductive glass 12(TCO) is also prepared on the outside of the top cell 15 and a back transparent conductive glass 2 is also prepared on the outside of the bottom cell 14. An upper electrode 13 is also prepared on the front transparent conductive glass 12. A lower electrode 1 is also prepared on the back transparent conductive glass 2.

Specifically, the bottom cell 14 includes a silicon substrate 5. The silicon substrate 5 is an N-type silicon substrate.

P is formed on the front surface of the silicon substrate 5⁺And (3) doping the layer 6. P⁺The dopant of doped layer 6 is preferably boron. P⁺The doped layer 6 forms a pn junction with the silicon substrate 5. P⁺The sheet resistance of the doped layer 6 is 80-150 Ω/□. SiO is sequentially prepared on the back of the silicon substrate 5₂Layer 4 and a phosphorus doped polysilicon layer 3. SiO2₂The thickness of the layer 4 is preferably 2 to 5 nm. The thickness of the phosphorus-doped polysilicon layer 3 is preferably 50 to 80 nm.

The top cell 15 includes a perovskite layer 10. The composition of the perovskite layer 10 is CH₃NH₃PbI₃The thickness is preferably 200 to 400 nm.

On the back of the perovskite layer 10 there is an electron transport layer. The electron transport layer comprises a first TiO₂A thin film layer 8 and a second TiO2 thin film layer 9. Second TiO₂The thin film layer 9 has a mesoporous structure. First, theTiO2₂The thickness of the thin film layer 8 is preferably 20-30 nm. The thickness of the second TiO2 thin film layer 9 is preferably 50-70 nm.

A hole transport layer 11 is prepared on the front surface of the perovskite layer 10. The composition of the hole transport layer 11 is 2,2',7,7' -tetrakis [ N, N-bis (4-methoxyphenyl) amino ] -9,9' -spirobifluorene (Spiro-OMeTAD), and the thickness of the hole transport layer 11 is preferably 100 nm.

Fig. 2 is an equivalent circuit diagram of a silicon-based tandem solar cell structure. As shown in fig. 2, the resistor Rs and the resistor R are respectively a series resistor and an external load of the tandem cell, and the two diodes are respectively: in the diode model of the top-bottom battery unijunction cell, the resistor Rsh1 is the parallel resistor of the top battery 13, the resistor Rsh2 is the parallel resistor of the bottom battery 14, and the resistor Rt is the equivalent resistor of the composite layer 7. As shown in fig. 2, the top cell 13 and the bottom cell 14 are connected in series by the composite layer 7.

The method for manufacturing the silicon-based laminated solar cell disclosed by the utility model comprises the following steps:

step one, surface cleaning and texturing. The silicon substrate 5 is a silicon wafer of N type. Cleaning the surface of the silicon substrate 5; and forming pyramid shape on the surface of the silicon substrate 5 by etching. Cleaning and damaging the surface of the silicon substrate 5 by using a low-concentration alkali solution, and corroding the surface of the silicon substrate 5 to form a pyramid-shaped surface appearance, wherein the weight percentage of the alkali solution in the corrosion reaction is 1.0-1.5 wt% of NaOH, the reaction time is 300-400 s, and the reaction temperature is 80-90 ℃. The reflectivity of the surface of the silicon substrate 5 after the reaction is 11-12%;

and step two, front boron diffusion. Adopting a thermal diffusion, spin coating or spray coating method to carry out boron diffusion on the front surface of the silicon substrate 5 to prepare P⁺Doped layer 6, P⁺The doped layer 6 and the silicon substrate 5 form a pn junction. P⁺The sheet resistance of the doped layer 6 is 80-150 Ω/□.

And step three, wet etching of the back. And protecting the front surface of the silicon substrate 5 by adopting a water film, enabling the back surface of the silicon substrate 5 to downwards float in an HF solution, corroding the lower surface and the edge of the silicon substrate 5 treated in the step two by utilizing an HF acid solution, and removing the P-type silicon on the edge of the silicon substrate 5 to enable the upper surface and the lower surface of the silicon substrate 5 to be mutually insulated. And polishing the back surface of the silicon substrate 5 by using KOH and a polishing additive, wherein the reflectivity of the back surface of the silicon substrate 5 after the polishing is 40-45%.

Step four, depositing SiO on the back₂And (4) a layer. Preparation of SiO Using LPCVD₂And (4) a layer. SiO is preferred₂The thickness of the layer 4 is 2 to 5 nm.

And step five, depositing a phosphorus-doped polycrystalline silicon layer 3 on the back surface. The phosphorus-doped polysilicon layer 3, i.e., the N + -poly-Si thin film, is prepared using LPCVD. Can select PH₃And SiH₄As a reactant. The thickness of the phosphorus-doped polycrystalline silicon layer 3 is preferably 50-80 nm. Step five provides good back surface passivation by tunnel oxide passivation contact technology.

Sixthly, removing borosilicate glass (BSG) and/or phosphorosilicate glass (PSG). And under the condition of room temperature, etching the front surface of the silicon substrate 5 by using 49% HF acid solution, and removing borosilicate glass and/or phosphorosilicate glass on the front surface of the silicon substrate 5.

And step seven, preparing the composite layer 7. The composite layer 7 is prepared on the front surface of the bottom battery 14 by adopting an atomic deposition (ALD) method, a magnetron sputtering method, a thermal evaporation method or a Chemical Vapor Deposition (CVD) method. The material of the composite layer 7 is preferably Indium Tin Oxide (ITO), fluorine-doped SnO2(FTO), Indium Zinc Oxide (IZO), or aluminum-doped zinc oxide (AZO). The thickness of the composite layer 7 is preferably 10 to 30 nm.

And step eight, preparing the electron transport layer. The preparation method of the electron transport layer comprises the following steps:

preparation of first TiO Using ALD method₂Thin film layer 8, first TiO₂The thickness of the thin film layer 8 is preferably 20-30 nm;

the second TiO2 thin film layer 9 was prepared using a CVD method or a magnetron sputtering method. The second TiO2 thin film layer 9 is of a mesoporous structure, and the thickness of the second TiO2 thin film layer 9 is preferably 50-70 nm.

And step nine, preparing the perovskite layer 10. Prepared by co-evaporation method on the electron transport layer. Under the vacuum condition, PbI is added₂And CH₃NH₃I, gas phase co-evaporation deposition, wherein CH with the particle size of 200-400 nm is generated by deposition₃NH₃PbI₃As a perovskite layer 10.

Step ten, preparing the hole transport layer 11. 100nm of 2,2',7,7' -tetrakis [ N, N-bis (4-methoxyphenyl) amino ] -9,9' -spirobifluorene (Spiro-OMeTAD) was deposited as the hole transport layer 11 by a spin coating method on the perovskite layer 10.

Step eleven, preparing front transparent conductive glass 12 on the outer side of the top cell 15 and preparing back transparent conductive glass 2 on the outer side of the bottom cell 14 by a magnetron sputtering method or a PVD method. The thicknesses of the front transparent conductive glass 12 and the back transparent conductive glass 2 are preferably 70-80 nm.

And a twelfth step of preparing an upper electrode 13 on the front transparent conductive glass 12. A lower electrode 1 is prepared on the back transparent conductive glass 2. And finishing the whole solar cell preparation.

The utility model discloses a range upon range of solar cell of silica-based to N type solar cell combines the passivation of tunneling oxide layer contact technique to form end battery, uses perovskite solar cell as the top battery. The two solar cells are combined in a series connection mode, and specifically, the two solar cells are connected in series through a composite layer to form a silicon-based series-connection type laminated double-sided solar cell.

The crystalline silicon solar cell has the characteristics of wide raw material source, simple and mature process steps, large process window, low manufacturing cost and the like; the perovskite material has the characteristics of adjustable forbidden band width, high light absorption in a short wave part, simple process, low manufacturing cost and the like, the laminated solar cell based on the silicon-based solar cell as a bottom cell and the perovskite cell as a top cell structure is one of the laminated solar cells which are most hopeful to realize commercialization, and the light absorption can be increased to the maximum extent and the generated energy can be increased by combining the crystalline silicon solar cell and the perovskite cell.

In this context, according to the general notation in the field of semiconductors and solar cells, use + stands for the doping level, P⁺Representing heavily doped P-type semiconductor. The doping of the N-type semiconductor can be analogized.

The above description is for the purpose of explanation and not limitation of the invention, which is defined in the claims, and any modifications may be made without departing from the basic structure of the invention.

Claims

1. A silicon-based tandem solar cell, characterized by comprising a top cell (15), a bottom cell (14) and a recombination layer (7); the top cell (15) is a perovskite solar cell; the bottom cell (14) is a silicon-based solar cell; the composite layer (7) is between the bottom cell (14) and the top cell (15); and the composite layer (7) connects the bottom cell (14) and the top cell (15) in series.

2. The silicon-based tandem solar cell according to claim 1, wherein the material of the composite layer (7) is indium tin oxide, fluorine-doped tin oxide, indium zinc oxide or aluminum-doped zinc oxide.

3. The silicon-based tandem solar cell according to claim 1, wherein said bottom cell (14) comprises a silicon substrate (5); p is arranged on the front surface of the silicon substrate (5)⁺A doped layer (6); SiO is sequentially arranged on the back surface of the silicon substrate (5)₂A layer (4) and a phosphorus doped polysilicon layer (3).

4. The silicon-based tandem solar cell according to claim 3, wherein SiO is₂The thickness of the layer (4) is 2-5 nm.

5. The silicon-based laminated solar cell according to claim 3, wherein the thickness of the phosphorus-doped polysilicon layer (3) is 50-80 nm.

6. The silicon-based tandem solar cell according to claim 1, wherein the top cell (15) comprises a perovskite layer (10); an electron transport layer is arranged on the back of the perovskite layer (10); a hole transport layer (11) is provided on the front surface of the perovskite layer (10).

7. The silicon-based tandem solar cell according to claim 6, wherein the thickness of the perovskite layer (10) is 200-400 nm.

8. The silicon-based tandem solar cell according to claim 6, wherein the electron transport layer comprises a first TiO₂A thin film layer (8) and a second TiO₂A film layer (9); the second TiO₂The thin film layer (9) is of a mesoporous structure.

9. The silicon-based tandem solar cell according to claim 8, wherein the first TiO is₂The thickness of the thin film layer (8) is 20-30 nm; the second TiO₂The thickness of the thin film layer (9) is 50-70 nm.

10. The silicon-based tandem solar cell according to claim 1, characterized in that a front transparent conductive glass (12) is prepared on the outside of the top cell (15) and a back transparent conductive glass (2) is prepared on the outside of the bottom cell (14); an upper electrode (13) is prepared on the front transparent conductive glass (12); and a lower electrode (1) is prepared on the back transparent conductive glass (2).