Bio-Inspired Nano Synthesis
Sponge studies lead to a method for making novel materials
SOURCE: “Kinetically Controlled Vapor-Diffusion Synthesis of Novel Nano-structured Metal Hydroxide and Phosphate Films Using No Organic Reagents” Birgit Schwenzer et al. Journal of Materials Chemistry 16: 401-407
RESULTS: Using mechanisms inspired by marine sponges, researchers at the University of California, Santa Barbara, have developed a technique for making a variety of thin-film materials, including semiconductors, structured at the nanoscale. Unlike other methods, the technique can produce semiconducting thin films without the use of harsh chemicals, and it works at room temperature, whereas some techniques require temperatures of 400 to 1,500 ºC. So far, the researchers have used the process to synthesize 30 types of materials, some of which have novel electronic and optical properties.
WHY IT MATTERS: The process is more environmentally sound and potentially less expensive than other techniques for manufacturing thin-film materials, which are used in a variety of electronic devices. Furthermore, it could open the way for new types of materials or allow existing materials to take on new properties. For example, the large surface area of the nanostructured films could lead to higher-power batteries and more efficient solar panels.
METHODS: The process is similar to one seen in marine sponges, which assemble their intricate glass skeletons with the help of an enzyme that doubles as a physical template. The researchers expose a solution of molecular precursors to ammonia vapor, which, as it slowly diffuses into the solution, catalyzes the assembly of the precursors into the desired material. The surface of the solution acts in some ways like the sponge’s enzyme template, helping to determine the material’s structure. At the surface, the vapor concentration is greatest, and the material forms a smooth, thin film. As the concentration of ammonia decreases, the material grows down, extending from the film like stalactites.
NEXT STEPS: The researchers are beginning to build and test rudimentary photovoltaic and electrical storage devices made from the new materials. To produce materials that perform as well as possible, they will also need to fine-tune the assembly method and apply it to additional compounds.