A significant luminescence modulation behavior based on photochromic reactions was observed in Ho³⁺‐doped (Na_0.52K_0.48)_0.92Li_0.08NbO₃ ceramics, fabricated by the conventional solid‐state reaction method. Under visible light irradiation (407 nm) for 20 second, the samples changed pale gray from initial pale green, and returned to their original color by a thermal stimulus of 230°C for 10 minutes, showing typical photochromic phenomenon. Under 453 nm excitation, the samples exhibited strong green emission at 551 nm. Interestingly, their green emission intensity can be effectively tailored by controlling photochromic reaction processes (irradiation wavelength and time), and the luminescent modulation ratio (ΔR_t) reaches up to 77%. And, the ΔR_t value has no any obvious degradation after 10 cycles by alternating visible light irradiation and thermal stimulus, showing excellent reversibility. These results make it potential applications in many fields as a kind of multifunctional material.

中文翻译：

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高掺杂对比度的Ho掺杂K0.5Na0.5NbO3压电材料的可逆发光调制

在掺Ho ³⁺（Na _0.52 K _0.48）_0.92 Li _0.08 NbO _3中观察到基于光致变色反应的显着发光调制行为。陶瓷，是通过常规的固态反应方法制造的。在可见光（407 nm）照射20秒后，样品从最初的浅绿色变为浅灰色，并在230°C的热刺激下持续10分钟恢复为原始颜色，显示出典型的光致变色现象。在453 nm激发下，样品在551 nm处显示出很强的绿色发射。有趣的是，通过控制光致变色反应过程（辐射波长和时间），可以有效地调整其绿色发射强度，并且发光调制率（ΔR _t）高达77％。并且，ΔR _t通过交替的可见光照射和热刺激，在10个循环后，该值没有任何明显的下降，显示出极好的可逆性。这些结果使其作为一种多功能材料在许多领域具有潜在的应用前景。