TOPCon assembly based on lamination optimization and preparation method thereof

Abstract

The invention provides a TOPCon assembly based on lamination optimization and a preparation method of the TOPCon assembly. The TOPCon assembly comprises a substrate, a tunneling oxide layer, a polycrystalline silicon layer, a lamination structure and an electrode which are sequentially laminated, the preparation method comprises the following steps. S1, performing treatment by adopting a cleaning and surface treatment process; s2, depositing a tunneling oxide layer; s3, depositing a polycrystalline silicon layer; s4, preparing a laminated structure, performing a step-by-step deposition process on each sub-layer, and realizing connection between the sub-layers through quantum tunneling interface treatment; at least one sub-layer comprises a nano photonic crystal structure; and S5, preparing an electrode on the laminated structure. By adopting a nanometer photonic crystal structure, a photonic band gap can be formed in a specific wavelength range, absorption and utilization of light with a specific wavelength are enhanced, and the photoelectric conversion efficiency is further improved. Meanwhile, due to the cubic lattice structure, light capture and utilization are more efficient, and efficient selective transmission of carriers is finally achieved.

Description

Technical Field

[0001] The present invention particularly relates to a TOPCon component based on stacking optimization and a preparation method thereof. Background Art

[0002] In today's era of profound changes in the global energy landscape, the development and utilization of solar energy, as an inexhaustible clean energy, has attracted much attention.

[0003] TOPCon solar cells occupy an important position in the field of solar cells with their outstanding performance potential. However, existing TOPCon modules still have room for improvement in many aspects. On the one hand, traditional single-structure modules are difficult to fully capture sunlight of different wavelengths, resulting in limited photoelectric conversion efficiency. On the other hand, existing preparation methods often have problems such as complex processes, high costs, and poor stability, which seriously restrict the widespread application and further development of TOPCon technology. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a TOPCon component based on stacking optimization and a preparation method thereof. On the basis of the existing tunneling oxide layer passivation contact technology, the selective absorption capability of sunlight is enhanced through stacking technology.

[0005] Specifically, the present invention discloses a TOPCon component based on stack optimization, including a substrate, a tunneling oxide layer, a polysilicon layer, a stack structure and an electrode laminated in sequence;

[0006] A substrate, wherein the substrate is a high-purity silicon wafer, and a regularly arranged microstructure is provided on the surface of the substrate, wherein the microstructure is used for scattering light;

[0007] A tunneling oxide layer grown on the substrate;

[0008] a polysilicon layer, deposited on the tunnel oxide layer;

[0009] A stacked structure, disposed on the polysilicon layer, the stacked structure consisting of a plurality of sub-layers of different materials, wherein at least one sub-layer comprises a nanophotonic crystal structure;

[0010] The electrode is prepared on the laminated structure.

[0011] In order to improve the absorption of light sources with a specified wavelength, the nanophotonic crystal structure is a three-dimensional periodic dielectric structure composed of alternating high-refractive index materials and low-refractive index materials.

[0012] In order to enhance the capture and scattering of light and improve the light absorption efficiency, the microstructure on the surface of the substrate is formed by laser etching, chemical etching or a combination of these methods.

[0013] The preparation method of the TOPCon component based on stacking optimization for the above structure comprises the following steps;

[0014] S1, treating a high-purity custom silicon substrate using a cleaning and surface treatment process, and then forming a surface microstructure array on the substrate;

[0015] S2, growing a tunnel oxide layer on the treated substrate using plasma enhanced atomic layer deposition technology;

[0016] S3, depositing a polysilicon layer having a unique crystal orientation distribution and a doping concentration gradient on the tunnel oxide layer by a vapor deposition process;

[0017] S4, preparing a stacked structure, wherein each sublayer is deposited step by step, and the sublayers are connected by quantum tunneling interface treatment;

[0018] S5. Prepare electrodes on the laminated structure.

[0019] Among them, the nanophotonic crystal structure is designed as a three-dimensional periodic dielectric structure, which is composed of alternating high refractive index materials and low refractive index materials. For example, silicon (high refractive index) and silicon dioxide (low refractive index) can be alternately stacked. The three-dimensional periodic dielectric structure is a cubic lattice structure composed of multiple units, each of which consists of a silicon sphere and a silicon dioxide shell surrounding it, and multiple such units are arranged periodically in three-dimensional space. This structure can form a photonic band gap within a specific wavelength range, enhancing the absorption and utilization of light of a specific wavelength.

[0020] The preparation of the nanophotonic crystal structure includes the following steps:

[0021] S11. Material preparation

[0022] Prepare high-purity silicon wafers and silicon dioxide targets;

[0023] S12. Preparation of self-assembled colloidal crystal templates

[0024] Monodisperse polystyrene microspheres are synthesized by emulsion polymerization and dispersed in water to form a uniform colloidal solution. The colloidal solution is deposited on the laminated structure surface of the TOPCon component by vertical deposition or spin coating, so that the polystyrene microspheres self-assemble to form a three-dimensional periodic colloidal crystal template;

[0025] S13, silicon layer deposition

[0026] The chemical vapor deposition method is used to deposit silicon in the pores of the template using silane as a precursor. The thickness of the silicon layer is controlled by adjusting the deposition temperature, gas flow rate and deposition time.

[0027] S14, silicon dioxide layer deposition

[0028] Switch the gas source, introduce oxygen, and deposit silicon dioxide on the surface of the silicon layer. Also, adjust the deposition parameters to control the thickness of the silicon dioxide layer.

[0029] S15, template removal

[0030] The polystyrene microsphere template is removed by high temperature annealing or chemical solvent immersion, leaving behind a nanophotonic crystal structure composed of alternating silicon and silicon dioxide.

[0031] The cleaning in step S1 includes ultrasonic cleaning, organic solvent immersion, and plasma cleaning. The electrode is prepared by printing nano silver paste.

[0032] Beneficial effects:

[0033] This scheme uses a nanophotonic crystal structure, which is composed of high-refractive-index silicon and low-refractive-index silicon dioxide arranged alternately to form a three-dimensional periodic dielectric structure. This structure can form a photonic band gap within a specific wavelength range, enhance the absorption and utilization of light of a specific wavelength, and further improve the photoelectric conversion efficiency. At the same time, each unit in the cubic lattice structure is composed of a silicon sphere and a silicon dioxide shell, and multiple units are arranged periodically in three-dimensional space, making the capture and utilization of light more efficient.

[0034] Secondly, the unique design of the polysilicon layer in this solution can optimize the carrier transmission path and improve the carrier collection efficiency, thus playing a positive role in improving the photoelectric conversion efficiency. At the same time, the tunneling oxide layer grown by plasma enhanced atomic layer deposition technology has a precisely controllable nanometer-level thickness and ultra-high uniformity, which can achieve efficient and selective transmission of carriers. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a process flow chart for preparing TOPCon components based on stacking optimization.

[0036] Figure 2 It is a process flow chart of preparing a sublayer having a nanophotonic crystal structure. DETAILED DESCRIPTION

[0037] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with embodiments and drawings. The embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0038] Embodiment 1:

[0039] 1. Select high-purity n-type silicon wafers with a resistivity of 1Ω·cm as substrate materials. Prepare silicon dioxide targets and silane (SiH4) and oxygen (O2) gas sources for chemical vapor deposition. At the same time, prepare nanosilver paste for electrode preparation.

[0040] 2. Substrate Processing

[0041] First, cleaning is performed: the silicon wafer is sequentially subjected to ultrasonic cleaning, cleaned in deionized water for 15 minutes, then immersed in an organic solvent (such as acetone) for 10 minutes, and finally subjected to plasma cleaning for 5 minutes.

[0042] The surface microstructure array is formed on the substrate by combining laser etching with chemical etching. The specific operation is as follows: the silicon wafer is etched with a laser of 532nm wavelength to form a preliminary microstructure, and then the silicon wafer is placed in a chemical etching solution (a mixed solution of hydrofluoric acid and nitric acid with a volume ratio of 1:3) for etching. The etching time is adjusted to 30 minutes and the temperature is 30°C to make the microstructure more regular and uniform. The final microstructure size is 500nm-1μm, which can effectively scatter light. According to tests, this microstructure can increase the scattering rate of incident light to 30%, thereby increasing the propagation path of light in the component and improving the light absorption efficiency.

[0043] 3. Tunneling Oxide Growth

[0044] The tunnel oxide layer was grown on the treated substrate using plasma enhanced atomic layer deposition technology. The reaction temperature was controlled to be 300°C, the plasma power was 100W, and the flow rates of silane and oxygen were 10sccm and 5sccm respectively. The growth time was 30 minutes, and a tunnel oxide layer with a thickness of 2nm was obtained. The oxide layer has high uniformity and good carrier selective transport performance. According to theoretical analysis, this tunnel oxide layer can reduce the carrier recombination rate to less than 10%, thereby significantly improving the open circuit voltage and fill factor of the solar cell.

[0045] 4. Polysilicon layer deposition

[0046] A polysilicon layer with a unique crystal orientation distribution and doping concentration gradient is deposited on the tunnel oxide layer by a low-pressure chemical vapor deposition process. The deposition temperature is controlled to be 600°C, the pressure is 100Pa, and the silane flow rate is 20sccm. The deposition time is 60 minutes, and a polysilicon layer with a thickness of 100nm is obtained. This polysilicon layer can optimize the carrier transmission path and improve the carrier collection efficiency. According to simulation calculations, this polysilicon layer can increase the carrier collection efficiency to more than 90%.

[0047] 5. Preparation of laminated structure

[0048] Nanophotonic crystal structure preparation:

[0049] S12: Monodisperse polystyrene microspheres with a diameter of 200 nm were synthesized by emulsion polymerization. The polystyrene microspheres were dispersed in water to form a colloidal solution with a concentration of 5%. The colloidal solution was deposited on the laminated structure surface of the TOPCon component by vertical deposition, so that the polystyrene microspheres self-assembled to form a three-dimensional periodic colloidal crystal template.

[0050] S13: using chemical vapor deposition method, using silane as a precursor, to deposit silicon in the pores of the template. The deposition temperature is controlled to be 500° C., the silane flow rate is 15 sccm, and the deposition time is 45 minutes, so as to obtain a silicon layer with a thickness of 50 nm.

[0051] S14: Switch the gas source, introduce oxygen, and deposit silicon dioxide on the surface of the silicon layer. Control the deposition temperature to 400° C., the oxygen flow rate to 10 sccm, and the deposition time to 40 minutes to obtain a silicon dioxide layer with a thickness of 50 nm.

[0052] S15: The polystyrene microsphere template is removed by high temperature annealing at 500°C for 60 minutes, leaving a nanophotonic crystal structure composed of alternating silicon and silicon dioxide. According to optical simulation, the nanophotonic crystal structure can increase the light absorption rate within a specific wavelength range to more than 40%, thereby further improving the photoelectric conversion efficiency of the solar cell.

[0053] Preparation of other sub-layers: According to the design requirements, sub-layers of other different materials are deposited in sequence by physical vapor deposition and other methods, and the sub-layers are connected through quantum tunneling interface treatment.

[0054] 6. Electrode Preparation

[0055] Electrodes were prepared by printing nanosilver paste on the laminated structure. The paste viscosity was controlled to be 50Pa·s and the printing pressure was 100Pa. The electrode pattern was printed on the component by screen printing technology, and then dried and sintered to obtain an electrode with good conductivity and stability. After testing, the resistance of the electrode can be reduced to below 0.01 ohms, which improves the current collection efficiency.

[0056] The TOPCon module based on stacking optimization prepared through the above steps can achieve a photoelectric conversion efficiency of more than 25%, has good stability and reliability, and an expected service life of more than 25 years.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. TOPCon components based on stack-up optimization, characterized in that: It includes a substrate, a tunnel oxide layer, a polysilicon layer, a stacked structure and an electrode which are laminated in sequence; A substrate, wherein the substrate is a high-purity silicon wafer, and a regularly arranged microstructure is provided on the surface of the substrate, wherein the microstructure is used for scattering light; A tunneling oxide layer grown on the substrate; a polysilicon layer deposited on the tunnel oxide layer; A stacked structure, disposed on the polysilicon layer, the stacked structure consisting of a plurality of sub-layers of different materials, wherein at least one sub-layer comprises a nanophotonic crystal structure; The electrode is prepared on the laminated structure.

2. The TOPCon component based on stacking optimization according to claim 1, characterized in that: The nano-photonic crystal structure is a three-dimensional periodic dielectric structure, which is composed of high-refractive index materials and low-refractive index materials arranged alternately.

3. The TOPCon component based on stacking optimization according to claim 2, characterized in that: The high refractive index material is silicon, the low refractive index material is silicon dioxide, and the three-dimensional periodic dielectric structure is a cubic lattice structure composed of multiple units, each of which is composed of a silicon sphere and a silicon dioxide shell surrounding it, and multiple such units are periodically arranged in three-dimensional space.

4. The TOPCon component based on stacking optimization according to claim 1, characterized in that: The microstructure on the substrate surface is formed by laser etching, chemical etching or a combination thereof.

5. A method for preparing a TOPCon component based on stacking optimization, characterized in that: The steps include: S1, treating a high-purity custom silicon substrate using a cleaning and surface treatment process, and then forming a surface microstructure array on the substrate; S2, growing a tunnel oxide layer on the treated substrate using plasma enhanced atomic layer deposition technology; S3, depositing a polysilicon layer having a unique crystal orientation distribution and a doping concentration gradient on the tunnel oxide layer by a vapor deposition process; S4, preparing a stacked structure, wherein each sublayer is deposited stepwise, and the sublayers are connected by quantum tunneling interface treatment; at least one sublayer comprises a nanophotonic crystal structure; S5. Prepare electrodes on the laminated structure.

6. The method for preparing a TOPCon component based on stacking optimization according to claim 5, characterized in that: The preparation of the nanophotonic crystal structure in S4 includes the following steps: S11. Material preparation Prepare high-purity silicon wafers and silicon dioxide targets; S12. Preparation of self-assembled colloidal crystal templates Monodisperse polystyrene microspheres are synthesized by emulsion polymerization and dispersed in water to form a uniform colloidal solution. The colloidal solution is deposited on the laminated structure surface of the TOPCon component by vertical deposition or spin coating, so that the polystyrene microspheres self-assemble to form a three-dimensional periodic colloidal crystal template; S13, silicon layer deposition The chemical vapor deposition method is used to deposit silicon in the pores of the template using silane as a precursor. The thickness of the silicon layer is controlled by adjusting the deposition temperature, gas flow rate and deposition time. S14, silicon dioxide layer deposition Switch the gas source, introduce oxygen, and deposit silicon dioxide on the surface of the silicon layer. Also, adjust the deposition parameters to control the thickness of the silicon dioxide layer. S15, template removal The polystyrene microsphere template is removed by high temperature annealing or chemical solvent immersion, leaving behind a nanophotonic crystal structure composed of alternating silicon and silicon dioxide.

7. The method for preparing a TOPCon component based on stacking optimization according to claim 5, characterized in that: The cleaning in step S1 includes ultrasonic cleaning, organic solvent immersion, and plasma cleaning.

8. The method for preparing a TOPCon component based on stacking optimization according to claim 5, characterized in that: The electrode is prepared by printing nano silver paste.

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