This project develops next-generation solid-state lighting materials that combine high energy efficiency with improved human health safety. While current white LEDs save an estimated 185 TWh/year, the U.S. Department of Energy aims to improve efficiencies to reach a savings of 500 TWh/year by 2035. Conventional multicomponent LEDs rely on high-intensity blue emission, which can disrupt circadian rhythms. We propose a single-component LED approach using novel rare earth phosphors in the form of chalcogenides or mixed-anionic compounds, which can produce efficient, tunable white light without the “blue hazard.” These materials may also be integrated as thin films in solar cells to enhance light harvesting and conversion efficiency. The work combines targeted solid-state synthesis, structural characterization via single-crystal and powder X-ray diffraction, and optical measurements to determine band gaps, photoluminescent behaviour, colour rendering, luminous efficacy, correlated colour temperature, and thermal stability. Band gaps can be tuned by varying compositions to yield desired optical properties. Design-of-experiment strategies will be employed to rapidly optimize performance. Advanced photoluminescence studies will be carried out in collaboration with Physics. This integrated approach targets lighting materials that are energy-efficient, health-conscious, and industrially scalable.