二维黑磷纳米片的液相剥离和稳定性研究

黑磷是一种具有天然褶皱结构的直接带隙二维半导体材料，因其拥有诸多传统二维半导体材料不具备的优秀特性，故自 2014 年起倍受研究人员的青睐。在该研究中，首先，通过液相剥离方法成功制备了不同尺寸大小的二维黑磷纳米片；其次，用扫描电子显微镜、透射电子显微镜和原子力显微 镜对样品的尺寸、形貌、厚度进行系统表征，并对不同尺寸大小的二维黑磷的拉曼散射光谱进行了研究。由于黑磷在水中会逐渐反应生成磷酸或亚磷酸，所以黑磷在水氧环境中会逐渐分解。而黑磷的可降解性是它作为可降解生物医用材料的重要基础，故对不同尺寸的黑磷纳米片的降解特性进行了一系列的检测。研究不同尺寸黑磷纳米片水溶液的吸收光谱和 pH 值随时间变化过程发现，黑磷纳米片在前 3 天会迅速降解，之后其降解速率逐渐平稳；同时发现纳米片的尺寸越小，其降解速率越快。

Liquid Exfoliation and Stability of Different-Sized Black Phosphorus Nanosheets

Black phosphorus (BP) is a kind of direct bandgap 2D semiconductor with natural fold structure. It has attracted lots of attentions since 2014 for its outstanding physical properties. In this article, different-sized 2D BP nanosheets were successfully prepared by liquid exfoliation. The sizes, morphologies and thicknesses were characterized by scanning electron microscope, transmission electron microscope and atomic force microscope. Then the size-dependent Raman scattering spectra were collected. The biodegradability provides a possibility of BP for the biomedical application. Thus, degradation characteristics of BP nanosheets in aqueous solution were investigated. The time-dependent absorption spectra and pH revolution both suggest that the smaller BP sheets degraded faster, the predominant degradation occurred in the incipient 3 days. The underlying mechanism is attributed to the generation of orthophosphoric acid or other phosphorous acid.