The upconversion luminescence modulation and its enhancement in Er³⁺‐doped Na_0.5Bi_0.5TiO₃ based on photochromic reaction

Abstract

A large and reversible upconversion (UC) luminescence modulation has been found in the Na0.498Bi0.498TiO3:0.002Er (NBT:0.002Er) based on the photochromic reaction. The dependence of luminescence modulation of the ceramics on the wavelength of irradiation light and sintering temperature was investigated. It was found that the optimized sintering temperature and irradiation wavelength were 1130°C and 405 nm, respectively. The highest ΔRt (defined as: ΔRt = (R0 – Rt)/R0×100(%), where R0 and Rt are the initial emission intensity and that after different irradiation time, respectively) value of 44.9% was obtained for the ceramics sintered at 1130°C after irradiation at 405 nm. More importantly, for the poled ceramics, ΔRt value was promoted to a high value of 75.5%, which was 168% of that of the unpoled ones. The mechanism of luminescence modulation and its enhancement via electric field poling were discussed. This study demonstrated that electric field poling was an effective strategy to enhance the PC reaction in the NBT ceramics.

Eu-doped K0.5Na0.5NbO3-(Ba,Sr)TiO3: A novel lead-free luminescent ferroelectric transparent ceramic with reversible photochromism

“…Photochromism phenomenon describes a process where the color of specimen can be changed (i.e., the coloration state and the decoloration state) via alternating visible/ultraviolet light irradiation, heat, or even electric field. 2,3 Among all the PC materials, inorganic solid oxides own outstanding thermal stability, mechanical strength and chemical resistance. 4,5 To date, RE-doped inorganic ferroelectrics, such as Na 0:5 Bi 2:5 Nb 2 O 9 , 6 Na 0:5 Bi 0:5 TiO 3 (NBT) 5 and (K 0:5 Na 0:5 ÞNbO 3 (KNN), 7 have been found to exhibit reversible PL modulation behavior based on PC reaction.…”

“…Environment-friendly lead-free KNN-based ceramics have been regarded as the most promising alternative to toxic lead-based piezoelectric materials, owing to their moderate dielectric constant, optimum piezoelectric response and good ferroelectricity. [8][9][10][11][12][13] Recently, RE-doped KNN ceramics have been verified to have both PC and PL modulation behaviors induced by vacancy-related defects (e.g., K/Na/O vacancies), [2][3][4][5][6][7] expanding the electrical applications to optoelectronic areas. Generally, pure KNN ceramics own poor relative density ($95%), low symmetry structure (orthorhombic phase) and large grain size (1-2 m).…”

Significantly Photo‐Thermochromic KNN‐Based “Smart Window” for Sustainable Optical Data Storage and Anti‐Counterfeiting

“…reported a series of Er 3+ doped Na 0.5 Bi 0.5 TiO 3 ‐based PC materials, and the PC reaction and luminescence contrast can be greatly enhanced via an electric field poling, which is correlated to the forming of a long‐ranged order ferroelectric state. [ 17,18 ]…”

Reversible multiplexing for optical information recording, erasing, and reading-out in photochromic BaMgSiO4:Bi3+ luminescence ceramics

“…Ferroelectrics and robust oxides are more suitable as optical storage materials because of their relatively fast response time and good reversibility. However, thermal bleaching may be required for most of the ferroelectrics and robust oxides such as Na 0.5 Bi 2.5 Nb 2 O 9 , Na 0.5 Bi 0.5 TiO [15,48,49]. Light-induced coloring and bleaching are particularly attractive in actual applications.…”