Making solar panels more efficient, cheaper and recyclable

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Last Updated03/01/2022

Scientists from the Indian Institute of Technology, Guwahati, have found a way to make solar panels more efficient, cheaper and recyclable — by stabilising hybrid perovskite-based solar or photovoltaic devices to produce electricity.
Perovskite-based devices are considered heavily used semiconductor materials as they are affordable and easy to manufacture.

While solar energy is the future, WEEE (Waste Electrical and Electronic Equipment) is a growing problem.
The International Renewable Energy Agency (IRENA) in a report published December 2021 estimated the global PV waste will touch 78 million tonnes by 2050, with India being one of the top five PV waste creators.
Recycling of any semiconductor, including the installed solar panels, is challenging.
There is no definite plan to recycle this waste generated from solar panels so far.
After 10-15 years, this waste will also pose a threat to the world,
India’s cumulative PV waste can go as high as 34,600 tonnes by 2030, according to a report prepared by the National Solar Energy Federation of India, SolarPower Europe and PVCycle, supported by EU in India and the Ministry of New and Renewable Energy.

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.

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.