Two-dimensional (2D) metal-free sheets with atomic thickness have been highly considered as promising candidates for fluorescent probes, due to their intriguing characteristics. In this work, 2D ultrathin boron nanosheets (B NSs) with a surface defect nanolayer can be effectively prepared by modified liquid phase exfoliation. The as-prepared ultrathin B NSs show blue fluorescence characteristics even with a quantum yield efficiency of up to 10.6%. Such luminescent behavior originates from the quantum confinement effect and the existence of a surface defect layer. In light of the advantages of being environmentally friendly, having high photostability and good biocompatibility, for the first time we have shown that ultrathin B NSs can be used as an emerging fluorescent probe for application in cellular bioimaging. It is believed that this work will open new avenues for ultrathin B NSs in biomedical fields, and it will also inspire the development of other elemental 2D nanomaterials.

中文翻译：

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超薄硼纳米片作为用于生物成像的新兴二维光致发光材料

由于其有趣的特性，具有原子厚度的二维（2D）无金属薄板已被认为是荧光探针的有前途的候选材料。在这项工作中，可以通过改性液相剥离有效地制备具有表面缺陷纳米层的二维超薄硼纳米片（B NSs）。所制备的超薄B NSs甚至具有高达10.6％的量子产率，仍显示出蓝色荧光特性。这种发光行为源自量子限制效应和表面缺陷层的存在。鉴于环保，具有高光稳定性和良好的生物相容性的优势，我们首次证明超薄B NSs可以用作新兴的荧光探针，用于细胞生物成像。