Photoluminescence properties of the magnetoplumbite-type BaMg₆Ti₆O₁₉:Mn⁴⁺ and spinel-type Mg₂TiO₄:Mn⁴⁺

Mn⁴⁺-doped magnetoplumbite-type BaMg₆Ti₆O₁₉ and spinel-type Mg₂TiO₄ red phosphors were synthesized by a solid-state reaction. BaMg₆Ti₆O₁₉:Mn⁴⁺ and Mg₂TiO₄:Mn⁴⁺ were formed as main and single phase above 1200 ºC, respectively. Although the emission peak of BaMg₆Ti₆O₁₉:Mn⁴⁺ and Mg₂TiO₄:Mn⁴⁺ were almost the same, the excitation peak of BaMg₆Ti₆O₁₉:Mn⁴⁺ and Mg₂TiO₄:Mn⁴⁺ were different. The⁴A₂→⁴T₁ spin-allowed transition peak of Mg₂TiO₄:Mn4+ shifted to a shorter wavelength side than that of BaMg₆Ti₆O₁₉:Mn⁴⁺ and 4A₂→4T₂ transition shifted to a longer wavelength side. The crystal field splitting energy of Mg₂TiO₄:Mn⁴⁺ was lower than that of BaMg₆Ti₆O₁₉:Mn⁴⁺. By the additional of R block, the racah parameter B increased and C decreased. Although the increase of B causes a blue-shift of the emission wavelength and the decrease of C causes a red-shift of the emission wavelength, PL emission wavelength was little different due to the influence of both racah parameter. Thus, it was suggested that the existence of R block results in a difference of photoluminescence properties.