利用光化学二次生长精细控制金纳米棒的长径比(英文)

Aspect Ratio Fine Control of Gold Nanorods by Photochemical Secondary Growth

研究了晶种媒介的金纳米棒光化学二次生长及其长径比的精细调控。在单一组份的表面活性剂生长溶液中,以十六烷基三甲基溴化铵(CTAB)封端的带正电荷的金纳米粒子作晶种,形貌均一的金纳米棒通过二次生长获得,其二次生长是在晶种媒介的化学生长反应达到平衡后于丙酮存在下用300 nm的紫外光照射来实现。通过改变银离子的加入量,具有约10 nm直径金纳米棒的长径比被精细调控在2.3～4.0范围内,相应的纵向等离子体带最大在730～840 nm之间。另外,纵向等离子体带达到最大之后,进一步的紫外光照射使金纳米棒变短。通过这一途径。

The seed-mediated photochemical secondary growth of gold nanorods （Au NRs） and their aspect ratio fine control were studied. In a single-component surfactant growth solution containing CTAB-capped positive charge gold nanoparticles as seed, Au NRs with uniform shape were obtained by the secondary growth which was realized by UV irradiation of 300 nm light in the presence of acetone after reaching the reaction equilibrium of seed-mediated chemical growth. The aspect ratios of Au NRs with an average 10 nm in diameter were finely controlled in the range of 2.3 to 4.2 by changing amount of Ag＋ ions added and corresponding longitudinal plasmon band （LPB） maxima were between 730 and 840 nm. In addition, after reaching LPB maximum, the further UV irradiation made Au NRs shortening. By this approach the aspect ratios of Au NRs could be also controlled in the above same range. The mechanism of shortening Au NRs by UV light is discussed briefly.