Collaborative Research: Continuous Manufacturing of Hetero-Nanostructures Enabled by Colloidal Atomic Layer Deposition

Cadmium selenide nanoplatelets are attractive materials for next generation, energy efficient displays and solid-state lighting devices. The synthesis of high-quality nanoplatelets is a multi-step process that is difficult to study and scale up using conventional approaches. This award supports collaborative research to develop a continuous manufacturing strategy that consistently produces highly efficient nanoplatelets. The projected strategy utilizes a layer-by-layer growth process that enables cost-effective synthesis of the high-performance nanomaterials. The project contributes to fundamental knowledge of the nanoplatelet growth process, the requirements of flow synthesis methods, and determine nanoplatelet structure through photoluminescence-performance relationships. If successful, the research could reduce the energy consumption of displays and solid-state lighting devices produced by mid to large-scale U.S. companies, and thereby benefit the nation's prosperity, health, and security. This collaborative research project involves integration of several fields including colloidal synthesis, reaction and chemical engineering, and materials science. This grant trains graduate and undergraduate students in the continuous manufacture of advanced materials. Additionally, the multi-disciplinary nature of this project facilitates participation of women and underrepresented groups in research and greatly impacts engineering education through hands-on experiments for undergraduate students. Furthermore, the YouTube is used to disseminate the acquired advanced manufacturing knowledge to a broader audience.

The continuous flow manufacturing process based on the colloidal atomic layer deposition (ALD) technique for synthesis of high-quality nanoplatelets is highly modular and versatile. Continuous flow manufacturing has the potential to overcome the current limitations of the batch scale production of emissive nanomaterials. However, some key scientific questions need to be thoroughly explored to realize the continuous manufacturing of semiconductor nanoplatelets using the colloidal ALD process. This research project develops the fundamental knowledge required for each step of the layer-by-layer growth process for nanomaterial synthesis. The continuous flow synthesis process is capable of synthesizing and purifying colloidal nanoplatelet heterostructures using a linear sequence of multiple reactor modules. The nanoplatelets manufactured in continuous flow are composed of a graded alloy emissive layer and several passivating shell layers engineered for solid-state lighting and micro-display applications. Continuous flow reactor design, a library of novel synthesis precursors, and in-line liquid-liquid phase separation technique enable unprecedented process intensification in advanced manufacturing of colloidal nanoplatelets. The novel continuous manufacturing process utilizing intensified flow reactors paves the way for in-flow manufacturing of other colloidal 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.