Transparent Solar Cell Cavities for Clarity and Power Generation
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Solution Overview
Problem
Existing transparent solar cells face a compromise between transparency and electrical efficiency, where increasing transparency reduces electrical performance and vice versa, making them unsuitable for applications requiring high transparency and efficiency, such as watchmaking and electronic devices.
Innovation Solution
A solar cell design featuring a transparent substrate with a first electrode having a rough internal face for diffusing light, an absorbent layer, and a second electrode, all perforated to create blind cavities. A transparent protective layer with a refractive index between 1.3 and 1.8 is applied 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 patent applies local quality by creating blind cavities at specific locations rather than uniform perforations. The cavities are positioned to allow light transmission while maintaining electrical functionality in other areas. This localized approach to transparency optimization resolves the contradiction by providing optical benefits where needed without sacrificing overall electrical efficiency across the entire solar cell surface.
Solution Approach 2:
The solar cell surface is segmented into multiple blind cavities distributed across the structure. This segmentation allows different regions to serve different functions - some areas provide transparency through cavities while other areas maintain electrical efficiency. The segmented approach enables simultaneous optimization of both transparency and electrical performance by distributing the functional requirements across multiple localized zones.
2Loss of energy
If a rough first electrode is used to increase light absorption and electrical efficiency, then the scattering factor increases causing blurring
Solution Approach 1:
The patent extracts the light-trapping function from the first electrode surface roughness and relocates it to the blind cavity structure. By removing the roughness from the electrode and replacing it with geometric cavity structures, the solution eliminates the harmful light scattering that causes blurring while preserving the beneficial light absorption and trapping effects. This extraction resolves the contradiction by separating the optical functions from the electrical conduction function.
Solution Approach 2:
The blind cavities act as an intermediary structure between the first electrode and the external environment. Instead of using electrode roughness to trap light, the cavities serve as intermediate optical elements that guide and trap light through their geometric structure. This intermediary approach provides light management benefits without the negative scattering effects, resolving the contradiction between electrical efficiency and image clarity.
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 high transparency while maintaining high electrical efficiency, allowing for clear observation through the solar cell and efficient power generation, suitable for applications in watchmaking and electronic devices.
Implementation Method 1
a first electrode made of a transparent electrically conductive material, formed on one face of the substrate and comprising an internal face opposite an external face oriented towards the substrate. The internal face has, over its entire surface, a roughness such that it is capable of diffusing incident light radiation
Implementation Method 2
an absorbent layer extending by an external face on the internal face of the first electrode
Implementation Method 3
the need has arisen for solar cells that can be hidden from the user's view, in order to provide a source of electrical energy... an absorbent layer suitable for absorbing light and converting it into electrical energy
Implementation Method 4
a transparent protective layer covering the second electrode and filling each cavity and having a refractive index of between 1.3 and 1.8
Implementation Method 5
The scattering factor is the ratio of the intensity of the scattered light to that of the total transmitted light. A scattering factor of at least 10% is typically desired to optimize the electrical performance of a solar cell... such a diffusion factor is not acceptable for a transparent solar cell
Data Source
Figure 1~6

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 internal face (111) opposite an external face (112) oriented towards the substrate (100), said internal face (111) having, over its entire surface, a roughness such that it is capable of diffusing incident light radiation, an absorbing layer (130) extending by an external face (131) on the internal face (111) of the first electrode (110), a second electrode (120) made of an electrically conductive material and extending on an internal face (132) of the absorbing layer (130) opposite the external face (131) of the latter,the absorbent 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 internal face (111) of the first electrode (110), the solar cell further comprising a transparent protective layer (150) covering the second electrode (120) and filling each cavity (140) and having a refractive index of between 1.3 and 1.8.,