- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Highly-efficient, Chemically-stable, UV/blue Light Excitable Biluminescent Security Ink to Combat Counterfeiting
摘要： A strategy has been demonstrated to design a biluminescent security ink using Eu(TTA)3Phen (ETP) and fluorescein for protecting the currency and other essential documents viz. passport, bank cheque, certificates against counterfeiting. Biluminescent security ink exhibits strong red and green emission under 367 and 445 nm excitations, respectively. As it is quite challenging to prepare a material that possesses two prominent (green and red) and distinguishable colors upon excitation with two separate LEDs sources, emitting at different wavelengths, the biluminescent security ink would be hard to counterfeit as compared to the existing luminescent security ink that exhibits single color under UV light exposure. To check its feasibility for security application the patterns printed out using biluminescent security ink were kept under a hot and humid atmosphere for 150 days. Also, the ETP and fluorescein fluorophores were exposed to UV light for a prolonged time, which do not show any sign of deterioration in their luminescence intensities. Furthermore, to check their chemical stability printed patterns were also exposed to chemicals which have potential to wiped-out ink viz. detergent, ethanol, acetone, and sodium hypochlorite (bleach) solution and noticed that it is well stable against these chemicals. Because of the reasons mentioned above and easy availability of 367 and 445 nm LEDs at low cost, authors believe that the application of this biluminescent security ink can trigger to realize the full potential of this advanced security feature in detecting fake currency.
关键词： luminescence,lanthanide,security ink,anticounterfeiting,fluorescein
更新于2025-09-09 09:28:46
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Er doped layered perovskites with Dual mode luminescent behavior and tunable multicolor upconversion emission
摘要： Er3+ doped BST nanoparticles with Aurivillius layered structure are synthesized through common solid state method. Photoluminescence spectroscopy has shown that these oxides are capable of emitting light under UV (366nm) and IR (980nm) source. The effect of Er3+ to Yb3+ concentration ratio on upconversion emission are investigated and possible upconversion and energy transfer mechanisms are suggested based on the number of photons participating in UC process. Shift in the upconversion emission from green to red region is visualized by CIE chromaticity diagram. The superiority of coexistence of stoke and anti-stoke emission in a single host lattice with a single activator ion, besides to tunability of UC luminescence only by controlling sensitizer/activator ratio are very interesting features which can be used to produce dual mode multicolor luminescent ink with high security level against forgery.
关键词： Aurivillius perovskites,Dual mode luminescent,Security ink,Upconversion
更新于2025-09-04 15:30:14