| 1. |
- Fernandez, Yuri A. Diaz, 1978, et al.
(författare)
-
The conquest of middle-earth: combining top-down and bottom-up nanofabrication for constructing nanoparticle based devices
- 2014
-
Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 6:24, s. 14605-14616
-
Tidskriftsartikel (refereegranskat)abstract
- The development of top-down nanofabrication techniques has opened many possibilities for the design and realization of complex devices based on single molecule phenomena such as e. g. single molecule electronic devices. These impressive achievements have been complemented by the fundamental understanding of self-assembly phenomena, leading to bottom-up strategies to obtain hybrid nanomaterials that can be used as building blocks for more complex structures. In this feature article we highlight some relevant published work as well as present new experimental results, illustrating the versatility of self-assembly methods combined with top-down fabrication techniques for solving relevant challenges in modern nanotechnology. We present recent developments on the use of hierarchical self-assembly methods to bridge the gap between sub-nanometer and micrometer length scales. By the use of non-covalent self-assembly methods, we show that we are able to control the positioning of nanoparticles on surfaces, and to address the deterministic assembly of nano-devices with potential applications in plasmonic sensing and single-molecule electronics experiments.
|
|
| 2. |
- Gschneidtner, Tina, 1985, et al.
(författare)
-
A Versatile Self-Assembly Strategy for the Synthesis of Shape-Selected Colloidal Noble Metal Nanoparticle Heterodimers
- 2014
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 30:11, s. 3041-3050
-
Tidskriftsartikel (refereegranskat)abstract
- The self-assembly of individual nanoparticles into-dimers so-called heterodimers-is relevant for a broad range of applications, in particular in the vibrant field of nano-plasmonics and nanooptics. In this paper we report the synthesis and characterization of material- and shape-selected nanoparticle heterodimers assembled from individual particles via electrostatic interaction. The versatility of the synthetic strategy is shown by assembling combinations of metal particles of different shapes, sizes, and metal compositions like a gold sphere (90 nm) with either a gold cube (35 nm), gold rhombic dodecahedron (50 nm), palladium truncated cube (120 nm), palladium rhombic dodecahedron (110 nm), palladium octahedron (130 nm), or palladium cubes (25 and 70 nm) as well as a silver sphere (90 nm) with palladium cubes (25 and 70 nm). The obtained heterodimer combinations are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), scanning transmission electron microscopy energy dispersive X-ray spectroscopy (STEM-EDX), dynamic light scattering (DLS), and zeta-potential measurements. We describe the optimal experimental conditions to achieve the highest yield of heterodimers compared to other aggregates. The experimental results have been rationalized using theoretical modeling. A proof-of-principle experiment where individual Au-Pd heterodimers are exploited for indirect plasmonic sensing of hydrogen finally illustrates the potential of these structures to probe catalytic processes at the single particle level.
|
|
| 3. |
- Jain, Titoo, et al.
(författare)
-
Additional Article Notification: Anisotropic growth of gold nanoparticles using cationic gemini surfactants: effects of structure variations in head and tail groups
- 2014
-
Ingår i: Journal of Materials Chemistry C. - 2050-7534 .- 2050-7526. ; 2:17, s. 3476-3485
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A library of gemini surfactants is employed to study surfactant directed anisotropic growth of gold nanoparticles. The surfactants are modified with respect to the length and type of the tails, as well as of the spacer group. By analyzing the structure of the anisotropic nanoparticles, it is possible to extract information on how the structure of the surfactants influences the anisotropic gold nanocrystal growth. We find that the tail length of the surfactants has a greater influence on the resulting nanoparticle aspect ratio compared to the chemical nature of the spacer group. While clear trends between the aspect ratio and the tail as well as spacer length remain elusive, we observe that surfactants with a critical micelle concentration of similar to 1 mM produce particles with the highest aspect ratio. A crystallographic analysis of nanorods obtained using gemini surfactants reveals that they grow along 100 and are bound by {310} facets. This observation, which is specific for gemini surfactants, is explained by taking into account the preferential alignment of gemini surfactants with surface steps as suggested by electronic structure calculations.
|
|
| 4. |
- Sun, Lanlan, 1981, et al.
(författare)
-
Single-molecule electronics: from chemical design to functional devices
- 2014
-
Ingår i: Chemical Society Reviews. - 1460-4744 .- 0306-0012. ; 43:21, s. 7378-7411
-
Forskningsöversikt (refereegranskat)abstract
- The use of single molecules in electronics represents the next limit of miniaturisation of electronic devices, which would enable us to continue the trend of aggressive downscaling of silicon-based electronic devices. More significantly, the fabrication, understanding and control of fully functional circuits at the single-molecule level could also open up the possibility of using molecules as devices with novel, not-foreseen functionalities beyond complementary metal-oxide semiconductor technology (CMOS). This review aims at highlighting the chemical design and synthesis of single molecule devices as well as their electrical and structural characterization, including a historical overview and the developments during the last 5 years. We discuss experimental techniques for fabrication of single-molecule junctions, the potential application of single-molecule junctions as molecular switches, and general physical phenomena in single-molecule electronic devices.
|
|
| 5. |
- Fernandez, Yuri A. Diaz, 1978, et al.
(författare)
-
Research Update: Progress in synthesis of nanoparticle dimers by self-assembly
- 2014
-
Ingår i: APL Materials. - : AIP Publishing. - 2166-532X. ; 2:1
-
Tidskriftsartikel (refereegranskat)abstract
- This article highlights recent advances in the controlled self-assembly of nanoparticles to produce dimeric nanoparticle structures. The relevance of this emergent field is discussed in terms of recent applications in plasmonics and chemical catalysis. The concept of bond-valence applied to nanoparticles will be discussed, emphasizing some general approaches that have been successfully used to build these structures. Further, the asymmetric functionalization of nanoparticles surfaces as a path to drive selective aggregation, the use of biomolecules to self-assemble nanoparticles into dimers in solution, and the confinement of aggregates in small cavities are discussed.
|
|
| 6. |
- Gschneidtner, Tina, 1985, et al.
(författare)
-
Progress in self-assembled single-molecule electronic devices
- 2013
-
Ingår i: Journal of Materials Chemistry C. - : Royal Society of Chemistry (RSC). - 2050-7534 .- 2050-7526. ; 1:43, s. 7127-7133
-
Tidskriftsartikel (refereegranskat)abstract
- Recent years have seen progress in several areas regarding single molecule electronic devices. A number of interesting structure-property relationships have been observed, including vibronic effects, spin transitions, and molecular electronic interference known as quantum interference. Together, these observations highlight what the rich opportunities in molecular design might bring in terms of advanced device properties. Pertinent challenges are related to development of high yield preparative procedures for fabrication of single molecule devices in a parallel and reproducible way. With this highlight article we review recent progress in the field considering self-assembled formation of metal nanogaps incorporating single molecules for single molecule electronics applications. We discuss methods for the formation of the nanogaps as well as methods attempting to achieve single molecule functionality in each individual device.
|
|
| 7. |
- Jain, T., et al.
(författare)
-
Anisotropic growth of gold nanoparticles using cationic gemini surfactants: effects of structure variations in head and tail groups
- 2014
-
Ingår i: Journal of Materials Chemistry C. - : Royal Society of Chemistry (RSC). - 2050-7526 .- 2050-7534. ; 2:6, s. 994-1003
-
Tidskriftsartikel (refereegranskat)abstract
- A library of gemini surfactants is employed to study surfactant directed anisotropic growth of gold nanoparticles. The surfactants are modified with respect to the length and type of the tails, as well as of the spacer group. By analyzing the structure of the anisotropic nanoparticles, it is possible to extract information on how the structure of the surfactants influences the anisotropic gold nanocrystal growth. We find that the tail length of the surfactants has a greater influence on the resulting nanoparticle aspect ratio compared to the chemical nature of the spacer group. While clear trends between the aspect ratio and the tail as well as spacer length remain elusive, we observe that surfactants with a critical micelle concentration of similar to 1 mM produce particles with the highest aspect ratio. A crystallographic analysis of nanorods obtained using gemini surfactants reveals that they grow along and are bound by {310} facets. This observation, which is specific for gemini surfactants, is explained by taking into account the preferential alignment of gemini surfactants with surface steps as suggested by electronic structure calculations.
|
|
| 8. |
- Arroyo, C.R., et al.
(författare)
-
Quantum interference effects at room temperature in OPV-based single-molecule junctions
- 2013
-
Ingår i: Nanoscale Research Letters. - 1556-276X .- 1931-7573. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- Interference effects on charge transport through an individual molecule can lead to a notable modulation and suppression on its conductance. In this letter, we report the observation of quantum interference effects occurring at room temperature in single-molecule junctions based on oligo(3)-phenylenevinylene (OPV3) derivatives, in which the central benzene ring is coupled to either para- or meta-positions. Using the break-junction technique, we find that the conductance for a single meta-OPV3 molecule wired between gold electrodes is one order of magnitude smaller than that of a para-OPV3 molecule. Theoretical calculations confirm the occurrence of constructive and destructive interference in the para- and meta-OPV3 molecules respectively, which arises from the phase difference of the transmission coefficients through the molecular orbitals.
|
|
| 9. |
|
|
| 10. |
- Börjesson, Karl, 1982, et al.
(författare)
-
Conjugated anthracene dendrimers with monomer-like fluorescence
- 2014
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:38, s. 19846-19850
-
Tidskriftsartikel (refereegranskat)abstract
- Two generations of highly emissive conjugated anthracene dendrimers containing up to 9 anthracene units are presented. In these dendrimers, anthracene-like absorption and emission properties are preserved due to the relatively weak electronic coupling between the anthracene units, while evidence of fast crosstalk within the molecular framework is still observed.
|
|
