Manganese-Activated Fluoride Phosphor IR Spectrum
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Solution Overview
Problem
Conventional fluoride phosphors in light-emitting devices experience a reduction in emission intensity over time, especially when exposed to high temperature and humidity, and their durability is compromised by surface treatments, leading to increased production costs and reduced performance.
Innovation Solution
A manganese-activated fluoride phosphor with a basic structure comprising potassium, silicon, and fluorine, characterized by a specific IR absorption spectrum with a peak intensity ratio of 0.1 or less in the range of 3570 to 3610 cm−1 to 1200 to 1240 cm−1, which is synthesized and treated with an organic solvent to maintain high emission intensity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluoride phosphors are used in light-emitting devices, then the device can be manufactured with standard materials, but the emission intensity reduces over time especially under high temperature and humidity conditions
Solution Approach 1:
A silane-based surface treatment agent is introduced as an intermediary substance between the fluoride phosphor particles and the external environment. This treatment agent forms a protective coating on the phosphor surface that prevents water penetration and chemical degradation, thereby maintaining emission intensity over time without altering the core phosphor material properties
Solution Approach 2:
The surface chemistry parameters of the phosphor particles are changed by applying a silane-based treatment. This modification alters the surface energy, hydrophobicity, and chemical stability of the phosphor particles, making them resistant to moisture and temperature-induced degradation while preserving their luminescent properties
2Reliability
If surface treatment with water-containing solution is applied to improve durability, then the phosphor durability under high temperature and humidity improves, but the emission intensity reduces due to water contact
Solution Approach 1:
The silane-based surface treatment agent acts as an intermediary barrier that prevents direct contact between water molecules and the phosphor surface. This protective layer allows the phosphor to be exposed to humid environments without the water molecules penetrating to the phosphor surface and causing emission intensity reduction
Solution Approach 2:
The surface treatment process is designed to be self-protective, where the silane-based treatment agent forms a hydrophobic coating that automatically repels water molecules. This self-service mechanism continuously protects the phosphor emission intensity without requiring external intervention or additional protective layers
3Reliability
If surface treatment with organic amines, quaternary ammonium salts, or other treatment agents is applied, then the phosphor durability under high temperature and humidity improves, but the production cost increases due to additional treatment steps
Solution Approach 1:
The silane-based surface treatment is applied as a preliminary step during the phosphor manufacturing process, before the phosphor particles are mixed with resin or encapsulated. This timing allows the treatment to be integrated into the existing production flow without requiring separate treatment stations or additional handling steps
Solution Approach 2:
The surface treatment parameters are optimized to use simple, low-cost silane-based agents that can be applied in aqueous or alcoholic solutions. The treatment conditions (concentration, temperature, time) are adjusted to achieve maximum protective effect with minimum material usage and processing time, thereby reducing overall production costs
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 maintains high emission intensity and stability, reducing the emission intensity maintenance ratio degradation and ensuring consistent performance in light-emitting devices, even under prolonged use and varying environmental conditions.
Implementation Method 1
A light-emitting diode (LED) light-emitting device mainly comprises a combination of a phosphor and a LED chip serving as an excitation light source
Implementation Method 2
shows an IR absorption spectrum in which an intensity ratio of a peak in a range of 3570 to 3610 cm−1 to that in a range of 1200 to 1240 cm−1 is 0.1 or less
Data Source
AI summary
Embodiments of the present invention provide a phosphor improved in the emission intensity maintenance ratio without impairing the emission intensity and further a light-emitting device employing that phosphor. The phosphor is activated by manganese and has a basic structure comprising at least one element selected from the group consisting of potassium, sodium and calcium; at least one element selected from the group consisting of silicon and titanium; and fluorine. In an IR absorption spectrum of the phosphor, the intensity ratio of the peak in 3570 to 3610 cm−1 to that in 1200 to 1240 cm−1 is 0.1 or less.