Solar Cell Laminated Passivation Structure for Reflection-Passivation Balance
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Solution Overview
Problem
Current laminated passivation structures for PERC solar cells, utilizing aluminum oxide and silicon nitride films, face issues with chemical passivation, field passivation, and back-surface light reflection due to differences in refractive indices and charge densities, leading to suboptimal conversion efficiency.
Innovation Solution
A laminated passivation structure comprising a P-type silicon substrate with sequentially arranged dielectric layers, including a silicon oxide layer, an aluminum oxide layer, a silicon oxynitride layer, and a silicon nitride layer, optimized in thickness and refractive index to enhance chemical and field passivation, as well as back-surface light reflection, through the use of PECVD or ALD deposition methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum oxide and silicon nitride films are laminated, then passivation is improved, but back-surface light reflection is reduced due to large refractive index difference
Solution Approach 1:
A silicon oxynitride intermediate layer is introduced between the aluminum oxide and silicon nitride layers. This intermediate layer has a refractive index that gradually transitions between the two materials, reducing the abrupt refractive index mismatch. This mediator layer minimizes optical reflection losses while maintaining the electrical passivation benefits of the laminated structure.
Solution Approach 2:
The patent modifies the refractive index parameter by introducing a silicon oxynitride layer with intermediate optical properties. This gradual transition in refractive index across the laminated structure reduces optical impedance mismatch, thereby improving light reflection at the back surface while preserving the passivation functionality.
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 proposed structure achieves an open-circuit voltage of 694 mV or more, a short-circuit current of 40.80 mA/cm² or more, and a conversion efficiency of 23.08% or more, significantly improving passivation and light reflection effects.
Implementation Method 1
through the use of PECVD or ALD deposition methods
Implementation Method 2
through the use of PECVD or ALD deposition methods
Implementation Method 3
back-surface light reflection ability
Data Source
AI summary
A laminated passivation structure of solar cell and a preparation method thereof are disclosed herein. The laminated passivation structure of solar cell includes a P-type silicon substrate, a first dielectric layer, a second dielectric layer, a third dielectric layer and a fourth dielectric layer sequentially arranged on the back surface of the P-type silicon substrate from inside to outside. The preparation method includes generating a first dielectric layer on the back surface of the P-type silicon substrate, and then sequentially depositing a second dielectric layer, a third dielectric layer and a fourth dielectric layer on the first dielectric layer.