Two-dimensional (2D) monoelemental bismuth (Bi) crystal, one of the pnictogens (group VA), has recently attracted increasing interest because of its intriguing characteristics. Here, uniformly sized 2D Bi quantum dots (BiQDs) with an average diameter (thickness) of 4.9 ± 1.0 nm (2.6 ± 0.7 nm) were fabricated through a facile liquid-phase exfoliation (LPE) method, and the corresponding photoresponse was evaluated using photoelectrochemical (PEC) measurements. The as-fabricated BiQDs-based photodetector not only exhibits an appropriate capacity for self-driven broadband photoresponse but also shows high-performance photoresponse under low bias potentials ranging from UV to visible light in association with long-term stability of the ON/OFF switching behavior. In terms of these findings, it is further anticipated that the resultant BiQDs possess promising potential in UV–visible photodetection as well as in liquid optoelectronics. Our work may open a new avenue for delivering high-quality monoelemental pnictogen QDs from their bulk counterparts, thereby expanding interest in 2D monoelemental materials.

中文翻译：

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超小铋量子点：便捷的液相剥离，表征和在高性能紫外可见光检测器中的应用

二维（2D）单元素铋（Bi）晶体是光致发光物质（VA组）之一，由于其引人入胜的特性，最近引起了越来越多的关注。在此，通过简便的液相剥离（LPE）方法制造了平均直径（厚度）为4.9±1.0 nm（2.6±0.7 nm）的均一尺寸的二维Bi量子点（BiQDs），并使用光电化学（PEC）测量。预制的基于BiQDs的光电检测器不仅具有适当的自驱动宽带光响应能力，而且在从UV到可见光的低偏置电势下均具有高性能的光响应，并且具有ON / OFF开关的长期稳定性行为。根据这些发现，可以预见的是，最终的BiQD在紫外可见光检测以及液态光电子学中具有广阔的应用前景。我们的工作可能会为从其批量同类产品中提供高质量的单元素光生素QD开辟一条新途径，从而扩大人们对2D单元素材料的兴趣。