Rise of the Charge Transfer Plasmon: Programmable Concatenation of Conductively Linked Gold Nanorod Dimers

• DOI: 10.1021/acsphotonics.6b00184
• Publication Date: 2016-04-27T18:25:56Z
• Authors: Jake Fontana; Nicholas Charipar; Steven R. Flom; Jawad Naciri; Alberto Piqué; Banahalli R. Ratna
• Keywords: Nanorod; Absorbance

The ability to tune the resonant frequency in plasmonic nanostructures is fundamental developing novel optical properties and ensuing materials. Recent theoretical insights have shown through conductive concatenation of nanoparticles that effective depolarization factor nanostructure, subsequent charge transfer plasmon (CTP) resonance, can be intricately controlled [Fontana, J.; Ratna, B. R. Appl. Phys. Lett. 2014, 105, 011107]. However, translating these from proof-of-principle experiments high-quality, macroscale quantities for material applications remains challenging. Here, we experimentally demonstrate by using an electrostatic-based molecular assembly approach how controllably concatenate gold nanorods end-to-end into discrete dimers, preventing unwanted longer structures forming a capacitively coupled (CCP) resonance along long axis dimer. Irradiating suspensions with femtosecond laser pulses at CCP dimer wavelength selectively welds only dimers together, bridging nanojunctions producing large, high-quality yields welded dimers. Macroscale (∼1012 dimers) absorbance measurements reveal CTP arising peak magnitudes as large 0.5 full-width-at-half-maximum 274 nm. We show controlling aspect ratio differ significantly (∼20%) single nanorod similar ratio, demonstrating modulate resulting resonance. also carried out three-dimensional finite element simulations showing less than 5% shift function contact point connecting relative orientation, agreement our experiments.