Presentation Information
[10p-E201-8]Photoluminescence Optical Response of Colloidally Dispersed Gold Nanoparticle Dimers with Angstrom-Scale Gaps
〇Keiko Esashika1, Bokusui Nakayama1, Toshiharu Saiki1 (1.Keio Univ.)
Keywords:
dimer,photoluminescence,SERS
Plasmonic nanogaps in the sub-nanometer regime provide extreme electromagnetic field confinement, where angstrom-scale structural variations strongly influence optical responses and interfacial molecular behavior. In this study, AuNP dimers with molecularly defined interparticle gap were fabricated using COOH-terminated alkanethiols with alkyl chain lengths C = 2 to 7. A template-free solution-phase assembly method enabled precise control of the interparticle gap down to approximately 0.6 nm. The dimers were isolated by agarose gel electrophoresis. The angstrom-level control of the gap generated intense electromagnetic hotspots, which were utilized for SERS measurements. Raman bands originating from the molecules were clearly observed, providing information on molecular structures and ionic states near the nano-interface. Photoluminescence spectra depended on the localized surface plasmon resonance wavelength, and the intensity exhibited an odd–even dependence on alkyl chain length.