1. INTRODUCTION
Energy , something that possess neither a beginning nor an end is the building stone of science technology and all the humane progresses. Taking different forms , Energy has driven the human race into a whole new level of achievements. Energy harvesting marked its beginning through the taming of fire and it has now reached a point where we are desperately trying to harness energy from literally every possible resource that we can.
The 19th and 20th century witnessed almost all of the unimaginable developments in science , industry and technology and it would not be wrong if we say fossil fuels boosted these swift and steady progress. Our dependence on them still has not been reduced , rather the demand for these non renewable energy sources have skyrocketed over the past three decades. Being in the bottleneck of an energy crisis , it is time that we put aside our sentiments and bid adieu to the conventional energy resources and welcome into our life the modern , renewable ones. The only possible way to tackle the impending global energy crisis is to embrace the modern energy technologies and adapt to the renewable energy as the new normal.
2. ADVANCEMENTS IN RENEWABLE ENERGY SOURCES
The global energy demand is anticipated to grow at an enormous rate in the next 30 years , ie the prediction is that the energy demands will be 60% higher in 2030 than of now. The rapidly developing countries account for this huge jump in consumption and it is vividly visible that the road of fossil fuels is nearing its inevitable end. This has pushed the scientists to look for an alternative, which by now we know as renewable energy sources and energy materials. Unlike petroleum fuel , coal and natural gas , these are replenishable and hold the answer to the global energy crisis. Starting from rain , winds , tides , sun and geothermal heat , advanced researches are proceeding in the area of energy materials which can store and deliver high amounts of energy. Development of renewable energy sources owes not just to the increased energy consumption alone. From the climate protection viewpoint also this needs to be considered urgently as the gas emissions from fossil fuel burning are tampering the environment. Even though biofuels , ethanol fuel , biodiesel , biogas , hydropower , windpower etc are gaining popularity due to their eco friendly nature and renewable status, the area into which the scientific world has invested its hardwork and hopes the most is Solar Energy.
FIG.1 ( A collage encompassing the prominent renewable energy sources)
3. SOLAR ENERGY : METHODS TO HARNESS AND CONSERVE
The significance and potential of solar power is underlined by the fact that in one daylight hour, the amount of solar energy which reaches the earth is more than the total amount of energy used by everybody on earth in a 1-year period. Sun , the ultimatum of energy can be exploited for solving both the energy and climate crisis simultaneously. Solar radiation can be made use of in numerous manners , including the conversion of light to electrical power by solid-state photovoltaic devices, as well as the direct heating of water or structures by incident infrared energy from the sun. Spinning off from the conventional early ways of harnessing solar power , a large variety of sophisticated commercial systems are available now. Ranging from thermal solar energy systems to photo voltaic cells, these are deployed throughout the world.
Solar energy adoption is predominantly made possible by solar cells , which expanded from curiosities and toys to a major component of the world’s energy systems within the past 50 years. Being an indispensable part of the space program , the photovoltaic cells were given primary importance and researchers were keen on enhancing it’s efficiency to match current energy production standards. The ubiquitous solar panel arrays and solar cells can be found on everything from communications satellites to space telescopes; from planetary probes to the Mars rovers. From the initial 1% efficiency , they have developed into 20-30% efficient energy materials. Researchers have been pushing the performance of solar cells to levels never reached before and this has urged the necessity to search for more efficient energy materials to be made use in solar /photovoltaic cells.
3.1 PEROVSKITE SOLAR CELLS
A perovskite solar cell is a type of solar cell which consists of a perovskite structured compound , most commonly an organic-inorganic lead or tin halide based material. The name Perovskite solar cell is derived from the ABX3 crystal structure of the absorber materials , which is known as a perovskite structure. The most commonly used perovskite absorber is CH3NH3PbX3, where X is a halogen ion. Metal halide perovskites possess unique properties which make them the best candidates for solar cell applications. To act as a solar cell , a material should possess electrons that can be kicked out from their place from by the energy of falling sunlight , thereby leaving sites called “holes” behind. These electrons can be fed through a circuit to create useful electric current and later they combine with the holes which are also moving by themselves through the material.
FIG.2 : Crystal structure of CH3NH3PbX3 perovskites
It is widely considered that perovskite solar cells could solve the global energy crisis. This ultra high efficiency material is a breakthrough in the chemical and material science research which aims at synthesising new energy materials of higher efficiency. These compound materials with special crystal structure can replace silicon, which for now is the conventional solar energy material of choice. By stacking perovskites together with silicon structures , solar devices can be made to capture frequencies of the solar spectrum that cannot otherwise be tapped. New research papers points out how the photovoltaic researchers are fine tuning a mixture of Tin and Lead to advance this technology into its maximum efficiency in the forthcoming years. Consistent efforts have brought the efficiency now to about 23% on average whereas the silicon solar panels on the market today have only around 18% efficiency. Solar cell efficiencies of lab-scale devices using these materials have dramatically jumped from 3.8% to 25.5%(in single junction diodes) and 29.15% (in silicon based tandem cells) within a time period of 2009 to 2020 , which exceeds the maximum efficiency achieved in single junction solar cells so far.
Perovskite solar cells are regarded as the fastest advancing solar technology with an outstanding potential of achieving even high efficiencies and being simpler and less expensive to manufacture , thus offering the economic feasibility of attaining solar power. Certain technical challenges still do remain , principally in enhancing the chemical stability of the crystal and increasing the energy converting efficiency of the cell. The use of lead in many perovskites are also a matter of concern , as this toxic element is not eco friendly. However , good progress are being made by researchers to create new lead free perovskite solar cells which reach upto the mark of previous ones.
4. CONCLUSION
One of the major crisis of this millennium is widely acknowledged to be the impending energy crisis and the current climate change scenario. Both can be accounted by the exploited use of fossil fuels which are now nearing an end. The search for a replenishable energy source has pointed towards the possibility of harnessing the abundant energy from the sun by various methods. Solar energy tech has advanced a lot over the past 50 years and the recent cutting edge breakthrough was the invention of highly efficient Perovskite solar cells. These cost effective solar cells turned out to be much more efficient than the conventional silicon based cells and is also better in other aspects as well. Proper development of these energy materials could single handedly solve the world’s energy crisis. By implementing the perovskite solar cells in a commercial level , the most affordable, efficient way to harness the cleanest, most abundant renewable energy source in the world becomes one step closer to reality.
By Adithy R Nair
adithy.r02@gmail.com
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