IIT Hyderabad develops eco-friendly solar cells using Kumkum Dye

A team from Indian Institute of Technology (IIT) Hyderabad has developed a Dye-Sensitised Solar Cell (DSSC) which is based on New Fuchsin (NF) dye with aqueous electrolyte and platinum-free counter electrodes. The research was published in Solar Energy journal.

Key Highlights

Need: Currently, most familiar solar cells today are made up of Silicon (Si) and can be seen in various overhead panels and other places. However, this technology is limited by huge fabrication costs as Si processing is very expensive and involves very high temperature methods that leave a large carbon footprint. Therefore to get around limitations of using Si, IIT Hyderabad team started working on solar cells based on organic materials for photovoltaic technology, which were supposedly inexpensive and easy to fabricate.

Initially, after facing many drawbacks IIT Hyderabad along with other researchers employed a very cheap magenta-dye called New Fuchsin, which is used to make kumkum or vermillion when grounded with turmeric. New Fuchsin is an inexpensive dye available off-shelf in most supermarkets in India, and in its purest form costs $2 per gram.

About Dye-Sensitised Solar Cell (DSSC)

It is a 3rd-generation thin-film organic Molecule-Based Energy Conversion Device.

DSSC is cheap, non-toxic and is soluble in water and does not degrade in presence of water. It takes inspiration from nature, almost mimicking primary process of photosynthesis phenomenon in plants.

DSSC has 3 components:

• Monolayer of dye molecule adsorbed on semiconductor material
• Titanium dioxide (TiO2) deposited on transparent conductive oxides, like indium tin oxide (ITO)
• Liquid electrolyte with an excess of electrons

Process involved: Sunlight is absorbed by dye molecule and gets excited. Electrons from excited dye molecule get injected into conduction band of TiO2 and then electrons are transported to charge collector. Dye cation (after losing its electron) takes an electron from surrounding electron-rich liquid electrolyte. The counter electrode, typically, is platinum-coated ITO.

DSSCs are generally considered eco-friendlier to produce than conventional solar cells because they require little energy to manufacture.

Drawbacks: Best performing DSSCs use organic solvent-based liquid electrolytes but these liquid-electrolytes come with drawbacks like high vapour pressure, toxicity and sometimes explosives resulting in severe environmental impact in addition to being corrosive to the platinum counter-electrodes, thereby limiting long-time stability of the devices.

Month: Current Affairs - July, 2019