Dual-enhancement of ferro-/piezoelectric and photoluminescent performance in Pr3+ doped (K0.5Na0.5)NbO3 lead-free ceramics

Abstract

A mutual enhancement action between the ferro-/piezoelectric polarization and the photoluminescent performance of rare earth Pr3+ doped (K0.5Na0.5)NbO3 (KNN) lead-free ceramics is reported. After Pr3+ doping, the KNN ceramics exhibit the maximum enhancement of ∼1.2 times in the ferroelectric remanent polarization strength and ∼1.25 times in the piezoelectric coefficient d33, respectively. Furthermore, after undergoing a ferro-/piezoelectric polarization treatment, the maximum enhancement of ∼1.3 times in photoluminescence (PL) was observed in the poled 0.3% Pr3+ doped sample. After the trivalent Pr3+ unequivalently substituting the univalent (K0.5Na0.5)+, A-sites ionic vacancies will occur to maintain charge neutrality, which may reduce the inner stress and ease the domain wall motions, yielding to the enhancement in ferro-/piezoelectric performance. The polarization-induced enhancement in PL is attributed to the decrease of crystal symmetry abound the Pr3+ ions after polarization. The dual-enhancement of the ferro-/piezoelectric and photoluminescent performance makes the Pr3+ doped KNN ceramic hopeful for piezoelectric/luminescent multifunctional devices.

Effect of molybdenum on upconversion emission and temperature sensing properties in Na0.5Bi0.5TiO3:Er/Yb ceramics

“…Since the radius of Mo ion is smaller than that of Bi ion, the structure asymmetry of the NBT host lattice can be enhanced with doping of Mo ions, leading to the lower symmetry around Er ions. Typically, the lower symmetry at the site of lanthanide ions means that the more uneven crystal field components can mix opposite-parity into 4f configurational levels and subsequently improve the intra-4f ED transition possibility of Er ions [4,8]. As a result, the UC emission intensity of NBT:0.5% Er/0.5%Yb ceramics was enhanced with moderate addition of Mo ions.…”

“…Some interesting phenomena, such as enhanced piezoelectricity, photoluminescence (PL), and upconversion (UC) emission, were observed in RE ions doped ferroelectric ceramics [4][5][6][7]. Hao et al [8] reported that the UC emission intensities of erbium (Er)/ytterbium (Yb) ions codoped BaTiO 3 thin films can be increased by applying an extra electric field.…”

Low-temperature thermometry based on upconversion emission of Ho/Yb-codoped Ba0.77Ca0.23TiO3 ceramics

“…Moreover, it was also revealed that poling is an effective method to modify the emission intensity of RE doped ferroelectrics [20,21]. Jia et al pointed out that the emission intensity of Pr-doped (K 0.5 Na 0.5 )NbO 3 ceramics was increased by 1.5 times after poling [22]. Furthermore, Xu et al mentioned that strong green UC emissions can be observed in Er doped (Ba 0.99 Ca 0.01 )(Ti 0.98 Zr 0.02 )O 3 ceramics [23].…”

Effects of doping and epitaxy on optical behavior of NaNbO3 films

“…[6][7][8] Moreover, the red-color photoluminescence (PL) can be excited by ultraviolet radiation in the Pr-doped NNO crystals and (K,Na)NbO 3 ceramics. [9][10][11] Bulk NNO possesses an orthorhombic crystal structure and exhibits an antiferroelectric behavior at room temperature. 12,13 When epitaxial NNO films are grown on top of cubic substrates, a monoclinic-type ferroelectric r-phase is expected to form in the films.…”