Photochromic and Electric Field-Regulating Luminescence in High-Transparent (K,Na)NbO₃-Based Ferroelectric Ceramics with Two-Phase Coexistence

Abstract

Rare earth Tb3+ doped (K0.465Na0.465Li0.07)­(Nb0.93Bi0.07)­O3 (KNNLB-x%Tb) lead-free transparent ferroelectric ceramics were designed and prepared. The effects of Tb3+ on phase structure, microstructure, optical transmittance, photoluminescence, and photochromic behaviors were studied. Although two ferroelectric phases coexist, the optical transmittance can reach the high value of 74% in the visible light region because of the fine grains, dense ceramic microstructure, large optical energy band gap, and relatively high symmetry of coexisting ferroelectric phases. In addition, Tb3+ works as a luminescent center, and the reversible photochromic modulation is achieved by alternate stimulation of illumination and heat treatment. Meanwhile, the luminescence contrast can be improved under in situ electric field stimulation due to the easy change of lattice symmetry in coexisting ferroelectric phases. The generation of color centers after illumination and the local crystal field around the luminescent center caused by in situ electric field contributes to above phenomena. These ceramics exhibit the great potential in optical data storage and anticounterfeiting.

Upconversion Luminescence Reversible Modulation of Photochromic Ba2YTaO6 Double Perovskite Phosphors Toward Anticounterfeiting Application

“…According to the discrepancy of photochromic mechanism, inorganic photochromic materials can be mainly divided into defectsinduced and ionic valence-depended types. [5] The photochromism of the former (e.g., K 0.5 Na 0.5 NbO 3 , [6][7][8][9][10][11] BaMgSiO 4 [12,13] ) is commonly associated with the formation of color centers induced by vacancy defects whereas the latter (e.g., PbWO 4 , [14] Nb 2 O 5 [15] ) is related to the charge transfer generated from the hopping of valence electrons in the chromophore. Based on two kinds of photochromic mechanism, numerous lanthanides doped inorganic photochromic materials including transition metal oxides, ferroelectrics, and some robust oxides were fabricated, [16,17] finding interesting potential applications in the fields of anticounterfeiting, fingerprint acquisition, and optical storage.…”

KNN–Eu transparent ferroelectrics: Local structure and luminescent property

“…Photoluminescence (PL) properties of rare-earth ions (RE 3+ ) have attracted wide attention because of their potential applications in lighting, display, detectors, sensors, and other fields. [1][2][3] Researches have shown that the modified PL can be obtained by conventional chemical methods such as changing the doping ions or changing the matrix materials. [4][5][6] The discrepancy of PL in different materials is attributed to the symmetry variation inducing crystal field around RE 3+ ions.…”

Comparison of electric field‐dependent property in BaTiO3‐based piezoceramics between single and coexisting phases

“…Lead‐free piezoelectrics are the research hotspot in recent years 1–6 . Barium titanate (BaTiO 3 , BT)‐based ceramics are promising lead‐free piezoceramics to use as environment‐friendly piezoelectric materials 7–10 .…”

“…Lead-free piezoelectrics are the research hotspot in recent years. [1][2][3][4][5][6] Barium titanate (BaTiO 3 , BT)-based ceramics are promising lead-free piezoceramics to use as environment-friendly piezoelectric materials. [7][8][9][10] Pure BT ceramic has the single tetragonal (T) phase at room temperature (RT), showing the high dielectric constant but inferior piezoelectric coefficient (d 33 ∼ 180-200 pC/N) compared to commercial lead-based piezoceramics (their d 33 is usually…”