Perovskite Solar Cells

Prelims – Current events of national Importance | General Science.

Mains (GS III) – Science and Technology- developments and their applications and effects in everyday life.

Why in news?

Recently scientists have developed a water-based recycling solution for perovskite solar cells.

Perovskite solar cells – A perovskite solar cell is a third-generation solar cell that employs a metal halide perovskite compound as a light absorber.
Perovskite solar cells are made up of multiple layers.
The perovskite layer can conduct and transport charges is sandwiched between metal electrodes and glass sheets.
They are a class of semiconductor materials are known for their unique optical, superconductivity and electronic properties.

Thin Film Pervskite Solar Cell

Metal halide perovskites (MHPs) were first discovered by Russian mineralogist L. A. Perovski.

Advantages – They are cheaper to produce than silicon-based solar panels and offer higher efficiency in energy conversion.
Disadvantages – But they contain toxic elements like lead that require careful disposal and have shorter lifespans than traditional solar panels.
Perovskite materials are extremely unstable towards ambient (humidity and oxygen) conditions that restrict their commercialisation.
Recycling – The components of the solar cells are recycled to minimize the emission and lower cost associated with solar energy generation.
By recycling the components of a perovskite solar cell can be used for as long as possible, to minimise waste and promoting circular economy.
Currently they are recycled using the toxic organic solvents.

The new water-based recycling process

Dissolving and recycling the lead-containing perovskite layer in water was a major challenge to overcome.
For this, the scientists added three key salts to help in the recycling process.
Sodium acetate –It binds with lead ions in solar cells to form lead acetate, which is easily soluble in water.
Sodium iodide – It helps in repairing and restoring degraded perovskite compounds.
Hypophosphorous acid – It acts as a long-term stabilizer.

Stabilizer is a substance that either prevents or slows down reactions, thus enhancing the stability of a system.

Ethanol and ethyl acetate solutions – They are also used to dissolve other components.
Results of the new method – Scientists recovered approximately 99% of different layers after multiple recycling rounds.
Recycled materials-maintained efficiency comparable to fresh materials even after five recycling cycles.

Quick facts

Carbon-based perovskite solar cells

Indian scientists have indigenously developed highly stable, low-cost Carbon-based perovskite solar cells with superior thermal and moisture stability.
The sensitivity of perovskite materials toward humidity and thermal stress is a major obstacle for practical implementation.
Carbon-based perovskite solar cells (CPSCs) have been successful in minimizing device stability issues.
It also reduces the fabrication costs.

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