| Stimuli-responsive luminescent materials are widely used in various field.Most reported stimuli-responsive luminescent materials focus on stimulus-responsive fluorescent materials due to room temperature phosphorescence(RTP)is more difficult to obtain.Compared with fluorescent materials,RTP materials exhibit the advantages such as large Stokes shift,good selectivity,strong anti-interference ability,and high sensitivity.Stimuli-responsive RTP materials can change RTP with external stimuli resulting in more extensive application than stimuli-responsive fluorescent materials.However,the reported stimuli-responsive phosphorescent materials usually involved in complex synthesis of phosphorescent molecules and phosphorescence matrix.Aiming at this problem,the present work developed a facile strategy to construct stimuli-responsive RTP materials based on supramolecular gels,the results are as following:1.A photo-responsive RTP material was obtained by entrapping Meso-tetra(carbonyl phenyl)palladium-porphyrin(Pd-TCPP)into hybrid supramolecular gel formed by Gemini surfactant G12-12-12 and gelator N,N'-dibenzoyl-L-cystine(DBC).The optimum concentration of Pd-TCPP,G12-12-12 and DBC for the resultant RTP material is 8.0×10-6 mol/L,5×10-4 mol/L,and 0.8 wt%.Upon UV irradiation,the RTP intensity,quantum yield and phosphorescence lifetime of the prepared RTP material increased 100,7 and 7 times,respectively.The results of ESR,SEM and XPS indicated that Pd-TCPP as a photosensitizer catalyzes the conversion of dissolved oxygen in the gel to singlet oxygen to oxidize DBC.As a result,the electrostatic interaction and hydrogen bonding interaction of the system enhanced leading to the non-radiative transition of Pd-TCPP is greatly suppressed.The results also suggested that RTP intensity can be easily tuned by controlling UV intensity and time.2.A thermal/pH/redox-responsive pure organic RTP material(Q/DBC)was constructed by entrapping 3,5-dibromoquinoline(3,5-2BrQ)in supramolecular gel formed by self-assembly of gelator DBC in a mixed solvent(DMSO:H2O,V/V=1:9).The optimum concentration of 3,5-2BrQ and DBC is 8.0×10-4 mol/L,0.6 wt%,respectively.It was found that the gel system exhibited thermal/pH/redox responsiveness due to the structural feature of DBC gels.The RTP intensity can be tuned by this responsiveness.Particularly,the deoxygenation of gel system is not required.Conversely,the dissolved oxygen in the system can be employed for redox reaction without the addition of any other oxidant. |
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