Solar Cell Electrode Grain Size Control for Contact Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The rear surface electrode type solar batteries face an issue with increased contact resistance between non-crystalline semiconductor layers and electrodes, which affects the performance of the photoelectric conversion element.
Innovation Solution
The photoelectric conversion element incorporates a semiconductor substrate with a first and second semiconductor layer of opposite conductive types, where at least one electrode includes metal crystal grains with an average crystal grain size greater than the electrode thickness, reducing contact resistance and improving element characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electrodes are formed on non-crystalline semiconductor layers, then the photoelectric conversion element can be manufactured with a rear surface electrode structure, but the contact resistance between the non-crystalline semiconductor layer and the electrode increases
Solution Approach 1:
The invention changes the physical parameter of the electrode by controlling the crystal grain size of the metal particles to be equal to or larger than the electrode thickness. This parameter change transforms the electrode from a fine-grained structure to a coarse-grained or single-grain structure, which reduces the number of grain boundaries and improves electron transport, thereby reducing contact resistance while maintaining the rear surface electrode structure
Solution Approach 2:
The invention uses a composite structure consisting of metal particles embedded in a metal matrix. The metal particles have crystal grain sizes controlled to be equal to or larger than the electrode thickness, creating a composite material with optimized electrical properties. This composite structure combines the advantages of particle reinforcement with reduced grain boundary resistance
Data Source
AI summary
There is provided a photoelectric conversion element which can prevent the contact resistance between a non-crystalline semiconductor layer containing impurities and an electrode formed on the non-crystalline semiconductor layer from increasing, and can improve the element characteristics. A photoelectric conversion element (10) includes a semiconductor substrate (12), a first semiconductor layer (20n), a second semiconductor layer (20p), a first electrode (22n), and a second electrode (22p). The first semiconductor layer (20n) has a first conductive type. The second semiconductor layer (20p) has a second conductive type opposite to the first conductive type. The first electrode (22n) is formed on the first semiconductor layer (20n). The second electrode (22p) is formed on the second semiconductor layer (20p). At least one electrode of the first electrode (22n) and the second electrode (22p) includes a plurality of metal crystal grains. The average crystal grain size of the metal crystal grains in the in-surface direction of electrode is greater than the thickness of the electrode.