Improved Chromaticity and Thermal Stability in White Light Emitting Diode Phosphor BaMgAl10O17: Eu2+, Mn2+

Abstract

A highly efficient white light emitting diodes phosphor BaMgAl₁₀O₁₇: Eu²⁺, Mn²⁺ coating with MgF₂ layer was prepared and characterized. The phosphor consisted of a host material BaMgAl₁₀O₁₇ doped with 0.05 mol % Eu²⁺ and co-doped 0.05 mol % Mn²⁺. The mechanism of energy transfer between Eu²⁺ and Mn²⁺ is dipole-quadrupole. The phosphor coated with MgF₂ reveals that the durability is greatly enhanced 9.8 % comparison with uncoated phosphor after thermal degradation tests. The CIE chromaticity coordinates (0.335, 0.330) of the phosphor fabricated light-emitting diodes has a very close to that of the standard white light point of (0.333, 0.333). And the colour rendering index increases from 79 to 85 after the BaMgAl₁₀O₁₇: Eu²⁺ phosphor co-doped with Mn²⁺. All the result could conclude that co-doped and surface coated were two promises approaches for improving the colour rendering index of the near UV light-emitting diode and the stability of BaMgAl₁₀O₁₇: Eu²⁺, Mn²⁺ phosphor.