Lifetime-tunable organic persistent roomtemperature phosphorescent salts for large-area security printing

Organic persistent room-temperature phosphorescent(RTP)materials are promising for applications requiring the secure recording and anti-counterfeiting features owing to their appealing optical properties.Several critical challenges,such as the difficulty to obtain high-quality patterns over large areas and low security levels,need to be addressed to meet the requirements for commercial purpose.Here,we prepared a series of quaternary phosphonium salts with different alkyl chains,which showed interesting organic persistent RTP.The ionic characteristics and the alkyl chains of these molecules impart abundant weak intermolecular interactions.This confers the molecules a high crystallinity,which helps to preserve the persistent RTP properties and cover large areas.Moreover,the RTP lifetime of these organic salts varies over a wide range(1.27 to 884.71 ms)and can be tuned by simply changing the alkyl chain length and counterions,which opens new possibilities in multi-level information encryption applications.It is believed that the engineering of organic salts with tunable persistent RTP lifetimes and large-area printing can promote early-stage demonstrations of security applications into mature commercialization.

Stimuli-responsive photofunctional materials for green and security printing

Information recording on paper has always been the most important approach to keep records of human activity and to spread civilization.With the progress of science and technology,paper with different functions should be exploited to conform to the increasing demands in various scenarios.In one aspect,traditional paper can only be used once,and using large amounts of paper causes deforestation,additional solid waste treatment,environmental pollution,and high energy consumption.Consequently,the development of rewritable paper that is environment-friendly,low cost,and can save resources is significant for green printing.In the other aspect,information leakage brings security issues,which may lead to severe consequences,such as war outbreak,economic loss,social problems,and so on.Therefore,the development of security printing has also attracted wide interests.Stimuli-responsive photofunctional materials that have reversible variations in absorption or emission in response to changes in the external environmental have a great potential for the achievement of green and security printing.To date,much progress has been made in these research areas.This paper lists different smart materials that respond to various external stimuli,such as light,water,pH,heat,and metal ions,and summarizes the recent advances towards green and security printing.Also,we discuss the current challenges and future directions in this rapidly growing research field.It is expected that this review article will stimulate and guide future studies for the advanced green and security printing.

调控分子间的电子耦合效应实现多彩超长有机室温磷光

有机超长室温磷光聚合物因其优异的可加工性、灵活性和可重复性等特点,在各种光电应用中表现出巨大的应用潜力.然而,实现全彩的室温磷光仍然是一个挑战.在本文中,我们通过在聚乙烯醇中掺杂不同浓度的三苯基膦盐,成功制备了一系列余晖颜色可调的有机室温磷光聚合物(从蓝色到红色).实验和理论计算证明:室温磷光聚合物颜色的宽范围调控归因于掺杂体膦盐分子间的电子耦合作用大小.此外,这些多彩的磷光聚合物可应用于柔性3D显示和防伪.