Doping-Guided Control of Lead-Sensitized Terbium Emission in Zinc Sulfide Nanoparticles: Implications for Lead Ion Sensing in Aqueous Media.

Pb²⁺ codoping enhances the Tb³⁺ emission in trivalent terbium-doped zinc sulfide [Zn-(Tb)-S] nanoparticles (NPs). The Tb³⁺-Pb²⁺ spatial proximity and a favorable codopant electronic energy level alignment contribute toward this emission brightening. This work tests the performance of the Tb³⁺ emission in the Zn-(TbPb)S and Zn-(Tb)-S/Pb NPs, where the dopants within parentheses and after slashes indicate their synthetic and postsynthetic doping, respectively. When screened against steady-state and time-resolved photoluminescence, photoelectron spectroscopy, zeta potential, and infrared absorption of surface capping ligands, the Zn-(TbPb)S NPs emerge as a superior sensitizer to generate Tb³⁺ emission. A core dominant Tb³⁺-Pb²⁺ interaction in Zn-(TbPb)S NPs prompts a stronger Tb³⁺ emission when compared to the surface dominant Tb³⁺-Pb²⁺ interaction in Zn-(Tb)-S/Pb NPs. This doping strategy guided the NP design principle to control lanthanide emission, which expands the palette of lanthanide-based NP luminophores for practical applications. The Pb^2+‑sensitized Tb³⁺ emission brightening in the ZnS NPs in the precation exchange reaction conditions can find applications in Pb²⁺ sensing, cellular imaging, and light emitting diodes (LEDs). [ABSTRACT FROM AUTHOR]