Nanotechnology is vital to many current industries, including
electronics,
energy, textiles, agriculture, and theranostics. Understanding the
chemical mechanisms of nanomaterial synthesis has contributed to the
tunability of their unique properties, although studies frequently
overlook the potential impact of impurities. Impurities can show adverse
effects, clouding the interpretation of results or limiting the practical
utility of the nanomaterial. On the other hand, as successful doping
has demonstrated, the intentional introduction of impurities can be
a powerful tool for enhancing the properties of a nanomaterial. This
Review examines the complex role of impurities, unintentionally or
intentionally added, during nanoscale synthesis and their effects
on the performance and usefulness of the most common classes of nanomaterials:
nanocarbons, noble metal and metal oxide nanoparticles, semiconductor
quantum dots, thermoelectrics, and perovskites.