Photovoltaic|Projects
Our work is mainly focused on solar cells, which directly converts sunlight into electricity without consuming any other resources. Our main objective is to develop novel techniques of synthesis and deposition of materials for solar cell applications in order to improve the competitiveness for large-scale production.
Our objective is to develop technology and processes in order to fabricate high efficiency thin-film solar cells at low-cost for large-scale applications.
To achieve these goals we focus our research on different main projects:
Synthesis processes: To develop non-vacuum synthesis methods, which simplifies the necessary equipment, thus reducing costs.
Deposition processes:Development of reproducible, up-scalable, low-cost growth and deposition processes for a potential industrialization.
Alternatine materials: Investigation of solar Cells based on Cu2nSnS4, wich use materials abundant in earth...
The results of our research is published and shared in scientific journals and conferences.
CIGSe
Low cost synthesis and deposition processes as base for large-scale production.
In particular, we concentrate our efforts in the CIGSe absorber layer, which is the most important part of the solar cell. We develop varios synthesis and deposition processes that meet the goal of being reproducible, up-scalable and cost effective for a future industrial implementation.
Photovoltaic|Projects
1. Synthesis of CIGS nanoparticles
Nanoparticle derived thin film formation is considered to be an effective way to reduce the cost of solar cell. We synthesize CIGS nanoparticles by both conventional chemical and physical routes.
Chemical route
Thermal decomposition is a facile and non-injection method which possess high reaction temperature, less reaction time and easy purification process. In our lab, we synthesize single phase CIGSe using thermal decomposition method at less reaction time with the optimum band gap of 1.2 eV.
Physical route: ball milling
Ball milling is a simple and versatile dry powder processing technique involving cold welding, fracturing, and rewelding of powder particles in a high-energy ball mill. In our lab, we synthesize single phase CIGSe nanocrystalline material at the low time of 2hr milling.
2. Deposition of CIGS films
CIGS film is deposited by both conventional vacuum (co-evaporation) processes and non-vacuum (solution based method, particulate methods) process. CIGS films are deposited using a nanoparticle-based ink and solution precursors. Different deposition techniques are used such as paste coating, spin coating and screen printing, spray pyrolysis. We also work with physical vapor deposition (co-evaporation), developing robust, up-scalable and potentially low-cost processes for production of high efficiency CIGS solar cells.
Photocatalysis
The Semiconductor photocatalysts have created a revolution in waste water treatment technologies thus attesting to be instrumental in removal of obnoxious compounds and splitting water for hydrogen production. They are capable of surmounting two global problems of the whole world i.e Energy and Water as part of an answer to the question raised by Professor Richard E. Smalley in 2002-2003, “What will be the Top ten Problems facing the World for next 50 years?, Photocatalysts are playing an important role in water splitting, degradation of organic pollutants and waste water treatment. In particular with wastewater treatment, in recent years, semiconductor photocatalytic processes have shown a great potential as a low-cost, environment friendly, and sustainable treatment technology to align with the “zero” waste scheme in drinking water/waste water industry.
Bismuth Vanadate (Doped and Undoped) photocatalysis
Bismuth Vanadate (BiVO4) has attracted much interest due to its unique properties namely oxygen evolution by photoelectrochemical water splitting, photocatalytic degradation of harmful pollutants, non-toxic yellow pigment, ferroelasticity, ionic conductivity and environmentally attractive “green” substitutes for lead, chromium and cadmium based paints. Our group is involved in synthesizing BiVO4 micro as well as nanoparticles using ball milling and hydrothermal method. We are also involved in BiVO4 thin film formation using Ultrasonic Spray Pyrolysis (USP) and RF-Sputtering. The photocatalytic degradation efficiencies achieved is in the range of 85-97% for Methylene blue. Furthermore, to enhance the photocatalytic efficiencies and degradation rate kinetics, BiVO4 was doped with Copper and Molybdenum.
Biomedical|Projects
Super Paramagnetic Iron Oxide Nanoparticles (SPIONs) are considered to create a niche in the field of therapeutics and diagnostics with their unique and distinct properties. They also possess enhanced magnetic moments as well as proton relaxivities hence quintessentially exploited as a competent MRI contrast agent. SPIONs have come to the rescue of medical scientists who deciphered that such nanoparticles possess a combination of T1 and T2 relaxivity, long vascular half-life and inhibit any interstitial leakage. This has led to the development of a proficient system for multi-modal imaging of tissues, an impossible endeavour coming true. SPIONs are efficient candidate for Theranostics (Therapeutics and Diagnostics) acting like an android having capability of molecular actions when interacting with a cell by means of antibody/surface markers such as Folic acid. The biocompatible polymers such as Biological polymers, Chitosan increase the stealthiness of SPIONs thus escaping the reticuloendothelial clearance from the circulation. Such functionalized SPIONSare proved to be an efficient MRI contrast agent causing Hyperthermia under magnetic field leading to actively targeting erred cells via receptor-ligand interaction. SPIONS, nano-scale “magic bullets”, are cataclysmic towards diseased cells since they possess enhanced magnetic moments and are superparamagnetic in nature leading to augmentation of Neel relaxation causing Hyperthermia.
The research group is involved in developing magnetic materials both doped (Co, Mn, Ni) and undoped Superparamagnetic iron oxide nanoparticles (SPIONs). Such nanostructures are exploited as a theranostic agent involved in Magnetic Resonance imaging for detection as well as magnetic hyperthermia and drug delivery system for therapeutics. Such SPIONic structures are also orchestrated with Gold to form core-shell nanoparticles. These core-shell nanoparticles are involved in
- Synaphic delivery of drugs,
- Eradicating cancer cells,
- Bio-imaging and,
- Biosensing element for detection of mutations viruses such as Dengue and Adenovirus.
Biomedical|Projects
Drug Delivery Nanoflotillas
We aim to synthesize magneto-plasmonic core-shell nanoparticles comprising of SPIONs and gold with different surface functionalization and liposome encapsulation so that the complex system can be used as an efficient drug-delivery cargo specifically targeting the cancer cells and release the drug molecules in a sustained manner in the tumour microenvironment. Further, magnetic hyperthermia can be exploited for enhanced drug release on heating making this magneto-plasmonic complex as a multifunctional therapeutic agent for cancer.
Magnetic Hyperthermia
We also focus on hyperthermia which is considered to be greatest advantage of iron oxide nanoparticles. It is a process in which the tumor region is injected with magneto-plasmonic core-shell nanoparticles and subjected to an alternating magnetic field (AMF) which causes flipping of spins in the nanoparticles leading to 2 important mechanism.
- Neel Relaxation.
- Brownian relaxation leading to heating of nanoparticles.
This heating causes increase in temperature within the tumor tissue. This temperature rise causes unfavorable condition for the cancer cells leading to cell death. As this technique is site specific it doesn’t damage the healthy cells which is one of the major advantage of this technique. So we employ the synthesized iron oxide, doped iron oxide nanoparticles and core/shell nanoparticles for hyperthermia application to make them as an efficient system to eradicate cancer.
Contrast agent for Magnetic Resonance Imaging (MRI)
SPIONS and core-shell nanoparticles can also be used as a contrast agent for MRI. Basically these nanoparticles differentiates the normal and cancer cells by enhancing the brightness. So this property is employed in MRI so that any kind of cancer tissue especially the initial stages of cancer can be detected.
The particles which we synthesize are biocompatible upto a high concentration of 1000µg/ml. recently we have reported that cobalt ferrite nanowhiskers synthesized by co-precipitation method as an efficient T2 contrast agent.
Biosensor
In the past decade, iron oxide nanoparticles have created a niche in the field of diagnostics by creating a platform for the measurement of macromolecules like DNA and proteins. This is exemplified by nuclear magnetic resonance (NMR) with hyperpolarized gas, nanoparticle sensors and SPR devices. They are also involved in various biomedical applications, such as magnetic separation and cell-labeling for purification and identification of biomolecules. We develop a core/shell complex which is made of the inner magnetic core and outer gold shell. This non-alloying conjugation leads to sensitive and specific detection of biomolecules due to alterations in dielectric constant and finally SPR. we also present a new generation bio-sensor involving two workhorses for enhanced efficiency – iron oxide nanoparticles forming an inner core and gold nanoparticles creating an outer shell.