Instituto de Ciencia de Materiales de Sevilla (CSIC-US), c/Américo Vespucio, 49, 41092 Seville, Spain.
Dalton Trans. 2018 Jun 25;47(25):8382-8391. doi: 10.1039/c8dt01202d.
Uniform Ba0.18Ce0.82F2.82 nanospheres have been obtained after aging a solution of barium and cerium nitrates and sodium tetrafluoroborate in a mixture of ethylene glycol and water at 120 °C for 20 hours. The diameter of the spheres could be tailored from 65 nm to 80 nm by varying the NaBF4 concentration while maintaining their colloidal stability in aqueous suspension. Increasing the aging temperature led to a phase transformation from hexagonal to cubic symmetry and to a concomitant increase of the Ba/Ce ratio, which reached a value close to the nominal one (50/50) at 240 °C. The same method was successful in obtaining Tb3+-doped nanospheres with homogeneous cation distribution and the same morphological features as the undoped material. An intense green emission was observed after the excitation of the Tb3+-doped samples through the Ce3+-Tb3+ energy transfer (ET) band. The ET efficiency increased with increasing Tb content, the maximum emission being observed for the 10% Tb-doped nanospheres. Aqueous suspensions of the latter sample showed excellent X-ray attenuation values that were superior to those of an iodine-based clinically approved contrast agent. Their fluorescence and X-ray attenuation properties make this material a potential dual bioprobe for luminescence bioimaging and X-ray computed tomography.
将硝酸钡和硝酸铈以及四氟硼酸钠的溶液在乙二醇和水的混合物中于 120°C 下老化 20 小时后，得到了均匀的 Ba0.18Ce0.82F2.82 纳米球。通过改变 NaBF4 浓度，可以将纳米球的直径从 65nm 调至 80nm，同时保持其在水悬浮液中的胶体稳定性。升高老化温度会导致从六方对称到立方对称的相转变，同时 Ba/Ce 比增加，在 240°C 时接近标称值（50/50）。同样的方法成功地获得了具有均匀阳离子分布和与未掺杂材料相同形态特征的 Tb3+掺杂纳米球。通过 Ce3+-Tb3+能量转移（ET）带激发 Tb3+掺杂样品后，观察到了强烈的绿色发射。随着 Tb 含量的增加，ET 效率增加，在 10% Tb 掺杂的纳米球中观察到最大发射。后者的水悬浮液显示出优异的 X 射线衰减值，优于基于碘的临床批准的对比剂。它们的荧光和 X 射线衰减特性使该材料成为用于发光生物成像和 X 射线计算机断层扫描的潜在双重生物探针。
