Asymmetric Nanostructured LSC Surfaces for Broadband Light Trapping
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Solution Overview
Problem
Current luminescent solar concentrators (LSCs) are inefficient, with 50-70% of light escaping via the top surface due to limitations in existing reflective and photonic structures, which are primarily effective for small bandgaps and fail to address asymmetric light propagation needs.
Innovation Solution
The implementation of nanostructures with a pyramidal shape and periodic arrays on substrates, such as aluminum oxide and polymethylmethacrylate, to facilitate asymmetric light propagation, allowing preferential light propagation in one direction and minimizing emission, thereby reducing light losses within a broadband wavelength range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If spectrally selective mirrors or Bragg reflectors are used to trap emission wavelengths, then light trapping efficiency is improved, but the bandgap is limited to small ranges and light entry is restricted
Solution Approach 1:
The patent employs asymmetric nanostructures (such as pyramidal or conical shapes with specific aspect ratios) arranged in periodic arrays that exhibit direction-dependent optical properties. These asymmetric structures allow light to enter the LSC across a broadband spectrum while preferentially trapping emission wavelengths through asymmetric scattering and interference effects, thereby resolving the contradiction between achieving wide bandgap light entry and maintaining effective wavelength trapping.
Solution Approach 2:
The invention changes the geometric parameters of the nanostructures (size, shape, spacing, aspect ratio) to optimize the asymmetric light propagation properties. By adjusting these parameters, the system achieves broadband light entry while maintaining effective trapping of emission wavelengths across a wider bandgap range, overcoming the limitations of conventional mirror-based approaches.
2Loss of energy
If conventional mirrors are used to prevent light escape, then light trapping is improved, but device complexity increases due to additional optical components
Solution Approach 1:
The patent merges the light trapping function directly into the LSC substrate by integrating asymmetric nanostructures into the waveguide matrix. This eliminates the need for separate mirror components or complex optical assemblies, as the nanostructures themselves provide the wavelength-selective trapping mechanism, thereby reducing device complexity while maintaining effective light trapping.
Solution Approach 2:
The asymmetric nanostructures serve as intermediary elements between the incident light and the LSC active medium. These nanostructures mediate the light-matter interaction by providing asymmetric scattering and interference effects that enable broadband light entry while trapping emission wavelengths, replacing the need for conventional mirror-based intermediate components.
3Adaptability or versatility
If nanostructures are designed for asymmetric light propagation, then broadband light entry is permitted, but manufacturing precision requirements increase
Solution Approach 1:
The patent segments the LSC surface into periodic arrays of discrete asymmetric nanostructures. This segmentation approach allows for modular manufacturing where individual nanostructures can be fabricated with standard precision, and the collective array effect achieves the desired broadband asymmetric light propagation. The periodic arrangement provides robustness against manufacturing variations while maintaining the asymmetric optical properties.
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 achieves significant reduction in light losses by allowing more light to enter and be trapped within the LSC, with up to 92% difference in forward and backward transmission in the optimal range of 700-1050 nm, enhancing the efficiency of light concentration and energy conversion.
Implementation Method 1
the plurality of nanostructures are configured to permit asymmetric light propagation. Specifically, the nanostructures allow preferential propagation of a wavelength range of light in a forward direction while minimizing propagation of the wavelength range of light in a backward direction
Implementation Method 2
The one or more waveguides are configured to guide light toward the one or more photovoltaic cells via total internal reflection within the luminescent solar concentrator
Implementation Method 3
These luminescent species have a specific absorption range and an emission range. Their purpose is to absorb light within a certain wavelength region and to emit light at a slightly lower energy level
Implementation Method 4
An LSC is typically made from a glass or plastic substrate that contains luminescent species (such as organic dye, quantum dots, or fluorophores)
Data Source
AI summary
A luminescent solar concentrator including a light propagation device, one or more photovoltaic cells, and one or more waveguides is provided. The light propagation device includes a plurality of nanostructures configured to permit preferential propagation of a wavelength range of light in one direction. The one or more photovoltaic cells are positioned adjacent an end of the light propagation device. The one or more waveguides are configured to guide light toward the one or more photovoltaic cells via total internal reflection within the luminescent solar concentrator.