Abstract Bi2O3 nanospheres co-doped with Yb3+/Er3+ upconverting ions pair have been successfully synthesized via a facile hydrothermal method followed by a heat treatment. The resulting Bi2O3:Yb3+,Er3+ nanospheres show a monodisperse spherical morphology with narrow size distribution (~180 nm) and display intense upconversion luminescence under 980 nm laser excitation. It is found that the crystal structure, morphology and upconversion luminescence properties of nanospheres have a direct relationship with the doping concentration of Yb3+ and the subsequent calcination temperature. These Bi2O3:Yb3+,Er3+ nanospheres can be prepared in large quantities and can be easily modified with a layer of biocompatible polyethyleneimine (PEI) molecules. The yielded nanospheres could not only maintain uniform size and morphological characteristics, but also show good water dispersibility and biocompatibility. Remarkably, these Bi2O3:Yb3+,Er3+ upconversion nanophosphors could also act as an effective contrast agent for X-ray computed tomography (CT) imaging, which show higher contrast efficacy than commercial iodine-based contrast agent. The proposed facile synthetic route and inexpensive matrix materials pave the way for broad use of these Bi2O3:Yb3+,Er3+ nanospheres as ideal dual-mode bioimaging probes in biomedical field.

中文翻译：

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用于光学和 X 射线计算机断层扫描成像的 Yb3+/Er3+ 共掺杂 Bi2O3 纳米球的可控合成和上转换发光特性

摘要 通过简单的水热法和热处理成功地合成了与 Yb3+/Er3+ 上转换离子对共掺杂的 Bi2O3 纳米球。得到的 Bi2O3:Yb3+,Er3+ 纳米球显示出单分散球形形态，具有窄尺寸分布（~180 nm），并在 980 nm 激光激发下显示出强烈的上转换发光。研究发现，纳米球的晶体结构、形貌和上转换发光特性与Yb3+的掺杂浓度和随后的煅烧温度有直接关系。这些 Bi2O3:Yb3+,Er3+ 纳米球可以大量制备，并且可以很容易地用一层生物相容性聚乙烯亚胺 (PEI) 分子进行改性。得到的纳米球不仅可以保持均匀的尺寸和形态特征，而且还表现出良好的水分散性和生物相容性。值得注意的是，这些 Bi2O3:Yb3+、Er3+ 上转换纳米磷光体还可以作为 X 射线计算机断层扫描 (CT) 成像的有效造影剂，其显示出比商业碘基造影剂更高的对比效果。所提出的简便合成路线和廉价的基质材料为这些 Bi2O3:Yb3+,Er3+ 纳米球在生物医学领域作为理想的双模生物成像探针的广泛应用铺平了道路。