Dr. Indranath Chakraborty's research interest is mostly centered on advancing the understanding and control of atomically precise materials for life. When particle sizes are shrunk below 2 nm, their properties change drastically due to the quantum effect. These ultrasmall nanoparticles, often called nanoclusters (NCs), show unique molecule-like optical properties, distinctly different from corresponding plasmonic metal NPs (Ag and Au). He has immensely contributed to this atomically precise nanocluster field by developing many new methods, newly synthesized nanoclusters, their exciting properties, and structure-properties correlations.

 

Manipulating atoms in materials has always been of great interest to the scientific community, particularly on a molecular level where manipulation can yield new materials with exciting properties. They can be made reproducibly with robust synthetic protocols, resulting in colored solutions, yielding powders, or diffractive crystals. They have unique molecule-like optical properties, distinctly different from corresponding plasmonic metal nanoparticles. He has developed several new synthesis protocols to design atomically precise pieces of material, such as high-temperature route and sunlight-mediated route, and created a wide variety of nanoclusters of different atomicity such as Ag55(SR)31, Ag152(SR)60, Ag44(SeR)30, etc. He has also investigated exciting properties of these emerging nanomaterials, such as SERS, inter-particle reactions, H-bond driven-assembly, sensing, and antibacterial activities. Recently he started exploring structure-property correlations to address the open questions on the origin of the photoluminescence of metal NCs.

 

Nanomaterials have been used in many applications, including catalysis, due to their high surface areas. However, most such studies focused on ensemble-based analysis, which might mask the dynamics of each single nanoparticle. Bimetallic nanostructures (NSs), with utility in catalysis, are typically prepared using galvanic exchange (GE), but the dynamics of the process dictate the final catalyst morphology. He has developed an In-situ single nanoparticle (NP) optical scattering spectroscopy, coupled with ex-situ electron microscopy-based methods to capture the dynamic structural evolution of a bimetallic NS formed in a GE reaction between Ag and [PtCl6]2−. Spectroscopy is an excellent tool for observing changes in nanoparticle surfaces in real-time. He has also contributed to understanding the metal (inorganic)-ligand (organic) interfaces and how that helps control particle sizes and shapes. Understanding inorganic-organic interfacial chemistry helps him develop an excellent catalyst for hydrogen evolution reactions and nanozymes.

 

He has contributed to developing novel methods to create biopolymer-protected particles of different sizes and shapes with reduced cytotoxicity and investigated their interaction with biological systems. study on nanoparticle-cell interaction through spectroscopy, microscopy, and mass spectrometry helps understand the bio-degradation pathway, one of the major issues for NP-based drug delivery.

​