Atomically precise nanoclusters (NCs) of noble metals with core dimension ˂3 nm are an emerging class of quantum materials connecting the gap between atoms and bulk metallic particles. Different noble metal based NCs, especially of gold, silver, copper and platinum, protected by various types of surface ligands such as thiols, imine-thiols, phosphines, alkynes, sulfonates, DNAs, proteins, etc., have been synthesized by following different synthetic protocols. Various physicochemical properties of these materials, such as narrow energy gap and associated multiple electronic transitions, luminescence, chirality, etc., have been used in numerous fields including optoelectronics, nanosensors, nonlinear optics, circularly polarized luminescence, and nanocluster sensitized solar cells, etc. Understanding atomic arrangements of the materials is of contemporary research interest to correlates structure with properties. This seminar will give an overview of monolayer protected metallic nanoclusters, their synthesis, purification, characterization, crystallization and various applications.
Surface ligands have a profound role in controlling the nuclearity of the nanocluster as well as their properties. We have synthesized a bidentate 2-pyrene imine thiol protected Ag35 nanocluster. The nanocluster is the first pyrene-protected dual emitting silver nanocluster. Next, we will discussed structural understanding of meta-carborane thiol (a twelve vertex nearly icosahedral boron and carbon framework) protected hexagonal-propeller like Ag21 molecule. Femtosecond and nanosecond transient absorption (fs ns-TA) proved the reason behind their molecular like multiple electronic transition and large stokes shift of 355 nm of the nanocluster. In the last, we will present the light-activated intercluster conversion of atomically precise silver nanocluster and associated their associated optical properties.
References:
(1) Jin, R.; Zeng, C.; Zhou, M.; Chen, Y. Atomically Precise Colloidal Metal Nanoclusters and Nanoparticles : Fundamentals and Opportunities. Chem. Rev. 2016, 116, 10346–10413.
(2) Chakraborty, I.; Pradeep, T. Atomically Precise Clusters of Noble Metals : Emerging Link between Atoms and Nanoparticles. Chem. Rev. 2017, 117, 8208–8271.
(3) Kang, X.; Zhu, M. Tailoring the Photoluminescence of Atomically Precise Nanoclusters. Chem. Soc. Rev. 2019, 48, 2422–2457.
(4) Kang, X.; Chong, H.; Zhu, M. Au25(SR)18: The Captain of the Great Nanocluster Ship. Nanoscale 2018, 10, 10758–10834.