Current RESEARCH interestS


Our current interest lies in Physics Motivated Sustainable Functional Materials and Technologies. Given below is a brief description of work in my research group:

(I) Fundamental Research

(A) Graphene Oxide and related systems as sustainable functional materials:

Background: Graphene oxide (GO), a monolayer sheet of graphite oxide, is a wonder material that has tremendous application potential. Primarily, it serves as a precursor for making reduced graphene oxide (rGO) which has superlative properties close to graphene in addition to the benefit of scalable synthesis. Besides this, the remarkable physical and chemical properties of GO makes it a highly sought after material for applications in a wide variety of areas including electronics, biomedicine, energy and environment.GO has promising biological applications demonstrated at laboratory scale which include drug delivery, antibacterial coatings, photo-thermal cancer therapy, and selective differentiation of mesenchymal and neuronal stem cells. Key environmental applications of GO include contaminant adsorption, water decontamination, solar desalination and environmental sensing. GO also finds niche applications in areas including tribology and energy storage. GO has been shown to be a highly flexible nanomaterial with a high stiffness. However, realizing all this in practice hinges on developing a safe, economic and scalable method for making GO.
[Students: Pranay Ranjan (Graduated), Apurva Sinha, Shirleen; Collaborators: Dr. T. Rajagopala Rao, Dr. S. K. Samanta, Dr. A. K. Chakraborty, Dr. J. Balakrishnan]

Our Key Contributions:
(a) Demonstration of a non-explosive, scalable technique for inexpensive high yield synthesis of GO. [npg link1]
(b) Elucidate the potential of GO based Photovoltaic devices. [npg link] [Elsevier link]
(c) GO and rGO for dye adsorption and separation of a mixture of cationic dyes. [Elsevier link1] [Elsevier link2]
(d) Sensing capabilities of GO and rGO. [Springer link] [AIP link]
(e) Origin and Nature of Magnetism in GO and related systems. [in progress]

(B) Thermoelectric Materials based on Oxides and their nano-composites:

Background: Thermoelectric (TE) materials help convert waste heat into useful electric power. In addition, the compact structure of TE devices are attractive for noise free refrigeration, e.g., in critical healthcare applications. Besides these there exist a host of other niche applications including power sources for deep space expedition. The utility of a TE material is evaluated using a dimensionless quantity called figure of merit, zT (= S2σ/κT ), where S is Seebeck coefficient, σ is electrical conductivity and κ is thermal conductivity which consists of electronic part of thermal conductivity and lattice part of thermal conductivity. Bi2Te3, PbTe and related materials have been found to exhibit excellent TE properties. However, these materials are toxic and undergo degradation at high temperatures limiting their large scale applications. In this context, complex oxide materials present themselves as viable alternative materials which are chemically inert and thermally stable. However, the known complex oxide materials are found to have very small S and a correspondingly a small zT.  Due to interesting interplay between charge, orbital and spin degrees of freedom in these materials, its physical properties can be tuned. This provides an opportunity to explore complex oxide materials with different compositions with a promise of finding an ideal TE candidate. Besides this, the use of Physics motivated strategies at nanoscale, there is huge promise for bulk nanostructured TE materials (viz., TE nanocomposites). The experimental work in our group is inspired by fundamental theoretical ideas propounded by the research groups of: (a) S. Maekawa  on the importance of spin state degeneracies in determining thermopower, and (ii) L. D. Hicks and M. S. Dresselhaus on the  role of quantum well structures in enhancing thermopower. [Students: Ashutosh Kumar (Graduated), Shantanu; Collaborators: Dr. D. Sivaprahsam, Prof. C. V. Tomy]

Our Key Contributions:
(a) Improving thermoelectric properties of lanthanum cobaltate via suitable co-substitution. [Elsevier link]
(b) Manganite-Cobaltate composite route to improved thermoelectic behavior. [Elsevier link]
(c) Magnetic field induced tuning of thermal transport poperties in Cobaltates. [IoP Science Link]
(d) Composite of Cobaltates with different carrier densities for improved thermoelectric properties. [IoP Science link]
(e)Colossal Thermopower in 3D superlattices based on Oxides. [in progress]

(C) Theoretical and Experimental Studies in Cu2ZnSnS4 (CZTS) Solar Cells:

Background: Despite tremendous promise due to their earth abundant ingredients and solution processable material preparation, the solar cell family based on Cu2SnZnS4 (CZTS) absorber materials suffers key challenges impacting its efficiency and eventual deployment. At the outset the physical origin of these challenges needs to be understood.  We are addressing some of these concerns in our lab. [Students: Atul Kumar]

Our Key Contributions:
(a) Role of Contact Work Function, Back Surface Field and Conduction Band Offset in CZTS Solar Cell. [IoP Science link]
(b) Improving Opto-electrical Properties of CZTS using suitable Nano-compositing Strategies. [Springer link]
(c) Comprehensive Loss Modeling in CZTS Solar Cells: I-V characteristics as a simple probe of loss mechanisms. [Elsevier Link]



Technology Development Research

In the following technology development works, we are trying to provide necessary Physics based interventions in key ongoing developmental projects in the Engineering Departments both at IIT Patna and elsewhere.

(A) Nano-materials for Disrupting Protein Aggregation in Neuro-Physicological Diseases
Background: Aggregation of certain proteins in brain cells leads to a number of neuro-physicological diseases, e.g., the aggregation of α-Synuclein in substancia nigra leads to Parkinson's syndrome, the aggreegation of β-Amyloid in neurons leads to Alzheimer diseases. A lot of international effort is trying to address this problem via development of nano-materials to arrest the aggregation of these specific proteins. Toxicity and size (to cross the blood-brain barrier) are crucial issues in this search. We are working on development of bio-compatible nano-materials for the purpose. [Students: Apurva Sinha; Collaborator: Prof. Ashutosh Mishra (IIT Bombay)]

(B) Developing Off-grid Atmospheric Water Harvesting System:


Background: We are working on the design and development of an all-season optimal atmospheric water harvester having a cooling power requirement of 3 Ton/10 kW with a flexibility for both grid based and off-grid operations. Due to constantly depleting ground water resources and industrial contamination of water bodies, shortage of reliable supplies of fresh water is a looming crisis across the world; mitigating it is therefore a global challenge. An increasing water demand for cities, industrial plants, agriculture and for the extraction of fossil fuels are straining an already burdened system. Nearly 1 billion people lack access to safe drinking water and sanitation due to lack of availability of clean water. Furthermore, the development of efficient modular water generation systems for rural, urban, tribal, national security, and disaster response scenario is highly desirable. Airborne moisture is a source of plentiful amount of freshwater that is accessible everywhere and can be harvested with a suitable off-grid energy source (biomass, solar energy, etc). Production of practically useful quantity of freshwater under a wide range of weather conditions and in an energy-efficient manner is therefore a very exciting research problem. In past, methods including radiative cooling, sorption-based water harvesting and solar distillation have been extensively studied. However, these studies lacked on crucial fronts including issues related to all weather condition operation, scalability and efficient system integration. We are also working towards developing robust and safe superhydrophobic coatings through environmental friendly approaches for the purpose.  Developing a scalable, cost-effective way to produce atmospheric water with all weather condition operation for the community is the prime goal of this work. [Students: Bathina Chaitanya, Sunil, Rabindranath Sarangi; Collaborator: Dr. Rishi Raj, Dr. V. Bahadur; Industry Partner: Shri Anurag Agarwal (New Leaf Dynamic Technologies Pvt. Ltd.)]
Link to Engineering Department Colleagues Homepage

Our Key Contributions:
(a) A Survey on Scope of Biomass Gasification Based Atmospheric Water Harvesting in India. [Elsevier link]
(b)Robust and safe superhydrophobic coating through environmental friendly approach. [Ongoing]

(C) Developing Biomass Gasification Based Off-grid Cold Storage System:

Background: We have developed a Novel Biomass-Gasification Based Hot Water Generation System (under the aegis of Ucchatar Aavishkar Yojana (UAY), Govt. of India) to run the Ammonia-CaCl2 cycle of the existing product GreenCHILLTM  of New Leaf Dynamic Technologies Pvt. Ltd. (our Industry partner). This has lead to the development of one of its kind Biomass-Gasification based Cold Storage System for preserving Farm products. We are working on further development of the climate control chamber so as to extend the ambit of this application (under IMPRINT-II).  [Students: Sunil, Rahul, Bathina Chaitanya, Birendra K. Rajan; Collaborator: Dr. Rishi Raj, Sri Anurag Agrawal, Dr. V. Bahadur]
Link to Engineering Department Colleagues Homepage

Our Key Contributions:
(a) Design, Fabrication and Performance Evaluation of a Novel Biomass-Gasification Based Hot Water Generation System. [Elsevier link]

(D) Developing Microrobotic Setup for Cell Manipulation:

Background: We are working on the design and development of magnetically actuated microbot for Cell manipulation applications. [Students: Dharamveer, Kishan, Pranav, Aditya, Akash, Shivam; Collaborator: Dr. Atul Thakur]
Link to Engineering Department Colleagues Homepage


 Our Key Contributions:
(a) Automated Non-prehensile Micromanipulation [ASME link]
(b) Single Cell Manipulation [In progress]

key RESEARCH contributions in past


  • Improving Thermoelectric Performance Metrics in several Chalcogenide Materials: We have studied a number of chalcogenide material systems for their thermoelectric properties and have explored ways to enhance their figure of merit in both polycrystalline and single crystal samples. [Springer link] [Science Direct link] [Elsevier link]
  • Pinning Mechanism in Iron Based Superconductors: We demonstrated  the existence of delta-l pinning mechanism in Fe-based superconductors. [link1]   [link2]
  • Vortex Matter in Thin Films with Nano-Engineered Disorder: We have explored the nature of vortex lattice matching phenomena in nano-engineered thin films of superconductors.[link]
  • Vortex Lattice Spinodal:We demonstrated a contact-less technique to determine the vortex lattice spinodal using third harmonic ac susceptibility. [link]
  • Modulation in state of partial order of vortex matter: We investigated the healing of transient disordered vortex states injected into a superconducting sample during the field ramping process in isothermal M-H measurements as a prescription to comprehend the modulation in the state of order of the underlying equilibrium vortex state in weakly pinned single crystals of a wide variety of superconductors. [link]
  • Role of Quenched Random Disorder on Vortex Phase Diagram: We explored the presence of a two-peak feature spanning the peak effect (PE) region in the ac susceptibility data and the magnetization hysteresis measurements over a wide fieldtemperature regime in weakly pinned single crystals of 2H-NbSe2 with different degrees of quenched random disorder. [link]

 

COLLABORATORS (Present and Past)



  • T. Rajagopala Rao (IIT Patna)
  • S. K. Samanta (IIT Patna)


LINKS

 

projects implemented at IIT Patna

 

Sl

Project Title

PI Name

Co-PI Name

Amount

Status

Date of Start

Date of Completion

Funding Agency

1 CZTS based flexible solar cells Ajay D. Thakur A. K. Thakur 14.16 Lakh Completed 09-May-2014 08-May-2015 SRIRU, CEE IIT Patna
2 Design and Development of an Agricultural Waste Based Gasifier Heating System for GreenCHILLTM Dr. Rishi Raj Dr. Ajay D. Thakur 95.07 Lakh Completed 17-Aug-2016 16-Aug-2018 MHRD, SERB and Industry UAY
3 Spin transport in 2D material/perovskites (LSMO) heterostructures Dr. Jayakumar Balakrishnan Dr. Ajay D. Thakur 31.79 Lakh Completed 08-Jun-2016 07-Jun-2019 DST Nanomission
4 Development of an agricultural waste based off-the-grid climate control unit for storage and processing of agricultural produce Dr. Rishi Raj Dr. Ajay D. Thakur 98.35 Lakh Ongoing 22-Feb-2019 21-Feb-2022 IMPRINT-II