Synthesis and mechanoluminescence study of Li6Y(BO3)3:Dy3+/Eu3+ phosphor

Li6Y(BO3)3 phosphor was prepared using solid‐state synthesis by varying europium/dysprosium (Eu/Dy) concentrations in the range 0.05–1.0 mol%. X‐ray diffraction and Fourier transform infrared characterizations provided insight into the phase, crystallinity, morphology and functional groups. Photoluminescence (PL) of the Li6Y(BO3)3:Dy3+ phosphor was also studied. Li6Y(BO3)3:Dy3+ displayed excellent PL due to the characteristic emission of Dy3+ ions in the visible region at 482 nm (4F9/2→6H15/2) and 580 nm (4F9/2→6H13/2,), when excited at 352 nm. The Li6Y(BO3)3:Eu3+ phosphor was discussed in our previous publication. Uniaxial compression experiments on Li6Y(BO3)3 showed that the mechanoluminescence (ML) intensity was linearly dependent on mechanical power. When pressure was applied to these phosphors mixed in an epoxy resin, initially the ML intensity increased with time, attained a peak value Im at a particular time tm, and decreased further with increase in time. After tm, ML intensity decreased exponentially, initially at a faster rate that subsequently slowed down, ML intensity increased linearly for a wide measurement range of dynamic load that made the Li6Y(BO3)3 phosphor a good elastico ML (EML) material to be utilized as a stress sensor with Li6Y(BO3)3:Eu3+ and showing greater ML intensity than Li6Y(BO3)3:Dy3+.