Tunable Luminescence Contrast in Photochromic Ceramics (1 – x)Na_0.5Bi_0.5TiO₃–xNa_0.5K_0.5NbO₃:0.002Er by an Electric Field Poling

Abstract

A binary solid solution of Er3+-doped (1 – x)­Na0.5Bi0.5TiO3–xK0.5Na0.5NbO3 (x = 0.02, 0.04, 0.06, 0.08, 0.10, 0.12) ferroelectric ceramics has been developed, and a reversible photochromic (PC) reaction and its associated luminescence modulation are realized via alternating the 405 nm light irradiation and thermal stimulation (200 °C). The basic crystal structure, domain structure, ferroelectricity, and dielectric behavior of the ceramics were measured. A moderate luminescence contrast ΔR t over 50% is obtained in the fresh samples. Meanwhile, a greatly enhanced luminescence contrast ΔR t is obtained via an electric poling for compositions x = 0.02, 0.04, 0.06. For example, ΔR t is promoted from 53.4 to 85.3% for x = 0.02. However, the luminescence contrast ΔR t of compositions x = 0.08, 0.10, 0.12 is depressed after poling. The mechanisms of enhanced PC reaction and luminescence contrast ΔR t are discussed and proposed. The present study may open a window for enhancing the PC reaction.

Tunable upconversion luminescence in new Ho3+/Yb3+‐doped SrBi4Ti4O15 photochromic ceramics for switching application

“…On the other hand, the electrons near the top of the valence band were excited to the isolated defect levels below the conduction band, subsequently captured in a metastable state by these defects. Both of the above approaches eventually led to the formation of color centers in the materials, which was consistent with previous works 21‐26 . These color centers possessed strong absorption in the visible light region, which caused the PC behavior of the ceramics.…”

“…Both of the above approaches eventually led to the formation of color centers in the materials, which was consistent with previous works. [21][22][23][24][25][26] These color centers possessed strong absorption in the visible light region, which caused the PC behavior of the ceramics. For example, the color of the samples transformed from light yellow to gray black after 405 nm irradiation.…”

“…Unfortunately, these compounds displaying luminescent regulation features were rather rarely observed. Interestingly, some ferroelectric PC compounds with reversible luminescence modulation behavior were reported recently 21‐26 . It is known that ferroelectric was an important information storage medium which has been applied in nonvolatile random access memories.…”

“…Interestingly, some ferroelectric PC compounds with reversible luminescence modulation behavior were reported recently. [21][22][23][24][25][26] It is known that ferroelectric was an important information storage medium which has been applied in nonvolatile random access memories. One can expect that the storage density may be greatly increased in ferroelectrics by combining two or more memory mechanisms, such as domain switching, PC effect, and switching of luminescence.…”

Ferroelectric domains and luminescent properties of Pr3+‐doped Ca2Nb2O7 ceramics

“…The voltage is marked in the rectangle region as shown in Figure A. Usually, the domain can be switched under such high local tip voltage . However, in the present case, no obvious change is observed after the application of the tip voltage (see Figure B).…”