Investigating the impact of molybdenum content on the room-temperature optical properties of Li2WO4 crystals grown by low-thermal-gradient Czochralski technique.

Li 2 WO 4 single crystals and Mo-doped Li 2 W 1– x Mo x O 4 ( x = 0.0125, 0.05) were grown by the low-thermal-gradient Czochralski technique. Optimal crystallization conditions were determined for obtaining single crystals with a length of 50 mm and a diameter of 30 mm: crystallization rate of 0.5 mm h −1 and rotation rate of 5 rpm. The crystal structure was investigated using powder X-ray diffraction, which confirmed the single-phase nature and trigonal structure (space group R 3 ) for all compositions. Differential scanning calorimetry did not reveal phase transitions in the temperature range 303–1153 K. The influence of partial substitution of W with Mo on the luminescence properties is demonstrated and a correlation between Mo concentration and emission characteristics is established.