A novel photochromic ceramics with reversible luminescence modulation and light bleaching behavior: Sm3+-doped KSr2Nb5O15

Abstract A novel tetragonal tungsten bronze (TTB) type Sm3+-doped KSr2Nb5O15 (KSN-Sm) optical ceramic is fabricated by atmosphere sintering technology. A reversible photochromic effect between faint yellow and olive colors and accompanied luminescence modulation behaviour can be realized by alternating the 395 nm light irradiation and thermal treatment. The thermal stimulus model is introduced to modify the classical resonance energy transfer mechanism. The results show that the optimal luminescence modulation ratio △Rt about the red emission (601 nm) intensity amounted to 60.0 %, and the KSN-Sm ceramic exhibits excellent luminescence modulation rate and reproducibility. The colored KSN-Sm ceramic can be partly bleached by external light stimulus (620 nm), and the luminescence emission intensity can be recovered from 45 % to 84.2 %. The light bleaching efficiency is strongly dependent on the irradiation wavelength, exposure duration and irradiation dose. These discoveries pave the way to develop new luminescence materials with TTB structure.