Development of novel solid state ionic materials and its device application
Science and Technology of Solid State Ionic materials and devices have recently emerged (termed as Solid State Ionics) with the availability of many superionic conductors or solid electrolytes. The materials of choice for electro-chemical device application are solid-solid composites,Fabrication of quantum dot sensitized solar cells,Dye sensitized solar cells,Thin films,Polymer Electrolytes and Ionic liquids.
In Material Research Laboratory (MRL), Sharda University our main research work is focused around the development of materials stated above and their successful application on various electrochemical devices in particular on Quantum dot sensitized solar cells (QDSC), dye sensitized solar cell (DSSC), Ion beam polymer interaction. In MRL, we have a dynamic group of researchers oriented towards this goal.
Quantum dot sensitized solar cells (QDSSC) are fabricated via following four steps - a mesoporous TiO2 layer upon supporting substrate acting as a photoanode, Quantum dots attached upon TiO2 layer playing role of sensitizer, an electrolyte with redox couple and a platinum coated counter electrode.
However Dye-sensitized solar cell (DSSC) came in consideration after the pioneering work of Prof. M. Gratzel in the year 1991. It consisted of a combination of three major thin layers sandwiched between two transparent conductive electrodes. These layers are High band-gap nanocrystalline semiconductor coated with a dye, which absorbs light and releases electrons, Electrolyte containing a redox couple which transports electrons from the platinized counter electrode to regenerate the dye and Platinized counter electrode to collect the electrons via an external electronic circuit.
It is known that thick mesoporous film of TiO2 nanoparticles having diameter of 10-20 nm is necessary for high efficient dye-sensitized solar cell (DSSC) since the position of conduction band edge of this material easily allows electron injection from the excited state of the dye. On the other hand, the electrolyte used in DSSC is mostly two types - (1) liquid electrolytes (2) solid electrolytes.
However, the liquid electrolytes shows good performance albeit it is still a threat for practical application due to many problems. Solid polymer electrolytes is another easy, low cost alternative. The prime aim of this proposed work is to develop a porous TiO2 electrode with solid polymer electrolyte material which is suitable for DSSC application.
Although the Ionic liquid (IL) have too many useful properties it can not be used in various applications due to their liquid nature at room temperature. One possible approach developed by our group is to doped these ionic liquids in a suitable polymer matrix and obtain the resulting electrolyte in the film form. Using this methodology our group is moving straightforward in developing efficient DSSC using various ionic liquid doped solid polymer electrolyte systems and published ~ 30 International Research Papers in refereed Journals.
Ion beam polymer interaction
Swift ion interaction with the electron conducting or insulating polymers have been extensively studied so far, but the interaction with the ion conducting polymers (which are electronically insulating) is almost not studied. The main aim of this proposal is to modify the chain length of an ion conducting polymer electrolyte [PEO:NH4I, PEO:Si or PEO:C] so that the crystallinity gets modified vis-a -vis the conductivity.
It is known that the bombardment of polymers by energetic ion produces dramatic changes. The original chemical bonding of the polymer gets disrupted and two different possibilities are seen, viz., cross-linking of the chain or chain scission . The later results to the fragmentation of the long chain at initial levels and can eventually result to the ejection of polymer fragments with a wide distribution of molecular masses. The hydrogen can also be released leading to polymer carbonization