Luminescence of M ions (M=C, Fe, Co, Ni, Mn, Ti) in a-Al2O3 phosphor: Insight into the effects of metal salt and sintering temperature on the luminescence of M:a-Al2O3 phosphor

A polyacrylamide gel route is used to synthesize the alumina-based light-emitting material M: α-Al₂O₃ (M=C, Fe, Co, Ni, Mn, Ti). Sintering temperature, pH value, organic additive, chelating agent, C and metal salt can significantly effects the formation of rhombohedral α-Al₂O₃ phase. The structure analysis shows that the carbon, Ti, Co, Ni doped Al₂O₃ powders obvious suppress the formation of α-Al₂O₃, in contrast, the Fe, Mn doped Al2O3 can accelerate the formation of α-Al₂O₃. The carbon and metal salt introduction to the Al₂O₃ precursor solution obvious influenced the sample morphology, band-gap, color and photoluminescence properties. The results show that the carbon and metal salt introduced to Al₂O₃ precursor solution reduces the band-gap values and enhances the photoluminescence properties of M: α-Al₂O₃ powders. The photoluminescence mechanisms of M: α-Al₂O₃ powders have been discussed on the basis of the experimental results. The M: α-Al₂O₃ composites making them promising candidates as efficient light-emitting materials, pigments, photocatalysts and radiation detection including space dosimetry, environmental dosimetry, medical dosimetry and personal dosimetry.