SrBaEuAlSiN Red Phosphor for High-Power LED Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional red phosphors used in white light emitting devices suffer from low thermal and structural stability, leading to color changes when used in high-output LED applications, which affects their performance over time.
Innovation Solution
A red phosphor with the empirical formula Sr1−x−yBaxEuyAlSi4N7 is developed, where the composition ratio of Ba (x) is between 0 and 0.3, and Eu (y) is between 0 and 0.1, offering improved thermal stability and high light emission characteristics, with a peak wavelength between 600 to 660 nm and internal quantum efficiency of 80% or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional sulfide-based or oxide-based red phosphors are used in high-output LED applications, then the device can be driven with high power, but the phosphor exhibits low thermal and structural stability causing color changes over time
Solution Approach 1:
The patent changes the chemical composition parameters of the red phosphor by substituting Sr with Ba and Eu at specific ratios (0 < x ≤ 0.3 and 0 < y ≤ 0.1 in the formula Sr1-x-yBaxEuyAlSi4N7), which modifies the crystal structure and electronic properties to achieve both high power compatibility and improved thermal stability
Solution Approach 2:
The patent creates a composite phosphor material by combining multiple elements (Sr, Ba, Eu, Al, Si, N) in a specific empirical formula Sr1-x-yBaxEuyAlSi4N7, where the synergistic interaction between these elements provides both high light emission characteristics and excellent thermal stability for high-power LED applications
2Illumination intensity
If conventional red phosphors are used to achieve high light emission characteristics, then the brightness is improved, but the thermal stability deteriorates leading to color changes
Solution Approach 1:
The patent optimizes the compositional parameters by controlling the substitution ratios of Ba (x) and Eu (y) in the empirical formula Sr1-x-yBaxEuyAlSi4N7, where specific ranges of these parameters simultaneously achieve high light emission intensity and excellent thermal stability
Solution Approach 2:
The patent introduces localized Eu2+ ion substitution at specific crystal lattice sites within the Sr2Si5N8 structure, creating local structural modifications that enhance both the light emission properties and thermal stability without compromising the overall crystal structure
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 red phosphor maintains its properties at high temperatures, enhancing brightness and stability, and when used in white light emitting devices, it improves color rendering index and light emission efficiency, making it suitable for LED-based applications.
Implementation Method 1
a red phosphor including a nitride represented by an empirical formula Sr1−x−yBaxEuyAlSi4N7... when an excitation light irradiates onto the red phosphor... emit light having a peak wavelength ranging from 600 to 660 nm, internal quantum efficiency of the red phosphor may be 80% or more
Data Source
AI summary
A red phosphor includes a nitride represented by an empirical formula of Sr1−x−yBaxEuyAlSi4N7. A composition ratio (x) of barium (Ba) satisfies 0<x≦0.3 and a composition ratio (y) of europium (Eu) satisfies 0≦y≦0.1.