Energy density capability and upconversion luminescence in Er3+/Yb3+-codoping BNT-based ferroelectric thin films

Smart materials with multiple functions are the preferred materials for technological applications in military, medical, aerospace science and technology, and architecture. However, developing newly single-phase material coupling with multiple functions is still subjects with enormous challenge. Herein, the rare-earth elements Er 3+ /Yb 3+ substitution of lead-free 0.7Bi 0 · 5 Na 0 · 5 TiO 3 -0.3Sr 0 · 7 Bi 0 · 2 TiO 3 (BNT-SBT) ferroelectric thin films are designed and fabricated to improve energy storage capability and upconversion luminescence. Optimized BNT-SBT thin films achieves superior discharged energy density of 52.4 J/cm 3 with high efficiency of 70.2%, as well as excellent temperature stability (RT to 150 °C) and fatigue endurance (10 7 circles). Additionally, the emission color of BNT-SBT thin films could be controlled through changing Yb 3+ ion concentrations. More importantly, the maximum sensor sensitivity of the Er 3+ /Yb 3+ codoped BNT-SBT thin films could reach 0.0049 K −1 at 363 K. This contribution paves a novel avenue for preparing lead-free multifunctional ferroelectric thin films, which are interested in potential application in the field of optoelectronic devices.