Left: The nanopatterned module appears green, independent of the angle.Right: Schematic of silicon nanoscatterer arrays on top of a sapphire cover slide, integrated into a commonly used solar panel design. Credit: Neder et al.

Solar panels have tremendous potential to provide affordable renewable energy, but many people see traditional black and blue panels as an eyesore. Architects, homeowners and city planners may be more open to the technology if they could install green panels that melt into the landscape, red panels on rooftops and white ones camouflaged as walls.

A new study published this week in Applied Physics Letters brings us one step closer to a future of colorful, efficient solar panels. Researchers have developed a method for imprinting existing solar panels with silicon nanopatterns that scatter green light back toward an observer. The panels have a green appearance from most angles yet only show about a 10 percent power reduction due to the loss of absorbed green light.

"Some people say 'why would you make solar cells less efficient?' But we can make solar cells beautiful without losing too much efficiency," said Verena Neder, a researcher at AMOLF and lead author of the paper. "The new method to change the color of the panels is not only easy to apply but also attractive as an architectural design element and has the potential to widen their use."

Most research on solar cells has focused on increasing efficiency and reducing cost. Currently, the solar panels sold to consumers can ideally turn up to 22 percent of the sun's light into usable energy. Colored solar panels are already on the market, but the dyes and reflective coatings that give them their color greatly reduce efficiency.

Neder and colleagues created their efficient, green solar panels through soft-imprint lithography, which works somewhat like an optical rubber stamp to imprint a dense array of silicon nanocylinders onto the cell surfaces. Each nanocylinder is about 100 nanometers wide and exhibits an electromagnetic resonance that scatters a particular wavelength of light. The geometry of the nanocylinder determines which wavelength it scatters and can be fine-tuned to change the color of the solar cell. The imprint reduces the solar panel's efficiency by about 2 percent.

"In principle, this technique is easily scalable for fabrication technology," said Albert Polman, a scientific group leader at AMOLF and senior author on the paper. "You can use a rubber stamp the size of a solar panel that in one step, can print the whole panel full of these little, exactly defined nanoparticles."

Unlike existing colored solar panels, the nanopatterns give a consistent appearance from different angles. "The structure we made is not very sensitive to the angle of observation, so even if you look at it from a wide angle, it still appears green," Neder said.

The nanopatterns also could be useful in making tandem solar cells, which stack several layers, each designed to absorb certain parts of the spectrum, to achieve efficiencies of greater than 30 percent.

Next, the researchers are designing imprints to create red and blue solar cells. Once they master these three colors, the primary colors of light, they can create any color, potentially even white. "You have to combine different nanoparticles, and if they get very close to each other they can interact and that will affect the color," Polman said. "Going to white is a really big step."

Explore further: Solar scientists rough up silicon panels to boost light capture

More information: "Efficient colored silicon solar modules using integrated resonant dielectric nanoscatterers," Applied Physics Letters (2017). DOI: 10.1063/1.4986796

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Nanotechnology gives green energy a green color - Phys.org - Phys.Org

Researchers in Ohio are using skin cells and small chips to develop treatments that can repair damage from wounds, stroke, and organ failure.

Your skin cells are programmable, allowing them to be converted into other types of cells.

And now researchers have discovered how to reprogram them, making your body a potential gold mine of cells that can be used to heal wounds, treat stroke damage, and even restore function to aging organs.

A recent study published in Nature Nanotechnology describes the development of Tissue Nanotransfection (TNT), a technology that can convert an adult cell from one type to another.

The study was led by Chandan Sen, PhD, and L. James Lee, PhD, researchers at The Ohio State University. Sen and his colleagues applied the chip to the injured legs of mice, reprogramming the mices skin cells into vascular cells.

Within weeks, active blood vessels formed, saving the legs of the mice.

The technology is expected to be approved for human trials within a year.

This breakthrough in gene therapy is made possible by nanotechnology, the manipulation of matter at a size at which unique properties of material emerge.

That means the physical, chemical, and biological characteristics of materials are different at the atomic scale than at the larger scale were seeing on an everyday basis.

A nanometer is a billionth of a meter. A DNA molecule is 2 nanometers in diameter. Nanotechnologys scale is roughly 1 to 100 nanometers.

At the nanoscale, gold reflects colors other than what it does at the scale visible to the unaided eye. This physical property can be used in medical tests to indicate infection or disease.

Gold is yellow in color at the bulk level, but at the nanoscale level gold appears red, said Dr. Lisa Friedersdorf, director of the National Nanotechnology Coordination Office (NNCO) of the National Nanotechnology Initiative.

The NNCO coordinates the nanotechnology efforts of 20 federal government agencies.

We now have tools to enable us to fabricate and control materials at the nanoscale, Friedersdorf told Healthline. Researchers can create a nanoparticle with a payload inside to deliver a concentrated drug release directly to targeted cells, for instance. Soon well be able to identify and treat disease with precision. We could have personalized medicine and be able to target disease very carefully.

TNT works by delivering a specific biological cargo (DNA, RNA, and plasma molecules) for cell conversion to a live cell using a nanotechnology-based chip.

This cargo is delivered by briefly zapping a chip with a small electrical charge.

Nanofabrication enabled Sen and his colleagues to create a chip that can deliver a cargo of genetic code into a cell.

Think of the chip as a syringe but miniaturized, Sen told Healthline. Were shooting genetic code into cells.

The brief (one-tenth of a second) electrical charge of the postage stamp-sized device creates a pathway on the surface of the target cell that allows for the insertion of the genetic load.

Imagine the cell as a tennis ball, Sen said. If the entire surface is electrocuted, the cell is damaged and its abilities are suppressed. Our technology opens up just 2 percent of the surface of the tennis ball. We insert the active cargo into the cell through that window, and then the window closes, so there is no damage.

Cell reprogramming isnt new, but scientists have previously focused on converting primarily stem cells into other types of cells. The process took place in labs.

We disagreed with this approach, Sen said. When switching a cell in the lab, its in an artificial, sterile, and simple environment such as a petri dish. When its introduced into the body, it doesnt perform as intended.

We went upside-down. We bypassed the lab process and moved the reprogramming process to the live body, he explained.

This point-of-action capability will allow hospitals to adopt TNT sooner than if the process was limited to research facilities.

Sens teams approach was to act first, figure it out second.

There are a number of procedures and processes at play, Sen said. We dont understand all of them, but we achieved our goal. Now that weve achieved our goal, we can get into the details of how it works.

The healing of injuries by converting skin cells into vascular cells to regenerate blood vessels is one proven application of TNT.

Sens team also created nerve cells by the conversion process, injecting the newly formed neurotissue from the skin of a mouse with brain damage from stroke into its skull. The replacement rescued brain function that would otherwise have been lost.

Sen envisions additional uses for TNT, including organ recovery.

We could go into a failing organ via an endoscopic catheter with a chip to reprogram cells and restore organ function, Sen said. It doesnt have to be a skin cell. It could be excessive fat tissue.

TNT could improve our quality of life as we age, too.

Im a runner, so I have joint issues, Friedersdorf said. Nanotechnology could enable the regeneration of cartilage. Im hoping these technologies will be available when Im in need of them.

Sen and his team are currently searching for an industrial partner to manufacture chips designed to work for humans.

Then comes testing.

Ultimately, Sen hopes to drive rapid advancement in nanoscience and health.

Im a scientist, but this was inspired by the need to make an impact on health, Sen said. Our main goal is impact.

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Nanotechnology May Be Used to Heal Wounds, Repair Organs - Healthline

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Carnegie Mellon Universitys Ge Yang, associate professor of biomedical engineering (BME) and computational biology, and Tzahi Cohen-Karni, assistant professor of BME and materials science and engineering, have determined that graphene is safe for neurons and non-neuronal cells and has long-term biocompatibility making it an excellent material to use in devices that interface with the nervous system. In a separate study, Cohen-Karni also found it was possible to grow graphene fuzz.

Graphene is nearly 200 times stronger than steel, flexible, nearly transparent and highly conductive. Since graphene is a single layer of carbon atoms connected in a hexagonal pattern, it is thin and lightweight, making it attractive for nanotechnology applications such as building nanodevices for biomedical applications.

Following this new finding, the research team will begin to use graphene with different types of tissues to better understand cell physiology.

Yang, who studies material transport in neurons, is working to better understand brains on the cellular level to improve treatment of neurodegenerative diseases.

The potential of using graphene to build devices that interact with neurons is amazing because of all of the interesting traits of the material, Yang said. The transparency allows you to shine lights through the graphene so that you can use optics to visualize and control chemical signals inside the cell. And because graphene is incredibly conductive, you can simultaneously do sensitive recordings of electrical signals of the neurons.

Graphenes ability to store electric charges is attracting the attention of technologies. This feature is largely derived from graphenes high amount of surface area relative to its volume.

Cohen-Karnis team was successful in growing graphene in 3-D by first creating a mesh of nanowires made of silicon, which acted as a surface for the graphene to grow on. Then, the team exposed the mesh to methane plasma, which resulted in carbon separating from the methane and depositing onto the mesh, forming graphene.

After using various levels of methane plasma and letting the mesh cook for various lengths of time, Cohen-Karnis team began to see tiny flakes or fuzz of graphene growing off the surface of the silicon nanowires. Unlike previous studies, the graphene was growing in three dimensions.

%%https://www.youtube.com/embed/zAp7sBj-dZI%%

Until this study, all of the graphene that people have grown are pinned to a surface it exposes 2-D topology, and you dont get the advantage of high surface-to-volume ratio that one could achieve if it were grown in 3-D, Cohen-Karni said. High surface-to-volume is necessary to make thin-film supercapacitors that can be used in miniaturized circuits.

Supercapacitors are devices that are able to store and deliver electric charge much, much faster than batteries.

Imagine a self-sustained system, where the power is supplied to the nanosensing unit from 3-D graphene-based super capacitors, Cohen-Karni said. Someday we could have sensors that measure hormone or toxin levels, and youd never have to replace the battery.

Carnegie Mellon Universitys Ge Yang, associate professor of biomedical engineering (BME) and computational biology, and Tzahi Cohen-Karni, assistant professor of BME and materials science and engineering, have determined that graphene is safe for neurons and non-neuronal cells and has long-term biocompatibility making it an excellent material to use in devices that interface with the nervous system. In a separate study, Cohen-Karni also found it was possible to grow graphene fuzz.

Graphene is nearly 200 times stronger than steel, flexible, nearly transparent and highly conductive. Since graphene is a single layer of carbon atoms connected in a hexagonal pattern, it is thin and lightweight, making it attractive for nanotechnology applications such as building nanodevices for biomedical applications.

Following this new finding, the research team will begin to use graphene with different types of tissues to better understand cell physiology.

%%https://www.youtube.com/embed/Xi_BMKaDORA%%

Yang, who studies material transport in neurons, is working to better understand brains on the cellular level to improve treatment of neurodegenerative diseases.

The potential of using graphene to build devices that interact with neurons is amazing because of all of the interesting traits of the material, Yang said. The transparency allows you to shine lights through the graphene so that you can use optics to visualize and control chemical signals inside the cell. And because graphene is incredibly conductive, you can simultaneously do sensitive recordings of electrical signals of the neurons.

Graphenes ability to store electric charges is attracting the attention of technologies. This feature is largely derived from graphenes high amount of surface area relative to its volume.

Cohen-Karnis team was successful in growing graphene in 3-D by first creating a mesh of nanowires made of silicon, which acted as a surface for the graphene to grow on. Then, the team exposed the mesh to methane plasma, which resulted in carbon separating from the methane and depositing onto the mesh, forming graphene.

After using various levels of methane plasma and letting the mesh cook for various lengths of time, Cohen-Karnis team began to see tiny flakes or fuzz of graphene growing off the surface of the silicon nanowires. Unlike previous studies, the graphene was growing in three dimensions.

Until this study, all of the graphene that people have grown are pinned to a surface it exposes 2-D topology, and you dont get the advantage of high surface-to-volume ratio that one could achieve if it were grown in 3-D, Cohen-Karni said. High surface-to-volume is necessary to make thin-film supercapacitors that can be used in miniaturized circuits.

Supercapacitors are devices that are able to store and deliver electric charge much, much faster than batteries.

Imagine a self-sustained system, where the power is supplied to the nanosensing unit from 3-D graphene-based super capacitors, Cohen-Karni said. Someday we could have sensors that measure hormone or toxin levels, and youd never have to replace the battery.

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Researchers Explore Graphene's Potential Use in Nanotechnology - I-Connect007