Bridgman growth and luminescence properties of Li2MoO4 single crystal

Large-size Li2MoO4 (LMO) single crystal was grown by vertical Bridgman method. The transmittance spectra, scatterance spectra, and laser-stimulated luminescence spectra as well as luminescence decay time of LMO crystal were investigated systematically. The polished LMO sample has a rather high transmissivity (85%) and a rather low scatterance in 400-800 nm wavelength range. Deliquescence property of LMO has great effects on the transmission and scatterance properties of crystal. LMO crystal has a wide luminescence peak around 551 nm as a result of intrinsic luminescence emission of tetrahedral MoO42−. Luminescence intensity under a 355 nm laser beam is very weak at 300 K. As ambient temperatures cool down, the luminescence intensity increases rapidly and reaches a maximum at 20 K, which is equal to approximately 20 times in contrast with the intensity at 300 K. The luminescence decay times decrease monotonically with the temperature increasing from 20 K to 200 K. The decay times at 20 K, 75 K, 150 K correspond to 11.5 μs, 1.5 μs and 0.25 μs, respectively.