A Guest Lecture was organized by the Department of Chemistry on 14th March, 2023, from 10:30 am to 12:30 pm, in Dr. M V Jayaraman Auditorium, on the topic ‘SOLID STATE CHEMISTRY AND MULTIFUNCTIONAL MATERIALS FOR ENERGY AND ENVIRONMENT SUSTAINABILITY AND BIOSENROS’, by Prof. C. Shivakumara, Principle Research Scientist, Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru.
The event was presided over by Hon’ble Principal, MVJCE, Dr. P. Mahavaleshwarappa. HOD of the Chemistry department and all the faculty members from the Departments of Chemistry and English attended the Lecture.
All First year students from all branches of the chemistry cycle attended the Guest Lecture.
Ms. Faazna, 1st year student from J-section, introduced the Speaker to the students. The event started with a prayer song by Atulya, Laya M and Kavana T S. Chaitra, 1st year student from J-section, gave an introduction about the guest lecture to the audience.
Hon’ble Principal Dr. P. Mahavaleshwarappa gave a talk on the relevance of the Lecture topic, and pointed out that it will be very useful for the students to enhance their knowledge and skills. He said that the Lecture will inspire the students to take up scientific challenges and work towards finding solutions that will not only enhance their subject knowledge but also help to secure internships in reputed institutions, which in turn will lead them to take up research.
Prof. C. Shivakumara then began his Lecture on the topic ‘Solid state chemistry and multifunctional materials for energy and environment sustainability and biosensors’, at 10:45 am. He began with an introduction to solid state/materials chemistry. He explained that solid state or materials chemistry deals with the synthesis, structure, properties and applications of materials. Traditional chemistry deals with the study of molecules, whereas solid state chemistry primarily involves the study of extended solids. Unit cell is the basic unit in solid state chemistry, while it is molecules in traditional chemistry. With the help of periodic table, Prof. Shivakumara explained the three states of mater, i.e., solid, liquid and gaseous states. He further went on to give insight on which elements are available as solids at room temperature, what are their properties, and how they react with other elements in the periodic table to form solid state materials which can be used in various engineering applications.
Prof. Shivakumara gave a historical perspective of the development of materials chemistry/solid state chemistry. Materials are probably more deep-seated in our culture than most of us realize. Materials are the substances of which something is composed or made of. Every segment of our everyday lives is influenced by materials – materials are used in transportation, building, clothing, communications, entertainment, datastore, cookware, and practically every aspect of our life is connected to materials chemistry.
The idea of this talk was to look at the materials/gadgets we use everyday from a materials chemistry point of view, i.e., how those materials are developed, why those materials are used for those specific application,s and what is the chemistry behind the properties of those materials. From this point of view, we should understand the relation between materials science and materials engineering. Materials science is a major scientific discipline which is primarily concerned with the research for basic knowledge about materials, i.e., structure, properties and processing of materials. Materials engineering is primarily concerned with using the applied knowledge about the materials. i.e., how to convert the materials into usable products. In this regard, materials are broadly classified into metals, ceramics, polymers and composites. Professor Shivakumara gave a detailed picture of the structure, properties and applications of these materials.
Prof. Shivakumara explained about different types of solids, crystalline solids and amorphous solids, and elucidated the difference between these two. The use of different materials characterization techniques like the X-ray diffraction methods and electron density graphs were shown. The principles involved in these techniques were introduced, for the understanding of the students.
There are several classes of materials like oxides, nitrides, sulphides, graphene or carbon based compounds etc. Professor Shivakumara explained about the formation ability of oxides verses nitrides, in relation to their dissociation energies. He described the properties of materials having a general formula ABX3, and how properties of these materials can be engineered to make products which have numerous applications in all walks of life.
Prof. Shivakumara mainly focused on oxides. He is working on polycrystalline materials, single crystal materials, and also on thin films, in the field of oxide materials. All these materials have unique properties and applications in various fields. Still, there is a lot of scope for fine tunning the properties of these materials for enhancing the properties, and thus their engineering applications.
Prof. Shivakumara then went on to talk about the various stages of materials development, which includes materials synthesis, characterization, study of their properties, and optimizing the synthesis parameters and properties.These phases of materials development involve the use of various characterization techniques and collaboration with various departments, and thus this is a multidisciplinary area.
For the benefit of students and aspiring researchers, the Professor gave an introduction about the various open source software tools which can be utilized in the characterization of synthesized materials. These open source software tools include Fullprof suite program/GSAS, Diamond/VESTA softwares for the Rietveld refinement of X-ray spectra. Other characterization techniques like electron microscopic techniques like SEM, TEM, AFM, STM etc were also presented. For the characterization of electronic materials, different methods of electrical resistivity measurements like 4-probe and 2-probe techniques were explained. Resistivity verses temperature measurements, and its connection to the development of superconductors and room temperature superconductors were also explained. Measurement of magnetic properties of materials and magnetic data interpretation using Curie-law and Curie-Weiss law were presented. The differences between hard and soft magnets were illustrated. The Professor also suggested some standard reference books for the benefit of students and researchers.
Prof. Shivakumara threw light on Graphene and different carbon materials like graphite, graphene, reduced graphene oxides, CNTs and Fullerenes. Identification and characterization of different carbon materials using Raman spectroscopy, STM, and SEM was also presented. He went on to talk about multifunctional materials, their impact on sustainability and their potential applications as biosensors. Innovative advanced materials make a direct and positive impact on economic growth, the environment, and quality of life. They allow for improved processes and products, and create several avenues to increasing sustainability. Multifunctional materials have impact on several areas like reducing environmental effects, increasing efficiency of processes, lightening the weight of products, lowering power consumption, reducing system cost, reducing complexity, increasing safety, increasing fuel flexibility, increasing versatility etc.
The Professor also touched on the different methods adopted for the synthesis of the multifunctional materials. Synthesis and applications of luminescent materials as biosensors and phosphors was explained. Methods adopted to increase the luminescence efficiency were discussed. The role of host material structure, activator elements and sensitizers was explained. Applications of phosphors or luminescent materials in the development of white LEDs were discussed in detail with the help of chromaticity diagrams.
Prof. C. Shivakumara has doen extensive research on phosphors. As an example for phosophers, he spoke about synthesis, properties, crystal structure, characterization and applications of phosphors materials having general formula MWO4, where M stands for Ca, Sr, Ba, and Pb. Methods of synthesis include precipitation method and co-precipitation method. The advantages and limitations of these methods were explained in detail by comparing these methods with other methods of synthesis like sol-gel, CVD, PVD, molten salt, and solid-state method. The phosphor nature of the synthesized materials was explained using chromaticity diagrams and the role of dopant elements in developing LEDs of desired color. The photocatalytic activities of some of these multifunctional materials were highlighted. The kinetics of materials photocatalytic activities in degrading methylene blue, Rhodamine orange, methyl orange explained using Langmuir-Hinshelwood formula.
Prof. Shivakumara later explained the synthesis of multifunctional materials with the general formula MWO4 by sol-gel combustion method and compared its advantages and limitations with other methods of synthesis. Application of these materials as photoluminescence materials was presented.
He concluded his talk at 12:30 pm, after which there was a Question and Answer session.
Vote of thanks was proposed by Ms. Faaza, J-section student.
Outcomes of the Guest Lecture:
Students understood the different methods of nanomaterials synthesis, as well as the advantages, limitations and suitability for different applications, of each method.
They understood characterization methods like powder XRD (including Rietveld refinement of XRD data), FT-IR, SEM, TEM, AFM, STM, Raman spectroscopy, magnetic measurements and PL.
They understood characterization methods like powder XRD (including Rietveld refinement of XRD data), FT-IR, SEM, TEM, AFM, STM, Raman spectroscopy, magnetic measurements and PL.