Charge Trapping Elements Based On Benzodithiophene Nanogrid:Design And OFET Memory

In recent years,organic field-effect transistor(OFET)memory has gained attention as a new type of semiconductor memory device due to its advantages of large-scale production,low-cost manufacturing processes,and application in flexible wearable fields.In the design of the chargetrapping layer of OFET devices,anthracene-based aromatic materials are used due to their unique closed-loop structure,which ensures the position of electrons and holes,making them have high mobility,scalability,and the ability to withstand structural damage caused by writing and erasing.The closed structure can protect the functional groups of the device and improve the storage capacity and transmission performance.Additionally,introducing different functional units such as dithienylthiophene and benzo[b]thiophene groups into the anthracene-based nanographene structure can further enhance its storage performance and photocontrol ability.Based on this,this study designed a series of anthracene-based nanographene materials and applied them as organic polar active layers in OFET memory devices.By systematically comparing the effects of different modified groups and different polycyclic rings on the molecular and hole-storage,the relationship between the storage performance of the device and the electronic structure of the storage material was examined.In chapter two,molecular modular synthesis methods were used to introduce thienothiophene and benzo[b]thiophene groups into the anthracene grid,further expanding the anthracene-based grid molecular storage material system.Storage materials SF-G and BDT-G bridged with thienothiophene and benzo[b]thiophene groups were designed and synthesized for comparison with non-gridded SFU and BDT-U.By analyzing the spectra and film morphologies of the materials,the differences in spectral,energy level,and morphology modulation among different bridging groups of the anthracene grid materials were studied.The above storage materials were introduced into OFET memory devices,and the multi-level window,fast write-in,maintenance time,read-write erase cycle and other storage characteristics of the devices were systematically studied,and the differences in storage between Utype materials and gridded materials were compared in detail.The influence of the gridded design on the charge storage capture mode and storage capacity was revealed,and the results showed that the gridded design can effectively improve all storage performance indicators.Furthermore,we compared the storage differences of anthracene grid bridged materials with different groups,investigated the ability of different substituents to capture and release charges,and verified the effectiveness of the benzo[b]thiophene bridged anthracene grid storage material design.In chapter three,the BDT-based anthracene grid synthesis reaction and SF-based anthracene grid synthesis reaction were optimized,and a series of polycyclic structures based on BDT and SF molecules were designed and synthesized.The polycyclic closed-ring structure of the anthracene grid molecules presents a rigid molecular conformation and a porous structure,while also exhibiting excellent film-forming properties and solubility.The optical properties,electrochemical stability,film morphology,and energy band gap design of the polycyclic molecules were analyzed.By introducing them into the OFET storage layer,the multi-level window,fast write-in,maintenance time,read-write erase cycle and other storage characteristics of the device were systematically studied,and compared with binary anthracene molecules,the multi-element grid structure has a better forward storage window and a lower operating voltage window rate(93%).At the same time,a comparison was made between BDT3-G and SF3-G based on different bridging anthracene grid structures,and BDT3-G showed a more prominent performance in the forward storage windowIn chapter four,the excellent photosensitivity of the BDT group was utilized to discuss whether the introduction of photosensitive materials in the anthracene grid system can achieve the fourth level control capability of materials as OFET devices.Based on the excellent photoresponsive properties of the BDT group,we prepared an OFET photocontrollable memory device,focusing on the device’s response performance to different energies and red,green,and blue light.BDT-G,BDT3-G,and SF3-G materials were selected,and their response to light of different wavelengths was tested to discuss the light control mode of the materials.By comparing the first two,the regulating capability of electrons with the introduction of the photosensitive group BDT was discussed,and the organic fieldeffect transistor memory performance under light control state,such as storage window,maintenance time,and read-write erase cycle,was studied.Thanks to the successful introduction of the photocontrollable group,this chapter achieved the specific photocontrollable capability of the anthracene grid structure.