Transparent Solar Cell Electrode Roughness for Clarity and Efficiency
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Solution Overview
Problem
Transparent solar cells face a trade-off between transparency and electrical efficiency, with increased transparency leading to lower efficiency and vice versa, which is particularly problematic in applications like watchmaking where clarity is crucial.
Innovation Solution
A solar cell design featuring a transparent substrate with a first electrode having a rougher internal face for light diffusion and a smoother external face to minimize scattering, combined with a perforated absorbent layer and second electrode to maximize transparency and electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the surface area covered by perforations is increased to improve transparency, then the electrical efficiency decreases
Solution Approach 1:
The first electrode is designed with non-uniform roughness: a first portion with high roughness for light diffusion and trapping to enhance electrical efficiency, and a second portion with low roughness for minimal scattering to enhance transparency. This local differentiation allows each region to optimize its function without compromising the other.
2Loss of energy
If roughness is increased on the first electrode to improve light absorption and electrical efficiency, then the scattering factor increases causing blurring
Solution Approach 1:
The first electrode incorporates spatially varying roughness characteristics: regions with high roughness (e.g., RMS > 50nm) for light trapping and diffusion to maximize electrical efficiency, and regions with low roughness (e.g., RMS < 10nm) for minimal scattering to maintain transparency and visual clarity.
Solution Approach 2:
The first electrode is segmented into functionally distinct portions: a light-trapping portion with high roughness for electrical efficiency and a transparent portion with low roughness for optical clarity. This segmentation allows independent optimization of each function within a single component.
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 design enhances both the transparency and electrical efficiency of solar cells, allowing for clear observation while maintaining optimal electrical performance by reducing series resistance losses and preserving diffusing power where necessary.
Implementation Method 1
the first electrode may have a roughness on one of its faces allowing it to diffuse the light and thus optimize its absorption by the absorbing layer by trapping the incident light radiation
Implementation Method 2
an absorbent layer adapted to absorb light and convert it into electrical energy
Data Source
Figure 1~5
AI summary
The present invention relates to a solar cell (10) for an electronic device comprising: - a substrate (100) made of a transparent material intended to be exposed to incident light radiation, - a first electrode (110) made of a transparent electrically conductive material, formed on one face of the substrate (100) and comprising an inner face (111) opposite an outer face (112) oriented towards the substrate (100), said inner face (111) comprising a first portion having a roughness greater than the roughness of a second portion, - an absorbing layer (130) extending by an outer face (131) over the first portion of the inner face (111) of the first electrode (110), - a second electrode (120) made of an electrically conductive material and extending over an inner face of the absorbing layer (130) opposite the outer face (131) of the latter,the absorbing layer (130) and the second electrode (120) being perforated so as to delimit a plurality of blind cavities (140), the bottom of each of which is formed by the second portion of the inner face (111) of the first electrode (110).