Bridgman growth and luminescence properties of Na-doped Li2MoO4 crystals

Na-doped Li 2 MoO 4 crystals were grown by the Bridgman method with Na 2 Mo 2 O 7 , Na 2 CO 3 , and Na 2 MoO 4 as dopants. X-ray diffraction and Raman spectroscopy confirmed that Na 2 Mo 2 O 7 doping preserves the host structure of Li 2 MoO 4 , while modifying the MoO 4 2- group vibrational modes and crystal field environment through the introduction of Mo 2 O 7 2- units. Fluorescence studies revealed small luminescence enhancements (1.3 and 1.6 times to pure Li 2 MoO 4 respectively) for samples doped with 1 mol% Na 2 CO 3 and 0.8 mol% Na 2 MoO 4 . In contrast, Na 2 Mo 2 O 7 doping yields a 9 times increase in luminescence intensity at room temperature, with an optimal concentration of 0.8 mol%. This substantial enhancement is attributed to the dominant role of Mo 2 O 7 2- groups, rather than Na + ions. The Na 2 Mo 2 O 7 -doped crystals display temperature-dependent luminescence behavior similar to pure Li 2 MoO 4 , with emission intensity increasing markedly as temperature decreases. • Li 2 MoO 4 crystals were grown via the Bridgman method using three different sodium sources for Na + doping. • Doping with 0.8 mol% Na 2 Mo 2 O 7 yielded the most significant result, achieving a 9-fold enhancement in luminescence intensity. • This crystal is a promising candidate for 0ν2β experiments at low temperatures.