Blue up-conversion emission of Yb3+-doped langbeinite salts

Abstract Yb 3+ -doped langbeinite salts were prepared by the solid solution method. X-ray diffraction patterns and vibrational spectroscopy confirmed that all obtained phases are highly pure, iso-structural and they crystallize in the cubic system with the space group P 2 1 3. The emission luminescence comes from the 2 F 5/2  →  2 F 7/2 transition of Yb 3+ ions. Moreover, intense blue cooperative emission was observed at 476 nm under excitation in the near infrared at 975 nm.