Aug 11, 2011
Solution casting yields biomolecule-based electrical bistable device
Researchers based in China from Soochow University, the Beijing National Laboratory for Condensed Matter Physics and Nanjing University, have teamed up to design and characterize biomolecule-based composite films for electronic applications. Highly ordered hybrid multilayers of phospholipid and nanoparticles were fabricated through a simple solution-cast method. Current-voltage scans on the Al/(lipid-nanoparticle composite film)/ITO/glass structures revealed an obvious bistable phenomenon. Further investigation of the bionanoparticle composite film points towards applications in future memory nanodevices with tailored performance.
The use of biomolecules for the fabrication of nanodevices is a promising direction for nanotechnology. The biomolecule-assisted assembly of inorganic nanoparticles for electronic applications could open to the door to the eventual development of molecular-sized devices, and maybe even molecular computers. However, few examples of biomolecule-nanoparticle electronic devices have been fabricated owing to the lack of charge transport through biomolecules and the difficulty in dispersing the inorganic nanoparticles into the composite with a long-range ordered structure.
Through a facile solution cast method, a new kind of organic bistable device based on the self-assembled multilayered film composed of phospholipid and CdTe nanoparticles has been fabricated. The design exhibits electrical bistable behaviour with a maximum on/off ratio up to 600.
Homogeneous and highly ordered
The self-assembly of biomolecules allows the production of ordered composite structures without the requirement for harsh fabricating procedures or high-precision patterning. X-ray reflectivity and transmission electron microscopy measurements showed the homogeneous distribution of nanoparticles within the lamellar lipid matrix with long-range ordering.
The team found that the interparticle distance of nanoparticles within each layer could be adjusted easily, which may provide the opportunity to change the macroscopic electrical properties of the composite film and eventually influence the memory ability of future devices. Also, the lipid-based composite film can be fabricated on flexible substrates for large-area applications thanks to the outstanding elasticity of the lipid membranes. Finally, the target particles in the composite are not restricted to CdTe nanoparticles (used in the test sample), which greatly broadens the possible number of uses for the material.
Full details can be found in the journal Nanotechnology.
About the author
Dr Bing Yuan (soon to be an associate professor) works at the Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University. She has been studying the self-assembly of organic-inorganic functional composite films based on phospholipid, graphene oxide and other biomolecules including DNA and proteins, as well as characterizing these materials and investigating their applications. Prof. Yuqiang Ma is head of the centre and guided the project. Drs Shuxin Hu and Ming Li are research fellows at Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences. One of their research interests includes biomimetic nanomaterials. Naiyan Lu and Fan Xu are PhD students in physics at the National Laboratory of Solid State Microstructures, Nanjing University. Kun Zhou is a PhD student at Soochow University.