Concerted Ge–H/Se–Se Bond Reorganization Enables Surface Selenylation of Germanium Quantum Dots

Colloidal germanium quantum dots (GeQDs) hold promise for solution-processable optoelectronics, yet their performance is often constrained by the limited reactivity of hydride-terminated surfaces and the insulating nature of conventional capping ligands. Here, we introduce a room-temperature selenylation strategy that harnesses the intrinsically weak and polarizable Ge–H bonds on freshly etched GeQD surfaces to drive Se–Se bond activation of diorganyl diselenides. This polarization-assisted concerted process proceeds without radical initiators or external stimuli, yielding robust Ge–SeR surface linkages that effectively passivate the GeQDs against oxidation while introducing a soft, polarizable chalcogenide-rich surface. The resulting RSe-GeQDs show notably improved optical properties and charge carrier mobilities compared to oleylamine-functionalized GeQDs. The direct, catalyst-free nature of this approach offers a versatile platform for the development of solution-processable germanium-based optoelectronic devices.