Mechanofluorochromic materials, which change their photoluminescence (PL) colors in responding to mechanical stimuli, can be used as mechanosensors, security papers, and photoelectronic devices. However, traditional mechanofluorochromic materials can only be adjusted to a monotone direction upon the external stimuli. Controllable pressure‐triggered blue‐ and red‐shifted PL is reported for C‐dots. The origin of mechanofluorochromism (MFC) in C‐dots is interpreted based on structure–property relationships. The carbonyl group and the π‐conjugated system play key roles in the PL change of C‐dots under high pressure. As the pressure increases, the enhanced π–π stacking of the π‐conjugated system causes the red‐shift of PL, while the conversion of carbonyl groups eventually induces a blue‐shift. Together with their low toxicity, good hydrophilicity, and small size, the tunable MFC property would boost various potential applications of C‐dots.

中文翻译：

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Mechanofluorchromic碳纳米点：可控的压力触发的蓝移和红移光致发光

响应于机械刺激而改变其光致发光（PL）颜色的机械氟致变色材料可用作机械传感器，安全纸和光电设备。但是，传统的机械荧光致变色材料只能在外部刺激时调整为单调方向。报告了C点的可控压力触发的蓝移和红移PL。基于点-点之间的结构-性质关系来解释C点中的机械荧光致变色（MFC）的起源。羰基和π共轭体系在高压下C点的PL变化中起关键作用。随着压力的增加，π共轭体系增强的π–π堆积会引起PL的红移，而羰基的转化最终会引起蓝移。毒性低，亲水性好，