Department of
Chemistry

Angshuman Nag completed his Master of Science in Chemistry from IIT Guwahati in 2003, and obtained his PhD from IISc Bangalore in 2009. He then completed two terms as postdoctoral researcher at IISc Bangalore and at the University of Chicago. In 2012, he started his own research group at IISER Pune as a Ramanujan Fellow. Presently, he is an Associate Professor.

Research

Optoelectronic properties of perovskite semiconductors and quantum dots

Developing novel semiconductors for optoelectronic properties is the main focus of research in Dr. Angshuman Nag’s group. Thermodynamics create intrinsic defects in a crystal. Additionally, nanocrystals have surface defects. The major contribution of their group is in rational design of semiconductor nanocrystals, microcrystals, and centimeter-sized single crystals to eliminate the detrimental effects of defects. They have shown that manipulation of energy levels of surface defects in lead halide perovskite nanocrystals yields efficient optoelectronic properties that are unprecedented for any other semiconductor nanocrystals. They have made important contributions in developing lead-free metal halide nanocrystals like Cs3Sb2I9, Cs3Bi2I9, and TlX (X = Br, I). Another way of defect manipulation is doping. They dope different nanocrystals to achieve new functionalities like luminescence (visible to near infrared), infrared plasmonic, and free carrier mediated magnetic interactions. Major research topics of their group are: (i) colloidal CsPbX3 (X = Cl, Br, I) perovskite nanocrystals, (ii) Pb-free metal halide perovskite for optoelectronics, (iii) optical properties of centimeter sized single crystals of 2D layered perovskites, (iv) doping semiconductors for luminescence, plasmonic and magnetism, and (v) surface engineering of nanocrystals for better charge transport.

Selected Publications

Arfin, H. and Nag, A. 2021. Origin of Luminescence in Sb3+- and Bi3+-Doped Cs2SnCl6 Perovskites: Excited State Relaxation and Spin−Orbit Coupling. J. Phys. Chem. Lett., 12, 10002−10008.

Sheikh, T.; Nawale, V.; Pathoor, N.; Phadnis, C.; Mandal, P. and Nag, A. 2021. Introducing Intermolecular Cation-π Interactions for Water-Stable Low Dimensional Hybrid Lead Halide Perovskites. Angew. Chem. Int.l Ed., 60, 18265–18271

Ravi, V. K.; Saikia, S.; Yadav, S.; Nawale, V. and Nag, A. 2020. CsPbBr3/ZnS Core/Shell Type Nanocrystals for Enhancing Luminescence Lifetime and Water Stability. ACS Energy Lett., 5, 1794−1796.

Sheikh, T.; Nawale, V.; Pathoor, N.; Phadnis, C.; Chowdhury, A. and Nag, A. 2020. Molecular Intercalation and Electronic Two Dimensionality in Layered Hybrid Perovskites. Angew. Chem. Int. Ed., 59, 11653–11659.

Arfin, H.; Kaur, J.; Sheikh, T. ; Chakraborty, S. and Nag, A. 2020. Bi3+-Er3+ and Bi3+-Yb3+ Codoped Cs2AgInCl6 Double Perovskite Near Infrared Emitters. Angew. Chem. Int. Ed., 59, 11307–11311.

Sheikh, T.; Shinde, S.; Mahamuni, S. and Nag, A. 2018. Possible Dual Bandgap in (C4H9NH3)2PbI4 Layered Perovskite: Single Crystal and Exfoliated Few-Layer. ACS Energy Lett., 3, 2940−2946.

Mir, W. J.; Mahor, Y.; Lohar, A.; Jagadeeswararao, M.; Das, S.; Mahamuni, S. and Nag, A. 2018. Postsynthesis Doping of Mn and Yb into CsPbX3 (X = Cl, Br, or I) Perovskite Nanocrystals for Downconversion Emission. Chem. Mater., 30, 8170−8178.

Pal, J.; Manna, S.; Mondal, A.; Das, S.; Adarsh, K. V. and Nag, A. 2017. Colloidal Synthesis and Photophysics of M3Sb2I9 (M=Cs and Rb) Nanocrystals: Lead-Free Perovskites. Angew. Chem. Int. Ed., 56, 14187–14191.

Mir, W. J.; Warankar, A.; Acharya, A.; Mandal, P. and Nag, A. 2017. Colloidal Thallium Halide Nanocrystals with Reasonable Luminescence, Carrier Mobility and Diffusion Length. Chem. Sci., 8, 4602–4611.

Swarnkar, A.; Chulliyil, R.; Ravi, V. K.; Irfanullah, M.; Chowdhury, A.; Nag, A. 2015. Colloidal CsPbBr3 Perovskite Nanocrystals: Luminescence Beyond Traditional Quantum Dots. Angew. Chem. Int. Ed. 54, 15424 –15428