Christine Reinhard, Karl Krämer, Daniel A. Biner and Hans-Ulrich Güdel
V³⁺ sensitized upconversion in Cs₂NaScCl₆:Pr³⁺;V³⁺ and K₂NaScF₆:Er³⁺;V³⁺
J. Alloys Comp. 134, 133-136 (2004)                 

Abstract: Photon upconversion (UC) processes from the near-infrared (NIR) to the visible (VIS) are studied in Cs₂NaScCl₆:Pr³⁺;V³⁺ and K₂NaScF₆:Er³⁺;V³⁺ by high-resolution optical spectroscopy. The transition metal ion with a broad d–d absorption in the NIR acts as a sensitizer and the lanthanide ion as an upconverter. UC processes do occur in both title systems, but with rather low efficiencies. Specific UC mechanisms can be identified from the spectroscopic results.