Zou Weiwei, Xie Hao, Ye Yang, Ni Weihai
Jiangsu Key Laboratory of Thin Films, School of Physical Science and Technology, Soochow University Suzhou 215006 People's Republic of China
RSC Adv. 2019 May 21;9(28):16028-16034. doi: 10.1039/c9ra02106j. eCollection 2019 May 20.
In many applications, the optical cross sections of gold nanorods (AuNRs) are required to be tailored at a fixed target longitudinal surface plasmon resonance (LSPR) wavelength depending on the excitation source and the photodetector. In this work, we demonstrate the fine tailoring of optical cross sections of AuNRs at a fixed target resonance wavelength, on the basis of AuNR overgrowth using a binary surfactant mixture consisting of 5-bromosalicylic acid (BSA) and cetyltrimethylammonium bromide (CTAB). A systematic study was performed on the sum effects of the BSA concentration and the volume of the growth solution, which gives a formula for quantitative instructions. Based on the formula, we gave examples for the successful synthesis of AuNRs with different optical cross sections at target LSPR wavelengths. From simulation, a nonlinear relationship was further derived to understand the relationship between the aspect ratio and the width of the AuNRs at a target LSPR wavelength for the dimension design of AuNRs. The ratio of optical against physical cross sections was calculated and plotted as a function of the width. The results clearly indicate that AuNRs with a width of 30 nm possess the highest efficiency in terms of optical per physical cross section. Our study provides reliable methods for the synthesis, as well as guidelines for the dimension design of AuNRs, for use in a variety of applications.
在许多应用中，根据激发源和光电探测器的不同，需要将金纳米棒（AuNRs）的光学截面调整到固定的目标纵向表面等离子体共振（LSPR）波长。在这项工作中，我们展示了基于使用由5-溴水杨酸（BSA）和十六烷基三甲基溴化铵（CTAB）组成的二元表面活性剂混合物对AuNRs进行过度生长，从而在固定的目标共振波长下对AuNRs的光学截面进行精细调整。我们对BSA浓度和生长溶液体积的综合影响进行了系统研究，得出了一个定量指导公式。基于该公式，我们给出了在目标LSPR波长下成功合成具有不同光学截面的AuNRs的示例。通过模拟，进一步推导了非线性关系，以了解在目标LSPR波长下AuNRs的纵横比与宽度之间的关系，用于AuNRs的尺寸设计。计算了光学截面与物理截面的比值，并将其绘制为宽度的函数。结果清楚地表明，宽度为30 nm的AuNRs在光学截面与物理截面方面具有最高效率。我们的研究为AuNRs的合成提供了可靠的方法，也为其尺寸设计提供了指导方针，可用于各种应用。
