Research

Our current research interest lies in the development of novel materials through the assembly of functional nanoscale building blocks. Our group has recently explored nanomaterial synthesis, self-assembly, and electronic studies of the nanocrystal arrays.

We have developed a generalized synthetic methodology for combining inorganic nanocrystals and nanowires with molecular metal chalcogenide (MCC) ligands.  This has turned colloidal nanocrystals into a versatile class of electronic materials, offering new directions for solution processed light-emitting, photovoltaic, and thermoelectric devices. We also reported self-assembly of nanocrystals into long-range ordered superlattices with aperiodic quasicrystalline packing.

Single- and multicomponent nanocrystal assemblies provide a powerful general platform for designing programmable solids with tailored electronic, magnetic, and optical properties. Unlike atomic and molecular crystals where atoms, lattice geometry, and interatomic distances are fixed entities, nanocrystal arrays represent ensembles of “designer atoms” with potential for tuning their electronic structure and transport properties [Prospects of NCs for Electronics & Optoelectronics (Review)]. Generally speaking, nanocrystal assemblies can be considered as a novel type of condensed matter whose behavior depends both on the properties of the individual building blocks and on the many-body exchange interactions.

Our research program combines chemical synthesis [Soluble Precursors for CIS/CIGS/CZTS with MCC-Capped NCs, Inorganically-Functionalized PbS-CdS NCs, Tuning Excitonic & Plasmonic Copper Chalcogenide NCs, Alkyl Chains Affect Anisotropic Growth of CdSe, Expanding Chemical Versitility of MCC Ligands, Antimony Telluride Zintl Ions for Nanostructured ThermoelectricsGold/Iron Oxide Core/Hollow Shell NCs, Quasi-Seeded Growth of PbSe NCs] with self-assembly [Structural Defects in BSNLs, Interlocked Octapods (Review), 3D NC Superlattices in Microfluidics, NC Superlattices with Thermally-Degradable Ligands, Energetic & Entropic Contributions to BNSL Self-Assembly, Size-Dependent Multiple Twinning in NC Superlattices, Quasicrystalline BNSLs] and nanocrystal assembly electronic characterization [All-Inorganic NC Transistors, Band-Like Transport in All-Inorganic NC Arrays, Magnet-in-Semiconductor Nanostructures, High Mobility of MCC-Capped CdSe, Colloidal NCs with MCC Ligands, Chemiluminescence of Transition-Metal NCs, Energy Transfer in NC-DNA-Dye Conjugates]

We explore the chemistry and physics governing self-assembly of nanocrystals into long-range ordered superlattices and develop novel chemical strategies for strengthening the electronic coupling between chemically synthesized nanocrystals. The latter is necessary for efficient charge transport and, ideally, can lead to the formation of collective electronic states (minibands) in the nanocrystal superlattices.

These highlights represent a unified focus of our group in development of novel functional materials. The ability to assemble precisely engineered nano-building blocks into complex, hybrid structures is opening the door to a new generation of complex materials where components and functionalities can be added, tuned or combined in a predictable manner. Our interdisciplinary approach, deeply rooted in synthetic chemistry and materials science, addresses both fundamental scientific problems and real-world challenges. New materials developed by our research group will be a source of rich chemistry and physics and has the potential to make an impact in electronics, photovoltaics, thermoelectrics, and solid-state lighting.