Chang Huei-Huei, Murphy Catherine J
Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
Chem Mater. 2018 Feb 27;30(4):1427-1435. doi: 10.1021/acs.chemmater.7b05310. Epub 2018 Jan 25.
Gold nanorods of small sizes have larger absorption cross sections and higher photothermal efficiency compared to larger ones. However, tuning the surface plasmon resonance of small gold nanorods remains a challenge because increasing an aspect ratio usually results from increasing dimensions. We demonstrate the synthesis of mini gold nanorods with tunable longitudinal surface plasmon resonance from ~600 to >1300 nm accompanied by precise control over widths <10 nm. Two weak reducing agents, ascorbic acid and even milder hydroquinone, were applied to a seed-mediated growth method to tune the aspect ratios of mini gold nanorods from 2.2 to 10.8 corresponding to average dimensions 19.3 × 9.0 nm through 93.1 × 8.7 nm, respectively. This seed-mediated growth of mini gold nanorods results in an average 96% of rods and yields of at least 79% based on gold ion reduction. The extinction coefficients of mini gold nanorods were established based on the gold content from inductively coupled plasma mass spectrometry. The longitudinal extinction coefficients range from 1.6 × 10 to 1.4 × 10 M cm depending on aspect ratio. We show that liter-scale mini gold nanorod syntheses are reproducible, and the dimensions, aspect ratios, and shape percent yields are comparable to those of a small-scale synthesis.
与较大尺寸的金纳米棒相比，小尺寸的金纳米棒具有更大的吸收截面和更高的光热效率。然而，调节小金纳米棒的表面等离子体共振仍然是一个挑战，因为长径比的增加通常是由尺寸增加导致的。我们展示了可合成纵向表面等离子体共振可调谐范围从~600到>1300 nm的微型金纳米棒，同时能精确控制宽度<10 nm。将两种弱还原剂，即抗坏血酸和更温和的对苯二酚，应用于种子介导生长法，将微型金纳米棒的长径比从2.2调节到10.8，对应的平均尺寸分别为19.3×9.0 nm到93.1×8.7 nm。这种种子介导的微型金纳米棒生长平均产生96%的棒状结构，基于金离子还原的产率至少为79%。微型金纳米棒的消光系数是根据电感耦合等离子体质谱法测定的金含量确定的。纵向消光系数根据长径比在1.6×10到1.4×10 M cm范围内变化。我们表明，升规模的微型金纳米棒合成是可重复的，其尺寸、长径比和形状产率与小规模合成相当。
