| Summary: | 碩士 === 國立嘉義大學 === 應用化學系研究所 === 99 === Photoinduced shape conversion from spherical silver nanoparticles (NPs) to the nanostructures with other shapes under the irradiation of green LEDs (520±20 nm, 35 mW/cm2 ) at various temperatures ( 60, 40, 20, 10, 5, and 0 ℃) were performed in this study. It is found that the temperature factor used in the reaction can influence the reaction rates, i.e., the process completed within 9, 15, 30, 60, 80, and 140 hours at 60, 40, 20, 10, 5, and 0 ℃, respectively. In addition, the temperature factor can also alter the morphologies of final products. The major products are silver nanoprisms at 60 ℃. However, they became decahedral silver NPs at 0 ℃. This is the first time to report that photochemical reaction with irradiation of green light is employed on synthesis of decahedral silver NPs. The percentages of decahedral silver NPs synthesized at 60, 40, 20, 10, 5, and 0 ℃ are 0, 1, 5, 45, 73, and 89 %, respectively. Measuring SERS spectra of R6G in the presence of KBr shows that both silver nanoprism colloids synthesized at 60 ℃ and decahedral silver NP colloids synthesized at 0 ℃ have good SERS activities.
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