Li Yingying, Fang Ranran, Wang Dong
Key Laboratory of Textile Fiber and Products, Ministry of Education, Wuhan Textile University, Wuhan 430200, China.
College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China.
ACS Appl Mater Interfaces. 2022 Jan 12;14(1):2219-2229. doi: 10.1021/acsami.1c18259. Epub 2021 Dec 28.
Plasmonic physical color generation, which mostly depends on selective absorption, creates unique colors by light transmission and scattering. Based on this, regulating plasmon and transparency with external stimulation is a promising approach for fabricating optical devices with enhanced visual displays; however, few studies have addressed the implementation of dual-optical modulation. In addition, developing a color response to environmental stimuli through the highly shape-sensitive plasmon depth modulation has long remained a significant challenge once the nanostructure is determined. Some stimulations also require high amounts of electricity, which can be costly. In this study, strategically designed hyaluronan-functionalized triangular silver nanoparticles (AgNPs) were embedded in polyvinyl alcohol-polyethylene nanofiber films to achieve a breakthrough in the moisture-responsive dual-optical modulation of the plasmonic color-Raman and transparency. Switchable colors that are reversible were induced in plasmon-resonance-modulation AgNPs via moisture stimulation, adjusting the expansion-tunable dielectric constant of hyaluronan-functionalized AgNPs and varying the electron density due to electron transfer. Furthermore, a moisture gradient was used to decrease the Raman scattering and increase the photoluminescence, which is a significant demonstration of smart-plasmonic evolution. This effect occurred due to the gradual transition from plasmon-driven photoluminescence quenching to photoluminescence enhancement as the interval of the Ag and hyaluronic acid molecules was increased. The transparency of the composite film was also dynamically regulated by turning moisture on/off. This occurred because of the significant difference in hygroscopic expansion between hyaluronan and the nanofibers, which generated a large variation in the total refractive index and caused changes in the surface roughness.
等离子体物理颜色的产生主要依赖于选择性吸收，通过光的透射和散射产生独特的颜色。基于此，利用外部刺激调节等离子体和透明度是制造具有增强视觉显示的光学器件的一种有前景的方法；然而，很少有研究涉及双光调制的实现。此外，一旦纳米结构确定，通过高度形状敏感的等离子体深度调制来开发对环境刺激的颜色响应长期以来一直是一个重大挑战。一些刺激还需要大量电力，这可能成本很高。在本研究中，将经过策略设计的透明质酸功能化三角形银纳米颗粒（AgNPs）嵌入聚乙烯醇 - 聚乙烯纳米纤维膜中，以在等离子体颜色 - 拉曼和透明度的湿度响应双光调制方面取得突破。通过湿度刺激在等离子体共振调制的AgNPs中诱导出可逆的可切换颜色，调节透明质酸功能化AgNPs的膨胀可调介电常数，并由于电子转移改变电子密度。此外，利用湿度梯度降低拉曼散射并增加光致发光，这是智能等离子体演化的一个重要证明。这种效应的发生是由于随着Ag和透明质酸分子间隔的增加，从等离子体驱动的光致发光猝灭到光致发光增强的逐渐转变。复合膜的透明度也通过打开/关闭湿度进行动态调节。这是因为透明质酸和纳米纤维之间的吸湿膨胀存在显著差异，这导致总折射率有很大变化并引起表面粗糙度的改变。
