Luminescent Composition for Secure Material Authentication
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Solution Overview
Problem
Current luminescent compositions based on lanthanide oxide sulfides for marking materials lack versatility and security in authentication due to limited emission spectra and susceptibility to falsification.
Innovation Solution
Development of a luminescent composition comprising yttrium oxide sulfide combined with multiple lanthanide oxide sulfides and dopants from main group and transition group elements, offering 'up converter' properties and a wide range of emission spectra for secure material authentication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional lanthanide oxide sulfides are used for marking materials, then the marking function is achieved, but the emission spectrum is limited and authentication security is insufficient
Solution Approach 1:
The patent employs composite luminescent materials combining multiple lanthanide elements (Eu, Tb, Dy, Ho, Er, Tm, Yb) with oxide and fluoride components to create a multi-phase system. This composite approach generates rich, multi-wavelength emission spectra that are difficult to replicate, thereby enhancing both spectral versatility and authentication security simultaneously
Solution Approach 2:
The patent introduces dopants (Al, Si, P, S) at specific local positions within the crystal lattice structure to modify emission characteristics at particular wavelengths. This local modification allows precise control over emission properties without affecting the entire material structure, enabling tailored spectral features for enhanced security verification
2Illumination intensity
If simple luminescent compositions are used, then the composition is easy to manufacture, but the luminescence intensity is insufficient
Solution Approach 1:
The patent systematically optimizes compositional parameters including the ratios of different lanthanides (e.g., Eu: 0.1-5%, Tb: 0.1-5%), oxide content (0.1-10%), and fluoride content (0.1-10%). This parameter optimization enables precise control over luminescence intensity while maintaining a manageable synthesis process through established solid-state reaction methods
Solution Approach 2:
The patent uses oxide and fluoride components as intermediary substances that facilitate energy transfer between different lanthanide ions. These intermediaries enable efficient energy migration and upconversion processes, significantly enhancing luminescence intensity while keeping the overall composition manageable through standard ceramic processing techniques
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 composition provides high luminescence intensity and unique emission spectra, enabling secure and versatile marking and detection of materials, resistant to falsification through characteristic emission lines, suitable for various applications including biological systems and security verification.
Implementation Method 1
This property, referred to as 'up conversion' or 'anti-Stokes fluorescence', can be attributed to the electrons of the 4f shell of lanthanide ions being raised by sequential multiple excitation on irradiation to an energy level which has been increased by more than the energy corresponding to absorption of a single photon
Implementation Method 2
This property, referred to as 'up conversion' or 'anti-Stokes fluorescence'
Implementation Method 3
A photon which has a higher energy than the originally absorbed photon can be emitted from this energy level on relaxation
Data Source
AI summary
The invention relates to a luminescent composition which is based on yttrium oxide sulfide and other oxide sulfides and to which at least one doping agent is added. The inventive composition has a characteristic emission spectrum and can optionally be used along with a reading system that is adjusted to the emission spectrum in order to mark substances or *substance mixtures.