Competitive effects of Mo6+doping and MoO₃ phase formation on the photochromic properties of KSr₂Nb₅O₁₅-based ceramics

Photochromic ceramics attracted great interests of researchers due to the potential applications in anti-counterfeiting, information storage and optical detector. However, the single color change and fixed photochromic absorption limited the further development in practical application. In this work, the Mo6+ was introduced into the typical KSr₂Nb₅O₁₅ (KSN) photochromic ceramics, and the effects on the microstructures and photochromic properties were systematically investigated. The results showed that, introducing of Mo6+ into KSN ceramics simultaneously caused both Mo6+ substitution and formation of MoO₃ secondary phase. And a competitive effect between these two variations in KSN host was existed and dynamically adjusted by the introducing concentration of Mo6+. Benefiting from these two variations, the distribution of carrier traps was optimized and the heterojunction structure between KSN and MoO₃ phases was established. The photochromic contrast value of KSN host was enhanced over 60 %, and the photochromic color change aslo modulated, the color difference △Eab increased from 7.5 to 22.5. This work provided a novel strategy for controllable modulation about the photochromic properties of oxide ceramics both in photochromic contrast and absorption behavior.