A Double‐Band Emitter with Ultranarrow‐Band Blue and Narrow‐Band Green Luminescence. Issue 10 (21st January 2020)

• Record Type: Journal Article
• Authors: Ruegenberg, Freia; Seibald, Markus; Baumann, Dominik; Peschke, Simon; Schmid, Philipp C.; Huppertz, Hubert
• Is Part Of: Chemistry. Volume 26:Issue 10(2020)
• Page Start: 2204
• Page End: 2210
• Publication Date: 2020-01-21
• Subjects: alkali metals -- high-temperature chemistry -- luminescence -- silicates -- solid-state structures; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201904526
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Understanding the origin and mechanisms of luminescence is a crucial point when it comes to the development of new phosphors with targeted luminescence properties. Herein, a new phosphor belonging to the substance class of alkali metal lithosilicates with the generalized sum formula Cs4− x − y − z Rb x Na y Li z [Li3 SiO4 ]4 :Eu 2+ is reported. Single crystals of the cyan‐emitting UCr4 C4 ‐type phosphor show a peculiar double‐band luminescence with one ultranarrow emission band at 473 nm and a narrow emission band at 531 nm under excitation with UV light ( λ exc =408 nm). Regarding occupation of the channels by the light metal ions, investigations of single‐crystal XRD data led to the assumption that domain formation with distinct lithium‐ and sodium‐filled channels occurs. Depending on which of these channels hosts the activator ion Eu 2+, a green or blue emission results. The herein‐presented results shed new light on the luminescence process in the well‐studied UCr4 C4 ‐type alkali metal lithosilicate phosphors. Abstract : Double peak : An alkali metal lithosilicate phosphor with generalized sum formula Cs4− x − y − z Rb x Na y Li z [Li3 SiO4 ]4 :Eu 2+ was synthesized by a solid‐state reaction. A special property of this UCr4 C4 ‐type compound is the peculiar green and blue double‐band luminescence. This property is apparently related to the filling of the light‐alkali‐metal channels to the extent that lithium and sodium domains are formed, which generate different environments for the activator‐ion site.