Electrochromic and bipolar memory switching properties of novel Eu(III)-polymer of multidentate Schiff’s base ligand

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In the past thirty years, scientists have put enormous efforts into developing smart materials with multiple functionalities. Among such existing intelligent materials, electrochromic and non-volatile memory materials synthesized via organic–metallic hybrid polymers have shown their remarkable presence. To date, a wide variety of transition metal ions have been adopted for forming these polymers. However, reports on the use of lanthanide metal ion for observing such smart behaviour are uncommon. Therefore, the present report focuses on synthesizing a novel Eu(III) metal ion-based organic–metallic hybrid polymer for observing the smart properties using previously reported Schiff’s base polydentate organic ligand. Further, its different possible coordination modes with the ligand have been discussed. The structure of the polymer has been fully supported by Nuclear Magnetic Resonance and Ultraviolet–visible titration. Along with this, the reversible redox properties of this polymer have also been established along with the study of their spectroelectrochemical properties between yellow and bleached colour. The Resistive Random Access Memory properties of this polymer have been observed by spin coating polymer on Indium Tin Oxide coated substrate for fabricating a Metal–Insulator–Metal structure. The bipolar Current–Voltage (I–V) characteristics of this polymer in both the biasing directions have been observed, with the repeatability of about 1000 cycles for Write-Read-Erase-Read operation. The retention capability of this polymer has also been established for 2000 pulses. Thus, the current work presents fascinating aspects of using a lanthanide metal ion collectively for studying both the redox-active properties, i.e. electrochromic and non-volatile memristive properties.