3D Solar Cell Tower Surface Roughness for Light Absorption
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Solution Overview
Problem
Conventional solar cells have low light gathering efficiency due to their flat surface design, which results in significant light reflection and increased electron-hole recombination, reducing the electrical current generated. Three-dimensional solar cells with nano-scale tower structures improve efficiency but can still benefit from increased surface area and light scattering to enhance energy capture.
Innovation Solution
The enhancement of surface roughness on nano-scale tower structures in three-dimensional solar cells through controlled etching parameters increases the light-gathering surface area and scattering of incident photons, leading to improved absorption and conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat surface is used in conventional solar cells, then the structure is simple and easy to manufacture, but light reflection increases and light gathering efficiency decreases
Solution Approach 1:
The patent transitions from a two-dimensional flat surface to a three-dimensional nano-scale tower structure array. This dimensional change increases the surface area available for light absorption and allows light to be trapped and absorbed from multiple angles, thereby resolving the contradiction between structural simplicity and light gathering efficiency.
Solution Approach 2:
The patent employs curved surfaces on the nano-scale towers rather than flat planes. The curved surfaces of the towers scatter and trap incident light more effectively, increasing the path length of light within the photovoltaic material and improving absorption efficiency while maintaining manufacturing feasibility through standard nanofabrication processes.
2Productivity
If the photovoltaic coating is made thick to capture more photons, then light absorption improves, but electron-hole recombination increases and electrical current decreases
Solution Approach 1:
By transitioning to a three-dimensional tower structure, the patent increases the surface area of the photovoltaic coating without increasing its thickness. The towers provide additional surface area for photon capture while maintaining a thin coating that reduces electron-hole recombination, thus resolving the contradiction between photon capture efficiency and electrical current generation.
3Productivity
If the surface area of nano-scale tower structures is increased to improve light gathering, then light absorption efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The patent divides the solar cell surface into multiple discrete nano-scale tower structures rather than using a single complex continuous surface. This segmentation allows each tower to be formed using standard photolithography and etching processes, making the manufacturing process manageable while achieving high total surface area for light absorption.
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 increased surface roughness of tower structures in three-dimensional solar cells enhances light absorption and scattering, increasing the conversion efficiency of photonic energy into electrical energy by providing a larger interaction area and reducing reflection losses.
Implementation Method 1
enhance surface roughness of each tower structure to increase the surface area available for light gathering
Implementation Method 2
convert the energy from the incident light. Released electrons then flow in a circuit provided
Data Source
AI summary
A nano-scale tower structure array having increased surface area on each tower for gathering incident light is provided for use in three-dimensional solar cells. Embodiments enhance surface roughness of each tower structure to increase the surface area available for light gathering. Enhanced roughness can be provided by manipulating passivation layer etching parameters used during a formation process of the nano-scale tower structures, in order to affect surface roughness of a photoresist layer used for the etch. Manipulable etching parameters can include power, gas pressure, and etching compound chemistry.