Solar Cell Passivation Stack With Graded Dielectrics for Ion Blocking
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Solution Overview
Problem
Current solar cell technologies face challenges in enhancing light absorption efficiency and preventing external ion diffusion, which can lead to power degradation and reduced photoelectric conversion efficiency due to the limitations of existing passivation and antireflection layers.
Innovation Solution
The implementation of a solar cell structure featuring a substrate with a first passivation stack comprising oxygen-rich and silicon-rich dielectric layers, a tunneling oxide layer, and a doped conductive layer, where the oxygen-rich dielectric layers have varying oxygen atomic fractions to form a gradient refractive index, effectively blocking external ions and improving light absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer passivation and antireflection structure is used, then the device complexity is low, but the light absorption efficiency is insufficient and external ion diffusion cannot be effectively blocked
Solution Approach 1:
The patent divides the passivation and antireflection function into multiple separate layers: a first passivation layer (silicon-rich SiOxNy with x<y) and a second passivation layer (oxygen-rich SiOxNy with x>y), each with distinct compositional characteristics. This segmentation allows each layer to be optimized for specific functions - the silicon-rich layer for antireflection and the oxygen-rich layer for ion blocking - thereby improving light absorption efficiency and reliability while maintaining manufacturing feasibility
Solution Approach 2:
The patent employs composite material structure by combining silicon-rich and oxygen-rich SiOxNy dielectric layers in a stacked configuration. The silicon-rich layer provides high refractive index for antireflection, while the oxygen-rich layer provides dense structure for ion diffusion blocking. This composite approach resolves the contradiction by achieving both high light absorption efficiency and effective ion protection through material composition optimization
2Illumination intensity
If a silicon-rich dielectric layer is used for antireflection, then the refractive index is high improving light absorption, but the density is lower reducing ion diffusion blocking capability
Solution Approach 1:
The patent segments the functional requirements by creating two distinct layers: the first passivation layer (silicon-rich, x<y) optimized for high refractive index and light absorption, and the second passivation layer (oxygen-rich, x>y) optimized for high density and ion diffusion blocking. This segmentation resolves the contradiction by assigning each function to a specialized layer rather than attempting to achieve both functions in a single layer
Solution Approach 2:
The patent applies local quality by giving each layer distinct compositional characteristics tailored to its specific function. The silicon-rich first layer has high refractive index locally optimized for optical performance, while the oxygen-rich second layer has high density locally optimized for ion blocking. This local optimization of material properties at different positions in the stack resolves the contradiction between light absorption and ion protection
3Object-affected harmful factors
If an oxygen-rich dielectric layer is used for ion diffusion blocking, then the density is high improving protection, but the refractive index is lower reducing light absorption efficiency
Solution Approach 1:
The patent segments the functional requirements by creating two distinct layers: the first passivation layer (silicon-rich, x<y) optimized for high refractive index and light absorption, and the second passivation layer (oxygen-rich, x>y) optimized for high density and ion diffusion blocking. This segmentation resolves the contradiction by assigning each function to a specialized layer rather than attempting to achieve both functions in a single layer
Solution Approach 2:
The patent applies local quality by giving each layer distinct compositional characteristics tailored to its specific function. The silicon-rich first layer has high refractive index locally optimized for optical performance, while the oxygen-rich second layer has high density locally optimized for ion blocking. This local optimization of material properties at different positions in the stack resolves the contradiction between light absorption and ion protection
4Reliability
If multiple passivation layers with different compositions are used, then the light absorption efficiency and ion blocking are improved, but the device complexity increases
Solution Approach 1:
The patent employs composite material structure by combining silicon-rich and oxygen-rich SiOxNy dielectric layers in a stacked configuration. The silicon-rich layer provides high refractive index for antireflection, while the oxygen-rich layer provides dense structure for ion diffusion blocking. This composite approach resolves the contradiction by achieving both high light absorption efficiency and effective ion protection through material composition optimization
Solution Approach 2:
The patent applies parameter changes by systematically varying the oxygen-to-silicon ratio (x/y) in the SiOxNy layers to achieve different material properties. The first layer uses x<y for high refractive index, while the second layer uses x>y for high density. This controlled variation of compositional parameters allows optimization of both optical and protective functions while maintaining manufacturing feasibility through a systematic material design approach
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
This configuration enhances light absorption efficiency by allowing different wavelengths to enter the substrate, reduces defect density and stress damage, and improves the photoelectric conversion efficiency while maintaining a high refractive index for effective antireflection.
Implementation Method 1
the oxygen-rich dielectric layers have varying oxygen atomic fractions to form a gradient refractive index, effectively blocking external ions and improving light absorption
Implementation Method 2
enhances light absorption efficiency by allowing different wavelengths to enter the substrate
Implementation Method 3
the oxygen-rich dielectric layers have varying oxygen atomic fractions to form a gradient refractive index, effectively blocking external ions
Implementation Method 4
a tunneling oxide layer, and a doped conductive layer
Implementation Method 5
a tunneling oxide layer, and a doped conductive layer
Data Source
Figure 1~2
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AI summary
A solar cell and a photovoltaic module including the same are provided. The solar cell includes a substrate having a first surface and a second surface opposite to each other; a first passivation stack disposed on the first surface and including a first oxygen-rich dielectric layer, a first silicon-rich dielectric layer, a second oxygen-rich dielectric layer, and a second silicon-rich dielectric layer that are sequentially disposed in a direction away from the first surface, wherein an atomic fraction of oxygen in the first oxygen-rich dielectric layer is less than an atomic fraction of oxygen in the second oxygen-rich dielectric layer; a tunneling oxide layer disposed on the second surface; a doped conductive layer disposed on a surface of the tunneling oxide layer; and a second passivation layer disposed on a surface of the doped conductive layer.