The evident aggregation-induced emission and the reversible mechanoresponsive behavior of carbazole-containing cruciform luminophore
The evident aggregation-induced emission and the reversible mechanoresponsive behavior of carbazole-containing cruciform luminophore
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含咔唑十字形发光体的明显聚集诱导发射和可逆机械响应行为
DOI：
10.1016/j.dyepig.2019.107786
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发表时间：
2019
影响因子：
4.5
通讯作者：
Chao Zhang
中科院分区：
文献类型：
--
作者：
Defang Xu;D;an Cheng;Ying Wang;Hongke Zhou;Xingliang Liu;Aixia Han;Chao Zhang
设计并制备了带有电子给体咔唑单元和电子受体二氰基乙烯基苯链段的新型D-A型十字形发光体TFMB-CBCEB。结果表明，TFMB-CBCEB 的发射波长受溶剂极性的强烈影响，表明分子内电荷转移（ICT）跃迁。有趣的是，TFMB-CBCEB表现出AIE行为，αAIE高达405，固态发光效率高达0.810。此外，TFMB-CBCEB表现出显着的机械荧光变色（MFC）特性。当制备好的样品进行研磨时，TFMB-CBCEB的发射红光从蓝色区域（λmax=566nm）移动到橙色区域（λmax=598nm）32nm。研磨引起的荧光发射的变化可以通过溶剂发烟来恢复并通过研磨再生，这表明转换过程具有良好的可逆性。 PXRD分析表明TFMB-CBCE的MFC机理归因于原态和基态之间的晶态-非晶相变。同时，研磨时PL光谱的红移来自分子构象平面化和随后的平面分子内电荷转移（PICT）过程引起的分子共轭延伸。
New D-A type cruciform luminophoreTFMB-CBCEBbearing electron-donor carbazole unit and electron-acceptor dicyanovinylbenzene segment was designed and prepared. The results show that the emission wavelengths ofTFMB-CBCEBare strongly affected by solvent polarity, indicating intramolecular charge-transfer (ICT) transitions. Interestingly,TFMB-CBCEBexhibits AIE behavior with high αAIEof 405 and high solid-state luminescence efficiency of up to 0.810. Moreover,TFMB-CBCEBshows remarkable mechanofluorochromic (MFC) properties. When the as-prepared samples are subjected to grinding, the emission ofTFMB-CBCEBred-shifts by 32 nm from the blue regions (λmax= 566 nm) to the orange regions (λmax= 598 nm). The changes of fluorescence emission induced by grinding can be restored by solvent-fuming and regenerated by grinding, suggesting excellent reversibility in the switching processes. PXRD analysis revealed that the MFC mechanism ofTFMB-CBCEBattributed to the crystalline-amorphous phase transformation between the original and ground states. Meanwhile, the red-shift in the PL spectra upon grinding comes from the extension in molecular conjugation caused by planarization of molecular conformation and subsequent planar intramolecular charge transfer (PICT) process.