A novel modification strategy for photochromic KSr2Nb5O15-based ceramics by establishing a heterojunction band structure

Because of their rapid response, high sensitivity, and excellent thermal and chemical stabilities, photochromic ceramics have attracted great potential for optical applications in anti-counterfeiting and optical information storage. However, the inferior photochromic contrast restricted the further development of photochromic ce-ramics. Herein, a novel modification strategy for photochromic behavior is proposed in a KSr2Nb5O15-based system. A new heterojunction band structure was established at the interfaces in ceramics by compositing with transition metal oxides and generated novel transition paths for the excited carriers. After compositing with the Nb2O5 second phase, the photochromic contrast oRdec was almost doubled by additional color centers from the heterojunction structure. The related mechanism was confirmed by the photochromic behavior, thermolumi-nescence spectra and band structure features. Moreover, rapid, convenient and reversible laser bleaching be-haviors was explored, and a more flexible anti-counterfeiting method was attempted through secondary laser adjustment of the photochromic pattern. This work aims to present a new modification viewpoint into photo-chromic ceramics by building a heterojunction structure.