Abstract
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.
摘要
有机室温磷光材料因其独特的光物理性质, 在安全记录和防 伪领域展现出了巨大的应用前景. 然而, 基于这类材料制备的防伪 图案或标签存在分辨低、安全性低、不易大面积加工等缺点, 极 大地限制了其大规模商业化应用. 本文设计、合成了一系列含不 同长度烷基链的有机膦盐来解决以上问题. 这类有机膦盐晶体中 存在较强的分子内/间相互作用, 使得它们具有高结晶能力, 因此 在经过研磨后仍然具有超长室温磷光. 此外, 通过改变烷基链长度 和卤素离子, 实现了室温磷光寿命的大范围调控(从1.27 ms到 884.71 ms), 并利用商用喷墨打印机成功实现了多重信息加密和防 伪.
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Acknowledgements
We thank the financial support from the National Funds for Distinguished Young Scientists (61825503), the National Natural Science Foundation of China (62075101, 21701087 and 61775101), the National Program for Support of Top-Notch Young Professionals, and the Postgraduate Research & Practice Innovation Program of Jiangsu Province (46030CX18010).
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She P, Ma Y, Zhao Q and Huang W conceived the idea for this paper and designed the experiments. She P and Qin Y performed the synthesis and security printing experiments. Li F, Lu J, Hu H, Liu X and Liu S contributed to the implementation of the experiments and measurements. Ma Y, She P and Zhao Q analyzed the data and wrote the manuscript. Liu S revised the manuscript and provided some suggestions. All authors discussed the results and commented on the manuscript.
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The authors declare no conflict of interest.
Yun Ma obtained his MSc degree from Nanjing University of Posts and Telecommunications in 2012, under the supervision of Prof. Qiang Zhao and his PhD degree from Hong Kong Baptist University in 2015, under the supervision of Prof. Wai Yeung Wong. He is currently an associate professor at Nanjing University of Posts and Telecommunications. His research focuses on the development of stimuli-responsive materials for advanced optical applications.
Qiang Zhao received his PhD degree in 2007 from Fudan University. He then became a postdoctoral fellow at Nagoya University in Japan. He joined Nanjing University of Posts & Telecommunications in 2008. He was promoted as a full professor in 2010. His research area is organic optoelectronics, including the design, synthesis and excited-state tuning of organic semiconductors for applications in optoelectronic devices and biomedical fields.
Wei Huang received his PhD degree from Peking University in 1992 and carried out postdoctoral research in the National University of Singapore. In 2001, he was appointed as a chair professor at Fudan University, where he founded and chaired the Institute of Advanced Material. His research interests include the synthesis, structures, and performance of organic/flexible optoelectronic materials and devices.
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She, P., Qin, Y., Ma, Y. et al. Lifetime-tunable organic persistent room-temperature phosphorescent salts for large-area security printing. Sci. China Mater. 64, 1485–1494 (2021). https://doi.org/10.1007/s40843-020-1544-6
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DOI: https://doi.org/10.1007/s40843-020-1544-6