N-Type Solar Cell Front Coating for Light Absorption and Passivation
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Solution Overview
Problem
Current N-type solar cells face challenges in enhancing photoelectric conversion efficiency, particularly in light absorption and isolation from external factors, due to limitations in the design of film layers on the front light receiving surface.
Innovation Solution
A novel solar cell design incorporating a laminated antireflection film composed of stacked first, second, and third antireflection layers, along with a passivation layer containing aluminum oxide, is introduced. The antireflection layers are made of silicon nitride, silicon oxynitride, and silicon oxide materials, respectively, with specific composition gradients to optimize light absorption and reduce surface defects, while the passivation layer enhances compatibility with the N-type silicon substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer or simple multi-layer antireflection film is used, then the device complexity is low, but the light absorption efficiency is insufficient
Solution Approach 1:
The antireflection film is segmented into three distinct layers (first antireflection layer with silicon nitride, second antireflection layer with silicon oxynitride, third antireflection layer with silicon oxide), each having different refractive indices and functions. This segmentation allows optimized light absorption at different wavelengths and angles, resolving the contradiction between maintaining simple structure and improving light absorption efficiency.
Solution Approach 2:
The patent employs composite materials by combining three different dielectric materials (silicon nitride, silicon oxynitride, and silicon oxide) in a laminated structure. Each material contributes unique optical properties, and their combination creates a synergistic effect that enhances overall light absorption efficiency while managing the complexity through systematic material selection and layer design.
2Reliability
If the passivation layer is directly formed on the N-type silicon substrate, then the manufacturing process is simple, but the interface passivation effect is insufficient
Solution Approach 1:
The first antireflection layer containing silicon nitride material serves as an intermediary layer between the N-type silicon substrate and the passivation layer. This intermediary layer improves lattice matching compatibility, reduces interface defects, and enhances the overall passivation effect, thereby resolving the contradiction between simple manufacturing and effective passivation.
3Reliability
If the third antireflection layer has uniform thickness, then the manufacturing precision is easier to control, but the light absorption efficiency is reduced
Solution Approach 1:
The third antireflection layer is designed with non-uniform thickness, where the thickness varies across different regions of the layer. This local quality variation allows the film to optimize light absorption at different positions and angles of incidence, with thicker regions providing enhanced absorption for specific wavelength ranges while thinner regions maintain appropriate optical pathways for other wavelengths, thereby improving overall light absorption efficiency despite increased manufacturing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design improves light absorption efficiency, increases short-circuit current, and enhances the photoelectric conversion efficiency of N-type silicon solar cells by reducing internal reflection and improving interface passivation, thereby increasing the solar cell's isolation from external contaminants.
Implementation Method 1
The passivation layer is formed over the front surface and includes an aluminum oxide material... improving the effect of isolation of the solar cell from the outside
Implementation Method 2
The first antireflection layer is formed over the passivation layer and includes a silicon nitride material... improving the light absorption efficiency of the solar cell
Data Source
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AI summary
Provided are a solar cell and a photovoltaic module. The solar cell includes: an N-type silicon substrate (100), where the N-type silicon substrate (100) has a front surface and a rear surface opposite to the front surface; a passivation layer (101) that contains an aluminum oxide material and that is located on the front surface; a first antireflection layer (102), a second antireflection layer (103), and a third antireflection layer (104) that are located on a side of the passivation layer (101) away from the substrate and stacked in a direction in which the substrate points to the passivation layer (101), where the first antireflection layer (102) contains a silicon nitride material, the second antireflection layer (103) contains a silicon oxynitride material; and the third antireflection layer (104) contains a silicon oxide material; a tunneling dielectric layer (105) located on the rear surface; and a doped conductive layer (106) located on the tunneling dielectric layer (105).