Synchronized Photoluminescence\nand Electrical Mobility\nEnhancement in 2D WS<sub>2</sub> through Sequence-Specific Chemical\nPassivation

Two-dimensional (2D) semiconducting dichalcogenides hold\nexceptional\npromise for next-generation electronic and photonic devices. Despite\nthis potential, the pervasive presence of defects in 2D dichalcogenides\nresults in carrier mobility and photoluminescence (PL) that fall significantly\nshort of theoretical predictions. Although defect passivation offers\na potential solution, its effects have been inconsistent. This arises\nfrom the lack of chemical understanding of the surface chemistry of\nthe 2D material. In this work, we uncover new binding chemistry using\na sequence-specific chemical passivation (SSCP) protocol based on\n2-furanmethanothiol (FSH) and bis(trifluoromethane) sulfonimide lithium\nsalt (Li-TFSI), which demonstrates a synchronized 100-fold enhancement\nin both carrier mobility and PL in WS<sub>2</sub> monolayers. We propose\nan atomic-level synergistic defect passivation mechanism of both neutral\nand charged sulfur vacancies (SVs), supported by ultrafast transient\nabsorption spectroscopy (TA), Hard X-ray photoelectron spectroscopy\n(HAXPES), and density functional theory (DFT) calculations. Our results\nestablish a new semiconductor quality benchmark for 2D WS<sub>2</sub>, paving the way for the development of sustainable 2D semiconductor\ntechnologies.