Nematic Director‐Induced Switching of Assemblies of Hexagonally Packed Gold Nanorods

Thomas, Michael R.; Klein, Susanne; Greasty, Robert J.; Mann, Stephen; Perriman, Adam W.; Richardson, Robert M.

doi:10.1002/adma.201201319

Cited by 16 publications

(12 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A related example of such GNR reorientation in electric fi elds was recently disclosed by Richardson and co-workers for shortrange ordered hexagonally packed GNR suspended in a nematic liquid crystal (5CB). [ 40 ] The key difference in the present work is that the GNRs assemble into nematic and to some degree smectic-type arrays with only a miniscule amount of free liquid crystal molecules (about 1% by weight). Hence, the free liquid crystal acts here as the dopant (or suspended entity promoting attractive interactions between GNRs) in contrast to GNR suspensions investigated by others.…”

Section: D)mentioning

confidence: 99%

Large Area Self‐Assembly of Nematic Liquid‐Crystal‐Functionalized Gold Nanorods

Umadevi

Feng

Hegmann

2012

Adv Funct Materials

View full text Add to dashboard Cite

Large Area Self-Assembly of Nematic Liquid-Crystal-Functionalized Gold NanorodsFascinating nematic-and smectic-like self-assembled arrays are observed for gold nanorods partially capped with either laterally or terminally attached nematic liquid crystals upon slow evaporation of an organic solvent on TEM grids. These arrays can be manipulated and reoriented by applying an external magnetic fi eld from quasi-planar to vertical similar to a Fréedericksz transition of common organic nematic liquid crystals. Birefringence and thin fi lm textures of these self-assembled gold nanorod arrays observed by polarized optical microscopy are strongly reminiscent of common organic nematic liquid crystal textures between crossed polarizers and, additionally, support the formation of ordered liquid crystal-like anisotropic superstructures. The ordering within these arrays is also confi rmed in bulk samples using small angle X-ray scattering (SAXS).

show abstract

Section: D)mentioning

confidence: 99%

Large Area Self‐Assembly of Nematic Liquid‐Crystal‐Functionalized Gold Nanorods

Umadevi

Feng

Hegmann

2012

Adv Funct Materials

View full text Add to dashboard Cite

show abstract

“…In previous work, we have shown that hexagonally packed clusters of gold nanorods (GNRs), modified with short alkyl thiol coatings, can be remarkably well directed by nematic liquid crystal hosts. [12]. Recently, Liu et al [13] achieved orientational control of GNRs as single particles which allowed control of the anisotropic plasmon resonance absorption to be demonstrated.…”

Section: Introductionmentioning

confidence: 97%

Stability and Orientational Order of Gold Nanorods in Nematic Suspensions: A Small Angle X-ray Scattering Study

Thomas

Hallett

Klein

et al. 2015

Molecular Crystals and Liquid Crystals

View full text Add to dashboard Cite

Stable suspensions of gold nanorods in have been prepared by capping the nanoparticles with polyethylene glycol (PEG). Small angle Xray scattering has been used to characterize the orientational order of the gold nanorods and the properties of any aggregates. It was found that the nanorods had a very high degree of orientational order with respect to the director of the 5CB matrix and this could be redirected by an applied electric field at 2kHz. Two different PEG molecular weights were investigated and it was found that the lower (1.9kDa) gave exceptionally high order parameters, above 0.9.

show abstract

“…[41, 42] However, a serious drawback met in the use of most of thermotropicliquid crystals corresponds to the induced aggregation of thenanorods. [36,[43][44] This aggregation is due to the distortions and disorder induced in the liquid crystal around most of the nanoparticles, which become reduced if the nanoparticles are aggregated. [36,45] In nematic liquid crystals, the best method to prevent aggregation of nanorods is to graft specific ligandsaround the nanorodsin order to allow for a weak anchoring of the liquid crystal molecules.…”

mentioning

confidence: 99%

Alignment of Rod‐Shaped Single‐Photon Emitters Driven by Line Defects in Liquid Crystals

Pelliser

Manceau

Lethiec

et al. 2015

Adv Funct Materials

View full text Add to dashboard Cite

We use arrays of liquid crystal defects, linear smectic dislocations, to trap semi-conductor CdSe/CdS dot-in-rods which behave as single photon emitters. We combine measurements of the emission diagram together with measurements of the emitted polarization of the single emitters. We show that the dot-inrods are confined parallel to the linear defects to allow for a minimization of the disorder energy associated with the dislocation cores. We demonstrate that the electric dipoles associated with the dotin-rods, tilted with respect to the rods, remain oriented in the plane including the smectic linear defects and being perpendicular to the substrate, most likely due to the dipole/dipole interactions between the dipoles of the liquid crystal molecules and the dot-in-rods ones. Using smectic dislocations, we can consequently orient nanorods along a unique direction for a given substrate, independently of the ligands' nature, without any induced aggregation, leading as well to a fixed azimuthal orientation for the associated dot-in-rods' dipoles. These results open the way for a fine control of nanoparticle anisotropic optical properties, in particular a fine control of single photon emission polarization.Control of single photon emitters is a major objective in the field of nanophotonics.[1] The synthesis of colloidal semiconductor inorganic nanocrystals having specific light-emission properties has been providing important advances in this field. In particular, recent developments in synthesis methodologies, fully compatible with standard nanofabrication technologies have enabled a superior 3 control on nanocrystals composition and morphology.Rod-shaped nanocrystals showing pronounced polarization, behaving as emitting linear dipoles, have been obtained. [2][3][4] The encapsulation of a spherical core into a rod-like shell [5] resulted in non-blinking inorganic single photon emitters, [6] hereafter referred to as dot-in-rods (DRs). Moreover it has been recently shown that, by increasing the thickness of the shell, it is possible to greatly suppress photoluminescence blinking and to improve DRs overall photo-stability, while keeping a low probability of multi-photon emission. [7] Such features are of primary importance when nanocrystalsare used in applications demanding a control of photons'polarization, such as coupling with complex photonic cavities [8][9] or quantum cryptography.[10] The control of the polarization of the emitted light also requires the capacity to control the particle orientation. Howevertechnologies aimed at guiding nanocrystal orientation at the single particle level are still poorly discussed in literature.Alignednanoparticleshave been obtained through mechanical rubbing, [11] short-range interactions [12][13] or patterned substrates. [14] Liquid crystal-like structures, composed of alarge number of elongated nanocrystalsassembled in multi-layers have also been evidenced on both solid substrates [15][16][17][18] and water films. [18][19][20] Orientation and positional ordering of CdS and CdSe...

show abstract

Nematic Director‐Induced Switching of Assemblies of Hexagonally Packed Gold Nanorods

Cited by 16 publications

References 34 publications

Large Area Self‐Assembly of Nematic Liquid‐Crystal‐Functionalized Gold Nanorods

Large Area Self‐Assembly of Nematic Liquid‐Crystal‐Functionalized Gold Nanorods

Stability and Orientational Order of Gold Nanorods in Nematic Suspensions: A Small Angle X-ray Scattering Study

Alignment of Rod‐Shaped Single‐Photon Emitters Driven by Line Defects in Liquid Crystals

Contact Info

Product

Resources

About