Enhancing spectral uniformity in full-spectrum white LEDs using an SiO₂ aerogel encapsulant

Area of Science:

• Materials Science
• Solid-State Lighting
• Nanotechnology

Background:

• Achieving high luminous efficacy and spectral uniformity in full-spectrum white LEDs (FS-WLEDs) is hindered by phosphor sedimentation during curing.
• Phosphor precipitation negatively impacts LED performance and reliability.

Purpose of the Study:

• To develop a method for suppressing phosphor sedimentation in FS-WLEDs.
• To enhance the luminous efficacy, spectral uniformity, and color rendering of FS-WLEDs.
• To evaluate the stability and scalability of the proposed solution.

Main Methods:

• Incorporation of 1.0 wt% SiO2 aerogel into a four-phosphor InGaN-based FS-WLED package.
• Utilizing Ce-line scan Electron Probe Microanalysis (EPMA) to provide direct evidence of sedimentation suppression.
• Conducting long-term stability tests (1008 hours at 150°C).

Main Results:

• SiO2 aerogel successfully mitigated phosphor precipitation.
• Luminous efficacy increased by 7.8% to 110 lm/W.
• Average Color Rendering Index (CRI) improved from 91 to 95.
• Angular color temperature deviation reduced by 194 K.
• Demonstrated long-term stability and reliability.

Conclusions:

• The SiO2 aerogel-doped composite is an effective, scalable, and low-cost solution for controlling phosphor sedimentation in FS-WLEDs.
• This approach offers significant improvements in LED performance and reliability for next-generation solid-state lighting.
• The method combines sedimentation control with material savings and proven stability.