Stackable Multijunction Solar Cell With Metamorphic Buffer
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Solution Overview
Problem
The manufacturing process of multi-junction solar cells using semiconductor bonding is expensive and reduces yield, and existing cells lack sufficient radiation hardness, especially at high radiation doses, while aiming to improve both beginning-of-life and end-of-life efficiencies and reduce manufacturing costs.
Innovation Solution
A stacked multi-junction solar cell design with sub-cells having specific energy band gaps and lattice constants, featuring a metamorphic buffer and no semiconductor bonds between sub-cells, utilizing GaInP and GaInAsP compounds for enhanced radiation hardness and efficiency, and adjusting the metamorphic buffer to compensate for increased band gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semiconductor bonding process is used to manufacture multi-junction solar cells, then multi-junction structure is achieved, but manufacturing cost increases and production yield decreases
Solution Approach 1:
The solar cell is divided into multiple independent subcells (first subcell with GaInP, second subcell with GaInAsP, third subcell with GaInAs) stacked in sequence, each with specific bandgap values. This segmentation allows each subcell to be optimized for specific wavelength ranges while avoiding the need for complex semiconductor bonding processes, thereby reducing manufacturing cost and improving yield while maintaining radiation hardness.
Solution Approach 2:
The invention changes the material composition parameters by using GaInAsP compound with controlled phosphorus content (1-35%) and indium content (>1%) in the second subcell, and specific lattice constant ranges for all subcells. These parameter changes enable lattice matching without requiring semiconductor bonding, thus reducing manufacturing complexity and cost while achieving the desired multi-junction structure for improved radiation hardness.
2Reliability
If semiconductor bonding process is used to manufacture multi-junction solar cells, then multi-junction structure is achieved, but production yield decreases
Solution Approach 1:
The solar cell is divided into multiple independent subcells (first subcell with GaInP, second subcell with GaInAsP, third subcell with GaInAs) stacked in sequence, each with specific bandgap values. This segmentation allows each subcell to be optimized for specific wavelength ranges while avoiding the need for complex semiconductor bonding processes, thereby reducing manufacturing cost and improving yield while maintaining radiation hardness.
Solution Approach 2:
The invention changes the material composition parameters by using GaInAsP compound with controlled phosphorus content (1-35%) and indium content (>1%) in the second subcell, and specific lattice constant ranges for all subcells. These parameter changes enable lattice matching without requiring semiconductor bonding, thus reducing manufacturing complexity and cost while achieving the desired multi-junction structure for improved radiation hardness.
3Reliability
If GaInAsP compound with phosphorus content greater than 1% is used in the second subcell, then radiation hardness is improved, but energy band gap increases
Solution Approach 1:
The invention changes the material composition parameters by using GaInAsP compound with controlled phosphorus content (1-35%) and indium content (>1%) in the second subcell, and specific lattice constant ranges for all subcells. These parameter changes enable lattice matching without requiring semiconductor bonding, thus reducing manufacturing complexity and cost while achieving the desired multi-junction structure for improved radiation hardness.
Solution Approach 2:
The invention applies different material compositions to different subcells: the second subcell uses GaInAsP with specific phosphorus and indium content to achieve high radiation hardness, while the first and third subcells use different compositions optimized for their respective functions. This local optimization allows each subcell to perform its specific function efficiently while the overall structure achieves improved radiation hardness.
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 achieves higher radiation stability and end-of-life efficiency with a slight reduction in beginning-of-life efficiency, reducing manufacturing costs and improving overall performance.
Implementation Method 1
the lattice constants of the buffer layers increase from layer to layer in the direction of the third subcell
Implementation Method 2
A metamorphic buffer is formed between the second and third subcells, wherein the metamorphic buffer and the metamorphic buffer have a sequence of at least three layers, and the lattice constants of the buffer layers are greater than the lattice constant of the second layer
Implementation Method 3
a stacked multi-junction solar cell design with sub-cells having specific energy band gaps and lattice constants
Data Source
Figure 1a~2d
AI summary
Stacked multi-junction solar cell (MS) comprising at least three subcells (SC1, SC2, SC3), wherein each of the three subcells (SC1, SC2, SC3) has an emitter and a base, and wherein the first subcell (SC1) comprises a first layer (S1) of a compound with at least the elements GaInP and the energy band gap (ES1) of the first layer (S1) is greater than 1.75 eV and the lattice constant (AS1) of the first layer (S1) is in the range between 5.635 Å and 5.675 Å, and wherein the second subcell (SC2) comprises a second layer (S2) of a compound with at least the elements GaAs and the energy band gap (ES2) of the second layer (S2) is in the range between 1.35 eV and 1.70 eV and the lattice constant (AS2) of the second layer (S2) is in the range between 5.635 Å and 5.675 Å. and wherein the third subcell (SC3) comprises a third layer (S3) of a compound with at least the elements GaInAs and the energy band gap (ES3) of the third layer (S3) is less than 1,25 eV and the lattice constant (AS3) of the third layer (S3) is greater than 5.700 Å, and comprises a metamorphic buffer (MP1) and at least one of the two layers (S2, S3) of the second subcell (SC2) or the third subcell (SC3) consists of a compound with at least the elements GaInAsP and has a phosphorus content greater than 1% and an indium content greater than 1%, and no semiconductor bond is formed between two subcells.