Solar Cell Passivation Stack for Short-Wave Reflectivity Reduction
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Solution Overview
Problem
The light absorption efficiency of solar cells is limited, restricting further improvement in conversion efficiency, and is influenced by the parameters of the passivation structure, including the type, material composition, and thickness of passivation layers.
Innovation Solution
A solar cell structure is developed with a specific sequence of passivation layers, including a dielectric first passivation layer, a silicon nitride second passivation layer, and a silicon oxynitride third passivation layer, optimized in terms of atomic ratios and thickness to enhance light absorption and reduce internal reflection, along with a tunneling oxide layer and doped conductive layer, all formed using specific deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional passivation structures are used, then manufacturing is simpler, but light absorption efficiency is limited and conversion efficiency cannot be further improved
Solution Approach 1:
The patent applies composite materials by constructing a multi-layer passivation structure consisting of a first passivation layer (silicon oxide), a second passivation layer (silicon nitride with specific stoichiometry), and a third passivation layer (silicon oxynitride). Each layer uses different materials with complementary properties to achieve both high light absorption efficiency and effective surface passivation, thereby improving conversion efficiency while maintaining manufacturability through established deposition processes.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the stoichiometric ratios of the passivation layers: the second passivation layer uses silicon nitride with an n/m ratio of 0.5-1, and the third passivation layer uses silicon oxynitride with a j/i ratio of 0.1-0.6. These specific compositional parameters optimize the refractive indices and optical properties of each layer, enabling enhanced light absorption across different wavelength ranges while maintaining structural stability and manufacturability.
2Productivity
If passivation layer parameters are optimized to improve light absorption, then conversion efficiency increases, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the passivation structure into three distinct functional layers, each with specific thickness ranges (first layer: 3-10 nm, second layer: 40-60 nm, third layer: 20-50 nm) and specific material compositions. This segmentation allows each layer to perform its specialized function optimally while simplifying the overall design by assigning clear roles to each layer, thereby managing device complexity through structured functional division.
Solution Approach 2:
The patent applies another dimension by introducing a gradient refractive index structure through the multi-layer configuration, where the refractive indices of the layers are arranged in a specific sequence to create optical interference effects that enhance light absorption. This dimensional approach to optical property distribution allows the structure to manipulate light propagation in multiple dimensions, improving conversion efficiency without proportionally increasing structural 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 optimized passivation structure significantly reduces light reflectivity, particularly in the short-wave range, leading to improved absorption efficiency and increased short-circuit current, enabling the solar cell to be dark blue or black, suitable for various application scenarios with enhanced power generation efficiency.
Implementation Method 1
The optimized passivation structure significantly reduces light reflectivity, particularly in the short-wave range, leading to improved absorption efficiency
Implementation Method 2
a tunneling oxide layer and a doped conductive layer sequentially formed on the rear surface
Implementation Method 3
the doped conductive layer and the substrate have a doping element of a same conductivity type
Data Source
AI summary
A solar cell, a method for producing a solar cell and a solar cell module are provided. The solar cell includes: a substrate having a front surface and a rear surface opposite to the front surface; a first passivation layer, a second passivation layer and a third passivation layer sequentially formed on the front surface and in a direction away from the front surface; wherein the first passivation layer includes a dielectric material; the second passivation layer includes a first silicon nitride SimNn material, and a ratio of n/m is 0.5˜1; the third passivation layer includes a silicon oxynitride SiOiNj material, and a ratio of j/i is 0.1˜0.6; and a tunneling oxide layer and a doped conductive layer sequentially formed on the rear surface and in a direction away from the rear surface, wherein the doped conductive layer and the substrate have a doping element of a same conductivity type.