Transactions on Electrical and Electronic Materials

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
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Effect of Chip Wavelength and Particle Size on the Performance of Two Phosphor Coated W-LEDs

  • Yadav, Pooja (Department of Physics, Shri Ramdeobaba College of Engineering and Management) ;
  • Joshi, Charusheela (Department of Physics, Shri Ramdeobaba College of Engineering and Management) ;
  • Moharil, S.V. (Department of Physics, R.T.M. Nagpur University)
  • Received : 2013.12.05
  • Accepted : 2014.02.03
  • Published : 2014.04.25
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Abstract

Most commercial white LED lamps use blue chip coated with yellow emitting phosphor. The use of blue excitable red and green phosphors is expected to improve the CRI. Several phosphors, such as $SrGa_2S_4:Eu^{2+}$ and $(Sr,Ba)SiO_4:Eu^{2+}$, have been suggested in the past as green components. However, there are issues of the sensitivity and stability of such phosphors. Here, we describe gallium substituted $YAG:Ce^{3+}$ phosphor, as a green emitter. YAG structures are already accepted by the industry, for their stability and efficiency. LEDs with improved CRI could be fabricated by choosing $Y_3Al_4GaO_{12}:Ce^{3+}$ (green and yellow), and $SrS:Eu^{2+}$ (red) phosphors, along with blue chip. Also, the effect of a slight change in chip wavelength is studied, for two phosphor-coated w-LEDs. The reduction in particle size of the coated phosphors also gives improved w-LED characteristics.

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