Solid Solution Phosphors for Use in Solid State White Lighting Applications

Brief Description

A new green- and yellow-emitting phosphor material via solid solution that can be used to create a white light emitting diode. 

Background

Most currently commercially available LED lamps for generating white light employ yellow-emitting Ce³⁺ phosphors that are excited by blue InGaN diodes. However, these phosphors have relatively weak emission in the red region of the emission spectrum, which has led to limitations on their efficiency and color rendering ability. Additionally, the output color from Ce³⁺ phosphors is strongly dependent on temperature and current, which becomes a significant problem in high-power LEDs. Due to these limitations, there have been extensive efforts to develop new yellow-emitting phosphors for use in blue-pumped LED applications; therefore, a new phosphor material is required to increase phosphor efficiency and color-rendering property in the red region. 

Description

Researchers at UC Santa Barbara have created a new green- and yellow-emitting phosphor material via solid solution that can be used to create a white light emitting diode. The phosphors created show a broad band emission from 430 to 760 nm when excited by existing InGaN-based blue LED and GaN-based long wavelength ultraviolet LED. LEDs that use the solid solution series phosphors are expected to have good color rendering properties with a wide spectral range and high efficiency for white lighting. The white light emission can be obtained using a wide variety of combinations of the new phosphor materials and blue or UV LED.  

Advantages

• Good color-rendering property
• Variety of combinations of phosphor materials and blue LEDs
• Improved device efficiency

Applications

• Solid state lighting systems
• Liquid crystal displays (LCDs)

Patent Status