Abstract Afterglow materials are of increasing importance. Here we report for the first time an intense long-lasting blue afterglow observed in a metal-activator-free boric acid calcined product. It was found that the afterglow intensity varied with the calcination temperature and reaches a maximum at around 250 °C, with a high phosphorescence lifetime of 1.87 s under 254 nm excitation (more than 25 s to the naked eye). Defects formed during the calcination process are associated with oxygen vacancies, which store the energy and are thought to be the origin of the afterglow. The as-prepared boric acid calcined product serves well as an afterglow material for anti-counterfeiting and time-resolved information protection.

中文翻译：

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来自氧化硼的室温长余辉：硼酸煅烧产品

摘要 余辉材料越来越重要。在这里，我们首次报告了在不含金属活化剂的硼酸煅烧产品中观察到的强烈持久的蓝色余辉。发现余辉强度随煅烧温度而变化，并在250°C左右达到最大值，在254 nm激发下具有1.87 s的高磷光寿命（肉眼超过25 s）。煅烧过程中形成的缺陷与氧空位有关，氧空位储存能量，被认为是余辉的起源。所制备的硼酸煅烧产物可以很好地用作防伪和时间分辨信息保护的余辉材料。