Elastico-mechanoluminescent enhancement with Gd^3+ codoping in diphase (Ba,Ca)TiO_3:Pr^3+

Elastico-mechanoluminescence (EML) in diphase (Ba,Ca)TiO3:Pr3+ with 60 mol% Ca content was greatly enhanced by Gd3+ codoping. The optimal EML intensity of (Ba,Ca)TiO3:Pr3+,Gd3+ is higher by 235% than that of (Ba,Ca)TiO3:Pr3+. The decreases of both photoluminescent intensity and reflectivity induced by Gd3+ codoping suggest the introduction of new trap centers. The thermoluminescent (ThL) measurement has been performed to investigate the effect of codoping on the trap depth and concentration. The consistent dependency correlations of EML intensity and ThL integral intensity on the Gd3+ concentration illuminate that the improved EML originates from the increased concentration of traps with suitable depth. A possible EML mechanism for (Ba,Ca)TiO3:Pr3+,Gd3+ is proposed on the basis of these experimental observations.