Truong Johnson, Stoner Andrew, Sytu Marion Ryan C, Tatlock T Rizana, Cho David H, Hahm Jong-In
Department of Chemistry, Georgetown University, 37th & O Sts. NW., Washington, DC 20057, USA.
Nanomaterials (Basel). 2022 Oct 11;12(20):3558. doi: 10.3390/nano12203558.
In this work, we examine how strain exerted on individual ZnO nanorods (NRs) can influence the fluorescence signals that are emitted from fluorophore molecules and subsequently coupled into and guided along the NR. We elucidate the relationships between the incremental levels of compressive and tensile strain on the NRs and measured fluorescence intensity of a model fluorophore, rhodamine 6G (R6G), as a function of the position on the NRs. We reveal that compressive strain on the NRs leads to a decrease in the guided fluorescence signal, while tensile strain leads to an increase in the fluorescence intensity. Compared to an unstrained state, approximately 35% decrease (increase) in R6G fluorescence intensity was observed from ZnO NRs when they were under compressive strain of -14% (tensile strain of +10%). Further, our systematic acquisition of the incremental addition of uniaxial strain result in a linear relationship of the coupled fluorescence signal and the amount of applied strain. The degree of fluorescence intensification on nanorod ends (DoF), which is a quantitative indicator for the amount of R6G signals coupled into and waveguided to the NR ends compared to those on the main body, also exhibits a linear relationship with strain. These outcomes, in turn, demonstrate that strain alters the waveguiding capabilities of ZnO NRs in a predictable manner, which can be exploited to modulate and optimize fluorescence and other light signals emitted by a nearby source. Considering the wide utility of ZnO NRs in photonics, optoelectronics, and sensors, insights from our study may be highly valuable to effectively controlling and enhancing optical signals from chemical and biological analytes through strain.
在这项工作中，我们研究了施加在单个氧化锌纳米棒（NRs）上的应变如何影响从荧光团分子发射并随后耦合到纳米棒中并沿纳米棒传播的荧光信号。我们阐明了纳米棒上压缩应变和拉伸应变的增量水平与模型荧光团罗丹明6G（R6G）的测量荧光强度之间的关系，该关系是纳米棒上位置的函数。我们发现，纳米棒上的压缩应变导致导波荧光信号减弱，而拉伸应变导致荧光强度增加。与未受应变的状态相比，当氧化锌纳米棒处于-14%的压缩应变（+10%的拉伸应变）下时，观察到R6G荧光强度下降（增加）了约35%。此外，我们系统地获取单轴应变的增量添加结果，得到了耦合荧光信号与施加应变大小之间的线性关系。纳米棒末端荧光增强程度（DoF）是一个定量指标，用于表示与纳米棒主体相比耦合到纳米棒末端并波导到末端的R6G信号量，它也与应变呈线性关系。这些结果反过来表明，应变以可预测的方式改变了氧化锌纳米棒的波导能力，可利用这一点来调制和优化附近光源发出的荧光和其他光信号。考虑到氧化锌纳米棒在光子学、光电子学和传感器中的广泛应用，我们研究的见解对于通过应变有效控制和增强来自化学和生物分析物的光信号可能具有很高的价值。
