“Designing multifunctional materials for an efficient optical, electrical, magnetic, energy storage, photovoltaic and biological applications”
Functional Materials Research Laboratory (FMRL) was established in June 2021 at Sri Sairam Engineering College, Chennai to promote innovation and to build up Functional Materials. Functional materials are a group of engineered and advanced materials such as Molecular crystals, Semiconductors, Polymers and Nanomaterials that are synthesized and designed for some unique function with tailor-made properties. The research on their characterization will give significant contribution for future technologies.
Therefore our research work mainly focuses on the Crystal growth, Nanomaterials, Thermoelectric, Photovoltaics, Ceramics, Polymers, Optical materials, Magnetic materials, Mechanical shock wave treatment and Biomaterials.
The FMRL centre gains more consideration due to its diverse field of research with large volume of publications in functional materials. The Prime Goal of FMRL is to develop unique materials for various optical, electronic and magnetic devices.
What is this? Furnaces are used to provide continuous heating to process samples and materials. They are generally built from carbide steel material so that they can maintain high temperatures without breaking down. Research furnaces are mainly used to study the structural nature of the materials at variable temperature.
Specifications: Temperature: 1200 ºC, Maintained environment, Programmable control panel, 16 segment
Research Focus: Preparation of Inorganic compounds, Heat treatment process on various nanocomposite and bone materials.
What is this? It is used in the Process of applying sound energy through an ultrasonic bath or an ultrasonic probe to agitate particles in a sample material. It is used in academic, clinical and forensic laboratories that need to disintegrate cells, bacteria, spores or tissue.
Specification: Operated up to 60 ºC, 230 V, 15 Amps.
Research Focus: Prepared Nanomaterials can be dispersed in to well defined particles which will be highly helpful in taking SEM/TEM photographs. It is also useful in the synthesis of nanocomposites.
What is this? A fume cupboard is a ventilation apparatus designed to remove hazardous or toxic vapors, fumes, and dusts outside the laboratory. This type of laboratory equipment is designed to protect workers or researchers from inhaling toxic gases while protecting the product or the experiment.
Specification: 18 Inches height, 2 exhaust fan motors.
Research Use: It is used in synthesizing organic and inorganic crystals, perovskites, nanocomposite. It is also used in temperature dependent synthesis and reflux processes.
Constant Temperature Bath with cooling
What is this? Constant temperature bath (CTB) is used to perform certain chemical reactions which occur at high temperature. It is highly preferred to use for flammable chemicals in order to prevent ignition.
Specification: Temperature range from 20 to 60 ºC, Temperature controller and in/out water circulation.
Research Use: For the growth of single crystals, constant temperature should be maintained throughout its growth period. Temperature uniformity in and around the mother solution is more important in crystal growth to avoid secondary nucleation. By using CTB, slow evaporation as well as slow cooling process can be applied for the growth of crystals.
What is this? : The Hydrothermal Autoclave is used for hydrothermal reaction process at high pressure and high temperature. It is Polytetrafluoroethylene (PTFE) or Teflon lined hydrothermal autoclave. It consists of two parts; outer high-quality stainless steel jacket and inner Teflon liner or Teflon chamber. In the Teflon-lined autoclave, the reaction is carried out at maximum 240 ºC. However the safe temperature is 200 ºC. This apparatus is widely used in the scientific laboratory, research and development labs, quality analysis section in industries and institutional organizations.
Specification: Operating temperature: ≤ 240 °C, Safe temperature limit: 200 °C, Pressure: ≤ 3 MPa, Heating/Cooling Rate: ≤5 °C/min.
Research Use: It is used to synthesize Inorganic Nanomaterials and Magnetic powders. It is also used in various low temperature heat treatment processes.
Research Activities: We are actively working on various research fields such as Crystallography, Crystal growth, Nanomaterials, Spectroscopy and DFT calculations, Thermal kinetics approaches and Biomaterials for the development of advanced functional materials and their potential use.
The ORTEP molecular structure of the Thiourea Silver (I) Nitrate crystalline compound, showing displacement ellipsoids drawn at 30% probability level. H atoms are removed for structure clarity.
We are synthesizing Organic and Inorganic crystalline materials at FMRL centre using solution process, mechanochemical synthesis method and solid state reactions. Synthesized materials are purified by repeated recrystallization processes and are subjected to single crystal X-ray diffraction study. The collected diffracted data will be analyzed and solved the crystal structure solved by directed methods (SHELXL-97) and refined by a full matrix (SHELXL-97) least square procedure.
Growth of single crystals is considered to be the pillars of advanced technology. “Who dominated, materials dominated technology”. To expedite research interest in crystal growth, it demands deep knowledge of science and technology since single crystals have vital importance in the technological world. Crystal growth never has an independent individuality and is the part of crystallography until few centuries back.
Many single crystals play vital role in important areas of service to the humanity, namely science, medicine, engineering, technology, defence and space science. In addition to above, crystals are mainly used in piezoelectric, photo-refractive, acousto-optic, electro-optic, photo-elastic applications. Crystals also have importance in radiation detectors, transducers, laser hosts, harmonic generators, parametric amplifiers, Bragg cells, etc. Thus the above mentioned developments could be achieved only by the availability of single crystals like silicon, germanium, gallium, gallium arsenide and growth of new nonlinear optical organic, inorganic and semi-organic single crystals.
Solution Grown single crystals grown at FMRL Laboratory
Solution growth is a simple, cost advantage method for the production of technologically important single crystals. It is the most widely used technique for the growth of crystals, when the starting materials are unstable at high temperatures. This method mainly depends on the solubility of solute on the thermodynamical conditions like temperature, pressure and solvent concentration. Hence, this method is adopted for the materials having moderate to high solubility in the temperature range from RT to 100 °C at atmospheric pressure. Bulk sized single crystals having high solubility with respect to the temperature, can be grown from solution growth.
Cut-Polished (a) LaFeO3 and (b) LaSrFeO3 Single Crystals using optical floatingzone method
Melt growth is the process of crystallization of fusion and resolidification of the pure material from a melt by cooling the liquid below its freezing point. In this technique, apart from possible contamination from crucible materials and surrounding atmosphere, no impurities are introduced in the growth process and the rate or growth is normally much higher than possible by other methods. Melt growth is commercially the most important method of crystal growth.
(a & b) development of LaFeO3 nanoparticles on rGO layers in 5 µm scale and
(c & d) spherical morphology of LaFeO3 nanoparticles on rGO layers in 2 µm scale
Nanotechnology is the general term for designing and making materials which depends on specific structure at the nanoscale (100 nm or less). It includes devices or systems made by manipulating individual atoms or molecules, as well as materials which contain very small structures. They may be in the form of particles, tubes, rods or fibers. The materials in the form of nano scale shows improved physico-chemical properties than that are in the in the bulk form.
Spectroscopy and DFT Calculations
Spectroscopy is a potential tool for studying the structures of atoms and molecules. The large number of wavelengths emitted by these systems makes it possible to inspect their structures in detail, including the electron configurations of ground and various excited states. Spectroscopy also provides a precise analytical method for finding the constituents in material having unknown chemical composition. In a typical spectroscopic analysis, concentration of a few parts per million of a trace element in a material can be detected through its spectrum.
Density functional theory (DFT) is a quantum-mechanical (QM) computational method used in chemistry and physics to calculate the electronic structure of atoms, molecules and solids. The real forte of DFT is its favourable price/performance ratio compared with electron-correlated wave function-based methods such as Møller–Plesset perturbation theory or coupled cluster. Thus, more relevant molecular systems can be studied with sufficient accuracy, thereby expanding the predictive power inherent in electronic structure theory. As a result, DFT is now by far the most widely used electronic structure method. The huge importance of DFT in physics and chemistry is evidenced by the 1998 award of the Nobel Prize to Walter Kohn ‘for his development of the density-functional theory’.
Thermal kinetics Approaches
(a) TG, (b) DTG and (c) DTA curves of Phenyl derivative molecule at different heating rates (5, 10 and 15 ºC min-1).
Methods of thermal analysis and their kinetic models are most widely used in almost all the branches, from foods and pharmacy to materials, glasses and polymers where changes in thermal activities of the sample are monitored under different temperature conditions like controlled heating and cooling atmospheres. We are focusing research work on the thermal kinetic studies to understand the fundamental characteristics of materials as well as their large range of utility in quality control, improvement and research in industry and academia.
SEM Photographs of human bones sintered at different temperatures ranging from 250 to 750 ºC.
Bone is a composite of proteins such as collagen and minerals such as calcium. Together these materials give bone a unique combination of strength and elasticity. We at FMRL centre studying the effect of temperature on human bone in order to understand their structure, porosity, strength, thermal stability and mechanical stabilities.