Capabilities to create, modify, functionalize, and utilize novel new nanomaterials with lower carbon footprints are the keys to revolutionizing the development landscapes of many of their applications. These include optoelectronics (sensors, photodetectors, quantum information) and energy devices (solar cells, thermoelectrics, batteries and supercapacitors). However, in some specific limit, one should realize that these nanomaterials are quantum objects with different properties when treated as individuals or when they exist collectively, forming ensembles. These properties are obviously different from their bulk materials. This talk will highlight the developments of various kinds of solution-processable nanomaterials (i.e. semiconducting colloidal nanocrystals and carbon nanomaterials), which their individual and collective properties can be controlled with different implications for their device applications. Among the examples that will be elaborated are the use of semiconducting quantum dots, individually or collectively, for novel quantum transistor devices; the assembly of semiconducting quantum dots as giant atoms to form more extensive superstructures, in which their electrical properties can be modulated to behave like a metal; and the implications on their optical properties. Furthermore, novel quantum nanomaterials that can be created only through colloidal synthesis will be shown. Understanding and controlling the properties of these nanomaterials will be fundamental for mineral downstream efforts and the technological developments based on them.

References:

• R. D. Septianto, R. Miranti, T. Kikitsu, T. Hikima, D. Hashizume, N. Matsushita, Y. Iwasa, S. Z. Bisri. “Enabling Metallic Behaviour in Two-Dimensional Superlattice of Semiconductor Colloidal Quantum Dots”. Nature Communications, 14, 2670 (2023).
• R. Miranti, R. D. Septianto, T. Kikitsu, D. Hashizume, N. Matsushita, Y. Iwasa, S. Z. Bisri. “π-SnS colloidal nanocrystals with size-dependent band gaps”. The Journal of Physical Chemistry C 126, 5323 (2022).
• L. Liu, R. D. Septianto, S. Z. Bisri, Y. Ishida, T. Aida, Y. Iwasa. “Evidence of band filling in PbS colloidal quantum dot square superstructures”. Nanoscale 13, 14001 (2021).
• R. D. Septianto, L. Liu, F. Iskandar, N. Matsushita, Y. Iwasa, S. Z. Bisri. “On-demand tuning of charge accumulation and carrier mobility in quantum dot solids for electron transport and energy storage devices”. NPG Asia Materials 12, 33 (2020).
• R. Miranti, D. Shin, R. D. Septianto, M. Ibanez, M. V. Kovalenko, N. Matsushita, Y. Iwasa, S. Z. Bisri. “Exclusive electron transport in core@ shell PbTe@ PbS colloidal semiconductor Nanocrystal Assemblies”. ACS Nano 14, 3242-3250 (2020).