Polydiacetylenes （PDAs）, an organic layered compound, show a series of intriguing properties, such as thermo- chromism and fluorescence emission in the red-phase. However, their irreversible color change, and weak a...Polydiacetylenes （PDAs）, an organic layered compound, show a series of intriguing properties, such as thermo- chromism and fluorescence emission in the red-phase. However, their irreversible color change, and weak and sin- gle-color fluorescence emitted only from the red-phase PDAs, have limited their applications. Herein, we report double-reversible PDA-Tb3＋ nanosheets of which both the color and the fluorescence can be reversibly switched between two colors. PDA-Tb3＋ nanosheets have the nearly defect-free intercalated structure in which a layer of Tb3＋ ions was intercalated in between each two PDA bilayers to tether almost all of the carboxyl groups at the end of the side chains of the PDA. When the PDA is in the blue phase, the PDA-Tb3＋ nanosheets emit the green fluo- rescence of Tb3＋ ions. When the PDA is in the red phase, the Tb3＋ fluorescence disappears while the intrinsic red fluorescence of PDA is effectively enhanced through the fluorescence resonance energy transfer （FRET） process; the PDA-Tb3＋ nanosheets emit stronger red fluorescence compared with the PDA in red phase. Moreover, the teth- ering of almost all of the carboxyl groups at the end of the side chains of the PDA endows the nanosheets with the double reversibility in both the color and fluorescence transitions.展开更多
基金This work was supported by the programs of the Na- tional Natural Science Foundation： of China （Nos. 21334001 and 21574025）, the Ministry of Science and Technology of China （No. 2016YFA0203302）, the Sci- ence and Technology Commission of Shanghai Munici- pality （No. 16JC1400702）, and the Open Project of State Key Laboratory of Supramolecular Structure and Materials （No. sklssm201737）.
文摘Polydiacetylenes （PDAs）, an organic layered compound, show a series of intriguing properties, such as thermo- chromism and fluorescence emission in the red-phase. However, their irreversible color change, and weak and sin- gle-color fluorescence emitted only from the red-phase PDAs, have limited their applications. Herein, we report double-reversible PDA-Tb3＋ nanosheets of which both the color and the fluorescence can be reversibly switched between two colors. PDA-Tb3＋ nanosheets have the nearly defect-free intercalated structure in which a layer of Tb3＋ ions was intercalated in between each two PDA bilayers to tether almost all of the carboxyl groups at the end of the side chains of the PDA. When the PDA is in the blue phase, the PDA-Tb3＋ nanosheets emit the green fluo- rescence of Tb3＋ ions. When the PDA is in the red phase, the Tb3＋ fluorescence disappears while the intrinsic red fluorescence of PDA is effectively enhanced through the fluorescence resonance energy transfer （FRET） process; the PDA-Tb3＋ nanosheets emit stronger red fluorescence compared with the PDA in red phase. Moreover, the teth- ering of almost all of the carboxyl groups at the end of the side chains of the PDA endows the nanosheets with the double reversibility in both the color and fluorescence transitions.
