Nanoscale

Nanoscale refers to length scales between roughly 1 and 100 nanometers, where a nanometer is one billionth of a meter. Objects at this scale include nanoparticles, nanowires, nanotubes, and nanosheets. In some contexts slightly larger sizes are discussed when addressing specific properties, but the common range is about 1–100 nm.

Properties of nanoscale materials often differ from bulk materials due to a high surface area to volume ratio, quantum confinement, and other size-related effects. These factors can lead to changes in optical, electronic, magnetic, mechanical, and chemical behavior. For example, quantum dots exhibit size-dependent color, and metal nanoparticles can show plasmonic resonances tied to their size and shape.

Nanoscale phenomena are studied with a range of techniques such as transmission and scanning electron microscopy, atomic force microscopy, and light scattering and spectroscopy. The field distinguishes objects by size and structure, including nanoparticles, nanorods, nanotubes, nanosheets, and broader nanosystems.

Fabrication methods are generally grouped into bottom-up approaches (chemical synthesis, self-assembly, templating) and top-down approaches (lithography, mechanical milling). Applications span medicine (targeted drug delivery and imaging), energy (batteries, photovoltaics), electronics and sensing, catalysis, coatings, and advanced materials.

Safety and regulation address potential biological and environmental risks, lifecycle considerations, and standardization for measurement and reporting. Nanoscale science and engineering integrates chemistry, physics, materials science, and engineering to exploit size-dependent phenomena and enable new technologies.