The field of molecular electronics explores molecular building blocks for the fabrication of ever-shrinking electronic elements. Much of the excitement of this area has arisen from the huge prospect of size reduction in electronics offered by the molecular level control of their properties. However, one of the biggest obstacles for molecular electronic to be practically exploited is the lack of techniques to make reliable and reproducible electrical contacts to single organic molecules of interest.
Scientists at Stanford University address this challenge by exploiting DNA, one of the most versatile and powerful molecules available for molecular fabrication and self/assembly, as a molecular template for metal electrodes. DNA molecules can be chemically linked to a variety of single organic molecules and can also be used as a template for metallic nanostructures.
The authors have developed a reproducible surface chemistry for tethering DNA molecules at tunable density and demonstrated shear flow processing as a rationally controlled approach for stretching/aligning DNA molecules of various lengths.
The proposed strategy starts with the synthesis of hybrid DNA – organic molecule – DNA (DOD) structures, followed by subsequent stretching/alignment and double tethering of the DOD assemblies between two microscopic metal electrodes. Further metallization of the DNA segments completes the fabrication of metal electrode – organic molecule – metal electrode (M – O – M) structures, thus realizing the conducting contacts to organic molecules.
This approach that utilizes DNA as a templated bridge to connect single organic molecules and microscopic electrodes is a bottom-up approach to integration at the nanoscale. It represents an important step toward the building of increasingly complex molecular circuits.
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Guihua Yu, Amit Kushwaha, Jungkyu K. Lee, Eric S. G. Shaqfeh, and Zhenan Bao
ACS Nano 2011 5 (1), 275-282