Session: Chemistry of Materials:

All-inorganic ternary group 11 halides have recently gained interest in the optical materials community as viable, relatively non-toxic alternatives for high-intensity luminescence applications. Bulk powder samples and single crystals of A₂MX₃ (A=Rb, K, NH₄; M= Cu, Ag; X= Cl, Br, I) were prepared using facile high temperature solid-state and solution techniques. The all-inorganic group 11 halides have been investigated through an in-depth optical characterization, including diffuse reflectance, photoluminescence, and radioluminescence. A₂CuX₃ are found to exhibit narrow blue photoluminescence peaks with record-high efficiencies as evidenced by the measured photoluminescent quantum yields up to unity (100 %). Conversely, A₂AgX₃ displays broad, white emission with tunability in color temperature. Through variation in the A⁺ cation site, the stability of the material can be dramatically increased, while retaining similar optical performance. For A₂CuX₃ the bright emission in this family has been attributed to self-trapped excitons localized on [CuX₃]^2- anionic substructure based on exhaustive photoluminescence studies supported by the density functional theory (DFT) calculations. Our combined experimental and computational study suggests strong potential of A₂MX₃ as phosphors for radiation detection and solid-state lighting applications.

Dr. Maohua Du

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