Rare Earth Complex with Polycyclic Ligand for Blue LED Excitation
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Solution Overview
Problem
Current rare earth light-emitting substances are inefficiently excited by visible light in the vicinity of 460 nm, limiting their application in white LED light sources and other technologies.
Innovation Solution
A rare earth complex comprising a rare earth ion coordinated with a ligand having a condensed polycyclic aromatic group, which enhances light emission efficiency when excited by visible light in the 420 to 480 nm range, utilizing a specific structure and semiempirical molecular orbital calculations to optimize absorption properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a rare earth light-emitting substance is used with typical excitation wavelength at 400 nm or less, then light emission efficiency is high, but compatibility with blue LED excitation (460 nm) is poor
Solution Approach 1:
The patent modifies the molecular structure of the ligand by introducing a condensed polycyclic aromatic group, which changes the absorption spectrum parameters to enable excitation at 460 nm while maintaining emission efficiency. This structural parameter change allows the rare earth complex to be excited by blue LED light.
Solution Approach 2:
The patent creates a composite structure combining a rare earth ion with an organic ligand containing condensed polycyclic aromatic groups. This composite material integrates the optical properties of both components, achieving both blue LED excitation compatibility and efficient light emission.
2Adaptability or versatility
If a rare earth complex with broad absorption band is used, then excitation flexibility is improved, but emission bandwidth increases reducing resolution
Solution Approach 1:
The patent achieves different optical properties in different spectral regions: the condensed polycyclic aromatic group provides broad absorption for flexible excitation, while the rare earth ion provides narrow emission for high resolution. Each component contributes its optimal local quality to the overall system.
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
The rare earth complex efficiently emits light with a narrow emission band, enabling effective application in white LEDs and optical coherence tomography, offering improved resolution and cost-effectiveness.
Implementation Method 1
The excitation wavelength band (absorption wavelength) of an intensive light-emitting rare earth light-emitting substance is typically at 400 nm or less
Implementation Method 2
A rare earth complex which exhibits emission of red light is expected to be applied to, for example, as fluorescent substance to constitute a white LED light source
Data Source
AI summary
A rare earth complex including a rare earth ion and a ligand coordinated with the rare earth ion and having a condensed polycyclic aromatic group. The condensed polycyclic aromatic group is a residue formed by removing a hydrogen atom from a condensed polycyclic aromatic compound represented by the following formula (I) or (II):