Molecular Materials Group, Chalmers

Molecular Materials Group, Chalmers

About the blog

On this blog I will highlight interesting developments in research, at Chalmers and of our own research.

Review on Single Molecule Electronics

Research PapersPosted by Kasper Moth-Poulsen Tue, August 05, 2014 13:33:57
We have written a "full scale" review entitled "Single-molecule electronics: from chemical design to functional devices" about single molecule electronics, with a focus on the progress in the field during the last 5 years. The review is published by RSC, Chemical Society Reviews DOI: 10.1039/c4cs00143e.

"Single-molecule electronics: from chemical design to functional devices"

Lanlan Sun, Yuri A. Diaz-Fernandez, Tina A. Gschneidtner, Fredrik Westerlund, Samuel Lara-Avila and Kasper Moth-Poulsen*

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.





Self-Assembly

Research PapersPosted by Kasper Moth-Poulsen Fri, March 07, 2014 21:10:37
Our paper on self assembly of dimers of 2 different nano particles into so-called heterodimers has been published in Langmuir. "A Versatile Self-Assembly Strategy for the Synthesis of Shape-Selected Colloidal Noble Metal Nanoparticle Heterodimers" DOI: 10.1021/la5002754


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 nm and 70 nm); as well as a silver sphere (90 nm) with palladium cubes (25 nm 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, tuning the optimal 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 the indirect plasmonic sensing of hydrogen finally illustrates the potential of these structures to probe catalytic processes at the single particle level.

Self-Assembly

Research PapersPosted by Kasper Moth-Poulsen Wed, December 18, 2013 08:43:58
In our paper, Yuri Diaz Fernandez, Lanlan Sun, Tina A. Gschneidtner, Kasper Moth-Poulsen"Progress in synthesis of nanoparticle dimers by self-assembly" published in the new open access journal "APL Materials" are we highlighting recent progress in the research field synthesis of dimers of nano particles. Nano particle dimers are interesting for a number of applications, such as sensing of a single or a few molecules via localized surface plasmons, or as building blocks for single molecule electronics components.

http://scitation.aip.org/content/aip/journal/aplmater


Gold Nanorod growth

Research PapersPosted by Kasper Moth-Poulsen Mon, December 16, 2013 11:19:24
In this recent paper, we set out to explore the mechanism of gold nano rod growth. The nano rods grow from isotropic seed particles into anisotropic rods. Why and how this is happening has always fascinated me. One of the leading hypothesis for the growth mechanism is that elongated micelles direct the anisotropic growth via a template effect.

To explore if this is true, we have employed gemini surfactants to the growth process. The gemini surfactants are known to form very elongated micelles. Based on our observations, we conclude that surface binding effects are more important for the anisotropic growth than the elongated micelle/template effect.

The paper can be found here:

Titoo Jain, Ali R. Tehrani-Bagha, Himanshu Shekhar, Ross Crawford, Erik Johnson, Kasper Nørgaard, Krister Holmberg, Paul Erhart, Kasper Moth-Poulsen"Anisotropic Growth of Gold Nanoparticles using Cationic Gemini Surfactants: Effects of Structure Variations in Head and Tail Groups" J. Mater. Chem C. 2014 (emerging investigator issue) DOI:10.1039/C3TC32057J