In SEMANTICS, we create various solutions-processable nanomaterials, particularly colloidal quantum dots, and develop different optoelectronic, energy harvesting and energy storage devices. We are curious to study the quantum confinement effect in different kinds of compounds when we make them into nanometer objects. They will show unique properties different from their bulk materials so that we can utilize them in new applications. From a different perspective, creating such nanoscale objects with different properties also means making artificial giant atoms. We can assemble these giant atoms to form superlattices and become new solid-state materials from which novel properties can emerge.
SEMANTICS performs interdisciplinary research that spans from the chemistry of material synthesis, intensive investigation of the physical properties, and the engineering of new optoelectronic and energy harvesting devices. At the heart of our research, we are exploring possibilities to find more sustainable ways to create and utilize the finite resources of materials. Also, we want to find solutions for creating a low carbon footprint society by providing alternative ways to harvest and store energy and reduce its consumption by exploiting quantum nanomaterial properties.
Development of novel sustainable nanoparticles and quantum dots
Colloidal quantum dots as giant atoms is one of the keywords of our research. Through colloidal synthesis, we can mix two or more chemical precursors to let them react and grow to become nanocrystals. By optimizing various parameters surrounding the colloidal synthesis, we can control the size and shape of the nanocrystals so that they will exhibit quantum confinement phenomena and behave as quantum dots. These inorganic nanocrystals will be protected by organic molecular ligands that provide them solubility in various solvents. Furthermore, colloidal synthesis can sometimes create nanocrystal compounds whose crystal structures are challenging to find in their natural and bulk material forms. It will allow us to discover new materials with new properties. Currently, our primary interest is establishing various new nanocrystals from abundant sources with minimal carbon footprints.
Electrical transport in colloidal quantum dot assemblies and the other solution-processable nanomaterials
For many optoelectronic, energy harvesting and energy storage devices, electronic transport is one of the most critical parameters. So far, it is still the main bottleneck for using colloidal quantum dot assemblies in those practical applications. Until now, many of the theoretical prospects of this class of materials (for solar cells, thermoelectric, etc.) have not been ultimately materialized due to the mediocre charge transport from one quantum dot to another. Therefore, using various tools, our group intensively investigates the relationship between the structure of the quantum dot assemblies and the related charge transport properties. Building field-effect transistors of these quantum dots is among the essential tools to investigate their charge carrier transport properties. For this purpose, we also develop a technique that utilizes the so-called electric double-layer transistor, in which electrolytes control the number of charges that flow within the assembly of the quantum dots. These techniques are also helpful in exploring potential applications of the materials for different kinds of devices based on transistors, including sensors.
Novel energy storage devices
Energy harvesting devices
Iontronics: Ion-Controlled Electronics