Tunable Luminescence Contrast in Photochromic Ceramics (1-x)Na0.5Bi0.5TiO3-xNa(0.5)K(0.5)NbO(3):0.002Er by an Electric Field Poling

A binary solid solution of Er3+-doped (1 - x)Na0.5Bi0.5TiO3-xK(0.5)Na(0.5)NbO(3) (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 degrees C). The basic crystal structure, domain structure, ferroelectricity, and dielectric behavior of the ceramics were measured. A moderate luminescence contrast Delta R-t over 50% is obtained in the fresh samples. Meanwhile, a greatly enhanced luminescence contrast Delta R-t is obtained via an electric poling for compositions x = 0.02, 0.04, 0.06. For example, Delta R-t is promoted from 53.4 to 85.3% for x = 0.02. However, the luminescence contrast Delta R-t of compositions x = 0.08, 0.10, 0.12 is depressed after poling. The mechanisms of enhanced PC reaction and luminescence contrast Delta R-t are discussed and proposed. The present study may open a window for enhancing the PC reaction.