Mechanistic Insights into Dislocation‐Mediated Single‐Atom Doping of 2D Transition Metal Dichalcogenides

Abstract Single‐atom doping represents a powerful approach for the atomic‐level modulation of the physicochemical properties of 2D materials. Yet, the incorporation of dopants at structurally complex dislocation sites remains largely uncharted, owing to the pronounced structural heterogeneity and intricate local bonding environments of these regions. Here, vanadium (V)‐doped monolayer MoS 2 as a model system is employed to directly resolve the atomic‐scale incorporation of V into distinct grain boundary (GB) architectures, using aberration‐corrected scanning transmission electron microscopy combined with electron energy loss spectroscopy. Two distinct doping modes are identified: i) in non‐60° GBs comprising periodic 5|7 dislocation cores, V atoms substitute Mo sites to form six well‐defined dopant configurations; and ii) in 60° GBs characterized by extended 4|8 and 4|4 dislocation arrays, V incorporation yields four previously unreported dopant geometries. Remarkably, these dislocation‐mediated configurations exhibit synergistic effects that surpass the performance of doping at either isolated dislocations or pristine basal planes, underscoring their potential for enabling site‐specific, atomic‐precision property engineering in 2D materials.