Journal Article Car-Parrinello molecular dynamics ab initio molecular dynamics 2D materials CIGS solar cells Cu-poor Cu(In,Ga)Se2 Cu-rich Cu(In,Ga)Se2 Monte Carlo Research Support, Non-U.S. Gov't X-ray absorption near edge structure X-ray absorption spectroscopy ab initio bifunctional oxygen electrocatalysts black phosphorus bonding carbon suboxide carbonaceous materials conjugated ladder polymers covalent materials crystal orbital Hamilton population density functional theory device simulations force matching grain boundaries indium nanowires infrared spectroscopy liquid water maximally localized Wannier functions metallic hydrogen molecular dynamics