Benzothiadiazole-based Donor-Acceptor Organic Nanogrids:Design,Synthesis And Memristive Properties

As an emerging electronic device in organic optoelectronics,organic memristor is considered to be a key component in simulating biological synapses and realizing artificial intelligence.However,there are few reports of organic memristor yet,and the ambiguous mechanism of memristor need to be solved urgently.Therefore,developing new organic memristive materials and clarifying organic memristive mechanisms are the core issues in the field of organic memristor.Systematically summarizing the reported organic memristive materials,we can find that the realization of the organic memristive effect is related to the process of charge transport and ion transport in the active layer.Based on this,we learned from the transmit ions characteristics of organic macrocyclic molecules,taking the fluorene-based nanogrid with nanopore diameters as the research target.We introduced electron acceptor benzothiadiazole group in fluorene-based nanogrid to tune the frontier orbital and transport types of nanogrid.Thus,a series of ion transport channels and bandgap adjustable benzothiadiazole-based donor-acceptor organic nanogrids were constructed to study their synthesis and memristive properties.In the second chapter of this thesis,we introduced the benzothiadiazole into crossbeam of "?" shape,choosing different thiophene bridges to design and synthesize three kinds of D-A type nanogrids(Grid-Th,Grid-DTh,Grid-TTh).And the ?-bridge effect of D-A type nanogrid was investigated.With the increasing of ?-bridge length,the synthesis yield of "?" type nanogrids increased,the structural rigidity weakened,the fluorescence quantum yield reduced.The Grid-TTh has a higher HOMO and LUMO level than Grid-Th and Grid-DTh.The two-terminal memristive device based on Grid-DTh doped tetrabutylhexafluorophosphate as the active layer exhibit voltage-dependent memristive characteristics,which simulates synaptic "exciting" and "depressing" successfully and provides experimental basis for the design of nanogrids semiconductors for organic memristor.In the third chapter,the benzothiadiazole and phenyl groups were introduced into the crossbeam of the high-yield intergranular nanogrid molecules,and we have synthesized benzothiadiazolyl nanogrid(Grid-BT-Cz)and phenyl nanogrid(Grid-Ph-Cz)successfully.The cross-beam effect of the nanogrid was observed in the band structure and optical properties.Grid-BT-Cz has a lower band gap and a smaller isomer spectral difference than Grid-Ph-Cz.The two-terminal memristive devices with the intergranular nanogrid(Grid-BT-Cz & Grid-Ph-Cz)as the active layer exhibit exhibited resistive switching performance.The two-terminal memristive devices with the doped intergranular nanogrid(Grid-BT-Cz/ Bu4NPF6 & Grid-Ph-Cz/ Bu4NPF6)as the active layer exhibit exhibited voltage-dependent memristive characteristics.In the fourth chapter,a new D-A type nanopolymer(P(Grid-TPA-DPP))was constructed by Stille polymerization using diketopyrrolopyrrole and "?" type nanogrid with triphenylamine ?-bridge.The UV-Vis absorption spectra showed that P(Grid-TPA-DPP)had broad-spectrum absorption behavior with three characteristic absorption peaks,and the optical band gap was 1.41 eV,which was a kind of narrow band gap nanopolymer.The two-terminal memristive devices based on P(Grid-TPA-DPP)as the active layer exhibit memristive characteristics.The construction of benzothiadiazole type D-A nanogrid / nanopolymer and the study of the I-V characteristic of the organic memristive device have proved the theoretical and experimental basis for the development of new organic memristive materials.