This grant supports research that advances knowledge to manufacture systems such as high efficiency solar cells, affordable photovoltaics, flexible color displays and biosensors more quickly, less expensively and free of the lead that results from more traditional manufacturing approaches. Lead-free metal halide perovskite nanocrystals emit light from the ultraviolet to the visible. Their wide use is dependent on the development of techniques for their scalable, low cost manufacturing. They are also candidates for replacement of lead-based perovskites, which are toxic. Most methods to manufacture perovskite nanocrystals are based on single batch approach, which has limited production capacity and considerable product variability. Research here will support a continuous manufacturing process. The ability to manufacture semiconductor nanocrystals in microfluidic-microreactor systems enables their fabrication with the desired size, shape and properties, thus, accelerating their applications in a variety of industries. The successful development of a scalable method to manufacture high-quality lead-free halide perovskite nanocrystals enables the development of continuously manufactured lead-free metal halide perovskite nanocrystals that leads to progress in the fundamental science of inorganic semiconductors. The results from this research help maintain and enhance U.S. competitiveness and leadership in these technologies, thus contributing to the nation's prosperity. The multidisciplinary nature of this research prepares the needed future workforce for U.S. industries with knowledge and skills in advanced materials and manufacturing. Special efforts are focused on the participation and training of women and under-represented minorities.
Using microfluidic-microreactor systems can overcome the difficulty in controlling the processing parameters, such as, temperature, time and local concentration for the fabrication of perovskite nanocrystals in the single batch methods and offer a possible approach to manufacture them with very short reaction time and high throughput. The lack of an understanding of the thermodynamics and kinetics controlling the formation and growth of nanocrystals in a fluidic system has hindered the development of microfluidic-microreactor systems to produce monodispersed nanocrystals of the same geometrical shapes. This research is to develop a polytetrafluoroethylene-based microreactor in a microfluidic system with in-line monitoring for continuous fabrication of metal halide perovskite nanocrystals and to investigate the fundamental mechanisms controlling their formation and growth. The research team establishes correlations between the processing parameters, such as, concentration, temperature, residence time and flow rate, and perovskite nanocrystal characteristics, such as, morphology and size. The team develops numerical models that can quantitatively analyze the growth of semiconductor nanocrystals in the microreactor system. These correlations provide fundamental understanding of the kinetics controlling the size distribution and morphologies of nanocrystals and help optimize the microreactor design for the scalable manufacturing of high-quality perovskite nanocrystals.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
