A Supramolecular Nanocomposite as a Near-Infrared-Transmitting Optical Filter for Security and Forensic Applications
A Supramolecular Nanocomposite as a Near-Infrared-Transmitting Optical Filter for Security and Forensic Applications
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DOI：
10.1002/adma.201703783
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发表时间：
2017-12-13
影响因子：
29.4
通讯作者：
Ajayaghosh, Ayyappanpillai
中科院分区：
文献类型：
--
作者：
Ghosh, Samrat;Cherumukkil, Sandeep;Ajayaghosh, Ayyappanpillai
可见光不透明但近红外（NIR）透明的材料是夜视摄影、安全成像和法医应用的重要组成部分。在此，一种新的超分子黑色染料的开发从二酮基吡咯并吡咯（DPP）为基础的低分子量有机胶凝剂进行了描述。在溶液状态下，由于从供体到受体单元的牢固的分子内电荷转移，DPP-酰胺的单体表现出深绿色颜色，在可见光区具有宽吸收。有趣的是，由于氢键和p-堆积的协同作用，DPP-酰胺可以在甲苯中形成黑色有机凝胶，其光谱覆盖范围从300至800 nm，并透射超过850 nm。在凝胶状态下，由于同时形成H型和J型聚集体，实现了完整的可见光谱覆盖，这通过吸收研究得到证实。为了产生独立的NIR透射弹性黑色滤光片，将DPP-酰胺（0.15重量%）的纳米级分子聚集体嵌入聚（二甲基硅氧烷）基质中。该纳米复合材料具有高的近红外透明性，具有良好的热稳定性和光稳定性，可用于实际应用。最后，使用开发的材料近红外摄影，安全和法医相关的应用程序进行演示。
Visibly opaque but near-infrared (NIR)-transparent materials are an essential component for night-vision photography, security imaging, and forensic applications. Herein, the development of a novel supramolecular black dye from a diketopyrrolopyrrole (DPP)-based low-molecular-weight organogelator is described. In the solution state, the monomer of DPP-Amide exhibits a deep green color with a broad absorption in the visible region due to firm intramolecular charge transfer from the donor to the acceptor unit. Interestingly, due to the synergistic effect of H-bonding and p-stacking, DPP-Amide can form a black organogel in toluene with complete spectral coverage from 300 to 800 nm, and transmits beyond 850 nm. In the gel state, complete visible-spectrum coverage is achieved due to the simultaneous formation of both H-and J-type aggregates, which is confirmed via absorption studies. To create a free-standing NIR-transmitting elastomeric black filter, nanoscopic molecular aggregates of DPP-Amide (0.15 wt%) are embedded into a poly(dimethylsiloxane) matrix. This nanocomposite possesses high NIR transparency with good thermal and photostability for practical applications. Finally, the use of the developed material for NIR photography, security, and forensic-related applications is demonstrated.