Xu Yang, Li Yuhan, Meng Yuhang, Li Huanrong
National-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources Utilization and Tianjin Key Laboratory of Chemical Process Safety, School of Chemical Engineering and Technology, Hebei University of Technology, Guangrong Dao No. 8, Hongqiao District, Tianjin, 300130, China.
Nanoscale. 2020 Aug 13;12(31):16433-16437. doi: 10.1039/d0nr02964e.
The exploration of new hotspot nanomaterials to acquire mechanofluorochromic (MFC) properties has drawn substantial interest. However, previously reported MFC nanomaterials have required external pressures on the level of gigapascals, and observing distinct reversible MFC phenomena in nanomaterials under low-pressure conditions is still a challenge. Herein, a kind of reversible MFC-carbon dots (CDs) under low pressure has been reported for the first time. The MFC-CDs exhibited an apparent solid-state fluorescence color change, with emission shifting from green to blue via anisotropic grinding, owing to the alteration of hydrogen bonds and stacking structure among the CDs. Notably, these MFC-CDs exhibited a reversible fluorescence resulting from their being treated with acid vapors. This reversibility was indicated from X-ray diffraction analysis to be due to recovery of the crystalline state. The results highlighted the relationship between reversible MFC properties and structure, and showed the utility of these MFC-CDs as security films for further applications.
探索具有机械致变色（MFC）特性的新型热点纳米材料引起了广泛关注。然而，先前报道的MFC纳米材料需要吉帕斯卡级别的外部压力，在低压条件下观察纳米材料中明显的可逆MFC现象仍然是一个挑战。在此，首次报道了一种在低压下具有可逆MFC特性的碳点（CDs）。MFC-CDs表现出明显的固态荧光颜色变化，通过各向异性研磨，发射光从绿色变为蓝色，这是由于CDs之间氢键和堆积结构的改变。值得注意的是，这些MFC-CDs经酸蒸气处理后表现出可逆荧光。X射线衍射分析表明，这种可逆性是由于晶体状态的恢复。这些结果突出了可逆MFC特性与结构之间的关系，并展示了这些MFC-CDs作为安全薄膜在进一步应用中的实用性。
