Photoelectric Conversion Element Reflective Gap Structure
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Solution Overview
Problem
Current photoelectric conversion elements, such as solar cells, face challenges in enhancing characteristics and reliability, particularly in the back electrode structure where light is not efficiently reflected back into the semiconductor substrate, leading to reduced photoelectric conversion efficiency.
Innovation Solution
A heterojunction back-contact cell configuration is introduced, featuring a semiconductor substrate with i-type and conductivity-type semiconductor films, electrode layers, and a reflective section composed of an insulating layer or irregularities placed in the gap region between the electrode layers to reflect light back into the substrate, enhancing light utilization and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a back electrode structure is used to increase incident sunlight, then light reception area is improved, but light reflection efficiency deteriorates
Solution Approach 1:
The back surface electrode structure is divided into multiple independent electrode regions (first electrode region, second electrode region, third electrode region) separated by gap regions. This segmentation allows the introduction of reflective sections in the gap regions without compromising the overall back contact functionality, thereby improving light reflection while maintaining large light reception area.
Solution Approach 2:
Different regions of the back surface are assigned different functions: electrode regions for electrical contact and gap regions for light reflection. The reflective sections are strategically placed only in the gap regions, creating local functional differentiation that optimizes both electrical performance and optical efficiency.
2Reliability
If electrodes are placed on the back surface to extract carriers, then electrical functionality is improved, but light utilization deteriorates
Solution Approach 1:
The back surface is segmented into electrode regions for carrier extraction and gap regions for light reflection. By separating these functions spatially, the electrode structure maintains its electrical functionality while the gap regions with reflective sections improve light utilization by reflecting incident light back into the semiconductor substrate.
Solution Approach 2:
The reflective sections act as intermediary elements placed in the gap regions between electrode regions. These reflective sections mediate between the incident light and the semiconductor substrate, reflecting light that would otherwise be lost back into the substrate to enhance carrier generation without interfering with the electrode's carrier extraction function.
3Productivity
If a reflective section is added to improve light reflection, then photoelectric conversion efficiency is improved, but device complexity increases
Solution Approach 1:
The reflective sections are introduced only in the gap regions between electrodes rather than covering the entire back surface. This segmented approach improves photoelectric conversion efficiency by reflecting light in specific areas while avoiding the complexity of implementing a complete back surface reflection structure.
Solution Approach 2:
The gap regions between electrodes serve multiple functions: they provide electrical isolation between adjacent electrodes and simultaneously serve as locations for light reflection. This multi-functionality reduces the need for additional dedicated reflective structures, thereby limiting the increase in device complexity.
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 reflective section effectively increases light reflection and usage within the photoelectric conversion element, resulting in improved characteristics and reliability by increasing photoelectric conversion efficiency compared to conventional designs.
Implementation Method 1
a reflective section placed in a gap region interposed between the first electrode layer and the second electrode layer
Implementation Method 2
sunlight is incident on a light-receiving surface of the semiconductor substrate and therefore carriers are generated in the semiconductor substrate
Data Source
AI summary
Provided are a photoelectric conversion element capable of enhancing characteristics and reliability more than ever before and a method for manufacturing the photoelectric conversion element. The photoelectric conversion element includes a base including a semiconductor substrate, a first i-type semiconductor film placed on a portion of a surface of the semiconductor substrate, a first conductivity-type semiconductor film placed on the first i-type semiconductor film, a second i-type semiconductor film placed on another portion of the surface thereof, and a second conductivity-type semiconductor film placed on the second i-type semiconductor film; an electrode section including a first electrode layer placed on the first conductivity-type semiconductor film and a second electrode layer placed on the second conductivity-type semiconductor film; and a reflective section placed in a gap region A interposed between the first electrode layer and the second electrode layer.