Rapid advances in nanotechnology have generated enormous expectations for applications. There is growing recognition that the rapid progress towards nanotechnologies risks stagnation unless challenges concerning scalable manufacturing and device integration are resolved. To address these challenges, this project aims to resolve roadblocks impeding progress in the field of nanoparticle technologies by developing the first large-scale, solution-phase synthesis of high-quality nanoparticles, and demonstrate their integration into devices. This work will represent a step-change in the approach to realize nanoparticle-based technologies by manufacturable approaches. The key is the use of a reactive precursor that had previously only been available for aqueous-phase synthesis. The PIs will first demonstrate this technique through production of metal sulfides. The method is applicable for a large variety of monodisperse metal sulfide nanoparticles, such as Cu2S, CdS, SnS, ZnS, MnS, Ag2S, Bi2S3, and CuInS2, and will be extended into other material systems (e.g., phosphides). This will benefit the application of semiconductor and semi-metal colloidal nanocrystals in high-tech devices. The Intellectual Merits of the project include: 1) The method is a low temperature, air-stable synthesis, with high conversion yields, enabling low production cost and integration into temperature-sensitive processes; 2) Development of kilogram-quantity batch production of high-quality nanoparticles with narrow distribution in size and composition, without the need for downstream refining processes; 3) Development of continuous synthesis of nanoparticles with <5% dispersion in size; 4) Scalable integration of nanoparticles into Li-ion battery and solar photovoltaic devices; 5).Establishment of principles for a novel nanomanufacturing process for devices by integrating electrophoretic deposition methods pioneered by the PIs, into continuous flow reactors; 6) Integration of nanoparticle synthesis with continuous surface treatments to passivate electronic traps critical for high-performance nanoparticle photovoltaics; and 7) Produce nanoparticle-coated large area, non-planar substrates, through assembly-line nanoparticle deposition.
This work will demonstrate a nanomanufacturing process with high potential to scale to economically and industrially relevant production levels. The inexpensive reactants used enable industrial scale, economic production. Scalable nanomanufacturing of metal sulfides will be impactful for batteries, solar cells, thermoelectrics, and catalysis. Additionally, metal sulfide nanoparticles provide a non-toxic alternative to popular metal chalcogenide systems. The Project's research will be closely integrated with an outreach and education program aimed to enhance a widespread understanding of nanoscience and nanotechnology. The outreach and education activities leverage the existing NSF-sponsored GK-12 program to work with high school teachers during the summer. The PIs have designed a workshop for the teachers that involves an initial survey about their perception of the opportunities, risk and hypes related to emerging nanotechnologies, a hands-on experience in the laboratory in creating nanotechnology prototypes, and a follow up assessment. Teachers will refine educational models about nanoscience for their classroom curriculum.
