Cone-Shaped Holes in Photovoltaic Substrates
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Solution Overview
Problem
Conventional photovoltaic devices face inefficiencies in absorbing incident radiation due to limited surface area and radiation transmission, leading to energy being converted into heat rather than usable electrical energy.
Innovation Solution
The formation of cone-shaped holes in a substrate with flat areas, created through lithographic patterning and dry etching, increases the surface area for absorption and enhances carrier collection efficiency by allowing radiation to be trapped and absorbed more effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional flat substrate is used, then manufacturing is simple, but surface area for light absorption is limited
Solution Approach 1:
The substrate surface is transformed from a flat two-dimensional plane to a three-dimensional structure with cone-shaped holes. This dimensional change increases the effective surface area available for light absorption and photovoltaic stack formation, directly resolving the contradiction between simple manufacturing and increased absorption area.
Solution Approach 2:
The substrate is engineered with an array of cone-shaped holes creating a porous structure. This porous configuration dramatically increases the surface area within the same footprint, providing more active sites for photon absorption and carrier generation while maintaining a manageable overall device structure.
2Loss of energy
If conventional flat surface is used, then radiation transmission is straightforward, but absorption efficiency is low
Solution Approach 1:
Cone-shaped holes with curved surfaces are introduced instead of flat geometries. The curved surfaces of the cones enhance light trapping through multiple internal reflections and increase the path length of photons within the substrate, improving absorption efficiency and reducing energy loss as transmitted or reflected radiation.
Solution Approach 2:
The cone-shaped holes act as intermediary structures between the incident radiation and the photovoltaic stack. They serve as light-trapping intermediaries that extend the interaction path between photons and the photovoltaic material, enhancing energy conversion efficiency before the light reaches the active layers.
3Power
If higher energy photons are absorbed, then more electrical energy can be generated, but more energy is converted to heat
Solution Approach 1:
The substrate is segmented into multiple cone-shaped holes rather than using a single flat surface. This segmentation increases the total absorption surface area, allowing more photons to be captured and converted. The distributed cone structures provide multiple pathways for photon absorption, improving overall power generation while the increased surface area helps manage heat distribution.
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 approach results in improved absorption of light spectra, increased surface area, and enhanced carrier collection efficiency, reducing energy loss as heat and increasing the overall performance of photovoltaic devices.
Implementation Method 1
Solar devices employ photovoltaic cells to generate current flow. Photons in sunlight hit a solar cell or panel and are absorbed by semiconducting materials, such as silicon. Carriers gain energy allowing them to flow through the material to produce electricity.
Implementation Method 2
When a photon hits silicon, the photon may be transmitted through the silicon, reflect off the surface, or be absorbed by the silicon, if the photon energy is higher than the silicon band gap value.
Implementation Method 3
lithographically exposing and developing the resist to create a pattern of cross-linked areas in the resist
Implementation Method 4
dry etching the substrate using the metal on the substrate as an etch mask to form a plurality of hole shapes in the substrate
Data Source
AI summary
A photovoltaic device includes a substrate having a plurality of hole shapes formed therein. The plurality of hole shapes each have a hole opening extending from a first surface and narrowing with depth into the substrate. The plurality of hole shapes form a hole pattern on the first surface, and the hole pattern includes flat areas separating the hole shapes on the first surface. A photovoltaic device stack is formed on the first surface and extends into the hole shapes. Methods are also provided.