Tunable plasmon modes in single silver nanowire optical antennas characterized by far-field microscope polarization spectroscopy

Tetrabutylammonium Tribromide-Induced Synthesis of Silver Nanowires with Ultrahigh Aspect Ratio for a Flexible Transparent Film

Silver nanowires (AgNWs) have gained significant attention from researchers as a promising material for producing flexible transparent conductive films, which can be utilized in touch and display screens. Thereinto, the ultrahigh aspect ratio AgNW network can theoretically decrease the contact resistance effectively while still retaining considerable mechanical and optical properties. However, fabrication of high-quality AgNWs with a fine diameter and high aspect ratio is still challenging. Herein, a simple and robust approach to synthesize ultrahigh aspect ratio AgNWs is presented. This study successfully fabricated AgNWs with the highest aspect ratio up to ∼4000 and an average length of ∼72 μm by utilizing tetrabutylammonium tribromide as an auxiliary additive. The manifestation of tetrabutylammonium tribromide was proven to be beneficial for the generation of silver seeds and the expansion of AgNWs. The obtained AgNWs were utilized to create a transparent conductive film that showed low sheet resistance of 22.4 Ω/sq and high transmittance and low haze of 87.71 and 4.15%, respectively. The transmittance and haze of the vacant poly(ethylene terephthalate) support were 90.13 and 2.05%, thereby offering great potential for application in flexible transparent electrodes.

Correlations between incident and emission polarization in nanowire-particle coupled junctions

Plasmonic nanostructures with subwavelength confinement are of great importance for the development of integrated nanophotonic circuits and devices. Here, we experimentally investigate how the polarization of the emitted light from nanowire-particle junction relies on the incident polarization. We demonstrate that the correlations can be effectively modulated by the particle position relative to the wire. By varying the wire-particle gap with only several nanometers, the nanowire-particle junction can be changed from polarization maintainer to rotator. Then, by moving the particle along the wire within half of the surface plasmon polariton (SPP) beat, the polarization behaviors can be tuned from positive to negative correlation. The mechanism can be well understood by the hybridization of wire-particle coupled mode and propagating SPP modes, which is verified by finite-difference time-domain simulations. These findings would provide a new degree of freedom for manipulating light polarization at the nanometer scale and additional flexibility for constructing nanophotonic devices.

Synthesis and the growth mechanism of ultrafine silver nanowires by using 5-chloro-2-thienylmagnesium bromide as the additive

The presence of 5-chloro-2-thienylmagnesium bromide is beneficial for the in situ formation of smaller AgBr and AgCl particles step by step and the final growth of ultrafine Ag NWs with an average diameter of ∼15 nm and an aspect ratio of over 1000.

Rational synthesis of silver nanowires at an electrode interface by diffusion limitation

We report an approach to synthesize silver nanowires by diffusion limitation.

One-step synthesis of ultra-long silver nanowires of over 100 μm and their application in flexible transparent conductive films

Silver nanowires (AgNWs) >100 μm and even 160 μm in length have been synthesized using a facile and rationally designed solvothermal method by heating preservation at 150 °C. The length of the as-synthesized AgNWs is over 4–5 times longer than those previously reported, while the diameter range is from 40 nm to 85 nm. A transparent conducting film (TCF) was fabricated using hydroxyethyl cellulose (HEC) as the adhesive polymer, and it achieved exceptional and stable optoelectronic properties. Its low sheet resistance of ∼19 Ω sq⁻¹ (on polyethylene terephthalate, PET) and high optical transmittance of ∼88% are superior to that of expensive indium tin oxide (ITO) films. More significantly, the AgNW network demonstrates excellent adhesion to PET substrates. This study indicates that ultra-long silver nanowires can serve as an alternative to ITO, which also demonstrates its potential application in flexible electronic devices.

Ultra-long silver nanowires (100–160 μm) were applied in flexible transparent conductive films showing low sheet resistance and high optical transmittance.

Orientation-and polarization-dependent optical properties of the single Ag nanowire/glass substrate system excited by the evanescent wave

As an important plasmon one-dimensional material, orientation- and polarization-dependent properties of single Ag nanowires/glass substrate system are investigated by a powerful platform consisting of evanescent wave excitation, near-/far-field detection and a micromanipulator. In the case of the nanowire perpendicular or parallel to the incident plane and p- ors-polarized evanescent excitation respectively, optical properties of the nanowire is measured both in far-field and near-field. For the perpendicular situation, scattering light from the nanowire shows strong dependence on the polarization of incident light, and period patterns along the nanowire are observed both in the near- and far-field. The chain of dipole model is used to explain the origin of this pattern. The discrepancy of the period patterns observed in the near- and far-field is due to the different resolution of the near- and far-field detection. For the parallel case, light intensity from the output end also depends on the incident polarization. Both experimental and calculation results show that the polarization dependence effect results from the surface plasmon excitation. These results on the orientation- and polarization-dependent properties of the Ag nanowires detected by the combination of near- and far-field methods would be helpful to understand interactions of one-dimensional plasmonic nanostructures with light.

Multiple hybridized resonances of IR-806 chromonic molecules strongly coupled to Au nanorods

Strong coupling of plasmons and molecules generates intriguingly hybridized resonance. The IR-806 molecule is a near-infrared cyanine liquid crystal dye with multiple molecular bands and its tunable absorption spectrum varies dramatically with concentration. In this article, we investigate multiple hybridized resonances of the Au nanorods (AuNRs) strongly coupled to IR-806 molecules. Five hybridized resonance peaks are observed in the extinction spectra of the AuNR@IR-806 hybrids. Two resonance peaks at approximately 840 and 912 nm in the hybrids are reported for the first time. The dependence of the multiple hybridized peaks on the bare plasmon resonance wavelength of AuNRs and the molecular concentration is also demonstrated. The observations presented herein provide a plasmon-molecule coupling route for tuning optical responses of liquid crystal molecules.

Plasmon-enhanced fluorescence of PbS quantum dots for remote near-infrared imaging

Gold nanoparticles enhance the fluorescence of PbS quantum dots upon excitation with near infrared laser to implement remote imaging.