IIT-B develops perovskite solar cell with 26% efficiency

Subject : Science and technology

Section: Msc

Concept :

The National Centre for Photovoltaic Research and Education (NCPRE) at the Indian Institute of Technology Bombay (IITB) has developed a perovskite solar cell (PSC). The cell has been demonstrated an efficiency of over 26 per cent.
To compare, with the best of the conventional solar cells in the market, you will be lucky to get an efficiency of 22 per cent.
Efficiency is the percentage of sun’s light energy that falls on the cell that is converted into electrical energy.

Perovskite

A perovskite is a material that has the same crystal structure as the mineral calcium titanium oxide, the first-discovered perovskite crystal. Generally, perovskite compounds have a chemical formula ABX3, where ‘A’ and ‘B’ represent cations and X is an anion that bonds to both.
A large number of different elements can be combined together to form perovskite structures.
Using this compositional flexibility, scientists can design perovskite crystals to have a wide variety of physical, optical, and electrical characteristics.
Perovskite crystals are found today in ultrasound machines, memory chips, and now – solar cells.

Perovskite Solar Cells

When used to create solar cells, they have shown potential for high performance and low production costs.
Perovskite solar cells have shown remarkable progress in recent years with rapid increases in conversion efficiency, from reports of about 3% in 2006 to over 25% today.
Perovskites can be tuned to respond to different colors in the solar spectrum by changing the material composition.
Perovskite solar cells of certain compositions can convert ultraviolet and visible light into electricity very efficiently, meaning they might be excellent hybrid-tandem partners for absorber materials such as crystalline silicon that efficiently convert infrared light.
It is also possible to combine two perovskite solar cells of different composition together to produce a perovskite-only tandem. Doing so could lead to even higher efficiency and more cost-effective tandem photovoltaic (PV) applications.
While perovskite solar cells have become highly efficient in a very short time, a number of challenges remain before they can become a competitive commercial technology:
Their stability is quite limited compared with that of leading PV technologies.
They don’t stand up well to moisture, oxygen, extended periods of light, or high heat. Current operational lifetimes are not commercially viable.

Semiconductors Vs Perovskite Solar Cells

All photovoltaic solar cells rely on semiconductors — materials in the middle ground between electrical insulators such as glass and metallic conductors such as copper — to turn the energy from light into electricity.
Light from the sun excites electrons in the semiconductor material, which flow into conducting electrodes and produce electric current.
Silicon has been the primary semiconductor material used in solar cells since the 1950s, as: its semiconducting properties align well with the spectrum of the sun’s rays and it is relatively abundant and stable.
However, the large silicon crystals used in conventional solar panels require an expensive, multi-step manufacturing process that utilizes a lot of energy.
In the search for an alternative, scientists have harnessed the tunability of perovskites to create semiconductors with similar properties to silicon.
Perovskite solar cells can be manufactured using simple, additive deposition techniques, like printing, for a fraction of the cost and energy.
Because of the compositional flexibility of perovskites, they can also be tuned to ideally match the sun’s spectrum.