Scaleable High-Yield Plasma Production of Functionalized Semiconductor Nanocrystals

Research under this grant focuses on developing a scalable high-yield, gas-phase process for creating surface-passivated or functionalized silicon nanocrystals for their luminescent properties. The approach will be based on a nonthermal plasma for the synthesis of nanocrystals. Studies will be performed to enable the synthesis of nanocrystals that are smaller than currently possible in order to achieve silicon nanocrystal luminescence that spans the entire range of the visible spectrum. Approaches to be pursued will include reducing agglomeration, avoiding particle fusion, and possibly gas-phase in-flight etching of larger particles. The second thrust of this grant is the development of gas-phase methods for surface passivation with inorganic layers in order to protect them from environmental attack, and surface functionalization through self-assembly of organic monolayers. Both efforts will converge into the development of a high-throughput, gas-phase process for luminescent silicon crystals.

The process to be developed under this grant may enable a wide range of optoelectronic applications of silicon nanocrystals. These nanocrystals are widely studied for applications in nanoparticle-based solar cells, as primary light emitters or phosphors in more energy-efficient solid state light sources, and as light emitters in optoelectronic devices for communication purposes. Compared to many other quantum dot materials, which may have excellent optical properties but contain toxic heavy metals, silicon is known as a non-toxic and environmentally benign material. The planned development of a large-scale integrated synthesis and surface passivation process for silicon nanocrystals will enable wide-spread application of silicon nanocrystal technology. A strong industrial outreach component of this grant will assure rapid adoption of research findings by industry.