Continuous Synthesis of Multilayered Indium-Based Nanoparticles in a Novel Two-Reactor Configuration

Semiconductor nanoparticles find use in a variety of applications - light emitting diodes (LED), photovoltaics, biological imaging agents, and optical memory elements due to the ability to tune their electronic properties based on size, aspect ratio and chemical composition. They can be synthesized in a variety of morphologies including quantum dots, nanorods, nanowires, tetrapods etc. Different morphologies have unique properties that depend on shape and size of the nanoparticles.

Conventionally, quantum dots are synthesized on a batch scale. However, batch syntheses suffer through various challenges including slow mixing, loading and unloading times as well as discontinuities between batches resulting in non-uniform reproducibility. Furthermore, achieving a tight control on particle size is hampered by slow heating and mixing times on batch scale. In order to tackle these obstacles, an in-house high throughput continuous flow reactor was designed. Through a novel, two-reactor configuration, the production of semiconductor nanoparticles can be scaled up to volumes as high as 10 mL/min. These millifluidic flow reactors enable good mixing of reactants, rapid heating/cooling times, and increased quantum yields of up to 60%.

Indium-based nanoparticles are specifically chosen as the chemistry of interest. These nanoparticles are less toxic than Cadmium-based nanoparticles. Furthermore Indium-based nanoparticles are known to have outstanding optical properties, particularly low scattering tunable bandwidth, high brightness, and are widely applicable in solar cells, LEDs, and electronic devices.