Bright reddish-orange emission and good piezoelectric properties of Sm2O3-modified (K0.5Na0.5)NbO3-based lead-free piezoelectric ceramics

Abstract

Reddish orange-emitting 0.948(K0.5Na0.5)NbO3-0.052LiSbO3-xmol%Sm2O3 (KNN-5.2LS-xSm2O3) lead-free piezoelectric ceramics with good piezoelectric properties were fabricated in this study, and the photoluminescence and electrical properties of the ceramics were systematically studied. Results showed that Sm2O3 substitution into KNN-5.2LS induces a phase transition from the coexistence of orthorhombic and tetragonal phases to a pseudocubic phase and shifts the polymorphic phase transition (PPT) to below room temperature. The temperature stability and fatigue resistance of the modified ceramics were significantly improved by Sm2O3 substitution. The KNN-5.2LS ceramic with 0.4 mol. % Sm2O3 exhibited temperature-independent properties (25–150 °C), fatigue-free behavior (up to 106 cycles), and good piezoelectric properties (d33* = 230 pm/V, d33 = 176 pC/N, kp = 35%). Studies on the photoluminescence properties of the samples showed strong reddish-orange emission upon blue light excitation; these emission intensities were strongly dependent on the doping concentration and sintering temperature. The 0.4 mol. % Sm2O3-modified sample exhibited temperature responses over a wide temperature range of 10–443 K. The maximum sensing sensitivity of the sample was 7.5 × 10−4 K at 293 K, at which point PPT occurred. A relatively long decay lifetime τ of 1.27–1.40 ms and a large quantum yield η of 0.17–0.19 were obtained from the Sm-modified samples. These results suggest that the KNN-5.2LS-xSm2O3 system presents multifunctional properties and significant technological potential in novel multifunctional devices.

Effect of Yb Codoping on the Phase Transition, and Electrical and Photoluminescence Properties in KNLN:Er/xYb Ceramics

“…Raman spectrum measurement is helpful to acquire the information on the phase structure of KNN‐based ceramics, because NbO 6 octahedron vibrations are relatively sensitive to the change in the phase structure . Figure (a) presents the Raman spectra of KNLN:Er/ x Yb ceramics with different Yb contents at RT, where ν 5 and ν 1 bands are relatively strong in the internal vibration modes of NbO 6 octahedron.…”

“…These RE‐doped materials own a great potential for device applications in low‐voltage field emission display (FEDs), vacuum fluorescent display, optoelectronic devices, and so on . Especially, RE‐doped ferroelectrics have been intensively investigated because they present both excellent piezoelectric and PL properties, which makes them become the promising materials for optical amplifiers, zero‐loss electro‐optical elements, monolithic multifunction compact devices . Moreover, RE elements with small ionic radii could modify the ferroelectric properties by improving the spontaneous polarization .…”

Microstructural, ferroelectric, and photoluminescent properties of (100)‐oriented Sm3+‐doped Na0.5Bi0.5TiO3 thin films

“…The BaTiO 3 ‐based solid solutions perform excellent electromechanical properties, but the low Curie temperature ( T C = 120°C) limits their applications in the devices which will be used under extreme conditions . The KNN, a solid solution of ferroelectric KNbO 3 and anti‐ferroelectric NaNbO 3 in the ratio of 1:1 with an ABO 3 perovskite structure, has attracted much attention because of its high Curie temperature ( T C = 420°C) and the excellent piezoelectric coefficient ( d 33 ) comparable to values obtained for Pb(Zr,Ti)O 3 . However, its high piezoelectric coefficient resulted from the polymorphic phase transition at room temperature generally leads to poor temperature stability, which would restrict its applications.…”

“…It has been demonstrated that the ferroelectric materials doped with rare‐earth elements (lanthanide), showed an enhancement in ferroelectricity as well as highly efficient photoluminescence (PL), so it is hopeful to achieve multifunctional properties in ferroelectric thin films by doping rare‐earth ions. Zhou et al demonstrated that Pr 3+ ‐doped Na 0.5 Bi 0.5 TiO 3 thin films simultaneously showed strong red emission and optimal ferroelectricity.…”

“…Zhou et al demonstrated that Pr 3+ ‐doped Na 0.5 Bi 0.5 TiO 3 thin films simultaneously showed strong red emission and optimal ferroelectricity. Similarly, Hao et al also reported that Sm 2 O 3 ‐modified (K 0.5 Na 0.5 )NbO 3 ‐based lead‐free piezoelectric ceramics exhibited bright reddish‐orange emission and good piezoelectric properties. Therefore, it is interesting to study the photoluminescence and electrical properties of Sm 3+ ‐doped NBT ferroelectric thin films and to design a new multifunctional lead‐free ferroelectric material that can exhibit excellent photoluminescence as well as enhanced ferroelectric properties.…”