Gallium Oxide Passivation in Crystalline Silicon Solar Cells

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Solution Overview

Problem

The photovoltaic conversion efficiency of crystalline silicon solar cells is limited due to high minority carrier recombination rates, primarily caused by unsaturated dangling bonds on the surface of the silicon atoms, which reduces the voltage and current output and overall efficiency of the solar cells.

Innovation Solution

A gallium oxide layer is directly applied to the P-type silicon layer in the crystalline silicon solar cells, utilizing its negative charges for chemical and field passivation to reduce the number of dangling bonds and minority carriers, thereby lowering recombination rates and enhancing the solar cell's performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional passivation layers are used on the silicon surface, then the manufacturing process is simple, but the minority carrier recombination rate remains high due to unsaturated dangling bonds

Engineering Contradiction:
Improveminority carrier recombination rateVSAvoidpassivation layer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a composite passivation structure consisting of a gallium oxide layer combined with a silicon oxide layer. The gallium oxide layer provides chemical passivation by bonding to silicon atoms and reducing dangling bonds, while the silicon oxide layer provides additional passivation and stability. This composite material approach resolves the contradiction by achieving superior passivation performance (reduced recombination rate) through material composition rather than increasing structural complexity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition and electronic properties of the passivation layer by introducing gallium oxide, which has different bonding characteristics and electronic structure compared to conventional silicon oxide alone. This parameter change in material composition enables effective chemical passivation of dangling bonds, reducing minority carrier recombination rates while maintaining a relatively simple two-layer structure.

Inventive Principle:
Principle #35Parameter changes

2Power

If the photovoltaic conversion efficiency is improved through better passivation, then the output power increases, but the manufacturing cost increases

Engineering Contradiction:
Improveoutput powerVSAvoidmanufacturing cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent modifies the compositional parameters of the passivation layer by incorporating gallium oxide, which provides enhanced chemical passivation capability. This parameter change improves photovoltaic conversion efficiency and output power by reducing recombination losses, while the process remains compatible with existing manufacturing techniques, thereby limiting the increase in manufacturing cost.

Inventive Principle:
Principle #35Parameter changes

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 implementation of the gallium oxide layer improves the photovoltaic conversion efficiency, increases output power, and reduces the cost per kilowatt hour of electricity, thereby enhancing the cost performance of photovoltaic power generation.

Implementation Method 1

negative charges of the gallium oxide layer are used to carry out chemical passivation and field passivation on the surface of the P-type silicon layer

Methodology Applied
Scientific EffectChemical passivation: Chemical Bonding

Implementation Method 2

negative charges of the gallium oxide layer are used to carry out chemical passivation and field passivation on the surface of the P-type silicon layer

Methodology Applied
Scientific EffectField passivation: Electric Field

Implementation Method 3

reduce the number of dangling bonds and minority carriers of silicon atoms on the surface of the P-type silicon layer, so that recombination rate of minority carriers at the surface of the P-type silicon layer is reduced

Methodology Applied
Scientific EffectMinority carrier recombination: Absorption (physical)

Data Source

PatentEP3783668B1Crystalline silicon solar cell and preparation method therefor, and photovoltaic assembly
Publication Date: 2023.08.30 JINGAO SOLAR CO LTD
  • EP3783668B1 patent drawingFigure 1~3
  • EP3783668B1 patent drawingFigure 4~5
  • EP3783668B1 patent drawingFigure 6~7

AI summary

The disclosure relates to a crystalline silicon solar cell and a preparation method, and a photovoltaic module, belonging to the technical field of solar cells. The crystalline silicon solar cell includes a gallium oxide layer in direct contact with a P-type silicon layer in the crystalline silicon solar cell. In the disclosure, the gallium oxide layer in direct contact with the P-type silicon layer is arranged on the P-type silicon layer of the crystalline silicon solar cell, negative charges of the gallium oxide layer are used to carry out chemical passivation and field passivation on a surface of the P-type silicon layer, and the number of dangling bonds and minority carriers of silicon atoms on the surface of the P-type silicon layer is reduced, so that a minority carrier recombination rate at the surface of the P-type silicon layer is reduced, the voltage and current of the solar cell are improved, and photovoltaic conversion efficiency of the solar cell is improved, thus improving output power of the photovoltaic module, reducing cost per kilowatt hour of electricity and improving cost performance of photovoltaic power generation. In addition, the gallium oxide layer has a relatively wide band gap and an appropriate optical refractive index, and also facilitates improvement of the performance of the crystalline silicon solar cell.