Nanomaterials for Energy and Electronics

International customers, please contact your local Sigma-Aldrich office. For worldwide contact information, please see back cover. Material Matters is also available in PDF format on the Internet at sigma-aldrich.com/matsci. Aldrich brand products are sold through Sigma-Aldrich, Inc. Sigma-Aldrich, Inc. warrants that its products conform to the information contained in this and other Sigma-Aldrich publications. Purchaser must determine the suitability of the product for its particular use. See reverse side of invoice or packing slip for additional terms and conditions of sale. All prices are subject to change without notice. Progress in the area of nanomaterials has pervaded the vast majority of technologies, from electronics to energy generation and storage. Over the last decade, the ability to manipulate and control materials at an atomic level has allowed for both the reduction in size and the increase in efficiency of electronic devices, solar cells and batteries, thus, revolutionizing the traditional way of living. Nanopowders (shown on the cover) are key elements to a diverse set of technology areas enabling high-density storage of information (see p. 50), conversion of solar light into electricity (p. 32) and storing it for later use (p. 42). Introduction Welcome to the issue of Material Matters™ focusing on Nanomaterials for Energy and Electronics. The term nanomaterials defines an extremely diverse group of materials, where morphological features do not exceed 100 nanometers. 1 The idea of manipulating materials on the atomic level goes back to Richard Feynman and his prominent lecture " There's Plenty of Room at the Bottom ". 2 However, the boom of nanomaterials began only in the 1990s and quickly spread out into a vast majority of modern technologies including energy and electronics. The main reasons for the rapid expansion of nanomaterials into different application areas are the unique properties stemming from nanoscale dimensions. Nanoparticles and nanostructures demonstrate an extremely high surface-to-volume ratio, enabling quantum effects that are impossible in the conventional, micrometer-sized materials. As an example, particles of crystalline BaTiO 3 usually have a cubic structure at their surface, but are tetragonal-ordered in the bulk. As the particle size decreases, the content of the cubic phase gradually increases until the tetragonal phase completely disappears when BaTiO 3 particles enter the nanosize region. The disappearance of the tetragonal phase changes the magnetic properties of the material, which becomes super-paraelectric (vs. ferroelectric in the conventional titanate). 3 Another reason for growing interest in nanoscale materials is device …