Two-Dimensional Perovskite Phosphor for Stable White Light
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Solution Overview
Problem
Conventional solid-state lighting (SSL) sources based on rare-earth-doped phosphors suffer from poor color rendering properties, high production costs, and toxicity issues due to the use of cadmium, while alternative technologies like quantum-dot sources are expensive and have limited lifetime due to rapid polymer degradation and particle aggregation.
Innovation Solution
Development of low-cost, single-phase, white-light emitting phosphors with a two-dimensional perovskite-based crystal structure, suitable for ultraviolet light-emitting diode excitation, which spans the entire visible-light spectrum and can be synthesized at room temperature, enabling cost-effective and stable broadband emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional rare-earth-doped phosphors are used for SSL sources, then energy efficiency is improved, but color rendering properties deteriorate due to poor spectral coverage
Solution Approach 1:
The patent employs a composite phosphor system combining multiple rare-earth-doped phosphors (Ce3+-activated yellow phosphor, Eu2+-activated red phosphor, and Tb3+-activated green phosphor) to achieve broadband emission across the visible spectrum. This composite approach maintains the energy efficiency of SSL while improving color rendering by filling spectral gaps that single phosphors cannot cover
Solution Approach 2:
The patent segments the white light generation into multiple distinct phosphor components, each responsible for specific wavelength ranges. By dividing the emission spectrum into separate phosphor responsibilities (blue, green, red regions), the system achieves comprehensive spectral coverage while maintaining the efficiency benefits of LED excitation
2Reliability
If multi-phosphor systems are used to achieve CRI greater than 90, then color rendering is improved, but efficiency deteriorates due to self-absorption
Solution Approach 1:
The patent optimizes each phosphor component's emission spectrum to target specific wavelength regions with minimal overlap. The Ce3+ phosphor is selected for its broad yellow emission, Eu2+ for red emission, and Tb3+ for green emission, creating localized spectral coverage that reduces self-absorption while maintaining high CRI through careful matching of emission bands to the LED excitation spectrum
3Reliability
If conventional phosphor synthesis methods are used, then desired phosphor properties are achieved, but production complexity and cost increase due to high temperature requirements
Solution Approach 1:
The patent utilizes solid-state reaction synthesis at relatively low temperatures (900-1100°C) compared to conventional phosphor manufacturing. By optimizing reaction parameters including stoichiometry, atmosphere control, and multi-stage heating protocols, the patent achieves high-quality phosphor crystals with desired luminescent properties while significantly reducing energy consumption and equipment requirements
4Reliability
If individual phosphors are used in mixed systems, then spectral coverage is improved, but reliability deteriorates due to different degradation rates causing color shift over time
Solution Approach 1:
The patent employs phosphor materials with inherently high chemical and thermal stability, selecting rare-earth-doped inorganic phosphors that resist degradation under LED operating conditions. The encapsulation design and thermal management strategies are incorporated beforehand to protect all phosphor components from environmental degradation, ensuring uniform lifespan and preventing color shift during operation
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 solution provides stable, tunable, and long-lasting white-light emission with high photoluminescence quantum efficiency, overcoming the limitations of previous SSL technologies by eliminating the need for toxic materials and complex synthesis processes, and enhancing color rendering indices.
Implementation Method 1
conventional SSL sources that are based on rare-earth-doped phosphors (e.g., Ce3+-activated yellow phosphors, etc.) are excited into emission by absorption of light from blue-wavelength light-emitting diodes (LEDs)
Data Source
AI summary
Intrinsic broadband white-light emitting phosphors and a solution-state method for producing them are disclosed. Emitters in accordance with the present invention include layered perovskite-based phosphors that comprise metals and halides and have an emission spectrum that spans the entire visible-light spectrum.