Let us know why a complete shift to solar energy isn’t feasible now

Delhi, our capital city, a few months ago was affected by a heavy smog leading to the closure and disruption of many schools and services.Did we ever think such a thing was possible 50 years ago? Numerous reasons can be attributed to this. One of the most prominent reasons is pollution due to the vehicles and industries in and around Delhi .So what is the solution? Everyone simply advised using other non-polluting sources of energy such as solar and wind power. But, is it practical?  If using it was so easy and nice, why aren’t people already using them and still rely on fossil fuels? Ponder this. The efficiency of a commercial solar cell is just around 20%, whereas the efficiency of a fossil fuel is around 35%-40%.

The cost of setting up a domestic solar power plant in India is around 1 lakh. Hence, not many have turned towards the alternative of solar power. So, let’s discuss why solar energy is so expensive to be implemented domestically. Solar cells are made of semiconductors such as Si, Ga, GaAs etc. Classification of materials into metals, semiconductors and insulators is based on their increasing band energy gap. The challenge for scientists here is to produce a material which can give us higher efficiency and at the same time is economically viable. Naturally occurring semiconductor materials are usually indirect band gap materials.(Read more about indirect band gap) Usually Indirect band gap is smaller than the direct band gaps. But indirect band gap materials require phonons (Read more about phonons) and solar energy as well for the electrons to jump from the valence band to the conduction band.This poses a problem.The direct band gap is sometimes too big for solar energy and the indirect ones require phonon assisted transition. Here, we are required to find a material in the Goldilocks zone (something just right for solar power) or a combination of materials .The highest ever theoretical efficiency achieved is 33.16% using multi-junction solar cells. But this was done under laboratory conditions and might not be commercially viable. So, this was about photo-voltaic cells. Another way to tap in solar energy is using isomeric organic molecules which can store energy. Cis-trans isomers of azobenzene are used .

There is an energy difference between the cis and trans isomer which is used to store the obtained solar energy.The number of times this can be done is quite low. Hence this is seen to be an nonviable solution. The attachment of carbon nano-tubes to the molecules helped improve the properties a bit. Similar materials with activation energy in the UV-visible region of electromagnetic spectra can be used.  (Ongoing research at MIT Boston by Prof. Jeff Grossman) But can these materials be put for commercial use ? This is huge question .These are some of the reasons why we cannot eliminate the use of fossil fuels completely and start relying on solar energy immediately.

Small things do matter !

So,most of us find the word NANO highly intriguing .Isn’t it ? Most of us like small things be it a baby , a puppy or a kitten.Nano is about something which is way smaller . It’s much smaller than u can actually imagine. It is 5-6 orders of magnitude smaller than an ant . So,we might think what is the use of something so small ? The small things always matter because they make up the bigger ones . Properties become really different when we go to the nano scale . For instance,gold is red in color. Unbelievable isn’t it ? We are used to saying golden color and stuff .Have we ever thought gold could be red in color ?The chemical properties also change due to quantum effects .That gives rise to unique properties which has evoked interest in this field .Even nature has its own share of nanoscale components . Lizards have nano particles on their foot to help them move.This is just one of the many examples . Nature always builds anything from smaller particles and Man mimics nature to manufacture the things he wants.This is called Bottom-Up approach where nano particles are built from smaller raw materials.But this has its own disadvantages.It is highly tough to get particles smaller than nano.And due to small size and repulsion,building up of particles also becomes tough. Hence,materials scientists have come up with a different and better approach of the reverse process known as the Top-Down approach .This is much simpler as this involves size reduction processes and not assembling process.Nano research started in the 80s around the world . This is coincident with the invention of the scanning electron microscope which helped in analysing minute components.India are quite late in nano research with most of the research happening in the late 90s .Most of the credits have to go to one man and that is Dr. C.N.R.Rao . He is the spearhead of India’s nano research and the newly opened institutes function under him. Not many of us know about this man . Well,he won the Bharat Ratna along with Sachin . But it’s not solely our fault on not knowing about research in various fields. We read and get to know about things which are being fed to us by the media. India produces more engineers and very few scientists . This has got to change in the near future and we need to produce and respect more scientists. Science and engineering go hand in hand and it’s high time we do higher level research and show the world who we are

Past,Present and the Future of Materials science in India

Chances are, you’re reading this blog on a mobile phone or a laptop. Have you ever stopped to wonder what exactly these objects are made of? The answer’s not that simple. Even the most rudimentary of computers is composed of millions of transistors, all working intricately in conjunction to process, render and display the information you’re currently absorbing!. As you might imagine, the transistor has to be extremely tiny for millions of them to fit onto a palm sized microprocessor! The fundamental breakthroughs in computing, and indeed the potential of the field itself, could only be realised if there was some material discovered which possessed the electrical properties necessary function as a switch (Transistors are essentially switches).That’s where the materials engineer comes in; the isolation of Silicon as the prime semiconducting element was, in retrospect, one of the most monumental achievements in human history. The speed of development in the field of computers, especially in regard to memory storage and transistor count. All of this would have been impossible without an active interface between computer scientists, materials scientists, and dozens of other auxiliary fields. With the advent of nanotechnology and quantum computing, the potential seems never-ending. It’s worth taking a look at the history of materials science, to better understand and appreciate the gigantic strides the field has taken.

Eras of history have been, quite literally, defined by the most prevalent material in use during said era!. Think of the stone age or the bronze age. Some eager commentators have already labelled the era we’re living through a “Silicon Era”. Materials Research never expires, it will continue to thrive as long as human beings continue to breathe! 
India was once, in stark contrast, at the forefront of scientific expertise. Materials science is no exception. A classic example is that of the Delhi Iron Pillar, built in the 14th century, still standing strong, to this day, without an inch of rust on its surface. Material Scientists might have mastered nanotechnology, but the art of 14th century metallurgy is still elusive. Sadly, it seems we have squandered that renown. A recent survey ranks us 6th in the amount of research papers published. Countries with a modicum of our human resources, and a millionth of our natural resources such as South Korea and Japan rank higher. It’s worth discussing why this is the case. Materials science is still relatively unpopular in India. It’s high time the Indian youth realise the potential that Materials Science holds. There are more than 15 broad domains which come under the ambit of materials science. To name a few, there are nanotechnology, ceramics, quantum chemistry etc.
If this interests you, keep following this blog for the latest news in materials science, along with student oriented resources to make your journey exploring this exciting field a bit less confusing!