See-through Thin Film Solar Cell Laser Etching
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Solution Overview
Problem
Current transparent solar cells have low photoelectric conversion efficiency and poor aesthetics due to large, recognizable aperture patterns, which hinder their adoption in high-value applications like building windows and vehicle sunroofs.
Innovation Solution
A method involving laser etching to form see-through patterns and arrays in a chalcogenide thin film solar cell, using a molybdenum layer and transparent electrode layers, allowing for high-efficiency photovoltaic performance and transmittance with aperture patterns less than 100 μm in size, thereby improving aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If mechanical scribing is used to form aperture patterns in chalcogenide thin film solar cells, then transmittance is achieved, but the aperture patterns have large line width and are recognizable by the naked eye, resulting in poor aesthetics
Solution Approach 1:
The patent replaces the mechanical scribing process with laser-based processing. The laser beam precisely ablates the absorber layer to form aperture patterns with dimensions of 100 μm or less, which are not recognizable by the naked eye. This substitution of mechanical method with optical/thermal method enables both transmittance and aesthetic appearance.
2Illumination intensity
If the absorber layer is made ultra-thin to reduce absorbance, then transmittance is improved, but photoelectric conversion efficiency decreases to 10-15%
Solution Approach 1:
The patent divides the continuous absorber layer into segmented regions by forming aperture patterns (holes or lines) through which light can pass. This segmentation allows the solar cell to simultaneously maintain thick absorber regions for high photoelectric conversion efficiency and create transparent regions for transmittance, achieving both goals without reducing the overall absorber layer thickness.
3Shape
If aperture patterns are made smaller than 100 μm to improve aesthetics, then product appearance is enhanced, but manufacturing precision and pattern formation difficulty increase
Solution Approach 1:
The patent uses laser processing instead of mechanical scribing to achieve precise aperture patterns of 100 μm or less. The laser beam can be precisely controlled in terms of position, duration, and intensity, enabling the formation of fine patterns with high precision that are not recognizable by the naked eye, thereby achieving both aesthetic appearance and manufacturing feasibility.
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 method achieves high photoelectric conversion efficiency and excellent transmittance while minimizing recognizable aperture patterns, enhancing the aesthetic appeal and practicality of see-through solar cells.
Implementation Method 1
The forming of the see-through patterns may include selectively removing parts of the Mo layer through laser etching
Implementation Method 2
The forming of the see-through array may include removing parts of the chalcogenide absorber layer, the buffer layer, and the transparent electrode layer deposited on the see-through patterns, through laser etching
Implementation Method 3
Chalcogenide thin film solar cells have excellent photovoltaic performance close to that of crystalline silicon solar cells and thus a Cu(In,Ga)(Se,S)2 absorber layer thereof may achieve a photoelectric conversion efficiency of 23.4%
Data Source
AI summary
Provided is a method of fabricating a see-through thin film solar cell, the method including preparing a substrate including a molybdenum (Mo) layer on one surface, forming see-through patterns by selectively removing at least parts of the Mo layer, sequentially depositing a chalcogenide absorber layer, a buffer layer, and a transparent electrode layer on the substrate and the Mo layer including the see-through patterns, and forming a see-through array according to a shape of the see-through patterns by removing the chalcogenide absorber layer, the buffer layer, and the transparent electrode layer deposited on the see-through patterns, by irradiating a laser beam from under the substrate toward the transparent electrode layer.