A Computational Toolkit for Generating WSe2 Grain Boundaries: Tilted, Mirror, and Polycrystals

Grain boundaries (GBs) are among the most common defects in 2D Transition-Metal Dichalcogenides (TMDs), critically influencing their electronic, optical, mechanical, and catalytic properties. Understanding and controlling the GBs is therefore essential for optimizing TMD performance in applications of flexible electronics, optoelectronics, catalysis, and lubrication. Yet the structural diversity and atomic complexity make both experimental characterization and modeling for atomistic simulations highly challenging. Here, we introduce an experimentally verified computational toolkit for generating and analyzing GBs in 2D TMDs. We demonstrate its capabilities by using tungsten diselenide (WSe 2 ) as a model material and validating the GBs produced by the toolkit against experimentally observed atomic-resolution scanning transmission electron microscopy images of WSe 2 , hBN and graphene. This tool enables the study of TMD materials to predict and tailor material properties through controlled defect generation. It not only advances our understanding of GBs dynamics in TMDs but also supports the broader application of these materials in various technological fields. • Program title: 2D-GBUILD • CPC Library link to program files: https://doi.org/10.17632/3g8ksykd7k.1 • Developer's repository link: https://github.com/KasraKnanosys/2D-GBUILD.git • Licensing provisions: CC by NC SA 4.0 • Programming language: Python • Nature of problem: The code can create Mirror-Twin Grain Boundaries (MTB), Tilt-Grain Boundaries and Polycrystalline TMD structures. • Solution method: The geometric GB templates (e.g., mirror and tilt types) constructed, mapped onto bi-atomic lattices, and chemical consistency enforced across defects. The structures are then energy-minimized using molecular dynamics to obtain physically realistic, experimentally validated TMD grain boundary models