Xu Lijie, Yin Ming-Li, Liu Shengzhong Frank
Key Laboratory of Applied Surface and Colloid Chemistry, Chinese National Ministry of Education; School of Materials Science &Engineering, Shaanxi Normal University, Xi'an 710062, China.
1] Key Laboratory of Applied Surface and Colloid Chemistry, Chinese National Ministry of Education; School of Materials Science &Engineering, Shaanxi Normal University, Xi'an 710062, China [2] School of Science, Xi'an Technological University, Xi'an 710032, China.
Sci Rep. 2014 Oct 23;4:6745. doi: 10.1038/srep06745.
Exceptional properties of graphene have triggered intensive research on other 2D materials. Surface plasmon is another subject being actively explored for many applications. Herein we report a new class of core-shell nanostructure in which the shell is made of a 2D material for effective plasmonic propagation. We have designed a much enhanced chemical sensor made of plasmonic Ag(x)@(2D-WO3) that combines above advantages. Specifically, the sensor response increases from 38 for Ag(x)-WO3 mixture to 217 for the Ag(x)@(2D-WO3) core-shell structure; response and recovery time are shortened considerably to 2 and 5 seconds; and optimum sensor working temperature is lowered from 370°C to 340°C. Light irradiation is found to increase the Ag(x)@(2D-WO3) sensor response, particularly at blue wavelength where it resonates with the absorption of Ag nanoparticles. Raman scattering shows significantly enhanced intensity for both the 2D-WO3 shell and surface adsorbates. Both the resonance sensor enhancement and the Raman suggest that the improved sensor performance is due to nanoplasmonic mechanism. It is demonstrated that (1) 2D material can be used as the shell component of a core-shell nanostructure, and (2) surface plasmon can effectively boost sensor performance.
石墨烯的优异特性引发了对其他二维材料的深入研究。表面等离子体激元是另一个正在被积极探索用于多种应用的课题。在此，我们报道了一类新型的核壳纳米结构，其中壳层由二维材料制成，用于实现有效的等离子体传播。我们设计了一种由等离子体Ag(x)@(2D-WO3)制成的性能大幅提升的化学传感器，它结合了上述优点。具体而言，传感器响应从Ag(x)-WO3混合物的38提高到Ag(x)@(2D-WO3)核壳结构的217；响应和恢复时间大幅缩短至2秒和5秒；最佳传感器工作温度从370°C降至340°C。发现光照射会增加Ag(x)@(2D-WO3)传感器的响应，特别是在蓝色波长处，此时它与银纳米颗粒的吸收发生共振。拉曼散射显示二维WO3壳层和表面吸附物的强度都显著增强。共振传感器增强和拉曼散射都表明，传感器性能的提升归因于纳米等离子体激元机制。结果表明：（1）二维材料可作为核壳纳米结构的壳层组分；（2）表面等离子体激元可有效提升传感器性能。
