Tunable Luminescence Contrast in Photochromic Ceramics (1 - x)Na0.5Bi0.5TiO3- xNa0.5K0.5NbO3:0.002Er by an Electric Field Poling.

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 Δ R t over 50% is obtained in the fresh samples. Meanwhile, a greatly enhanced luminescence contrast Δ R t is obtained via an electric poling for compositions x = 0.02, 0.04, 0.06. For example, Δ R t is promoted from 53.4 to 85.3% for x = 0.02. However, the luminescence contrast Δ R t of compositions x = 0.08, 0.10, 0.12 is depressed after poling. The mechanisms of enhanced PC reaction and luminescence contrast Δ R t are discussed and proposed. The present study may open a window for enhancing the PC reaction.