Growth and Luminescence Properties of Large‐Size Na₂Mo₂O₇ Single Crystal by the Vertical Bridgman Method

This study investigates the growth and luminescence properties of Na 2 Mo 2 O 7 crystal for the application in the low‐temperature radiation detectors, specifically for neutrinoless double β decay research. φ25 and φ40 mm Na 2 Mo 2 O 7 transparent crystals are grown by the vertical Bridgman method. The crystal phase is characterized using X‐ray diffraction (XRD), Raman spectrometer, thermogravimetric‐differential thermal analysis (TG‐DTA), and energy dispersive spectroscopy (EDS). UV–vis spectrophotometry reveals that the crystal exhibits high transmittance, reaching up to 84%. Fluorescence spectrometry indicated that the emission spectrum of Na 2 Mo 2 O 7 reaches its maximum intensity at 80 K. The luminescence decay time increases with decreasing temperature, and the decay time at 10 K is 697.5 µs. The activation energy (E a ) of the crystal is fitted to be 193.3 meV. The result shows that the Na 2 Mo 2 O 7 crystal has excellent luminescence properties at low temperatures.