Colloidal semiconductor nanocrystals, known as quantum dots (QDs), have emerged as novel materials for applications such as biological sensing and imaging to LED displays and solar energy harvesting. The new system can be used to continuously manufacture high-quality QDs for use in these applications.
Based on the NanoRobo microfluidic platform the researchers unveiled two years ago, the Nanocrystal (NC) Factory as the authors call it starts with cesium lead bromide perovskite quantum dots and introduces various halide salts to precisely tune their fluorescence color across the entire spectrum of visible light.
Anions in these salts replace the bromine atoms in the green-emitting dots with either iodine atoms (to move toward the red end of the spectrum) or chlorine atoms (to move toward blue).
"Because the NC Factory can precisely control both chemical composition and processing parameters, it can be used to continuously manufacture perovskite quantum dots in any color with the highest quality," explains corresponding author Milad Abolhasani.
The NC Factory system consists of three "plug and play" modules. The researchers developed a pre-mixing module to expedite the mixing of halide salts and quantum dots, in order to improve product quality. The system also incorporates a velocity sensor that allows users to monitor reaction times accurately. The synthesized QDs are then monitored in situ using the NanoRobo process-monitoring module.