| Fluorescent and phosphorescent materials have many great potentials in many fields such as photoelectrical displaying,chemical sensing,anti-counterfeiting,detection and biological imaging.There is no doubt that the fundamental studies about the principles of fluorescence are of great importance,which can be proved by the fact that the Nobel Prize in Chemistry 2014 was awarded for the development of super-resolved fluorescence microscopy.However,one thing should be kept in mind is that it is better to use fluorescence as a tool to solve some existing issues in many other fields.Due to the highly ordered structure and weak interactions such as Van der Waals,?-?stacking and hydrogen bonds,self-assembly can be used to modulate the photophysical properties of fluorescent materials,which can promote the study of fluorescent materials.My research mainly focuses on the field of the construction of fluorescent self-assemblies and its application in sensing,optical waveguiding and bioimaging during my Ph.D.study.As we all know,fluorescent probes have become a powerful tool for sensing trace amounts of chemical and biological samples due to the high sensitivity,specificity and fast response of fluorescence detection.Up to now,current sensing systems are categorized into fluorescence turn-on/-off and ratiometric types,turn-on/-off types are commonly perturbed by background interference,as well as fluctuation of the experimental conditions.On this account,we sought to develop a FRET sensor for mercury ion with hydrophilic methoxypolyethylene glycol decorated a-cyanostilbene chromophore as donor,chromophore as the energy donor,Rhodamine B derivative as the energy acceptor,this dyad-based FRET system provides a feasible avenue to detect mercury ions in water.This project can be used to detect other analysts as well.Fluorescent supramolecular assemblies are rising stars in the field of optoelectronic devices because of its excellent photophysical properties.Employing one-dimensional(1D)structures for optical waveguide interconnectors has demonstrated promise for next-generation information and communication technologies.As for 1D organic materials,?-conjugated polymers and small-molecule based crystals are regarded as two candidates.For ?-conjugated polymers,there are many existing issues such as inhomogeneous structure and amorphous property.Incontrast,monodisperse ?-conjugated small molecules have poor processability and difficulty in size/shape control for the resulting crystals,owing to their strong stacking tendency.All of the disadvantages above hamper the waveguiding performances.On this account,we sought to develop fluorescent supramolecular polymer by self-assembling ?-aromatic platinum acetylides monomers via cooperative mechanism,which combined hydrogen bond and multiple non-covalent interactions such as ?-?stacking together.And the resulting supramolecular polymer has promising potential for optical waveguiding application.Hence,it demonstrates that rational engineering of self-assembly mechanism is of crucial importance for controlled supramolecular polymerization and the development of high-performance optoelectronic materials.Also,expanding the above project with room temperature phosphorescence is attractive.Nowadays,existing phosphorescent materials are organometallic systems with noble metal such as iridium,platinum and ruthenium,their toxicity and instability in aqueous environments hamper the application.Purely organic room temperature phosphorescence(RTP)can solve these issues.N-substituted naphthalene diimides(NDIs)were explored as purely organic RTP materials through rational design,it was found that relatively high HOMO and electron-donating abilities of the substituents can make ICT from the donor to the acceptor hap-pen and thus bridge the ISC of the dye,resulting in RTP.The introduction of bromide could further enhance the red/NIR RTP of the NDI-initiated PLA and make it robust enough for imaging applications in biological systems. |
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