Reversible luminescence modulation behavior upon the photochromic effect endows the photochromic ceramics with great potential in anti-counterfeiting and data storage applications. Here, Sm³⁺-doped KSr₂Nb₅O₁₅ photochromic ceramics exhibit superior anti-counterfeiting ability: good covertness and considerable modulation ratio of luminescent emission intensity after photochromic reaction. The results show that the photochromism originated from oxygen and cation vacancies, which were directly identified by electron paramagnetic resonance and positron annihilation lifetime spectra. Unexpectedly, oxygen vacancies work more effectively than cation vacancies during photochromic reactions. Moreover, the extraordinary anti-counterfeiting ability was attributed to the high energy transfer rate, which was particularly caused by the short mean distance below 1 nm between the Sm³⁺ and vacancies. The work here has provided atomic-scale structural evidence and made a progress in understanding the photochromic origins and mechanism in color-center theory.

光致变色效应的可逆发光调制行为赋予了光致变色陶瓷在防伪和数据存储应用中的巨大潜力。这里，Sm ³⁺掺杂的KSr ₂ Nb ₅ O ₁₅光致变色陶瓷具有优越的防伪能力：光致变色反应后的发光强度具有良好的隐蔽性和相当大的调制比。结果表明，光致变色源于氧和阳离子空位，通过电子顺磁共振和正电子湮没寿命光谱直接识别。出乎意料的是，在光致变色反应过程中，氧空位比阳离子空位更有效。此外，非凡的防伪能力归功于高能量转移率，特别是由于 Sm ³⁺之间的平均距离小于 1 nm和空缺。这里的工作提供了原子尺度的结构证据，并在理解色心理论中的光致变色起源和机制方面取得了进展。