Doctoral Thesis Title:
“Electrical and Photoelectrical Properties of ZnO Nanowire Films by Defect Manipulation and Surface Functionalization”
Institute: Indian Institute of Technology Bombay (IIT-Bombay), Powai, Mumbai-400076, India.
Advisor: Prof. M. Aslam,
Master Thesis Title:
“Study of DC Conductivity in a-Se90Ge10-xInx Thin Films”
Institute: Christ Church College Kanpur, (CSJM University), Kanpur-208026, India.
Advisor: Prof. Santosh Kumar
Nanomaterials Synthesis, Photovoltaic device, Photoelectrochemical water splitting
(A) Nanomaterials Design, Growth and Fabrication of Devices
(I) Design and Growth of Nanomaterials:
Fundamental properties of nanomaterials depend on their shape, size, structural geometry and surface functionalities, which are well documented in literature. A wide range of control on material characteristics can be successfully achieved, that will be very unique from their bulk counter parts and capable to open further opportunity to apply the old materials in many new applications. The more efficient devices could be realized by designing suitable nanomaterials as per specific requirement. One of our research interest belongs to this category, in which we would like to develop new synthesis techniques and process to grow various nanostructures in large scale. We are focused on design and growth of nanostructures of ZnO, TiO2, SnO2, CuO, Fe2O3, CZTS, Au, Ag, Graphene,Graphene Quantum dots and 2-D materials. Further, our interests are to explore the effect of surface modification, functionalizations and nanostructures design on optical and electrical properties of nanostructures. Moreover, we wish to apply these nanostructures to fabricate optoelectronic devices, gas sensors and optical detectors.
(II) Defects in Semiconductors and Optoelectronics Properties:
We are interested in exploring the effect of surface modification, functionalizations and nanostructures design on defects states of various metal-oxide/semiconducting nanostructrues. The impact of surface functionalization and modification on optical and electrical properties of nanostructures and optoelectronic devices is one of the focus area of our group research.
(III) Electrodeposition and Electrochemical Sensors:
Deposition of metal oxides and/or metals nanostructures film and investigations of their electrochemical/photoelectrochemcial properties. Development of thin films/micro sized electrochemical sensors for detections of chemical species.
(IV) 2-D Materials Based Electronic Devices:
Fabrication of Graphene/Graphene-Oxide based Transitor/FET (MOS) devices, specially interested in exploring the world of M-xenes for electronic devices and sensor applications.
(B) Energy Conversion Devices
(I) Solar Energy Harvesting Using Earth Abundant Materials:
Solar driven water splitting for hydrogen production: Photoelectrochemical (PEC) water splitting is an ecofriendly and safer process to generate hydrogen and have good potential to resolve energy challenges by producing an environmental friendly fuel. Hybrid/composite and core-shell nanostructures have shown better performance for water splitting. Our group research is focused in this direction and we are exploring various earth abundant materials to develop photoelectrodes. The CuO, Cu2O nanostructures, α-Fe2O3, graphene quantum dots, CZTS nano-crystal are few examples, to apply in PEC water splitting. The aim of our research is to harvest the wide solar spectrum in whole UV to NIR wavelength range. While, most of the research were focused on only visible light harvesting, which is not an efficient way to convert solar energy into chemical fuel, as near-IR spectra consist ~ 50% energy of solar light. Therefore, we are directed to harvest this component of light either by designing nano-junction between wide bandgap materials with low bandgap materials (which have absorption in near-IR range) or with materials having photo upconversion properties.
Quantum dot sensitized/ thin film solar cell: The similar strategies, as planned for PEC electrodes, could be also applied to fabricate quantum dot sensitized solid state solar cell as in case of PEC electrode fabrication. More specifically, CZTS Quantum Dots (QDs)/ Graphene QDs and semiconducting ODs would be used as active material for excitons generation and metal oxide nanowire films or graphene electrode as electron/hole collector. Additionally, we are studying the effect of surface passivation and functionalization of metal oxide nanostructures on solar cell performance. We are aiming to develop all-oxide based solar cell using fully solution processed techniques.
(II) Mechanical Energy Harvesting:
The waste mechanical energy can be utilized to generate electrical energy by applying peizoelectrical process. Vibrations or stress can be used as the sources of mechanical energy. We are interested in developing piezoelectrical materials to harvest waste mechnical energy. ZnO has shown excellent piezoelectric properties and its 1-D structures will be very beneficial to design and fabricate the energy harvesting devices.
(C) Energy Efficient Coatings
(I) Electrochromic Devices:
Electrochromic devices can switch their transparency by applying an electrical field and can be designed to modulate visible light, near-IR and microwave for multiple applications. Electrochromic devices can be used in three different functionalities such as displays, mirrors, and smart window. The visible and NIR light active electrochromic glasses can be used to design energy efficient buildings to reduce the energy consumption. Such kind of electrochromic glasses are commonly known as smart glass or smart windows. The high cost of smart glasses is mainly restricting their use in day to day applications; thus, we aim to develop wet-chemical process to deposit the electrode and electrochromic materials at low cost in larger scale.
(II) Multifunctional Coatings:
The coating for multifunctional application is another area of interest. We investigate the anti-fouling, anti-static, scratch resistance, self-healing, self-cleaning properties, photocatalytic and super-hydrophobic/hydrophilic, phosphorescent coatings using inorganic materials. We are interested in developing solution based coating process to achieve multi-functionality in metal oxide films. Mixed metal oxide, doped metal oxide or metal decorated metal oxide coatings with tailored morphology and dimensionality are being considered for multi-functional coatings.