Highly efficient white-light-emitting diodes fabricated with short-wavelength yellow oxynitride phosphors

摘要

We have already reported orangish yellow Ca-α-SiAlON:Eu~(2+) phosphors, and applied them to fabricate warm white light-emitting diodes (LEDs). In this letter, we report on greenish yellow Li-α-SiAlON:Eu~(2+) phosphors, and use them to create daylight when coupled to an InGaN blue LED chip (460 nm). The newly discovered Li-α-SiAlON:Eu~(2+) phosphors emit at shorter wavelengths of 573-577 nm under the 460 nm excitation, and exhibit a smaller Stokes shift than Ca-α-SiAlON:Eu~(2+) does. By using this short-wavelength yellow oxynitride phosphor, bright daylight emissions from white LEDs can be generated. Thus, highly efficient white LEDs with tunable white light can be fabricated with α-SiAlON: Eu~(2+) phosphors, enabling them for a wider range of applications.