(7dm) Solution Processable Multicomponent Nanomaterial for Next Generation Transparent Electronic/Optoelectronic Devices

Multicomponent nanomaterials combine several chemical compositions, crystal structures, and/or morphologies into a single hybrid nanocomposite structure. The “hybrid” nature of such systems extends beyond the physical description of the material components to their functionality. In such architectures, it is possible to design a single structure for multiple functionalities (optical, plasmonic, magnetic), as well as to design for new amplified functionality, where one component modifies the behavior of the other. Such systems bring many potential opportunities to the field of nanostructured materials. Their incorporation into functional devices can present challenges. In particular, interface engineering (structure and quality) in these multicomponent nanomaterials often holds the key to device performance. My vision for this research direction is to develop a novel combinatorial approach to solution-processable inorganic multicomponent nanomaterials as a new route to the complex physical properties required for efficient transparent electronic/optoelectronic devices. In particular, I plan to experimentally observe correlations between material synthesis (doping crystal structure, morphology) and structural (defects and interface) properties/device performance. The proposed research ideas will not only result in the development of multicomponent/nanocomposite materials that can address varying problems from electrode materials to opto-electronic devices, but will also provide fundamental understanding towards structure, morphology, dopants and the role of interfaces in surface functionality.

My PhD thesis and post-doctoral work focused on the development of novel synthetic routes and macroscale assembly for semiconductor nanocrystals (NC). A versatile colloidal approach was developed to synthesize both simple binary semiconductors NCs and more complex compound semiconductor NCs [Cu₂ZnSnS₄, CuInGaS₂, CdSe/CdS/ZnO, Sn/F-In₂O₃, etc.], with tight control of shape, size and crystal phase. Specifically, I developed a synthesis in which the shape (spherical, rod, cube, octahedral etc.), doping, and crystal structure (stable and metastable phases) of the NCs are precisely controlled by reaction conditions – the culmination of this work was the synthetic achievement of the hexagonal wurtzite phase in alloyed copper chalcogenide (CIGS and CZTS), which is a metastable structure for these materials. Annealing of these metastable NC precursor films not only enabled growth of micron size grains, but did so at much lower temperatures (325-400° C) than traditional processing. This work uncovered a simple process to make large grain high quality thin films of compound semiconductors from nanocrystals using solution processing. This synthesis path not only reduces the cost and temperature requirement from an industrial prospective, but also contributes new understanding to the semiconductor thin film community.

In the current project, I am trying to elucidate, at the atomic scale, the nature of the core-shell interface that is buried within the nanostructure of core-shell nanocrystal. These observations will provide unparalleled insight into structural and interface properties of core/shell nanocrystals. The findings will also be highly useful for the application of these materials to the solid-state lighting industry. Furthermore, I am interested in developing a new type of optical nanomaterial, namely, novel plasmonic metal oxides. I plan to explore their potential to dramatically enhance the light-emitting properties of traditional semiconducting nanomaterials used in high-efficiency solid-state lighting and as single-photon sources for quantum communication/computing devices. The plasmonic metal oxides could also serve as a new material for transparent conducting electrodes. My poster will highlight the key aspects of my research along with an outline of future projects.

Teaching Interests: Materials, Electronics