Mechanoluminescence of Ba2 MgSi2 O7 doped with Eu(2+) and Dy(3+) phosphor by impulsive deformation

Di-barium magnesium silicate phosphor doped with Eu(2+) and Dy(3+) was prepared using a solid-state reaction technique under a reducing atmosphere. The sample underwent impulsive deformation by impact from a piston for mechanoluminescence (ML) investigations. The temporal ML characteristics of the phosphor were observed, which expressed a single sharp peak with a long decaying period. To investigate the luminescence centre responsible for the ML peak, the ML spectrum of the phosphor was also observed. The recorded ML spectrum was similar in shape and peak wavelength to the photoluminescence (PL) spectrum, which verifies the existence of a single emission centre due to the transition of Eu(2+) ions, i.e. transitions from any of the sublevels of the 4f(6)5d(1) configuration to the (8)S7/2 level of the 4f(7) configuration. Decay rates for different impact velocities were also calculated using curve-fitting techniques. The time of the ML peak and the rate of decay did not change significantly with respect to increasing impact velocity of the load and peak ML intensity varied linearly. The mechanism of the ML emission was also discussed.