J.N. Tata Chair Lecture by Prof. D D Sarma in Faculty Hall @ 4pm

Location: Faculty Hall

Title : A new generation of miraculous photovoltaic materials: Organic-inorganic hybrid perovskites

Abstract :

The multifarious energy crisis in all its diverse manifestations is a much-discussed topic today. Its impact on environmental, health, and technological spheres is a source of much debate, great concern and tremendous efforts. Many innovative solutions are being sought in the entire landscape connected with energy, starting from sourcing the basic materials, generation or conversion, storage, transmission, monitoring and utilisation. With such a deep level of world-wide effort, it is likely that we are at a cusp in the history of modern human civilisation and may see over the next several decades a qualitative shift coming in the paradigms connected with one or the other aspect of energy. In this sense, it is one of the most exciting time to be involved in energy research.

Within the sub-area of energy generation, utilisation of the abundant solar energy has been a recurring theme over the last several decades, with steady improvements in the technology making it viable and widely accepted across the globe; consequently, much hope and policy decisions have been pinned on it. This field has recently seen an unexpected entry in the form a new generation of photovoltaic materials: Organic-inorganic hybrid perovskites. It has been recently discovered that this class of materials based on organic-inorganic hybrid methyl ammonium (MA) lead halides (MAPbX3, with X = I, Br, and Cl) compounds can have extraordinary photovoltaic properties, with efficiencies reaching beyond 22%. The efficiency of PV devices based on this class of materials has grown from year to year at a rate that is an order of magnitude faster than any other in the history of photovoltaics. In addition, these materials also have many other attractive features, such as solution processability. While a large part of the international effort is aimed at further improving the efficiency or to improve other technological aspects, such as the stability or to replace toxic Pb, there is also an intense effort in understanding the intrinsic properties of these compounds. Curiously enough, there does not appear to be any universally accepted understanding of even the most basic properties of these materials.

I shall discuss some of these issues, with an emphasis to underline the cause of the excitement in the field and the open issues that challenge our understanding.

About the Speaker :

D. D. Sarma obtained a 5-year Intergrated MSc degree in Physics from Indian Institute of Technology, Kanpur in 1977 and a Ph.D. Degree in 1982 from Indian Institute of Science (IISc), Bangalore. He worked in Kernforschungsanlage, Jülich, Germany, as a Visiting Scientist during 1984-1986. Since 1986, he has been a faculty member at Solid State and Structural Chemistry Unit of IISc. His research interest spans the science of strongly correlated electron systems, primarily based on transition metal compounds, and semiconductor nanocrystals using a wide range of experimental as well as theoretical tools. He has published more than 450 scientific papers and holds several patents. He is an elected Fellow of all three Science Academies and the Engineering Academy in India, The World Academy of Sciences (TWAS) and American Physical Society. He has received many national and international awards and recognitions, including multiple Honoris Causa Doctorate degrees. He is also a Senior Editor of ACS Energy Letters. Further details can be found on his group webpage (http://sscu.iisc.ac.in/people/DDSarma/).