Renewable energy-Perovskite PV cells are hoped for a better future.

Solar power is key to our energy future. Silicon solar cells are serving the purpose but have many disadvantages. One big problem is that the solar grade silicon is expensive and not very efficient as far as energy conversion is concerned. When sunlight is abundant the efficiency may not be counted but then how many solar panels you can spread over your rooftop to get the required amount of electricity? Why not think about the solar cells which can be hung around even on your cloth lines to harvest energy? Let us think about the solar cells which are very light, easy to carry, cheaper and more efficient to produce energy.

A wonderful synthetic mineral Perovskite is the answer to the search of the more efficient solar cell. The perovskite structure is adopted by many oxides that have the chemical formula ABO3.

perovskite

The green coloured atom when replaced by calcium is called as calcium titanium oxide or calcium titanate. This calcium titanium oxide is a compound which shows good solar energy conversion efficiency up to 35%.

Synthetic perovskites have been identified as possible inexpensive base materials for high-efficiency commercial photovoltaics– they showed a conversion efficiency of up to 15% and can be manufactured using the same thin-film manufacturing techniques as that used for thin film silicon solar cells. Methylammonium tin halides and methylammonium lead halides are of interest for use in dye-sensitized solar cells. Similarly, many perovskite structures are tested for solar energy conversion and the results produced are better than the silicon solar cells.

pero1
The structure of methylammonium lead halides and other perovskites.

The perovskites that hold such promising photovoltaic or solar energy generating properties are a group of synthetic versions discovered in 2009 by Japanese scientist Tsutomu Miyasaka (https://www.cc.toin.ac.jp/sc/miyasaka/en/index.html) and colleagues. Miyasaka was talked about in 2018 as a potential Nobel prize recipient.

Scientists synthesized perovskites by mixing two inexpensive salts, lead halides and organic halides. This solution forms an ink, which can be applied in an ultrafine, uniform layer by using inkjet printing or spin coating. The film deposited is very thin of the order of 500 nanometers but enough to absorb sunlight to generate electricity. A little perovskite can generate huge power in a much less expensive way. This is because producing less defective perovskites are much easier than producing defect-free solar grade silicons.

Also, one more possibility to harvest solar power is to stacking up perovskite layer and silicon layer alternatively. This is advantageous as silicon can absorb the lower energy radiations(Red) and perovskite absorbs highest energy radiations(blue). A layer of perovskite cell on top of a silicon cell harvests the bluer light and converts it into electrical power. The rest of the light then travels through the silicon cell below, which absorbs the red light and converts them into power. Hence, when both layers are acting, almost all the radiations falling on them are converted into electricity! This increase in efficiency in conversion cuts down the number of solar panels that are to be installed to generate the same amount of electricity, thereby cutting down the expenses.

The synthetic perovskite solar cells can bring revolution to generate electricity worldwide when mostly we struggling to get a sufficient amount of electricity. In most of the developing countries, the people residing in rural areas have not seen electricity or they avail it for a very shorter duration of time. Even though in many villages Governments are trying to provide electricity by silicon PV cells but they are not cost effective which are bearing a hole in government pockets. If these perovskites can be used instead of silicon or in combination with silicon then the electricity will be reached to the remotest part of the world, because these are very light and thin. These can be dumped on trucks and can be hanged on the cloth lines. The only need is to do the extensive research on these materials and manufacture of these cells in more quantities.

After all the war is for holding the stocks on nonrenewable energy. Forget the war and jealousy and let us focus on the various ways to harvest renewable energy. The world will live in peace with cheaper, cleaner energy and people will become happier with more power to access every day!!

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