Tuning electroluminescence performance in Pr-doped piezoelectric bulk ceramics and composites

Alternating current electroluminescence (ACEL) shows great potential in lighting, display and intelligent skin. Herein, the ACEL properties of Pr3+-doped Ba0·85Ca0·15Ti0·90Zr0·10O3 ceramic and its PDMS-based composite have been investigated. Intense red EL emission was obtained in the ceramic sample whereas blue EL emission of Pr3+ was observed for the first time in the composite counterpart. The red EL emission should be attributed to the impact of hot electrons driven by the large piezoelectric electric field. Owing to the cross-relaxations through the 4f5d levels and Pr-to-metal charge transfer state, the 3PJ emissions were completely quenched, and thus leading to an enhancement in red emission. However, external E field induced a large local piezoelectric deformation of the ceramic particles embedded in the PDMS matrix, which in turn caused a bending of CB and then a downwards shift of the 4f5d levels from the CB. Hence the cross-relaxations were hindered, and the blue EL emission was observed in the composites. The results would attract attention of functional materials studies and expand our understanding of such facile structure and oxide EL devices to facilitate their use in integral part of flexible device systems.