Upconversion Phosphors for UV-C Antimicrobial Plastics
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Solution Overview
Problem
Current antimicrobial plastic products rely on the release of active ingredients, which can be harmful to humans and the environment, and often require chemical diffusion processes that damage the plastic matrix and are prone to resistance development.
Innovation Solution
Development of plastic products incorporating specific phosphors that emit UV-C radiation upon irradiation with lower energy wavelengths, providing a physical antimicrobial action without the need for active ingredient release, using phosphors of the formula A1−x−y−zB*yB2SiO4:Ln1xLn2z, which are doped with praseodymium and optionally co-doped with gadolinium, and are at least partially crystalline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical biocides or disinfectants are used to achieve antimicrobial action, then microorganisms are effectively killed, but the substances are harmful to humans and the environment and promote resistance development
Solution Approach 1:
The patent replaces chemical antimicrobial agents with a physical mechanism - UV-C radiation generated by upconversion phosphors. The phosphors absorb lower energy light (visible or infrared) and convert it to high-energy UV-C radiation that kills microorganisms through physical damage to their DNA/RNA, eliminating the need for harmful chemical substances while maintaining effective antimicrobial action
Solution Approach 2:
The patent changes the energy parameter of light by using upconversion phosphors that convert low-energy photons (visible/infrared range) into high-energy UV-C photons. This parameter transformation enables the generation of germicidal radiation without requiring chemical substances, thus resolving the contradiction between effectiveness and environmental harm
2Reliability
If active antimicrobial ingredients are integrated into plastic compositions, then antimicrobial effect is achieved, but the active ingredients are released into the environment causing endangerment
Solution Approach 1:
The patent substitutes chemical diffusion-based antimicrobial action with a physical radiation mechanism. The upconversion phosphors embedded in the plastic generate UV-C radiation upon light absorption, which kills microorganisms through direct physical damage rather than through release and diffusion of chemical active ingredients, thereby preventing environmental contamination
Solution Approach 2:
The phosphors are self-activating - they automatically convert absorbed light energy into UV-C radiation when exposed to light sources. This self-service mechanism eliminates the need for external activation or release of chemical agents, providing continuous antimicrobial protection without substance loss to the environment
3Reliability
If chemical diffusion processes are used for antimicrobial action, then microorganisms are affected, but the plastic matrix is damaged
Solution Approach 1:
The patent replaces chemical diffusion processes that penetrate and damage the plastic matrix with a physical radiation mechanism. UV-C photons generated by the phosphors act on microorganisms from within the plastic without requiring chemical substances to diffuse through or react with the plastic polymer chains, thus preserving matrix integrity while maintaining antimicrobial efficacy
4Object-affected harmful factors
If UV-C radiation is generated through upconversion phosphors, then antimicrobial action is achieved without chemical release, but energy conversion efficiency must be optimized
Solution Approach 1:
The patent optimizes the energy conversion process by selecting phosphors with specific upconversion characteristics that efficiently convert visible or infrared light into UV-C radiation. By carefully controlling the phosphor composition, particle size, and distribution in the plastic, the system maximizes the conversion efficiency while maintaining the benefit of eliminating harmful chemical release
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 phosphor-based plastic products achieve antimicrobial action through up-conversion, effectively inactivating microorganisms by emitting UV-C radiation, thereby avoiding the drawbacks of chemical diffusion and environmental harm, and maintaining the integrity of the plastic matrix.
Implementation Method 1
specific phosphors which, on irradiation with electromagnetic radiation having lower energy and longer wavelength in the range from 2000 nm to 400 nm, preferably in the range from 800 nm to 400 nm, emit electromagnetic radiation having higher energy and shorter wavelength in the range from 400 nm to 100 nm, preferably in the range from 300 nm to 200 nm
Data Source
AI summary
Plastic products containing at least one synthetic material and at least one luminophore of general formula (I) A1−x−y−zB*yB2SiO4:Ln1xLn2z can be produced. A is selected from the group of Mg, Ca, Sr and Ba; B is selected from the group of Li, Na, K, Rb and Cs; B* is selected from among the group of Li, Na and K; and B=B* or B≠B*, preferably B≠B*. Ln1 is selected from among the group consisting of praseodymium (Pr), erbium (Er) and neodymium (Nd); Ln2 is gadolinium (Gd); x=0.0001 to 0.0500; z=0.0000 or z=0.0001 to 0.3000, with the proviso that y=x+z. Objects that are made of the plastic products can be produced.