| Summary: | 碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 97 === Novel phenylacetylene-functionalized Si (PH-Si) nanoparticles were synthesized and their photoluminescence (PL) properties were analyzed, in order to achieve Si nanoparticles that were well-dispersed in solutions with strong and stable PL. Compared with styrene-functionalized Si nanoparticles (ST-Si), which contained –Si-C-C-Ph linkage instead of the –Si-C=C-Ph linkage of the PH-Si, the PH-Si nanoparticles had significantly higher PL efficiency, better PL stability over time stored in air (no change for 18 days vs. rapid degradation in 12 days), and stronger ligand-Si-interactions-induced PL characteristics, while both PH- and ST-Si nanoparticles showed greatly improved dispersion in solvents over non-functionalized Si nanoparticles. The stronger and more stable PL of the PH-Si was attributed to the greater reactivity of the acetylene moiety of phenylacetylene than the ethylene moiety of styrene, which achieved more complete passivation of the Si surface. Excitation-wavelength dependence of the PL spectra and the PLE spectra of the Si nanoparticles indicated that the PL of the PH-Si and S-Si nanoparticles were both combinations of the individual PL of the functional group and the Si core, but that the PL of the PH-Si nanoparticles contained significant contributions from functional-group-to-Si interactions while the PL of the S-Si nanoparticles did not. The significant functional-group-to-Si interactions of the PH-Si nanoparticles were attributed to the –Si-C=C-Ph linkage, which may enhance charge transfer between the PH group and the Si core through the conjugated structure; on the other hand, the S-Si linkage (-Si-C-C-Ph) were not conjugated and thus did not show such interactions.
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