Semiconductor nanocrystals (NCs) are of great interest for their tunable electronic and optical properties. Traditional colloidal synthesis produces NCs capped with long hydrocarbon chains which complicate their applications in electronic and optoelectronic devices such as solar cells, photodetectors, transistors and thermoelectric heat-to-electricity converters. Our group has developed inorganic surface ligands that include molecular metal chalcogenide (MCC) and metal-free chalcogenide ligands. These small inorganic molecules provide stabilization of NCs in colloidal solutions while not blocking the electronic communication in the layers of close-packed NCs. We will discuss the utility of inorganic surface ligands for various practical applications of colloidal semiconductor NCs. Our recent developments include the synthesis of novel functional MCC ligands and inorganically-capped III-V semiconductor NCs with high electron mobility.We also used inorganic surface ligands as active elements for design of novel functional materials and composites. For example, the combinations of colloidal NCs with MCC ligands were used as soluble precursors for CuInSe2 (CIS) and Cu2ZnSn(S,Se)4 (CZTS) films for thin-film photovoltaics. The combinations of Bi or Bi2S3 NCs capped with Sb2Te74- MCC ligands allowed obtaining nanostructured Bi2-xSbxTe3 phase with high thermoelectric figure of merit. Similar approach was applied to Bi1-xSbx NCs for design of low-temperature thermoelectric materials. These and other examples demonstrate general utility of inorganic surface ligands for applications of semiconductor nanomaterials as solution-processed semiconductors for a broad range of practical applications.

Design of solution-processed semiconductors from colloidal nanocrystals for photovoltaics and thermoelectrics

246th National Meeting (2013)

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