Chitosan, a Cationic Polymer-Loaded CuS:Ni Nanoparticles Well Suited for Pseudocapacitors, Optical Switching and Sprintronic Devices

Chitosan, a cationic polymer, is loaded on Ni-doped copper monosulfide (CuS) NPs with optimal Ni doping concentration, and electrochemical, third-order nonlinear, magnetic and antibacterial characteristics of chitosan unloaded and loaded CuS:Ni nanoparticles are compared. The crystallite size of pure CuS increased with Ni doping and the 10wt.% Ni-doped CuS NPs exhibit a maximum crystallite size of 41nm. The presence of Ni in the doped samples was acknowledged by the existence of Ni 2p(3/2) and Ni 2p(1/2) peaks at binding energies 851eV and 873.1eV, respectively from the XPS spectrum. Optical reflectance decreased with Ni doping and the optical band gap varied from 2.56eV to 2.4eV. Specific capacitance increased with Ni doping. Diamagnetic nature of CuS changed to ferromagnetic with Ni doping. The 10wt.% Ni-doped CuS exhibits a high third-order nonlinear absorption coefficient and susceptibility value. Bacterial growth inhibition nature of CuS improved with Ni doping. Among the doped samples, the 10wt.% Ni-doped sample exhibits improved electrochemical, third-order nonlinear, magnetic and antibacterial properties. Keeping this as the optimized Ni concentration, chitosan was loaded. Chitosan-loaded samples exhibited a reduction in crystallite size and an increase in band gap. A high specific capacitance of 96F/g was realized for the chitosan-loaded sample. Saturation magnetization of 10wt.% CuS:Ni decreased with chitosan loading.