Conductive Polyimide Adhesive for Inverted Metamorphic Solar Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing of III-V compound semiconductor multijunction solar cells is complex due to challenges in choosing appropriate materials and fabrication steps, particularly for inverted metamorphic structures, which affect their efficiency and radiation resistance.
Innovation Solution
A method involving the growth of subcells on a substrate in a reverse sequence, using a sequence of semiconductor layers with specific band gaps and lattice constants, and attaching a second substrate with a conductive polyimide adhesive to expose the top subcell, while removing the initial substrate to optimize the solar cell structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inverted metamorphic solar cell structures are used to achieve high efficiency and radiation resistance, then energy conversion efficiency and radiation resistance are improved, but manufacturing complexity increases due to challenges in material selection and fabrication steps
Solution Approach 1:
The patent applies inversion by growing the solar cell subcells in reverse sequence on the substrate, with the bottom subcell (having the smallest band gap) grown first and the top subcell (having the largest band gap) grown last. This inverted growth sequence simplifies the fabrication process by eliminating the need for complex material selection and intermediate transfer steps, while still achieving the desired high efficiency and radiation resistance performance
Solution Approach 2:
The patent changes the growth sequence parameter of the subcells, growing them in reverse order from bottom to top based on increasing band gap energy. This parameter change simplifies the manufacturing process by allowing continuous epitaxial growth without requiring substrate removal and reattachment steps, thereby reducing manufacturing complexity while maintaining the inverted metamorphic structure's high efficiency and radiation resistance
2Manufacturing precision
If substrate removal is performed to expose the top subcell surface, then manufacturing precision and cell performance are improved, but additional fabrication steps and process complexity are required
Solution Approach 1:
The patent applies preliminary action by designing the inverted metamorphic structure with the top subcell grown last and positioned at the highest point, so that the substrate removal step automatically exposes the top subcell surface without requiring additional etching or patterning steps. This preliminary structural arrangement simplifies the overall fabrication process while achieving the desired manufacturing precision
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 approach enhances the energy conversion efficiency and radiation resistance of solar cells, improving the power-to-weight ratio and making them suitable for space and terrestrial applications.
Implementation Method 1
applying a conductive polyimide adhesive to the second substrate; attaching the second substrate on top of the back metal contact
Implementation Method 2
depositing on the first substrate a sequence of layers of semiconductor material forming a solar cell including a top subcell and a bottom subcell
Data Source
AI summary
The present disclosure provides a method of manufacturing a solar cell including: providing a first substrate and a second substrate; depositing on the first substrate a sequence of layers of semiconductor material forming a solar cell including a top subcell and a bottom subcell; forming a back metal contact over the bottom subcell; applying a conductive polyimide adhesive to the second substrate; attaching the second substrate on top of the back metal contact; and removing the first substrate to expose the surface of the top subcell.