Reversible multimode modulations in photochromic transparent Eu3+doped K0.5Na0.5NbO3 based ceramics

Rare-earth doped transparent photochromic materials have attracted extensive attention in applications of optical information storage and optical switching, in which the high transparency and large fluorescence modulation ratio are required. In this work, 0.94 (K _0.5Na _0.5)NbO ₃-0.06 (Sr _0.5Ba _0.5) (Zn _1/3Bi _2/3)O ₃: x wt% Eu ₂O ₃ ceramics (KNN-SBZB: xEu) with x=0.1, 0.2, 0.3, 0.4 were prepared by traditional high temperature solid state sintering reaction method. High transmittance ( T) was achieved due to the small grain size (less than 110 nm) and the highly symmetrical phase structure. High optical transmittance of 69.27 % at 780 nm and 78.24 % at 1100 nm were obtained in the KNN-SBZB: 0.3Eu ceramic, while large luminescence intensity modulation ratio (∆ R _L) ∼94.9 %, transmittance (∆ R _T) ∼5.76 % and diffuse reflectivity (∆ ABS) ∼12.59 % were achieved in KNN-SBZB: 0.2Eu ceramic ( T ∼62.92 % at 780 nm). Additionally, both the transmittance modulation and luminescence intensity modulation of KNN-SBZB: xEu ceramics show good stability after 10 cycles.