Size-tunable and scalable synthesis of uniform copper nanocrystals

Synthesizing Cu nanocrystals with tunable sizes in the sub-100 nm regime and good uniformity is essential for their applications in microelectronics. In this paper, we demonstrate a facile and scalable synthetic route to uniform Cu nanocrystals with tunable sizes in the range of 20-100 nm based on an ethylene glycol (EG)-assisted synthetic method with appropriate alkylamine and fatty acid as surfactant and co-surfactant, respectively. In this approach, the size of Cu nanocrystals could be readily controlled by varying alkyl chain length of alkylamine, fatty acid, or both. We also demonstrate that these Cu nanocrystals can be successfully applied to the fabrication of solution-processed electrodes for organic field-effect transistors with reasonably high hole mobility.