Low Thermal Budget Photonic Curing as a Rapid and Facile Method for the Preparation of Nickel Oxide/Carbon Composites

Low thermal budget photonic curing technique can process metal organic precursors and convert them into nanocomposites in short period of time (few seconds). In this work, we demonstrate that nickel acetylacetonate (Ni(acac)) can be converted into nanocomposite thin films of nickel oxide and reduced graphitic oxide (NiO-rGO) using this technique. Systematic investigation of morphology, structure, and electrochemical properties of films prepared using different bank voltages of photonic curing (500V, 600V, and 700V) is performed. During photonic curing at these voltages, samples are processed using light energy with peak power per unit area 8.2 kW/cm², 14 kW/cm², and 22 kW/cm² respectively. The total energy irradiated per unit area is kept constant at 43J/cm² for all films by varying the number of pulses. As the peak power used to process the sample increases, maximum temperature of the film also increases, which in turn affects the porosity, quality of crystallinity, and elemental composition in the composites. We studied these films using SEM, TEM, Raman Spectroscopy, and EDXS. We also used films prepared at 700V to construct a hybrid capacitor device with activated carbon as negative electrode and NiO-rGO as positive electrode. CV, GCD and EIS measurements were performed to study the energy storage properties of the films. Thermal profiles of films are also estimated using simulations based on physical properties of the precursor molecules and processing parameters used during photonic curing. Analysis of simulations and experimental results indicate that, to understand and optimize the resulting nanostructures, photochemical reactions also need to be taken into consideration. The study also sheds light into the importance of using higher power as opposed to processing over longer period.