Blue Phosphor Quantum Efficiency via Composite Host Structure
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Solution Overview
Problem
Conventional blue phosphors have low emission quantum efficiency, which limits the performance of white LEDs in terms of color rendering and reproducibility.
Innovation Solution
A (Ba1−z,Srz)3MgSi2O8:Eu2+ based phosphor is developed, incorporating a mixed crystal of (Ba1−z,Srz)3MgSi2O8 and (Ba1−z,Srz)MgSiO4 as the host crystal, with Eu2+ as the luminescent center, to enhance quantum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional blue phosphors are used, then the structure is simple and ease of manufacture is maintained, but emission quantum efficiency is low
Solution Approach 1:
The patent employs composite crystal structure by combining (Ba1−z,Srz)3MgSi2O8 and (Ba1−z,Srz)MgSiO4 phases within the same phosphor particle. This composite approach allows the material to achieve high emission quantum efficiency (exceeding 60%) by leveraging the complementary properties of both crystal phases, while maintaining a relatively simple overall structure that can be synthesized using conventional ceramic methods.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the Sr substitution ratio (z value) and the phase composition ratio between the two crystal phases to optimize emission quantum efficiency. By controlling the sintering temperature, composition ratios, and Sr content, the patent achieves peak efficiency without requiring complex synthesis procedures, demonstrating how parameter optimization can resolve the contradiction between efficiency and simplicity.
2Productivity
If higher emission quantum efficiency is achieved, then light-emitting device performance is improved, but the phosphor structure becomes more complex
Solution Approach 1:
The dual-phase composite structure combines the high quantum efficiency characteristics of (Ba1−z,Srz)3MgSi2O8 with the optical properties of (Ba1−z,Srz)MgSiO4, achieving superior light-emitting device performance. The composite nature allows each phase to contribute its strengths while maintaining manufacturability through conventional ceramic processing techniques.
Solution Approach 2:
The patent applies local quality by creating distinct regions within phosphor particles where different crystal phases are distributed. This local phase distribution allows different portions of the phosphor to perform specialized functions - one phase primarily contributing to quantum efficiency while the other enhances optical performance - thereby improving overall device performance without requiring the entire structure to be complex.
3Quantity of substance
If Eu content is reduced, then material cost and complexity are decreased, but emission efficiency may be compromised
Solution Approach 1:
The patent utilizes parameter changes by optimizing the Eu dopant concentration within specific ranges (0.01-5 at%) while adjusting the host phase composition and Sr substitution ratio. This multi-parameter optimization allows the system to maintain high emission quantum efficiency with reduced Eu content, as the enhanced host lattice structure compensates for lower dopant concentrations by improving energy transfer efficiency and reducing non-radiative recombination pathways.
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 achieves higher emission quantum efficiency, leading to improved light-emitting device performance with enhanced color rendering and reproducibility, and reduced Eu content usage, especially at higher energy densities.
Implementation Method 1
a (Ba1−z,Srz)3MgSi2O8:Eu2+ based phosphor... with Eu2+ as the luminescent center... to enhance quantum efficiency
Data Source
AI summary
The present disclosure provides a (Ba1−z,Srz)3MgSi2O8:Eu2+ based phosphor with high emission quantum efficiency. Specifically, the present disclosure provides a blue light emitting phosphor including: a (Ba1−z,Srz)3MgSi2O8 based crystal where z satisfies 0≦z<1 and a (Ba1−z,Srz)MgSiO4 based crystal where z satisfies 0≦z<1 as a host crystal; and Eu2+ as a luminescent center.