Synergistic effect of a crystal modifier and screw dislocation step defects on the formation mechanism of nickel micro-nanocone

The synergestic role of boric acid, as a crystal modifier, and screw dislocation step defects on the crystal growth and formation mechanism of nickel micro-nanocones during electrocrystallization is explained using density functional theory (DFT) and Monte Carlo (MC) calculations. Earlier atomic force microscopy (AFM) studies provided direct evidences on the effect of boric acid on morphology distribution of nickel micro-nanocones and confirmed the presence of terraces and steps due to the spiral growth of screw dislocation. In the presence of boric acid, the formation of nickel-borate complex leads to a decrease in the system’s supersaturation and in turn provides an appropriate condition for screw dislocation driven-growth. DFT and MC simulations reveal that the nickel-borate complex primarily adsorb in the step edges with the lowest adsorption energy barrier, after which the crystal growth is inhibited on these edges resulting in the formation of nanocone structures.