As a member of UA professor Neal R. Armstrong's research group, Placencia conducts research aimed at creating a thin, flexible organic solar cell that could power a tent or keep a car charged between trips to work and back home again.
He's passionate about renewable energy and says it's a waste that so little solar has been incorporated into society. "I have a little flat panel that I walk around with," Placencia said. "I usually put that on my backpack, and I charge my cell phone when I'm walking to school."
The sun is clean and free. "Here it is," he said. "Why not use it?"
Across the University, professors, researchers, students and others involved in policy planning and economic analysis are working to make that question moot. In a region noted for abundant sunlight, they are chipping away at problems like how to employ solar at the utility-generating plant level, how to harness it to charge the newly indispensable products of the day – cell phones, MP3 players, laptops – what to do at night and when clouds halt the energy giveaway from the sky.
The research proceeds in labs amid state-of-the-art equipment funded by multimillion-dollar federal grants. It's the product of students' hunches and long careers spent unlocking the mysteries of science. Along the way, students are being immersed in a nascent industry that many hope will be the economic engine of the next decade.
"Looking at renewable energy is a perfect place to emphasize that we don't know where the next breakthrough is going to be," said Leslie P. Tolbert, UA vice president for research, graduate studies and economic development. "Somewhere in a lab someplace, there's somebody figuring out a whole new way to capture sunlight. In fact, there are many people doing that. And even they are depending on knowing that there is, behind them, a cadre of basic science researchers producing new information that will feed their thoughts."
Armstrong, a professor of chemistry and optical sciences at the UA, occasionally teaches freshman chemistry. He decided one day near the end of the semester to try to make the material even more relevant. "I said to myself, well, lithium ion batteries in my cell phone, in my iPod," – his daughter had given him one – "I wonder how much coal we burn to charge those guys up at the end of the day. Because that's one of the big drivers for portable power, to get all this stuff off the grid." After making some very conservative calculations, he arrived at an answer, which he shared with the class: "You burn about a quarter of a pound of coal per charge of your lithium ion battery, and you generate about half a pound of CO2 per charge, per battery, per day .... The room got really quiet."
The next time, he intends to calculate how much coal is burned per Twitter tweet.
"It really is chilling," Armstrong said. "You start doing the math and thinking about the number of consumer electronic devices that you and I have added to our lives in the last decade that I charge up typically once every night – my laptop computer and my cell phone. Then you start thinking about, 'What if I do buy an electric car, and I come home at night and plug that sucker in,' and you do the same thing. We'll shut this grid down in no time."
In April, the U.S. Department of Energy announced it was funding Armstrong's Center for Interface Science as one of 46 Energy Frontier Research Centers. The mission of these centers, which will receive $2 million to $5 million a year for five years, is "to address current fundamental scientific roadblocks to clean energy and energy security," according to the DOE.
Ever since Armstrong was a graduate student during the first Arab oil embargo in 1973, he's experienced a succession of government distress calls over energy. One such emergency led him to discover the work of Heinz Gerischer and Frank Willig in Germany. They had figured out how to adsorb dye molecules to the surface of oxides and split water with light from the sun. "I thought, 'That's it. That's what I'm going to do my career on.'"
He moved to the UA in 1978, attracted by a program in photo-thermal solar energy conversion. In the 1980s, with gas cheap and plentiful again, solar went back on the back burner.
The next call came about four years ago. "DOE was beginning to sense that the tides were about to shift again, big-time," Armstrong said. "And they were really concerned that they didn't know what to do – how to present this to Congress in a way that would lead to new funding and which would have a rationale associated with it so that by the middle of this century we had someplace to go."
Armstrong realized it was time to come back to the problem that he wanted to work on 30 years before. "This time, we were really well-equipped," he said. "We've learned how to image molecules at the molecular level, we've learned how to measure energies of incredibly thin films, we've learned how to make devices, we've collaborated with physicists and material sciences and that sort of thing, we've done a lot of interesting other stuff and I suddenly realized I could bring it all back together here."
In his office, he displays a sample of his work: a 1-inch square of glass on which is deposited a thin film of indium tin oxide, a conducting transparent oxide commonly found in display technologies like computer screens. On top of that is a thin film of organic dyes. The last layer is an aluminum electrode.
"You'd have a roll of plastic with these cells laid out on it," he explained. "The idea is for you to go to Target or something like that and buy this roll of plastic and roll it out. It's got two wires connected to it, and you plug in your battery or your laptop and charge it up."
"The grand total in terms of the thickness is about 400 nanometers, which is one ten-thousandth the thickness of a human hair. And yet, shine a light on it and you get electricity out of it. Now we'd like it to be a bit thicker. We have to keep them thin in order to get all of the electrical charge out of the device. But if you think about this as a sandwich structure, we've made this incredibly thin sandwich and then each of the layers in contact with each other have to be just right in terms of the chemical composition, the orientation of the molecules, how well they adhere to each of the underlying surfaces. And if I go in and change just one molecule layer, the composition – that's at the level of 1 nanometer in thickness – I can take a good device and turn it into a bad device; I can take a bad device and turn it into a good device. That's the kind of level of control that we need. And we don't fully understand it."
But the equipment available now – optical microscopes capable of imaging individual molecules and revealing their electrical properties and spatial orientation – are helping his team understand. His goal is to figure out how to have the molecules arrange themselves – every time – in a way to produce lots of electricity. "They have to all line up like little soldiers," he said.
"We have to give you a technology that is going to look like an ink, like a blue ink, that you can spray down on one of these surfaces and the molecules at the nanometer level are going to say, 'OK, we're going to get organized this way,' and in doing so, when I put that top electrode on and shine a light, I'll get lots and lots of electricity out of there," Armstrong said.
A high vacuum photoelectron spectrometer allows them to build each molecular layer, moving it within the vacuum to study it, and then continue with another molecular layer. Other tools, like a silicon microtip, which looks like a tiny phonograph needle, can be positioned to +/- 0.01 nanometers. "Well inside the diameter of a molecule," he said. Bouncing a laser off the back of the tip yields an image. Passing current through the tip, they can map the electrical properties of molecules. All this can help them build a template to create the ideal array of the molecule assemblies.
Erin Ratcliff joined the team as a postdoctoral electrochemist with a doctorate from Iowa State. "My background wasn't in solar cells at all," she said. "I had to come here and had to learn everything, where grad students get it from Day One at the UA."
She spoke of the business school curve, resembling a hockey stick, when progress begins to accelerate rapidly. "We're right at the magic moment when the hockey stick starts to take off, when you go from flat to hockey stick. We're right there. It's exciting to read the literature and hope that, yes, we will take off. It will be exciting to look back and say 'I was there for that.'"
Johnny Cruz | EurekAlert!
Laser sensor LAH-G1 - optical distance sensors with measurement value display
15.08.2017 | WayCon Positionsmesstechnik GmbH
Engineers find better way to detect nanoparticles
14.08.2017 | Washington University in St. Louis
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences