Band-Upward Engineering of 2D Silver-Organic Chalcogenides via Fused Nitrogen-Heterocycle Coordination: A MicroED-Assisted Structure–Property Investigation

Developing high-performance 2D metal–organic chalcogenides (MOCs) requires precise control over both molecular coordination and electronic band structures. Herein, we report a strategic “band-upward” engineering of silver-MOCs through the incorporation of a fused nitrogen-heterocycle, 2-mercaptobenzoxazole (MBO). Utilizing MicroED for atomic-scale structural elucidation, we unveil a unique coordination transition from a symmetric AgS 4 tetrahedron to a highly distorted 3S1N pseudo-tetrahedron in AgMBO. This nitrogen-coordinated environment enriches the electron density at the silver core, facilitating efficient in-plane charge transfer. Consequently, AgMBO displays a substantial upward shift of the valence band maximum ( E VBM ) to –7.08 eV, compared to –8.31 eV for benchmark AgSPh, while maintaining a wide bandgap. Morphologically, the rigid MBO framework facilitates the growth of ultrathin nanosheets, simultaneously promoting an directional charge-transfer pathway and maximizing the exposure of catalytic edge sites. The resulting AgMBO electrode exhibits superior electrocatalytic activity for [Cu(dmp) 2 ] 2+/1+ (dmp = 2,9-dimethyl-1,10-phenanthroline) redox shuttles, leading to enhanced power conversion efficiency in dye-sensitized solar cells. This work provides a robust blueprint for modulating the semiconducting properties of 2D MOCs via heteroatom-induced coordination and electronic tuning.