Synthesis And Electronic Memory Characteristics Of Carbazole-naphthalimide Polymer

During the past few decades, Polymeric materials for use in memory devices haveattracted signifcant scientifc interest due to their molecular，design good mechanicalperformance and solution processability. So far, a lot of polymeric materials exhibitconductance switching phenomena. Nowadays, manufacturing polymer memory devices islimited to binary materials based on electrical bistability (i.e.,“0” and “1”) in response toan applied electric feld. In order to overcome the defects storage mode, as well as achievehigh density information storage requirements, these materials by increasing the number ofmemory states or multimodal responsiveness to multilevel states are highly desirable andgradually developed. In this paper, we have designed and synthesized the series polymer,which exhibit the ternary data storage ability induced by double mechanisms.(1) On the basis of PMCz, we introduce a small amount of1,8-naphthalimidemoieties by different ways in PMCz to achieve a ternary polymer memory device induceddouble driving mechanisms. Based on Al/PMCz8-b/co-PMBNa2/ITO device, bothpolymers exhibit the ternary memory performances that attributed to field-inducedconformational ordering of carbazole ring in the side chain, and subsequent charge transferbetween carbazole and1,8-naphthalimide moieties. Through further studying thephotoelectric performance and AFM morphology, we obtain that D/A interaction has greatinfluence on the device performance, so the PMCz8-co-PMBNa2shows the betterperformance than the PMCz8-b-PMBNa2. Yet, in further increasing the content of the1,8-naphthalimide moieties, the PMCzx-co-PMBNay show Stronger interaction, so as toreduce the power consumption of the device (Vths). Thus, it has a positive role for thefuture design of material and energy consumption reduction.(2) Both novel random copolymer PMNN and PMNB based Al/polymer/ITO devicesexhibit the ternary memory performances. The observed tristable electrical conductivityswitching could be attributed to field-induced conformational ordering of naphthalene ringin the side chain, and subsequent charge trapping of1,8-naphthalimide moieties. More interestingly, the tunable memory properties (from PMNN nonvolatile memory behavior(WORM) to PMNB volatile memory behavior (SRAM)) could be achieved by adjustingthe inherent steric effect of the pendant1,8-naphthalimide moieties.(3) We have demonstrated ternary memory properties controlled by a dual mechanism,achieved with P4VPCz copolymers. Through tuning the content of fexible lateral carbazolemoieties and the doped ions, the devices based on P4VPCz were able to show variouselectrical behaviors such as bistable switching, tristable switching and a conductorbehavior. Thus, it could offer a guideline to achieve a high-performance multilevelmemory material, via combining different mechanisms as well as doping ions.(4) Based on Azo-Cz small molecules with ternary storage performance, we have thealkyl modification by RAFT polymerization, thus we obtain a uniform thin film throughsimple spin-coating processes by spin coating, but the forming film is disoriented state soas to just show the binary WORM type. Besides, in further increasing alkyl chain, thedevice shows a higher Vths and ON/OFF current ratio.Learn from the above system research, we hope we can offer a guideline to achieve ahigh-performance multilevel memory material, via combining different mechanisms. Inaddition, the space steric hindrance, film order of molecular and morphology have animportant influence on the performance of the electricity.