Using chemical bath deposition to create nanosheet-like CuO electrodes for supercapacitor applications.

We report the effect of ionic liquids on chemically synthesized hierarchical-like copper oxide (CuO) thin films for supercapacitor applications. Concisely, the CuO thin films were deposited via chemical bath deposition (CBD) using 2-dimethylimidazolium chloride [HPDMIM(C1)], 1-(2',3'-dihydroxypropyl)-3-methylimidazolium chloride [DHPMIM(C1)], and N-(3-methyl-2-oxopropyl)pyridine chloride [MOCPP(C1)] ionic liquid solvents. The effects of the ionic liquid solvents on the morphological evolution of the as-prepared films were analyzed, and electrochemical properties were investigated. The highest specific capacitance was achieved for the electrode with a nanosheet-like structure produced by functionalization with the HPDMIM(C1) ionic liquid. The maximum specific capacitance achieved for the HPDMIM(C1):CuO hybrid electrode was 464 F g-1 at 5 mV s-1 in a 1 M Na2SO4 electrolyte. Thus, our findings, in addition to the stability of the HPDMIM(C1):CuO, indicate that it is a candidate for energy-storage applications.

Mimicking the Synaptic Weights and Human Forgetting Curve Using Hydrothermally Grown Nanostructured CuO Memristor Device.

In the present investigation, we have fabricated copper oxide (CuO) thin film memristor by employing a hydrothermal method for neuromorphic application. The X-ray diffraction pattern confirms the films are polycrystalline in nature with the monoclinic crystal structure. The developed devices show analog memory and synaptic property similar to biological neuron. The size dependent synaptic behavior is investigated for as-prepared and annealed CuO memristor. The results suggested that the magnitude of synaptic weights and resistive switching voltages are dependent on the thickness of the active layer. Synaptic weights are improved in the case of the as-prepared device whereas they are inferior for annealed CuO memristor. The rectifying property similar to a biological neuron is observed only for the as-prepared device, which suggested that as-prepared devices have better computational and learning capabilities than annealed CuO memristor. Moreover, the retention loss of the CuO memristor is in good agreement with the forgetting curve of human memory. The results suggested that hydrothermally grown CuO thin film memristor is a potential candidate for the neuromorphic device development.

Electrochemical behavior of chemically synthesized selenium thin film.

The facile and low cost simple chemical bath deposition (CBD) method is employed to synthesize red colored selenium thin films. These selenium films are characterized for structural, morphological, topographical and wettability studies. The X-ray diffraction (XRD) pattern showed the crystalline nature of selenium thin film with hexagonal crystal structure. The scanning electron microscopy (SEM) study displays selenium nanoparticles ranging from 20 to 475 nm. A specific surface area of 30.5 m(2) g(-1) is observed for selenium nanoparticles. The selenium nanoparticles hold mesopores in the range of 1.39 nm, taking benefits of the good physicochemical stability and excellent porosity. Subsequently, the electrochemical properties of selenium thin films are deliberated by cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) techniques. The selenium thin film shows specific capacitance (Cs) of 21.98 F g(-1) with 91% electrochemical stability.

Supercapacitive activities of potentiodynamically deposited nanoflakes of cobalt oxide (Co3O4) thin film electrode.

In the present work, the Co3O4 thin films are successfully prepared via potentiodynamic electrodeposition method onto inexpensive stainless steel substrate. As-deposited films were heat treated at 623K for their conversion into Co3O4. These films were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) techniques. The X-ray diffraction (XRD) study revealed the formation of cobalt oxide (Co3O4) with cubic crystal structure. The FT-IR study supports the formation of Co3O4 material. The SEM image of Co3O4 film showed nanoflake-like morphology with an average thickness of 100 nm. Supercapacitive properties of Co3O4 thin film electrode were examined using cyclic voltammetry and charge-discharge techniques. The Co3O4 thin film electrode showed maximum specific capacitance of 365 Fg(-1) in 1M KOH electrolyte at the scan rate of 5 mV s(-1). The charge-discharge technique was employed to estimate the values of specific energy, power and coulombic efficiency as 64 W h kg(-1), 21.53 kW kg(-1) and 99%, respectively.