Precision control over semiconductor nanocrystals' organization into size-tunable superstructures broadens the horizon for optoelectronic and biomedical applications
Semiconductor nanocrystals (NCs) possess the intriguing capability to self-assemble into a variety of NC-superstructures. These organized formations can take shapes from 1D, 2D, to 3D, each carrying unique characteristics. Their potential utility in lighting, optoelectronics, and biomedical sensing has been recognized, although the fabrication of uniformly distributed and size-controlled 3D superstructures or supraparticles (SPs) has remained a challenge.
In a new development, the application of microfluidic template-assisted self-assembly method has made it possible to synthesize monodisperse and size-adjustable CsPbBr3 supraparticles. Microfluidic synthesis, with its enhanced mass and thermal transport, facilitates meticulous control over the reaction and flow conditions. The use of a droplet-based microfluidic reactor enables the production of monodisperse CsPbBr3 SPs, allowing precise control over SP size.
By adjusting the nanocrystal concentration and droplet size, the average supraparticle size can be precisely controlled. This method has been successful in creating highly monodisperse, sub-micron supraparticles with diameters ranging from 280 to 700 nm. The microfluidic templating approach also ensures size tuneability over the entire visible spectrum and guarantees low polydispersity in droplet size, directly leading to supraparticles with a narrow size distribution. The resulting supraparticles are composed of intact nanocrystals that arrange themselves into a distorted simple cubic lattice.
This approach, leveraging microfluidic synthesis and templating, has significantly advanced the ability to control the self-assembly of nanocrystals into superstructures. As a result, it holds great promise for advancements in light-emitting devices, nanoscale sensors, and biomedical imaging applications.
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