The electrical conduction mechanism of resistive switching Prussian white (PW) thin films obtained by the electrodeposition method was examined by AC impedance spectroscopy and DC current–voltage measurements. Using an electrode tip to contact PW grown over Au, robust unipolar resistive switching was observed with a current change of up to three orders of magnitude, high repeatability, and reproducibility. Moreover, electrical impedance spectroscopy showed that the resistive switching comes from small conductive filaments formed by potassium ions before the establishment of larger conductive channels. Both voltammetry and EIS measurements suggest that the electrical properties and conductive filament formation are influenced by defects and ions present in the grain boundaries. Thus, PW is a potential material for the next generation of ReRAM devices.
In this work, iron hexacyanoferrate (FeHCF—Prussian blue) particles have been grown onto a reduced graphene oxide substrate through a pulsed electrodeposition process. Thus, the prepared FeHCF electrode exhibits a specific volumetric capacitance of 88 F cm−3 (specific areal capacitance of 26.6 mF cm−2) and high cycling stability with a capacitance retention of 93.7% over 10,000 galvanostatic charge–discharge cycles in a 1 M KCl electrolyte. Furthermore, two identical FeHCF electrodes were paired up in order to construct a symmetrical supercapacitor, which delivers a wide potential window of 2 V in a 1 M KCl electrolyte and demonstrates a large energy density of 27.5 mWh cm−3 at a high power density of 330 W cm−3.
Impedance-based biosensors are effective tools for rapid and specific detection. However, they often rely solely on charge transfer resistance as an indicator of surface structural changes upon analyte binding and other valuable data are constantly ignored. In this work we explore different data obtained for a biosensor designed for water toxin (Saxitoxin) detection using electrochemical impedance spectroscopy. We established a safe potential range for ensuring sensor stability using cyclic voltammetry and determined the potential where the constant phase element values were more pronounced. The data showed that capacitance values could not reliably evaluate the system due to their high deviations. The impedance modulus (Z) revealed the highest number of acceptable frequencies and the values of the imaginary impedance (-Z") exhibited signal differences exceeding 30%, indicating their potential for signal enhancement during saxitoxin detection. The relative standard deviation can be reduced by increasing the concentration of the redox probe. The obtained results highlight the importance of carefully selecting parameters for characterizing the electrochemical behavior of the system to identify the most reliable and informative parameters for detection. This research contributes to broader electrochemistry sensing applications, opening new horizons for improving the accuracy and reliability of electrochemical analysis.
Perylene-based columnar liquid crystal (LC) devices exhibit unipolar resistive switching (RS), clearly identified on cyclic J-V curve hysteresis, stable for several cycles. Trap-controlled SCLC conduction is responsible for the charge transport in the active layer, where the “set” and “reset” processes occur. The incorporation of ZnO@SiO2 quantum dots significantly enhances the RS response. The distinguishing result presented here is the ability to write-read-erase-read, controlling the "on" and "off" states by applying an external electric field, allowing to store and read information multiple times. An endurance of nearly one order of magnitude between the low and high RS states was determined over 50 consecutive cycles. The device proved to be resilient, preserving the resistive switching effect and memory capacity even after one year maintained at room temperature in ambient atmosphere. DFT calculations indicate a conduction mechanism based on reversible reductions of the perylene LC molecules. This article highlights the ability of LCs to store and process information via their resistivity, with potential for the production of low-cost and large-area nonvolatile printed organic memories.