Herein, ratiometric fluorescence-based carbon dots (N-CDs) with blue emission were prepared by using simple one-step hydrothermal methods from benzimidazole and L-tryptophan as precursors. Dual emission peaks were observed at 356 and 442 nm under the excitation wavelength of 303 nm. Upon addition of sulfide ions (S^2-), the fluorescence intensity at 442 nm decreased significantly, while that at 356 nm increased. The F₄₄₂/F₃₅₆ intensity ratio (where F₃₅₆ and F₄₄₂ refer to the fluorescence intensity at 356 and 442 nm, respectively) exhibited a linear relationship with the concentration of S^2- (0-60.0 μmol·L^-1), and the detection limit was determined to be 0.076 μmol·L^-1. The fluorescence detection mechanism was ascribed to the static quenching effect. Furthermore, this fluorescence probe was successfully used for the determination of S^2- in real samples with satisfactory recoveries. Finally, the analytical greenness metric for sample preparation (AGREEprep) and blue applicability grade index (BAGI) tools indicated the high sustainability of this platform.

电磁干扰(EMI)日益制约着柔性多功能电子材料的发展，但非对称结构设计与功能集成仍存在局限。本文报道了一种Janus层级膜材料——液态金属@聚多巴胺-MXene/Fe₃O₄@纤维素聚丙烯腈纳米纤维(LM@PDA-MXene/Fe₃O₄@CPNF)，通过静电纺丝制备Fe₃O₄掺杂的纤维素/聚丙烯腈纳米纤维支架，并采用真空辅助组装法构筑插层有核壳结构LM@PDA纳米颗粒的MXene层制得。该多尺度结构耦合了三种损耗机制：MXene渗流网络实现导电损耗，LM@PDA间隔物抑制堆叠并形成微电容器引发界面与偶极极化，多孔磁性入口改善阻抗匹配。在X波段，70 μm单层膜的平均电磁屏蔽效能(SET)达45.1 dB，厚度归一化比屏蔽效能(SSE/t)达8.87 × 10³ dB cm² g⁻¹；四层堆叠后SET提升至70.8 dB。该膜还具有取向依赖性热功能，这种超薄、环保、轻质膜在单一平台集成了吸收主导型EMI屏蔽与双向热管理功能，为下一代可穿戴电子设备的电磁防护与红外调控提供了实用化路径。