Design,Synthesis And Detection Application Of Aggregation Induced Emission Self-Assembled Molecular Materials

With the increasing demand for trace explosive detection in the field of counter-terrorism and security inspection,trace detection technology needs to further improve its portability and response speed.The development of new materials and technologies used for the detection of trace explosives has important scientific research value and application significance.Fluorescent materials have been widely reported as explosive probes because of their low cost and high sensitivity.However,traditional organic fluorescent materials are still far from the actual application due to the aggregation-caused quenching(ACQ)effect.New materials with aggregation-induced emission(AIE)properties,due to their weak fluorescence in dilute solution and strong fluorescence at high concentrations aggregate state,will overcome this shortcoming and be more widely used.This thesis focusing on the“design,synthesis and application of aggregation induced emission self-assembled molecular materials”,used molecular engineering to design and synthesize organic fluorescent probe molecules,and obtain the most suitable molecular structure for the system.Then this work prepared and studied the sensing performance of related devices for gaseous nitro aromatic explosives,which provides new ideas for the development of subsequent security inspections and explosion-proof technologies.This thesis mainly includes the following four aspects:1.Designed and synthesized a series of organic fluorescent molecules TPE-PA-n(n=3-11)with AIE effect.1,1,2,2-tetraphenylethene(TPE)was selected as the functional core.Through the design and modification of the side chain,the phosphoric acid group is connected to the TPE fluorescent group through the alkyl chain.Studies have found that phosphoric acid can be used as a rivet group to form a covalent bond with the HfO2 substrate,which enables the molecule to have the ability to self-assemble.2.Prepared and characterized the self-assembled monolayer(SAM)based on TPE-PA-n(n=3-11)molecules.Tests such as contact angle,X-ray photoelectron spectroscopy,X-ray reflection,and atomic force microscopy have proved that molecules can form a film on the HfO2 substrate and are connected to the substrate through covalent bonds.3.Studied and analyzed the influence of alkyl chain length on molecular functions.In this thesis,by characterizing the TPE-PA-n(n=3-11)series of molecules in terms of UV-vis spectrum,fluorescence spectrum,quenching efficiency,etc.,it is clear that the molecule with the best fluorescence characteristic under this system is TPE-PA-8.4.Prepared and tested the sensor's detection characteristics for nitroaromatic compounds(NACs).This thesis prepared SAM sensor with TPE-PA-8.and the fluorescence quenching sensing test was carried out with nitrobenzene as the detected object.Through the analysis of the fluorescence spectrum,the reversibility test,the selectivity test,the detection limit test,etc.were carried out,and the fluorescence quenching mechanism was analyzed.