Solar Cells That Harvest Energy All Day Every Day

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One huge drawback of going solar is the fact that it only makes sense in areas which get abundant sunshine year-round. However, a team of scientists from China has now come up with a new solar cell, which can harvest energy even when it’s raining.

This solar cell is made using graphene, which has proven to be a very promising material for use in the production of solar cells in the past. One of these properties of graphene is its conductivity, which is such that it allows electrons to flow freely across its surface. So when this material is put into an aqueous solution, the so-called Lewis acid-base reaction occurs, namely that pairs of positively charged ions bind with the material’s negatively charged electrons. Studying this property of graphene, the team developed a solar cell, which can generate power from raindrops.

Raindrops are comprised of various salts, which have positively and negatively charged ions. So when rainwater hits graphene the positive ions bind with the negative ions on its surface. Where the rainwater and graphene come into contact, they form a double-layer of electrons and positively-charged ions, which creates a so-called pseudocapacitor. The two layers thus have a difference in potential, which is sufficient to generate a voltage and current.

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The scientists have produced a prototype dye-sensitized solar cell and applied a thin film of graphene to it. They tested this cell in a lab, using salty water made to closely resemble rain. The cell they tested successfully generated hundreds of microvolts and had the solar to electricity conversion efficiency of 6.5 percent. Their next step will be to further refine the cell, and they are confident that they will succeed in creating a market-ready all-weather solar cell soon.

New Breakthrough with Perovskite Solar Cells

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As you’re probably already aware, perovskite solar cells have the greatest potential of being the most prominent source of solar energy in the near future. They’re cheap to make and flexible enough to be applied to most any surface.

And now a team of researchers from the University of New South Wales (UNSW) in Sydney, Australia has made a breakthrough by creating the biggest perovskite solar cell so far, and setting a new efficiency record with it.

According to them, they have managed to achieve a 12.1 percent energy conversion efficiency rating for a 6.3 sq in (16 sq cm) perovskite solar cell. This cell is also about 10 times larger than any existing high-efficiency perovskite cell. The team also managed to achieve 18 percent efficiency for a 0.5 sq in (1.2 sq cm) single perovskite cell, as well as 11.5 percent for a 6.3 sq in (16 sq cm) four-cell perovskite mini-module. They are also confident that they can achieve a 24 percent efficiency within a year or so.

These cells get their name from the crystals they are made of, which are grown into a structure called perovskite. Due to their special characteristic, such as the smooth layers of perovskite with large crystal grain sizes, these cells can absorb more light than solar cells made of silicon. They are also much cheaper to produce.

Perovskite cells can also be created in different colors, or be transparent due to their chemical composition. This means that they can be used to cover virtually any surface, such as the sides or roofs of buildings, gadgets, cars and even windows.

One of the major downsides of perovskite solar cells is the fact that they are not very durable. However, the team believes that they can also improve their durability as they strive for even higher levels of efficiency.

Yingli uses new n-type solar cell production process to improve bifacial efficiency

Yingli Green Energy Holding Co. says it has produced the first interdigitated back contact (IBC) n-type solar cells based on 6-inch wafers at an industrial pilot line within just three months by adopting the new production process co-developed by Dutch research center ECN and equipment manufacturer Tempress.

yingli solarThe production process is based on Yingli’s commercialized PANDA process for the low-cost production of conventional n-type solar cells (n-PERT). The process was adapted for IBC-type cells using the screen printing technology for patterning and metallization. The production of IBC cells in Yingli’s industrial pilot line proves that the commercial production of efficient IBC cells is feasible on short term.

ECN is focusing its research on n-type silicon solar cells as these are potentially more efficient than p-type cells and are less sensitive to degradation and impurities. Additionally, the back contact design of solar cells offers several advantages. They exhibit a higher voltage and deliver a higher current, because of reduced losses via recombination and a larger surface on the sunny side.

RELATED: Why high-efficiency modules are the best value for installers, homeowners 

By producing the cells at Yingli, the consortium has now tackled the complexity of producing such cells. The consortium aims to produce cells that have an efficiency of 22 percent by the end of 2017. The development and production of commercial modules is expected for 2018. Moreover, the inherent bifacial character of the IBC cells will also allow pursuing the route of truly bifacial module technology.

“This result shows once again the synergy of our long lasting and fruitful cooperation with Yingli and ECN, who did the majority of work to achieve this. For Tempress this is an important opportunity to adapt and develop equipment and process that can be used in the production process of these next generation cells. A partner like Yingli combined with ECN, puts us in a position where developments can go really fast, which I think is best demonstrated by achievements like this. We are very thankful to have such valuable partners.” commented Albert Hasper, general manager of Dutch Solar Equipment company Tempress.

The cooperation with Yingli is very important for this development, says ECN researcher Dr. Ilkay Cesar. “Yingli has the facilities to produce high-quality solar cells on a large scale at low cost. This greatly enhances our opportunities for research and development on the cell process and module integration in a new way for our program. We are happy to partner with Yingli to continue the development of commercial processes for n-type solar cells. The pilot line now provides IBC cells in sufficient quantities to enable efficient back-contact module development which will boost the Dutch and EU PV tool and material supplier industry. The ECN Industry Research Program (IRP) aims to bring our simplified IBC technology to 23% within 3 years. IRP partners can start pilot production in less than 3 months as already demonstrated by Yingli.”

“It is our honour to cooperate with ECN and Tempress in producing IBC cells and we appreciate their highly industrial focus, which will enhance the chances to bring this product to the market in the short term. This cooperation and the pilot production of IBC cells are consistent with our long-term commitments to making solar electricity affordable and accessible for all through continued technology innovation,” said Dr Dengyuan Song, Chief Technology Officer of Yingli.

— Solar Builder magazine

Roses Inspire a More Efficient Solar Cell

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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.

A User-Friendly Guide to Solar for the Home

Until quite recently, most people thought of solar panels as expensive and impractical. However, thanks to several significant tax breaks and advances in solar technology, solar power is no longer the sole possession of the elite. More and more people are opting for the clean, environmentally-friendly energy offered by solar panels for the home. If you’re thinking about making the switch to solar, here’s a few basic guidelines to get you started.

Why Solar Panels?

There are many benefits to installing solar panels. While the cost for home solar panels is still relatively steep, their overall cost has dropped by about 60% in the last four years, thanks to improved technology and tax incentives. The cost of solar panels is expected to continue to drop.

These tax incentives vary depending on your location, but at least a few constant rates exist. For instance, the Solar Investment Tax Credit offers a 30% tax credit for homeowners who purchase solar systems. Incentives like this, along with solar power’s ability to save you money on energy bills, ultimately saves most homeowner’s an average of $84 per month. Over time, these savings easily make up for solar power’s initially hefty investment.

Terms You Should Know

1. Buy vs. lease

It’s important to consider whether you want to buy your system or merely lease it. Leasing a solar panel system reduces the initial costs, and for many people, this is a much more accessible way of achieving solar energy for the home. However, actually owning a solar system will ensure enhanced tax benefits and will also add value to your home. It’s worth taking some time to weigh both options carefully.

2. Solar Photovoltaic vs. Solar Thermal

Solar cells, also called photovoltaic (PV) cells, convert sunlight directly into electricity for your home. A typical home uses about 10 to 20 solar panels to power the home.

Solar thermal, or solar water heating, systems feature storage tanks and solar collectors. Solar water heaters use the sun to heat either water or a heat-transfer fluid in the collector. This provides hot water for your home.

Solar Panel Basics

1. Hire a professional: Installation is involved, so don’t expect to effortlessly haul your panels up to the roof on your own. A talented solar installer can also help you navigate the permit process.

It’s essential that you hire a professional who can give you a solid warranty. Look for solar energy companies that have been around for awhile–these contractors will have a better chance of still being around several years down the line when it’s time to honor your warranties. Your solar installer should also have several reliable past referrals and a valid license number.

2. Secure sunlight: Make sure your roof gets significant sunlight during the sunniest portion of the day (generally the hours between 10 o’clock in the morning and 2 o’clock in the afternoon). It may be necessary to trim any encroaching foliage if it’s blocking your access to the sun.

3. Expect some delays: Although wiring and installing the system only requires a few days to be completed, expect several months to pass between the moment you sign the contract and the moment installation actually begins.

In short, solar panels are no longer the exclusive property of the wealthy and progressive. Solar panels for your home are a practical investment, creating significant longterm savings for your home and allowing you to live in a cleaner, more sustainable way. If you have a roof and no solar panels, get started today with SolarContact’s convenient database of local solar contractors.