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

Abstract

Ceramics 0.94(K 0.5 Na 0.5 )NbO 3 -0.06LiNbO 3 :Er/xYb with x = 0, 0.002, 0.004, 0.006, 0.008 were fabricated in this study, and phase structure, dielectric, piezoelectric, ferroelectric, and upconversion photoluminescence properties of the ceramics were systematically studied. Results show that all ceramics are in the polymorphic phase transition region near room temperature. However, a relaxor-like phase transition was observed as Yb increasing to over x = 0.004. The optimized dielectric, piezoelectric, and ferroelectric properties, and maximized photoluminescence intensity ratio are obtained at x = 0.004. And the electrical and photoluminescence properties of the ceramics were discussed from the point view of the normal to relaxor-like ferroelectric phase transition. The present study demonstrates that both the electrical and upconversion photoluminescence properties of the ceramics have an intimate correlation with the normal to relaxor-like ferroelectric transition induced by Yb doping.

The NbO6 octahedral distortion and phase structural transition of Eu3+‐doped K0.5Na0.5NbO3–xLiNbO3 ferroelectric ceramics

“…The insets of Figure display the schematic structures of these compositions from the orthorhombic phase to PPT, and finally transformed into tetragonal phase. Note that, the absence of secondary impurity phase assigned to K 5.75 Nb 10.85 O 30 (PDF#38‐0297), which is commonly presented in KNN‐based ceramics in these synthesized samples, is a remarkable advance in this study. Such advancement could be ascribed to the efficiently supplement of K + and Na + evaporation during sintering.…”

“…The X‐ray powder diffraction patterns of KNN– x LN:0.006Eu 3+ ceramics are displayed in Figure . The phase structure can be determined by the relative height between the two split peaks around 45.5° . When x ≤ 0.05, the (202) peak is higher than the (020) peak, indicating that KNN– x LN:0.006Eu 3+ ceramics have a major orthorhombic phase (O phase) at room temperature.…”

“…From the XRD results, the ceramics with composition of x < 0.05, 0.05 ≤ x ≤ 0.06 and x > 0.06 correspond to the orthorhombic (PDF#71‐2171), PPT and tetragonal phases (PDF#71‐0945), respectively. The introduction of LN into KNN makes the original orthorhombic phase structure unstable and finally be transformed into tetragonal phase . The insets of Figure display the schematic structures of these compositions from the orthorhombic phase to PPT, and finally transformed into tetragonal phase.…”

Reversible luminescence modulation of Ho‐doped K0.5Na0.5NbO3 piezoelectrics with high luminescence contrast

“…For example, Jia et al reported dual‐enhancement between the ferro‐/piezoelectric polarization and the photoluminescent performance of rare earth Pr 3+ ‐doped (K 0.5 Na 0.5 )NbO 3 (KNN) lead‐free ceramics, and observed the polarization‐induced luminescent enhancement . Similar behavior is also observed in Er/Yb co‐doped 0.94(K 0.5 Na 0.5 )NbO 3 –0.06LiNbO 3 or Pr 3+ ‐modified 0.93(Bi 0.5 Na 0.5 )TiO 3 –0.07BaTiO 3 ceramics . Up to now, Ln‐doped KNN‐based materials have drawn many researchersʼattentions, the focus of attention is to realize the coexistence of ferro‐/piezoelectric and luminescent properties, and investigate the relationship between them.…”

Reversible upconversion switching for Ho/Yb codoped (K,Na)NbO3 ceramics with excellent luminescence readout capability

“…The studies on KNN materials mainly focus on the enhancement of its piezoelectric properties. Nowadays, many groups take advantage of the ferro‐/piezoelectric properties of KNN host in combination with lanthanide ions acting as activators, realizing the simultaneous existence of ferroelectric and optical properties . These interesting characteristics also provide an opportunity for us to develop a series of “smart” materials with luminescent emission, which can be modulated by external stimuli of electric field, magnetic field, mechanical force, or temperature (Scheme ).…”