White organic light-emitting devices fabricated utilizing a down-conversion CaAl₁₂ O₁₉:Mn phosphor layer

White organic light-emitting devices (OLEDs) were fabricated utilizing a CaAl₁₂ O₁₉:Mn phosphor layer. X-ray diffraction patterns for CaAl₁₂ O₁₉:Mn phosphors showed that Mn ions in the CaAl₁₂ O₁₉:Mn phosphors were completely substituted into Ga ions. Field-emission-scanning electron microscopy images showed that the sizes of the CaAl₁₂ O₁₉:Mn phosphor crystals were approximately between 0.1 and 3 μm. Although a broad band approximately between 250 and 550 nm of an excitation spectrum for CaAl₁₂ O ₁₉:Mn appeared, peaks were observed at 639, 654, and 665 nm of the fluorescence emission spectrum. The color coordinates of the electroluminescence spectra for white OLEDs with phosphor thicknesses of 0.25 and 0.35 mm shifted to the white emission side because the generated blue light from the blue OLEDs combined with the red light converted by the CaAl₁₂ O₁₉:Mn phosphor down-conversion layer. The color conversion efficiency of white OLEDs was significantly affected by the excitation source and the thickness of the phosphor layer.