Synthesis and Photoluminescence Properties of Sm3+-Doped Ca10(PO4)6(OH)2 Nanowire

The Sm3+-doped Ca10(PO4)6(OH)2 nanowires are synthesized by hydrothermal method. X-ray diffraction confirmed that the nanowires are made of the hexagonal Ca10(PO4)6(OH)2. Scanning electron microscope and transmission electron microscope analysis show that the lengths of the nanowires are approximately 5μm, and their diameters are around 100 nm, and the aspect (length/diameter) ratio is about 50. The room temperature photoluminescence (PL) spectra of Sm3+-doped Ca10(PO4)6(OH)2 nanowires doped with different Sm3+ concentration under 405 nm excitation has been investigated. It is found that there are three main sharp emissions peaks at near 569, 604, and 649 nm. The three emissions are due to the f-f forbidden transitions of the 4f electrons of Sm3+, corresponding to 4G5/2→6H5/2 (569 nm), 6H7/2(604 nm), and 6H9/2(649 nm), respectively. In addition, concentration quenching is also observed. It is found that the Sm3+4G5/2→6H7/2(604 nm) emission intensity of Sm3+-doped Ca10(PO4)6(OH)2 nanowires significantly increases with the increase of Sm3+ concentration, and shows a maximum when Sm3+ doping content is 0.5%. If Sm3+ concentration continues to increase, namely more than 0.5%, the Sm3+4G5/2→6H7/2 emission intensity decreases.