Research activities in our group comes under the umbrella of Renewable Energy and falls in two major verticals of Solar Photovoltaics and Solar Fuels aligning with the various missions of Government of India (Make in India, Smart City Mission, Digital India, Skill India etc.) and also line up with ´Atmanirbhar Bharat´ making India a self-reliant nation in the field of Photovoltaics through import substitution measures.
I. Dye-sensitized Solar Cells/Modules:
In the area of DSCs our activities spans into both basic and technology focused applied research as detailed below with re-aligned focus and objectives based on end-user requirements
(A) Basic Research
- Dye: Design and development of new organic dyes and thiocyanate free dyes that efficiently prevents recombination, compatible with alternate redox shuttles, stable, efficient and having spectral match with artificial/indoor lights realizing higher efficiencies in presence of CFL and LED lights (>25%). We are also working on dyes with variable colours for BIPV applications.
- Alternate Electrolytes: Synthesis of new cobalt and copper based electrolytes which are unreactive to silver grid lines in modules and is capable of achieving voltage above 1V from single junction device replacing conventional iodide/triiodide redox shuttles.
- Engineered Semiconductor Materials: With better scattering properties enabling higher performance in full sun and low light without compromising transparency for designs which are unique for BIPV DSSC façade applications.
- Polymer Conductive Electrodes: Cost-effective polymer electrodes such as PEDOT, metallized polymers, carbon/graphene based system etc. that are compatible with alternate electrolytes.
- Device Engineering: Modifications done in device architecture to suit to new molecules and material requirement’s. Currently involved in innovative device designs such as Zombies, Direct Contact Devices, Spacer Free Devices and Hole Free Devices.
- Indoor Photovoltaics: Optimization of indoor light measuring and characterization techniques partnering with EPFL, Switzerland and technical support from Dyenamo, Sweden.
- Device Physics: Optimization of a range of advanced electrical and optical perturbation techniques such as EIS, IMPS, IMVS, OCVD, charge extraction, current transients, PIA, Toolbox techniques etc. which gives an adept knowledge of performance limiting processes at various interface in DSCs.
(B) Applied Research
- Design and development of fabrication equipment’s for photovoltaics partnering with industry.
- Process optimization and fabrication of dye solar modules in various architectures.
- Integration of dye solar master-plates with energy harvesting and management backbone to realize self-powered gadgets.
- Development of spray pyrolysis machine for Conductive Coatings along with optimization of sols and process.
- Engineering Flexible Dye-sensitized Cells/Modules.
- Custom Modified Modules for BIPV Applications.
II. Perovskite Solar Cells/Modules:
A better understanding of the mechanism of photocurrent generation and subsequent optimization of cell fabrication techniques could render perovskite photovoltaics the champion among thin film photovoltaic technologies. In this regard our interdisciplinary team focusses on developing new blocking and scaffolding materials, and fabrication of highly efficient perovskite solar cells based on standard and newly made materials with metal contact and metal free scalable architectures leading to efficient, stable and scalable PSCs in both smaller and larger substrates. We are currently exploring the following aspects in PSC research.
- Optimization of efficient devices in n-i-p and p-i-n architectures
- HTL based and HTL free devices
- Printable Perovskite cells/modules using carbon materials
- Advanced characterization to probe the device dynamics employing perturbation techniques
III. Molecular Photocatalysis (Solar Fuels)
(A) Metal complexes for catalytic hydrogen generation and water oxidation
Efficient conversion of sunlight into electricity is not the complete answer to the impending energy crisis – we need to be able to store and transport energy. In this regard, many have championed the hydrogen economy as a clean fuel, but hydrogen is currently derived from methane and other petroleum-based products. Currently with our expertise on potential transition metal complex catalysts we are designing molecular and heterogeneous photocatalysts and electrocatalysts based on transition metal complexes, such as Ru, Co, Cu and Fe complexes that are capable of extracting hydrogen from water using sunlight as the energy source. We are particularly interested in gaining mechanistic information surrounding the complicated reaction landscape of water splitting, and to apply this information to commercially viable catalysts.
(B) Photocatalytic fuel generation with dye-sensitized water splitting devices
Molecular photocatalysis in solution will be extended to devices by immobilizing the molecular water reduction/oxidation catalyst on respective anode and cathode electrodes and designing devices for electrochemical and photo-electrochemical water splitting. Here, we want to build up on the reasonably well understood principles of dye-sensitized TiO2 (as used in dye-sensitized solar cells) and incorporate transition metal catalysts producing H2 from water (instead of producing electricity). We focus on developing solar H2 evolution systems that operates under visible light irradiation in water at room temperature.
IV. Phosphorescent Metal Complexes for OLED Applications
Research on organic light emitting diodes (OLEDs), has been focused on devices composed of thin films containing organic/organometallic molecules that directly convert electricity to light. Heavy metal organometallic complexes have gained tremendous research interest for fabricating highly efficient phosphorescent OLEDs. These phosphorescent emitters are mainly derived from the family of the third-row transition metal (IrIII, ReI, OsII and PtII) complexes. With the rapidly growing market for OLED technology and its potential to revolutionize display technologies, we will be focusing on the development of new and novel iridium based structurally engineered metal complexes for lighting application.