Nanostructured Solar Cell with Imprint Lithography
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Solution Overview
Problem
Thin-film amorphous silicon (a-Si) solar cells have low power conversion efficiency and stability compared to crystalline silicon (C-Si) solar cells, and existing nanostructured solar cell fabrication methods are costly and lack control over nanostructure dimensions, leading to lower efficiency.
Innovation Solution
The use of nano-imprint lithography with low-viscosity UV-curable imprinting fluids and drop-on-demand fluid dispensing to create nanostructured solar cells with optimized nanostructures that increase surface area and light trapping, combined with a-Si deposition on patterned substrates, enhances efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fabrication methods are used for nanostructured solar cells, then manufacturing cost is reduced, but manufacturing precision and control over nanostructure dimensions are worsened
Solution Approach 1:
The patent applies preliminary action by first forming a relief pattern in a formable layer before transferring it to the substrate. This pre-formed pattern serves as a template that guides subsequent material deposition, ensuring precise control over nanostructure dimensions while using conventional, cost-effective manufacturing processes. The relief pattern is created in advance to define the exact geometry of the nanostructures before the actual solar cell materials are deposited.
Solution Approach 2:
The patent uses copying by transferring a pattern from a formable layer to an underlying substrate through imprint lithography. The relief pattern in the formable layer is copied onto the substrate, creating a replicated nanostructure pattern. This copying mechanism enables precise dimensional control by using the formable layer as a master template, while the replication process itself can be performed using cost-effective conventional fabrication methods.
2Device complexity
If thin-film amorphous silicon is used instead of crystalline silicon, then manufacturing cost and device complexity are reduced, but power conversion efficiency and stability are worsened
Solution Approach 1:
The patent applies local quality by creating nanostructures with specific geometric features (relief patterns) in localized regions of the solar cell. These nanostructured regions have enhanced light-trapping properties compared to flat regions, improving local efficiency without changing the entire solar cell structure. The a-Si material is deposited selectively on these nanostructured surfaces, creating zones of enhanced performance while maintaining overall device simplicity.
Solution Approach 2:
The patent uses curvature by forming relief patterns with curved surfaces in the nanostructures. These curved surfaces enhance light trapping through multiple internal reflections and scattering effects, improving light absorption in the thin-film a-Si layer. The curved geometry increases the optical path length without increasing the physical thickness of the solar cell, thereby improving efficiency while maintaining the simplicity of thin-film construction.
3Ease of manufacture
If thin-film amorphous silicon is used instead of crystalline silicon, then manufacturing cost is reduced, but power conversion efficiency is worsened
Solution Approach 1:
The patent uses curvature by forming relief patterns with curved surfaces in the nanostructures. These curved surfaces enhance light trapping through multiple internal reflections and scattering effects, improving light absorption in the thin-film a-Si layer. The curved geometry increases the optical path length without increasing the physical thickness of the solar cell, thereby improving efficiency while maintaining the simplicity of thin-film construction.
Solution Approach 2:
The patent applies dimensionality change by transitioning from a two-dimensional flat surface to a three-dimensional nanostructured surface with relief patterns. This adds vertical dimensionality to the light-trapping interface, creating multiple reflection surfaces and increasing the effective optical path length. The nanostructured surface provides enhanced light absorption in the third dimension (depth) without increasing the lateral footprint of the solar cell, thereby improving power conversion efficiency at low cost.
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 high power conversion efficiency and improved stability of a-Si solar cells at a lower cost, with the ability to control nanostructure dimensions and interfaces, surpassing the efficiency of conventional flat solar cells.
Implementation Method 1
low-viscosity UV-curable imprinting fluids
Implementation Method 2
optimized nanostructures that increase surface area and light trapping
Implementation Method 3
a-Si deposition on patterned substrates, enhances efficiency and stability
Data Source
AI summary
Systems and methods for fabrication of nanostructured solar cells having arrays of nanostructures are described, including nanostructured solar cells having a repeating pattern of pyramid nanostructures, providing for low cost thin-film solar cells with improved PCE.