Luminescent properties of Tm3+-activated phosphors with rosiaite structure.

A series of solid solutions with compositions of La 1-x Tm x Ga 0.5 Sb 1.5 O 6 (x = 0.03, 0.05, 0.1) and La 1-x-y-z Tm x Tb y Dy z Ga 0.5 Sb 1.5 O 6 (x = 0.04, 0.07, 0.1; y = 0.04, 0.07, 0.1; z = 0.04, 0.04, 0.06) has been synthesized. It is shown that all the compounds have rosiaite structure (PbSb 2 O 6 , sp.gr. P-31m). Morphology, spectral-luminescent characteristics and color coordinates of the samples were studied. It was found that luminescence spectrum of thulium-activated samples recorded upon 351 nm excitation is typical for Tm3+ ions. At the same time, under excitation by radiation with λ = 457 nm and a power density of J = 4.7 kW/cm2, broadband thermal emission is observed, against which the bands corresponding to the 1G 4 →3H 6 , 1G 4 →3F 4 , 3F 4 →3H 6 и 3H 4 →3H 6 transitions of Tm3+ are detected. The luminescence spectra of the samples co-activated with Tm3+, Tb3+ and Dy3+are characterized by a relatively low intensity of the Tm3+ emission, which may be due to efficient energy transfer processes between Tb3+ and Dy3+ ions. A shift from the blue to the green color regions is observed in the color coordinates of the co-activated samples upon 351 nm excitation. Radiation with λ = 457 nm led to a shift in the emission colour to orange. Thus, it is shown that it is possible to create phosphors emitting in the blue, green and orange spectral regions by changing the wavelength of exciting radiation and activator composition for compounds with rosiaite structure. • La 1-x Tm x Ga 0.5 Sb 1.5 O 6 phosphorus exhibit blue emission under UV excitation. • nm intense excitation leads to thulium and broadband emission. • Co-doping by Tm3+, Tb3+ and Dy3+ shifts emission colour to green under UV excitation. • nm excitation of samples co-doped by Tm3+, Tb3+ and Dy3+ leads to orange emission. [ABSTRACT FROM AUTHOR]