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We are so close to artificial photosynthesis!

As summer is kicking off, glimpses of the sun lovers basking with their headphones and sunglasses on, on beaches or in other pleasant places is not rare. Imagine you are one of them. You happen to be on one the wonderful beaches, basking, listening to your favourite playlist on your mp3 player. You are having delightful time and suddenly you hear an intimidating beep notifying you that it is out of battery jeopardizing your divine moment. What will you do? Will you continue basking disappointed or take off your glasses and use them for charging your mp3 player? Yes! You read it right, sunglasses can be actually made to charge your mp3 player or your phone for that matter! Self-energy converting sunglasses based on a dye sensitized solar cell (DSSC) present this opportunity. Not limited to glasses, DSSC technology can make skylights, windows, even building facades (which are exposed daylight) capable of producing electricity. This third generation solar cell can be likened to artificial photosynthesis due to the way in which it mimics natures’ absorption of light energy. According to researchers in this field this is the closest we have been to photosynthesis. This new generation of solar cells are greener, smaller, more flexible and inexpensive as compared to the early generation solar cells. These advantages are due to the usage of dye as photosensitive material which also makes the working mechanism simple. Dye molecules respond to light by transferring electrons to the titanium dioxide layer which helps in the movement of electrons constructing current. The circuit is completed by the electrolyte present in the cell transferring the electrons back to the dye.

Although this DSSC technology has produced a record efficiency of 11% conversion of solar energy to electrical energy, researchers all over the globe are trying to elevate the efficiency of the system by synthesizing and incorporating new dyes with different structures and functional groups with electron donating capacity.

DSSC scheme.

Generally dye used in DSST consists of electron donor, linker and electron acceptor moieties connected to each other. In a very fine effort to optimize the structure of the dye, Zhongquan Wan, Chunyang Jia etal, cited below, investigated effect of different linker moieties in the dye structure on the efficiency and overall working of the solar cell. The 3 different linker moieties investigated were benzene, thiophene and furan. They not only successfully synthesized dyes with different linker moieties but also calculated the working efficiency and performance of the cell. They reported that furan as linker moiety works best as compared to other 2 linkers. Also they successfully reported synthesis of star-burst shaped dyes which reduces aggregation between the dye molecules giving rise to better performance of the cell. This high impact study will certainly contribute to make this green DSSC technology more efficient and hence commercialized.

Phenothiazine–triphenylamine based organic dyes containing various conjugated linkers for efficient dye-sensitized solar cells

Zhongquan Wan, Chunyang Jia, Yandong Duan, Linlei Zhou, Yuan Lin and Yu Shi

J. Mater. Chem., 2012, 22, 25140-25147
DOI: 10.1039/C2JM34682F

Padmanabh Joshi is a guest web writer for the Journal of Materials Chemistry blog. He currently works at the Department of Chemistry, University of Cincinnati.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

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“Fingerprinting” chemical contaminants using light?? Awesome!!

“What? Why? How?” All kinds of “wh” questions I bombarded at my buddy Marc when he apprised me that he is not going to make it to the long awaited trip. “Somebody tried to poison me” followed by guffaw was the jocular repartee from Marc. After a demented pause from my side, Marc cleared the air of confusion and sickeningly reported that he is suffering from food poisoning. The next morning I drove down to his place to see how he is doing. In one of the friendly banters which we always indulge into, he said” Non sense, this food poisoning man, I wish I could have some device like a phone which can detect the contaminants in food right away, so that I can make store owner eat that food once I find it’s contaminated” followed by burst of  laughter. “Typical Marc” I muttered with smirk. But on my way back home that ‘device’ thought of Marc’s stuck in my head and being a chemist I started screening all the techniques used for the detecting chemicals and asked myself which technique can be exploited to make such a handy device to detect chemical contaminants. The answer came without a waste of second, its Surface Enhanced Raman Scattering(SERS)!

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Working out outside?.. check the humidity level first..!!!

The audience at Arthur Ashe Arena at Flushing Meadows were on their feet with a huge round of applause after the scintillating first set of tennis between Shui Peng and Caroline Wosniacki at the US Open 2014, one of the biggest and most renowned stages for tennis championships. It was 82F(29 oC) out there with grueling conditions for playing. One of the finest tennis contests was being produced until suddenly Shui was struck by cramp in her left leg which is a symptom of  many heat related illnesses. After 10 minutes of  high drama in the presence of nearly 20000 tennis frenzied crowds, Shaui Peng had to retire after several futile attempts to pursue her quest for the US open title. Multiple events of this sort have  prevailed in the history of the sports, also cases where athletes have withdrawn from competitions because of grueling weather forecasts are omnipresent . Being a sport enthusiast, I was forced to wonder, is it just temperature that is a culprit for heat illness or there is something else as a “partner in crime”?!

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Ever heard of useful collision? Here it is!!

“It’s cold and white everywhere. What else can you expect on early January’s very snowy evening!” I mumbled to myself and was heading towards home exhausted when I witnessed the almost ungovernable sliding inevitable collision of two nice looking vehicles with people on driving seats trying hard to salvage the situation. It was not a gratifying view for the spectators let alone for the vehicle owners and insurance companies (of course). Knowing that not much could be done from my side, I resumed my meticulous “frictionless” walk but this time pondering over the collisions.

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Can you treat cancer this way too?! Really?!!

Imagine a scenario where one morning, a close friend of yours calls you and painfully conveys the news of him being diagnosed with cancer and you, instead of sitting horrified and helpless, casually say “Hey don’t worry man, we have PDT!” That sounds fascinating right?! Yes, Photodynamic therapy has shown potential to do that. With the same fascination towards the idea of photodynamic therapy, inventors of PDT pursued research on this therapy and shaped an unconventional out of box method of treating cancer.  The simple mechanism of working of this technique is widely known. Drugs used in this technique are light sensitive. In response to specific light irradiated on the drug molecule, it converts surrounding molecular oxygen into form of oxygen which kills nearby cancer cells. The reasons this therapy called as out of box here are multifold. First, there are many photosensitizers easily available approved by FDA which can easily respond to specific light and produced the effect explained above. Second it makes use of naturally available oxygen molecules surrounding cancer cells. Last and importantly all the conventional drugs/ therapies for the cancer are immunosuppressive meaning they suppress our immune system after treatment unlike PDT, which is immunostimulative which stimulates immune system of the patient after treatment.

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Is it a bird? Is it a plane? Possibly, its Graphene the Wonder Material!

“Wonder material” they called it when it was discovered last decade and it started to be center of attention from 2010. To understand the reasoning behind calling graphene a wonder material, one need not be a rocket scientist. The beauty of this material is so conspicuous that it can fascinate anybody on the globe. Graphene is one the few materials in existence which is very thin, conductive, transparent and flexible at the same time. The wonder of this material’s thinness is so intriguing, that according to scientists, just ounce of graphene could cover 28 football fields. Only a single atom thick, Graphene could take electronics to the next level with much thinner, faster and cheaper components compared to the current silicon based electronics.

We all know the saying nothing is perfect, however researchers all over the globe are claiming that Graphene may not be perfect but it is close to perfect. The major challenges for making Graphene a game changer in electronics are control over chemical and physical properties by chemical functionalization and processing them upon up-scalable approaches.

Graphene composite.
Investigators addressing these major challenges have explored the field of composites of graphene with organic semi-conductors and their findings are making graphene close to perfect if not perfect. A. Schlierf, P Samori and V.Palermo brilliantly reviewed the processes involved in modification of Graphene with organic semi-conductors in the article cited below. Combining the properties of organic semiconductors like well defined and tunable band gaps with the properties of graphene like flexibility, a dream material for the semi-conductor industry can be developed.  A. Schlierf, P Samori and V.Palermo, in this article, not only review the   modification of the graphene in solid, liquid and gases phases but also briefly summarize the electronic, magnetic and optical properties of the composite. This review gives precise insight into path graphene should be taken onto to make it perfect material for electronics.

Graphene-organic composites for electronics: optical and electronic interactions in vacuum, liquids and thin solid films
A. Schlierf, P. Samori and V. Palermo
J. Mater. Chem. C, 2014, 2, 3129-3143. DOI:10.1039/C3TC32153C

Padmanabh Joshi is a guest web writer for the Journal of Materials Chemistry blog. He currently works at the Department of Chemistry, University of Cincinnati.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

Article link: http://xlink.rsc.org/?doi:10.1039/c3tc32153c
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Hot Article: Rubicene: a molecular fragment of C70 for use in organic field-effect transistors

If cells are the building blocks of life, an analogy can be made that transistors are the building blocks of the digital world. They could be credited as the discovery of the 20th century. One of the IEEE milestones, transistors can be counted as biggest step in technology. For the first 20 years after the discovery of transistors, Germanium based transistors were used all over the globe replacing vacuum tube based gadgets. Germanium transistors certainly helped kick off the table size computer age, but silicon based transistors revolutionized the design of it and produced an entire industry in California namely silicon valley. But researchers would not be termed researchers if they stopped inventing and innovating making this world a better place to live. Inventions of materials like graphene, carobon nanotubes and fullerens are stretching the boundaries and making a dent in bringing a new generation of transistors which would shrink the size of electronic gadgets even further with landmark speed.

Excellent Performance of the Rubicene as semiconductor for transistor

Rubicene, a molecule with unusual electronic properties, is capturing the imagination of researchers as a molecule for a new generation transistors. Lee et al. successfully attempted use of this promising organic semiconductor material for organic field effect transistors. Rubicene, molecular fragment of C70 also a type of cyclopenta fused polycyclic aromatic hydrocarbon is well suited for the this application because of the high electron affinity. Lee et al studied theoretical electronic properties along with energy level alignments. Investigators also investigated the performance of Rubicene on the pentafluorobenzenethiol(PFBT) self-assembled mono-layer on Au electrodes. They found the mobility of the charge carriers was increased remarkably and also showed that systems like Rubicene based transistors will take the transistors to the higher levels. This suggests that no matter where development goes, transistors will continue to drive product research and technological advances.

Rubicene: a molecular fragment of C70 for use in organic field-effect transistors
Hyunbok Lee, Yue Zhang, Lei Zhang, Timothy Mirabito, Edmund K. Burnett, Stefan Trahan, Ali Reza Mohebbi, Stefan C. B. Mannsfield, Fred Wudl and Alejandro L. Briseno
J. Mater. Chem. C, 2014, Advanced Article. DOI:10.1039/C3TC32117G

Padmanabh Joshi is a guest web writer for the Journal of Materials Chemistry blog. He currently works at the Department of Chemistry, University of Cincinnati.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

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