Vu Xuan Hoa, Dien Nguyen Dac, Ha Pham Thi Thu, Van Truong Nguyen, Ca Nguyen Xuan, Van Thu Vu
Faculty of Physics and Technology, TNU-Univeristy of Sciences Tan Thinh Ward Thai Nguyen City Vietnam
Faculty of Labour Protection, Vietnam Trade Union University 169 Tay Son, Dong Da District Ha Noi City Vietnam.
RSC Adv. 2021 Apr 20;11(24):14596-14606. doi: 10.1039/d1ra01477c. eCollection 2021 Apr 15.
Ag/Au bimetallic nanostructures have received much attention in surface-enhanced Raman scattering (SERS). However, the synthesis of this nanostructure type still remains a challenge. In the present research, Ag/Au nanoframes were synthesized a simple room temperature solution phase chemical reduction method using pre-synthesized triangular Ag nanoplates as templates in the presence of appropriate amounts of HAuCl. Controlling experimental parameters was applied for understanding of the growth mechanism. The galvanic exchange reaction resulted in a uniform deposition of the Au shell on the Ag nanoplates and the Ag core was removed which generated triangular hollow nanoframes. It is found that the amount of HAuCl added to the growth solution played a key role in controlling the Ag/Au nanoframes. The resultant silver/gold nanoframes with average size of 50 nm were applied in detecting methyl red (MR) in the solution-phase using an excitation wavelength laser of 532 nm. The SERS signal was greatly enhanced owing to the tunable plasmonic peaks in the visible region (400-650 nm). The limit of detection (LOD) of MR in diluted solution was 10 M. The enhancement factor (EF) was about 8 × 10 toward 10 M of MR. Interestingly, the linear dependence between the logarithm of the SERS signal intensity (log ) and the logarithm of the MR concentration (log ) occurred in the range from 10 to 10 M. Our work promises the application of Ag/Au nanoframes as a chemical sensor in detecting MR molecules at low concentration with high performance.
银/金双金属纳米结构在表面增强拉曼散射（SERS）领域备受关注。然而，这类纳米结构的合成仍然是一个挑战。在本研究中，以预先合成的三角形银纳米片为模板，在适量的氯金酸存在下，通过简单的室温溶液相化学还原法合成了银/金纳米框架。通过控制实验参数来理解其生长机制。电化交换反应导致金壳均匀沉积在银纳米片上，银核被去除，从而生成三角形空心纳米框架。研究发现，添加到生长溶液中的氯金酸量在控制银/金纳米框架方面起着关键作用。所得平均尺寸为50 nm的银/金纳米框架被用于在溶液相中使用532 nm激发波长激光检测甲基红（MR）。由于在可见光区域（400 - 650 nm）可调谐的等离子体峰，SERS信号得到了极大增强。稀释溶液中MR的检测限为10⁻⁸ M。对于10⁻⁶ M的MR，增强因子（EF）约为8×10⁵。有趣的是，SERS信号强度的对数（log I）与MR浓度的对数（log C）之间的线性关系出现在10⁻⁸至10⁻⁶ M的范围内。我们的工作有望将银/金纳米框架作为一种化学传感器，用于高性能检测低浓度的MR分子。
