Synthesis And Properties Of Bithienylethene Based Tetraphenylethylene Contained Photochromic Fluorescent Material

The elaboration of molecular systems combining photochromism and fluorescence properties constituted a promising research field for their potential in sensor,information storage,anti-counterfeiting,cell image and super-resolution imaging for their high sensitivity,resolution,contrast,and fast response times especially the remarkable fatigue resistance.However,the fluorescence of traditional fluorophores,which suffered from ACQ,will be debased or quenched in aggregation state,and that limit their applications greatly.Grafting AIEgens to BTEs is a promising strategy to solve this issue.In this paper,we combined TPE and BTE together via serval strategy to obtained newly degsined AIE-actived BTE derivatives.And the photochromic,AIE properties as well as fluorescence tunability were also investigated.The detailed works are mainly described on the following parts.In the second chapter,TPE was grafted to BTE segment via barbituric acid section to investigate the impact of barbituric acid and TPE segments to the photochromic and AIE properties of dyads.Although three compounds exhibited poor performance on photochromism,the fluorescence can be reversibly switched on/off by alternant visible/UV light.In the third chapter,aromatic substituent was grafted to another side of unilateral TPE substituted bithienylethene dyads to investigate the impact of substituent on photochromic and AIE properties of dyads.All the five newly obtained dyads exhibited typically AIE characters.The substituents have almost no influences on the maximum emission wavelength,but the photochromic properitied are dominated by substituents.Besides,the fluorescence can be reversibly switched on/off by alternant visible/UV light.In fourth chapter,a fluorescence photoswitch was constructed based on a host–guest pseudo[3]rotaxane between an AIE-active pillar[5]arene host bearing tetraphenylethylene moieties and a photo-responsive dithienylethylene guest containing two cyano-triazole branches.Its fluorescence on/off switching could be controlled by the photochromism reaction of the dithienylethylene unit.This study could provide a fundamental method to prepare the fluorescence photoswitch.In fifth chapter,we designed and synthesized three new TPE derivatives.The results shown three dyes exhibited evident AIE properties with wavelength tunable emission.In addition,the solution or film of TPA-TPE shown results in distinct fluorescence from“ON”to“OFF”observation as well as color change from orange yellow to colorless by naked eyes when the addition of toxic Cl₂ gas.These results indicate TPA-TPE is a promising candidate chemosensor for the detection of Cl₂ gas.In sixth chapter,three novel quinoxaline based donor-?-acceptor type organic dyes were synthesized and explored as sensitizers in dye-sensitized solar cells?DSSCs?.The impacts of various?-conjugation configurations which contain different quinoxaline derivatives on the absorption properties,electrochemical properties and photovoltaic performances,as well as theoretical calculations have been investigated systematically.The results confirm that the extended of the?-conjugation of the dyes could extend the light harvest region,but the molar extinction coefficients may decrease,weaken the light harvest ability.Consequently,quinoxaline-based organic dye TQ01 obtains the highest efficiency of 8.20%.