论文标题
探测蓝色的长持续EU2+/nd3+激活（Ca $ _ {0.9} $ SI $ _ {0.1} $）
Probing blue long persistent Eu2+/Nd3+ activated (Ca$_{0.9}$Si$_{0.1}$)Al$_2$O$_6$ emerging phosphor based novel invisible ink for knocking out fake security papers and combat counterfeiting
论文作者
论文摘要
在当前的工作中，使用高温（1000-1500oc）固态反应方法合成了新型（Ca0.9Si0.1）Al2O6：EU2+，ND3+长持续的磷光。此外，使用环氧基胶体悬浮液将磷光材料配合到磷光墨水中。有趣的是，磷光墨水吸收的环境能量，例如来自D65的白光和钨灯，阳光，人造灯等，储存能量并发出有效的蓝色光致发光（PL），显然可见了很多小时，以了解黑暗适应性的人眼。但是，以〜450 nm为中心的最佳PL发射以〜365 nm的激发注册，这归因于从4f65d1到EU2+离子的4F7能级的过渡。 PL的持续性较长，这是由于位于距离带频段附近的ND3+地点的孔捕获和捕获而引起的。在磷光器的优化化学计量组成中，在极黑的条件下，持久性持续了4个小时。此外，长期持久性的现象使使用快速响应（QR）代码模式在商品和证书上创建/设计独特的隐藏标记。已经对在紫外线（〜365 nm）激发下保存的各种模板上进行了系统研究，以有效地识别假货币，条形码和战斗伪造。
In the current work, a novel class of (Ca0.9Si0.1)Al2O6:Eu2+,Nd3+ long persistent phosphor was synthesized using high-temperature (1000-1500oC) solid-state reaction method. Further, the phosphor material was formulated into a phosphorescent ink using epoxy based colloidal suspension. Interestingly the phosphorescent ink absorbs ambient energies such as white light from D65 and tungsten lamps, sunlight, artificial lights etc., stores up the energy and emit as efficient blue colored photoluminescence (PL) apparently visible for many hours for dark adapted human eye. However, the optimum PL emission centred at ~450 nm has been registered at ~365 nm excitation that is attributed to transitions from 4f65d1 to 4f7 energy levels of Eu2+ ions. The longer persistence of PL aroused due to trapping and de-trapping of holes at Nd3+ sites situated proximate to valance band. In the optimised stoichiometric composition of the phosphor, the persistence lasted for >4 hours in extremely dark conditions. Furthermore, the phenomenon of long persistence enables to create/design unique hidden markings on goods and certificates using quick response (QR) code patterns. Systematic studies have been performed on various templates kept under UV (~365 nm) excitation to identify fake currencies, barcodes and combat counterfeiting effectively.
