The synthesis of PbS nanocrystal and their self-assembly into complex nanowire and nanocube structure

Date
2011
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Publisher
University of Delaware
Abstract
For the last 50 years, bulk lead-chalcogenide semiconductors have been key materials for infrared light sources and lasers, photodetectors and highperformance thermoelectrics. Meanwhile, the colloidal synthesis of chalcogenide semiconductor nanocrystals has provided a new pathway to producing optoelectronic materials with unique physical properties at low cost, including lead-chalcogenide nanocrystals. In this thesis, we synthesized various sizes of lead salt nancrystals that exhibit remarkable photoluminescence efficiencies across the near infrared region at room-temperature, which can be appealing active material for light emitting devices, photovoltaic devices, and bio-imaging. Meanwhile, we developed the catalyst-free self-attachment of PbS nanowires in hot colloidal solution using a combination of multiple surfactants. We demonstrate the controllable self-attachment of star-shaped nanocrystals can lead to radically-branched nanowires while the assembly of octahedral nanocrystals leads to zigzag nanowires. The synthesized nanowires exhibit strong position dependent quantum confinement, which occurs at the side arms and high faceted edges of the nanowires. Those novel structures give rise to the appealing optical properties of the nanowires, with strong photoluminescence in the near infrared region.
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Keywords
Nanowire
Citation