Simulation of Site-Selective Etching by Invoking Effects of Ligands and Reactant Diffusion

Area of Science:

• Materials Science
• Chemical Engineering
• Computational Chemistry

Background:

• Crystal etching in wet chemistry is complex, influenced by reactant and ligand dynamics.
• Conventional simulations often oversimplify diffusion and adsorption/desorption processes.
• Understanding these factors is crucial for controlling nanomaterial morphology.

Purpose of the Study:

• To develop a kinetic Monte Carlo model incorporating non-equilibrium reactant and ligand diffusion.
• To investigate the origin of inequivalent etching on equivalent crystal sites.
• To elucidate the mechanisms behind selective etching and abnormal crystal morphologies.

Main Methods:

• Development of a novel kinetic Monte Carlo simulation model.
• Inclusion of reactant and ligand diffusion rates as key parameters.
• Simulation of etching processes on gold triangular nanoplates.

Main Results:

• Non-equilibrium ligand control induces selective etching at specific crystal sites (corners, edges, facets).
• Ligand effects create positive feedback, while slow reactant diffusion imposes negative feedback.
• Simulations accurately reproduce experimental etching products and morphological details like notches and holes.

Conclusions:

• The developed model highlights the critical role of non-equilibrium ligand control and diffusion in crystal etching.
• The model successfully explains selective etching phenomena and reproduces experimental observations.
• This simulation approach can be extended to diverse systems for understanding abnormal crystal growth mechanisms.