3D Structured Photovoltaic Cells for Light Trapping
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Solution Overview
Problem
Conventional photovoltaic cells have limitations in power generation capability due to their flat pn-junction structure, which results in low photo carrier collection efficiency and inability to absorb a wide range of the solar spectrum, leading to inefficient energy conversion and high production costs.
Innovation Solution
The development of photovoltaic cell structures featuring pyramid, trapezoidal, and cylindrical shapes with nano or micrometer-scale blocks that increase the junction area and amplify light incidence, combined with graded refractive index antireflection coatings to reduce reflection losses and enhance light absorption across a broader spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional flat pn-junction structure is used, then manufacturing is simple, but power generation capability and photo carrier collection efficiency are low
Solution Approach 1:
The patent transitions from a conventional two-dimensional flat pn-junction to a three-dimensional structured junction with pyramid, trapezoidal, and cylindrical shapes. This dimensional change increases the junction area and light absorption path length, thereby enhancing power generation capability and photo carrier collection efficiency while maintaining manufacturing feasibility through established semiconductor processing techniques.
Solution Approach 2:
The patent employs curved surfaces including cylindrical shapes and pyramidal structures with inclined facets instead of flat planes. These curved and angled surfaces reduce light reflection, increase light trapping, and expand the effective junction area, leading to improved energy conversion efficiency without significantly complicating the manufacturing process.
2Productivity
If conventional flat structure is used, then manufacturing cost is low, but light absorption efficiency and spectrum coverage are limited
Solution Approach 1:
By creating three-dimensional pyramid and cylindrical structures, the patent increases the light absorption path length and junction area within the same footprint, thereby improving energy conversion efficiency. These structures can be fabricated using modified conventional semiconductor processes, balancing enhanced performance with manufacturing cost considerations.
Solution Approach 2:
The patent modifies geometric parameters such as pyramid height, base width, and cylinder diameter to optimize light trapping and junction area. By carefully controlling these dimensional parameters, the patent achieves superior energy conversion efficiency while using standard manufacturing techniques, thus managing production costs effectively.
3Area of stationary object
If conventional pn-junction is used, then structure is simple, but junction area and photo carrier collection are insufficient
Solution Approach 1:
The patent creates three-dimensional pyramid and cylindrical structures that provide multiple surfaces for pn-junction formation. This dimensional transformation increases the total junction area available for photo carrier collection while using fabrication processes that are extensions of conventional planar junction techniques, thus managing structural complexity.
Solution Approach 2:
The patent divides the junction into multiple segmented surfaces on pyramid faces and cylindrical structures. This segmentation increases the total junction area and creates multiple collection pathways for photo carriers, improving collection efficiency while maintaining a systematic approach that does not excessively complicate manufacturing.
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
These structures significantly increase the conversion efficiency of photovoltaic cells to over 50% using silicon materials and over 80% for other materials, while reducing production costs by minimizing the use of expensive substrates and improving energy generation capabilities both during the day and at night.
Implementation Method 1
graded refractive index antireflection coatings to reduce reflection losses and enhance light absorption across a broader spectrum
Implementation Method 2
graded refractive index antireflection coatings to reduce reflection losses
Implementation Method 3
photovoltaic cells where light is converted into electric power
Data Source
AI summary
This invention relates to a novel structure of photovoltaic devices (e.g. photovoltaic cells also called as solar cells) are provided. The cells are based on the micro or nano scaled structures which could not only increase the surface area but also have the capability of reducing the reflection and increasing the absorption of incident light. More specifically, the structures are based on 3D structure which are made of electric materials covering semiconductors, insulators, dielectric, polymer, and metallic type materials. By using such structures reflection loss of the light from the cell is significantly reduced, increasing the absorption, which results in increasing the conversion efficiency of the solar cell, and reducing the usage of material while increasing the flexibility of the solar cell. The structures can be also used in other optical devices wherein the reflection loss and absorption are required to enhance significantly improve the device performances.