Supporting Information for: Magnetic Modulation of Surface Plasmon Resonance by Tailoring Magnetically Responsive Metallic Block in Multi-segment Nanorods Insub Jung†, Hee-Jeong Jang‡, Songhee Han‡, Jesus A. I. Acapulco Jr. ‡, and Sungho Park*,†, ‡ †Department of Energy Science, Sungkyunkwan University, Suwon, 440-746, South Korea ‡
Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, South Korea
*
Electronic mail:
[email protected] Figure S1. Single-component Au nanorods as a control group. (A) A FE-SEM image of Au nanorods with ~ 150±11 nm in length and the right panel demonstrates the nanorod size distribution measured out of 100 nanorods. (B) Corresponding UV-vis spectra under a magnetic field with different field directions, indicating no response of Au nanorods due to non-magnetic nature of Au, indicating all the changes in this work solely arise from Ni contents.
1
Figure S2. (A) An energy-dispersive X-ray spectroscopy (EDS) spectrum of as-synthesized Au/Ni/Au nanorods shown in Figure 2A. (B) A hysteresis curve showing ferromagnetic nature of Ni.
2
Figure S3. UV-vis spectra of Au nanorods for changes of dipole modes. (A) A FE-SEM image of Au/Ni/Au multi-segmented nanorods with a total length of 190 nm. UV-vis spectra of nanorods under a magnetic field (B) perpendicular (C) parallel to the incident light. Each inset shows the color change of solution depending on the field direction, indicating the selectively enhancing (or suppressing) transverse (or longitudinal) peak.
3
Figure S4. The ratio of longitudinal to transverse modes as a function of magnetic fields, indicating the opposite behavior due to different easy axis of Ni segment under the same direction of magnetic field.
4
Figure S5. (A) Schematics of plasmon excitation of nanorods with disk-like Ni segment under zpolarized light dependent upon the direction of applied magnetic field. (B) Corresponding UV-vis spectra of Case I and Case II.
5
Figure S6. A FE-SEM image of Au/Ni/Au nanorods containing two Ni segments with relatively larger gap distance (~ 245 nm) compared to that from Figure 6A(ii) (~ 100 nm).
6