Trap modification and mechanoluminescence improvement by Si substitution for Sn in Sr2SnO4:Sm3+ ceramics

A series of Sr1.96Sn1-xSixO4:0.04Sm(3+) (x = 0, 0.1, 0.15, 0.2, 0.3, 0.4) were synthesized from solid-state reaction. The mechanoluminescence (ML) performance of Sr1.96SnO4:0.04Sm(3+) was greatly enhanced by partial Si4+ substitution for Sn4+ , and the sample of Sr1.96SnO4:0.04Sm(3+) showed weaker afterglow and twice stronger ML intensity than that in Sr1.96Sn0.8Si0.2O4:0.04Sm(3+). The stress response of Sr1.96Sn0.8Si0.2O4:0.04Sm(3+) ranged from 250 to 1200 N, and its linearity was greatly restored. Particularly, it was very sensitive in the minimal stress response range. These properties of no load threshold for stress sensing and weak afterglow make Sr1.96Sn0.8Si0.2O4:0.04Sm(3+) superior to other excellent ML materials. The introduction of Si4+ caused lattice distortion and promoted defect formation in the system. The trap level energy greatly increased and the trap depth changed, which enhanced the trap ability and therefore improved effectively the ML properties.