Tm2+ Inorganic Luminescent Materials for Solar Conversion
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Solution Overview
Problem
Current luminescent materials used in solar radiation conversion devices, such as luminescent solar concentrators and conversion layers, face challenges with limited spectral absorption, overlapping absorption and emission spectra, and self-absorption issues, which hinder efficient solar energy conversion.
Innovation Solution
The use of Tm2+ based inorganic luminescent materials that exhibit broadband absorption across the UV, visible, and infrared spectrum with a large Stokes' shift, reducing self-absorption and matching the emission spectrum with photovoltaic devices for optimal energy conversion, specifically utilizing Tm2+ doped inorganic crystalline host materials like CaI2 or NaI for enhanced absorption and emission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic dyes are used as luminescent material, then ease of manufacture and integration are improved, but spectral absorption width and conversion efficiency deteriorate
Solution Approach 1:
The patent changes the chemical composition parameter from organic dyes to Tm2+ doped inorganic host materials, which fundamentally alters the absorption and emission characteristics. This parameter change enables broadband absorption across UV, visible, and infrared regions while maintaining ease of material synthesis through established doping techniques.
Solution Approach 2:
The invention uses composite material structure consisting of Tm2+ ions doped into inorganic host materials such as oxides, fluorides, or halides. This composite approach combines the advantages of inorganic materials (broadband absorption, photostability) with the ability to control optical properties through host-guest interactions, achieving both high conversion efficiency and manufacturability.
2Quantity of substance
If conventional luminescent materials are used, then cost is reduced, but self-absorption losses increase due to overlapping spectra
Solution Approach 1:
The patent changes the emission wavelength parameter by selecting Tm2+ materials with specific 4f-5d transition characteristics that emit in the infrared region (900-1200 nm). This parameter change creates a large Stokes shift between absorption (UV-visible) and emission (infrared), eliminating spectral overlap and self-absorption losses while maintaining cost-effectiveness.
3Adaptability or versatility
If luminescent materials with broad absorption are used, then spectral coverage is improved, but emission matching with PV cells deteriorates
Solution Approach 1:
The patent applies local quality by designing the luminescent material to have broadband absorption characteristics (covering UV, visible, and infrared) while maintaining a sharp, localized emission peak at specific infrared wavelengths (900-1200 nm) that match the bandgap of common PV cells. This localized emission quality ensures optimal energy transfer to the photovoltaic cell.
Solution Approach 2:
The invention changes the emission wavelength parameter to infrared region (900-1200 nm) which corresponds to the bandgap energy of silicon and other common photovoltaic materials. This parameter change ensures that the emitted photons have optimal energy for electrical conversion while the broadband absorption captures maximum solar spectrum.
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
Tm2+ based inorganic luminescent materials absorb more than twice the solar radiation compared to conventional dyes, minimizing self-absorption and optimizing energy conversion efficiency by aligning the infrared emission peak with the 1.13 eV bandgap for improved solar spectrum conversion in single-junction cells.
Implementation Method 1
Tm2+ based inorganic luminescent materials for converting solar radiation of at least part of the UV and/or visible and/or infrared solar spectrum into infrared solar radiation
Implementation Method 2
A considerable fraction of the light is trapped in the plate that acts as a light guide by total internal reflection
Implementation Method 3
photovoltaic cells for converting at least part of said infrared solar radiation into electrical power
Data Source
AI summary
A solar radiation conversion device is described that uses a luminescent Tm2+ inorganic material for converting solar radiation of at least part of the UV and/or visible and/or infrared solar spectrum into infrared solar radiation, preferably the infrared solar radiation having a wavelength of around 1138 nm; and, a photovoltaic device for converting at least part of the infrared solar radiation into electrical power.