以植晶法合成具系統性形狀演化的金奈米粒子-由立方體演繹至菱形十二面體

• Main Authors: Wu, Hsin-Lun, 吳欣倫
• Other Authors: Huang, Michael Hsuan-Yi
• Format: Others
• Language: en_US
• Online Access: http://ndltd.ncl.edu.tw/handle/93063985870471861312

碩士 === 國立清華大學 === 化學系 === 97 === We report the synthesis of gold nanocrystals with a systematic shape evolution from cubic to rhombic dodecahedral structures by a seeding growth approach. Unusual cubic, trisoctahedral, and rhombic dodecahedral structures can be synthesized by using cetyltrimethylammonium chloride (CTAC) surfactant as capping agent and ascorbic acid as reducing agent in the presence of NaBr. The transitional products can also be prepared. By adding 25 μL of the seed solution, particles with a monodispersed size of around 75 nm were synthesized. The shape evolution can be achieved by adding different amounts of ascorbic acid. By increasing the amount of ascorbic acid, the gold nanocrystals formed can be transformed from cubes to trisoctahedra, and then to rhombic dodecahedra. Structural characterization confirmed that the cubes are bounded by {100} facets, whereas the rhombic dodecahedra are bounded by {110} facets. We have successfully used a systematic method to synthesize gold nanocrystals with entirely {100} or {110} facets and found the relationships among these shapes. Truncated cubes can also be synthesized by using this growth approach. These nanocrystals should allow the examination of their various properties as a function of particle shapes and surfaces. By introducing different quantities of the seed solution, we were able to successfully control the size of the cubic and rhombic dodecahedral gold nanocrystals. The more seed solution was added, the smaller the particle size is. As the amount of the seed solution was increased to 45 and 65 μL, the gold cubes and rhombic dodecahedra showed smaller sizes of around 55 and 40 nm. The gold nanocubes can get even smaller to a size of approximately 30 nm by adding 100 μL of the seed solution.