Super-Thin Solar Cell

thincell

Solar energy will very likely be the main source of power as the world continues to strive toward greater sustainability. But it won’t be just the large panels that get the job done. In fact, I’m willing to bet that ultra thin and flexible solar cells that can be attached to virtually any surface will be the future. Which is why breakthroughs in this area are so important. And now a team of South Korea scientists has successfully created a super thin solar cell, which is so flexible it can be wrapped around a pencil without causing damage or too much strain to it.

The solar PV cell that they created is one micrometer thick (which is even thinner than a human hair) and it is this thinness that gives it the extreme flexibility it boasts of. It is made from a semiconductor gallium arsenide, which is stamped onto a flexible metal substrate. No adhesive is used in this process, instead it is fused with the electrode on the substrate with a cold welding process that involves applying pressure at 170 degrees Celsius. And the metal layer also acts as a reflector that directs light back onto the cell.

Testing the limits of the cell’s flexibility they found that it can be bent around an object with a radius of 1.4 millimeters. Despite their thinness, the solar cells have an energy conversion efficiency comparable to thicker ones. They also exhibited only one quarter of the strain from the bending compared to a 3.5 micrometers thick cell.

The real-world application of this type of cell would be far-ranging. It could be used on smartphones, fabric, and smart glasses, while it could also easily be integrated into self-powered devices, such as, for example, environmental sensors located in hard to reach places.

There is no definitive word yet on when and if they plan to bring this cell to market.

Super-Thin Solar Cell

thincell

Solar energy will very likely be the main source of power as the world continues to strive toward greater sustainability. But it won’t be just the large panels that get the job done. In fact, I’m willing to bet that ultra thin and flexible solar cells that can be attached to virtually any surface will be the future. Which is why breakthroughs in this area are so important. And now a team of South Korea scientists has successfully created a super thin solar cell, which is so flexible it can be wrapped around a pencil without causing damage or too much strain to it.

The solar PV cell that they created is one micrometer thick (which is even thinner than a human hair) and it is this thinness that gives it the extreme flexibility it boasts of. It is made from a semiconductor gallium arsenide, which is stamped onto a flexible metal substrate. No adhesive is used in this process, instead it is fused with the electrode on the substrate with a cold welding process that involves applying pressure at 170 degrees Celsius. And the metal layer also acts as a reflector that directs light back onto the cell.

Testing the limits of the cell’s flexibility they found that it can be bent around an object with a radius of 1.4 millimeters. Despite their thinness, the solar cells have an energy conversion efficiency comparable to thicker ones. They also exhibited only one quarter of the strain from the bending compared to a 3.5 micrometers thick cell.

The real-world application of this type of cell would be far-ranging. It could be used on smartphones, fabric, and smart glasses, while it could also easily be integrated into self-powered devices, such as, for example, environmental sensors located in hard to reach places.

There is no definitive word yet on when and if they plan to bring this cell to market.

Shape-Shifting Solar Cells

eiffel

The wider adoption of solar cells is largely being stalled by their cost. That’s why a lot of new research in this field has been focused on making solar cells more affordable. And now a group of engineers at MIT and Singapore University of Technology and Design (SUTD) have made a breakthrough.

They’ve created a 3D printed material, which is able to change shape when heated or cooled, and then return to it’s original form on it’s own. Among the many applications of such a material it could also be used as the turning mechanism for solar cells, which would allow them to effortlessly capture more solar energy.

The 3D printed material they created is capable of remembering its original shape, and always returning to it when certain key conditions are met. In other words, it can be bent, twisted, stretched and used to build complex shapes (such as a replica of a flower or the Eiffel Tower). These structures bend and stay in the new form until they are heated to between 104 to 356 degrees Fahrenheit when the material becomes rubbery and once again assumes its original shape.

unscrew

To create these structures, they used a special 3D printing method called microstereolithography, which etches patterns onto the polymers using light as they are layered. The thinner the structure the faster it reacts to temperature changes and they are actually calling this new tech 4D printing, since the changing of shape happens across the fourth dimension of time.

Designing an effective way of combining this new tech with PV cells would make them much more efficient at harvesting solar power, as well as make it possible to use solar cells in a lot more places. More efficient solar cells would also lessen the need for large battery banks.

Roses Inspire a More Efficient Solar Cell

rosesolar

Breakthroughs big and small are important in the quest towards greater reliance on renewable power, of which solar power is at the top of the list. And one such breakthrough was recently achieved by a team of scientists from the Karlsruhe Institute of Technology (KIT) and the Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) in Germany. Inspired by the rose’s ability to convert sunlight into energy they designed a film that greatly increases the efficiency of solar cells.

Basically, they lifted an imprint off the petals of a rose and used it to create a film that can be attached to existing solar cells. They started the process by first studying the epidermal layer of cells from many different plants, since this outer layer actually has the ability to absorb, as opposed to reflect, light. They chose rose petals since their epidermal cells were best at this task. This is due to the fact that the epidermis of rose petals is made up of a disorganized arrangement of densely packed microstructures, and there are also additional ribs, which are created by randomly positioned nanostructures. Because of these characteristics, rose petals are able to absorb more light.

This unique surface was duplicated by making an imprint of it using a silicon-based polymer, which produced a mold. Next, they poured clear optical glue into the mold and dried it using a UV light. The result was a transparent copy of the epidermal layer of the rose petal, which was then applied to the solar cell.

Compared to normal solar cells, they found that cells with the film attached had a 12 percent boost in efficiency when placed vertically, and an amazing 44 percent boost in efficiency when the cell is placed at an 80-degree angle.

They are currently working on further researching the role played by the disorganized surface (like that of the rose petal’s epidermis) in other photosensitive surfaces. The researchers also hope to find ways to even further improve the film they created so that it will yield an even greater energy efficiency improvement.

Researchers Develop Semi-Transparent and Decorative Solar Cells

transparent-color-solar-cells.jpg.662x0_q100_crop-scale

A team of researchers at the University of Michigan has successfully developed a prototype of a semi-transparent photovoltaic solar cell, which they hope will make solar arrays more attractive to consumers and lead to a more widespread adoption. Existing solar panels are far from aesthetically pleasing, but this new invention could be used to cover the sides of buildings, window shades and even billboards without obscuring what lies beneath.

The team wanted to produce a solar cell that could be placed anywhere, and not just on rooftops as is the case with currently available solar panel arrays. At the same time they wanted to create a solar cell that would give designers more freedom when creating plans for solar powered homes. The solar cells they developed can be made into an ultrathin sheet available in various semi-transparent colors.

The cells the team developed are made of an ultrathin (6 to 31 nm) sheet of amorphous silicon, which is sandwiched between two semi-transparent electrodes. These enable sunlight to hit the semiconductor, while they are also capable of carrying the electrical current generated by the cell.

Utilizing a hybrid organic and inorganic structure in the production of the solar cells allowed the researchers to make them10 times thinner than traditional amorphous silicon solar cells. The organic layer utilized in the cells also replaces a thick ‘doped’ region that would typically control the flow of electricity in a standard solar cell.

The cells the researchers developed are mechanically structured to transmit specific wavelengths of light, which is made possible by varying the thickness of the amorphous silicon layer that they contain. To illustrate this, the team made a prototype of a cell that is colored like the US flag, in which the red regions are 31 nanometers thick, while the blue regions are only 6 nanometers thick. Both regions work to transmit or reflect those colors to the human eye.

flag and voltage

One of the drawbacks of these new solar cells is the fact that they are not as effective at transforming sunlight into energy as traditional, black colored solar PVs are. This is mainly due to the fact that the colored areas of the new cells reflect the colors back to our eyes, rather than using it all to create power. But the fact that these new cells could be used anywhere on a building, and become part of the building design itself, could lead to a much more widespread adoption of solar arrays. This would render their lower efficiency a moot point.

Related Articles on JetsonGreen.com:
Researchers Develop Self-Healing Solar Cells
Solar Cells Might Soon be Made of Paper
Colored Solar Panels Hit California Market