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

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.

Connecting Academic R&D with Product Innovation: A few case studies and a way forward

India's contribution to the world's R&D and Intellectual Property is steadily increasing. In certain specialized areas such as Nanotechnology, India is among the top 3 countries in the world in terms of research publications and patent filings. Despite the low percentage of GDP spending for R&D in India, Indian researchers have excelled in research output, when measured in terms of the number of research publications. Though these are excellent achievements, the situation is entirely different when one looks at the innovation or the product development potential in the country. For example, India ranks very poorly on the Global Innovation Index (GII), and the research undertaken by Indian academic institutions, whether public or private, has hardly resulted in any major technological breakthrough of significant commercial value.
Given this scenario, in order to make the Indian research competitive and sustainable in terms of innovation and product development, a multitude of initiatives have recently been contemplated and launched by the Govt. of India at the national level. In this talk, we will discuss the changing scenario for product innovation in Indian academic and R&D institutions, and also see how one can accelerate the culture of product innovation in the country through a multi-disciplinary approach.

Curiosity, Serendipity and Logicality in Organic Synthesis

Many important scientific discoveries, which actually changed the world, were accidentally observed and established later. Organic Synthesis is no exception and in fact, serendipity and organic synthesis go hand in hand since the early stage of chemical synthesis.1 Many medicines, artificial sweeteners, polymers have been discovered serendipitously and are very well documented in textbooks. Several reactions like, Birch reduction, Friedel-Crafts, Hetero Diels-Alder, Wittig reaction have all been discovered accidentally and benefited the synthetic community in a huge way. In this lecture, some of our serendipitous observations leading to the synthesis of natural products and some pharmaceutically important heterocycles will be discussed in detail.2,3 Our logical efforts leading to the first enantioselective formal synthesis of (-)-vinigrol usinga novel [1,2,3,4] transformation comprising of a domino enyne metathesis/IMDA sequence4 will also be discussed.

Nanoparticles with atomic precision

Research in the recent past has resulted in a large number of nanoparticles whose properties depend on the number and spatial arrangement of their constituent atoms. This distinct atom-dependence of properties is particularly noticeable in ligand protected atomically precise clusters of noble metals. They behave indeed likemolecules. They show unusual properties such as luminescence in the visible and near-infrared regions. Their molecule-like behavior is most elegantly shown by atom and structure conserving chemical reactions between them. Several clusters, which are archetypal nanoparticles, Ag25(SR)18 and Au25(SR)18 (-SR = alkyl/aryl thiolate) have been used for such reactions. Despite their geometric robustness and electronic stability, reactions between them in solution at room temperature produce alloysAgmAun(SR)18 (m+n=25), keeping their M25(SR)18 composition, structure and topology intact. We captured one of the earliest events of the process, namely the formation of the dianionic adduct, [Ag25Au25(SR)36]2-, by electrospray ionization mass spectrometry. Molecular docking simulations and density functional theory (DFT) calculations also suggest that metal atom exchanges could occur through the formation of adducts. Such isomorphous transformations between nanoparticles imply that microscopic pieces of matter can be transformed completely to chemically different entities, preserving their structures, at least in the nanometric regime.Intercluster interactions can also produce cluster dimers and unusual, well-defined alloys.They reflect the shell structure of certain reactants. Atom exchanges suggest interesting dynamics in solution, early results of these investigations will be presented. New experiments in this subject area confirm the fascinating chemical diversity possible in such systems. They are shown to exhibit properties useful for applications.

Key references
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Excitations and plasmons : A tale of two elementary excitations and their interaction