Kazuo Inamori School of Engineering, Alfred University, 2 Pine Street, Alfred, NY 14802, USA.
Biomaterials. 2010 May;31(15):4259-67. doi: 10.1016/j.biomaterials.2010.02.009. Epub 2010 Feb 25.
We present a detailed analysis of the luminescence behavior of europium-doped hydroxyapatite (HAp) and calcium-deficient hydroxyapatite (Ca-D HAp) nanopowders. The results show that, while both powders are similar in crystallite size, particle size, and morphology, the luminescence behavior differs significantly. For the HAp:Eu powders, the emission is clearly from Eu(3+) ions and corresponds to typical (5)D(0) --> (7)F(J) emissions, whereas for the Ca-D HAp:Eu powders, we also see a broad emission with two peaks at 420 and 445 nm, corresponding to the 4f(6)5d(1) --> 4f(7) ((8)S(7/2)) transition of Eu(2+). The powders are weakly luminescent in the as-synthesized state, as expected for combustion-synthesized materials and have higher emission intensities as the heat treatment temperature is increased. Luminescence spectra obtained using an excitation wavelength of 254 nm are weak for all samples. Excitation wavelengths of 305, 337, and 359 nm, are better at promoting the Eu(3+) and Eu(2+) emissions in hydroxyapatites. We propose that fluorescence measurements are an excellent way of qualitatively determining the phase composition of europium-doped hydroxyapatite powders, since powders that exhibit a blue emission contain substantial amounts of Ca-D HAp, allowing the determination of the presence of this phase in mixed-phase hydroxyapatites.
我们对掺铕羟基磷灰石（HAp）和缺钙羟基磷灰石（Ca-D HAp）纳米粉末的发光行为进行了详细分析。结果表明，虽然两种粉末在晶粒尺寸、粒径和形态上相似，但发光行为却有很大的不同。对于 HAp:Eu 粉末，发射明显来自 Eu(3+)离子，对应于典型的 (5)D(0) --> (7)F(J)发射，而对于 Ca-D HAp:Eu 粉末，我们还看到了一个在 420nm 和 445nm 处有两个峰的宽发射，对应于 Eu(2+)的 4f(6)5d(1) --> 4f(7) ((8)S(7/2))跃迁。正如预期的那样，燃烧合成材料在合成状态下发光较弱，随着热处理温度的升高，其发射强度更高。对于所有样品，使用 254nm 激发波长获得的发光光谱都很弱。305nm、337nm 和 359nm 的激发波长更有利于促进羟基磷灰石中的 Eu(3+)和 Eu(2+)发射。我们提出荧光测量是定性确定掺铕羟基磷灰石粉末的相组成的一种极好方法，因为显示蓝色发射的粉末含有大量的 Ca-D HAp，从而可以确定在混合相羟基磷灰石中存在这种相。
